Glaucoma

Glaucoma – An Overview

  • “Glaucoma” is a disease of the eye, in which the pressure within the eye is increased (pressure within the eye is known as “intraocular pressure” or IOP)
  • High intraocular pressure that causes characteristic degenerative changes in the optic nerve and retina with subsequent loss of vision; the “optic nerve” is the nerve that runs from the back of the eye to the brain; the “retina” is the innermost lining layer (located on the back surface) of the eyeball; it contains the light-sensitive rods and cones and other cells that convert images into signals and send messages to the brain, to allow for vision
  • Diagnosis—intraocular pressure greater than 25–30 mm Hg in dogs, as determined by specialized pressure measurements (such as applanation, rebound, or Schiötz tonometry) with evidence of changes in vision or appearance of the optic nerve or retina
  • Glaucoma may be “primary” or “secondary”; “primary” refers to a condition in which the pressure within the eye (intraocular pressure) increases without a preceding eye problem; “secondary” refers to a condition in which intraocular pressure increases as a complication or secondary to an eye disease or injury

Genetics

  • Dogs—abnormality of the structure of the eye that makes development of glaucoma more likely in some dogs is thought to be inherited; mode of inheritance uncertain

Signalment/Description of Pet

species

  • Dogs—primary and secondary glaucoma

Breed Predilections

  • Developmental abnormality of the angle between the iris and the cornea of the eye (known as “goniodysgenesis”)—Arctic circle breeds (such as Norwegian elkhounds, Siberian huskies, Alaskan malamutes, Akitas, Samoyeds); Bouvier des Flandres; basset hounds; chow chows; Chinese shar-peis; spaniels (such as American and English cocker spaniels, English and Welsh springer spaniels)
  • Narrow filtration angles—spaniels; chow chows; Chinese shar-peis; toy breeds (such as poodles, Maltese, and shih tzus)
  • Secondary to movement of the lens out of its normal location (lens luxations)—terriers (such as Boston terriers, cairn terriers, Manchester terriers, Dandie Dinmont terriers, Norfolk terriers, Norwich terriers, Scottish terriers, Sealyham terriers, West Highland white terriers, Parsons Jack Russell terriers, and fox terriers), Chinese shar-peis

Mean Age and Range

  • Primary glaucoma in dogs—any age; predominantly affects middle-aged dogs (4–9 years of age)
  • Secondary to movement of the lens out of its normal location (lens luxations) in dogs—usually affects young dogs (2–6 years of age)
  • Secondary to long-term (chronic) inflammation of the iris and other areas in the front part of the eye (uveitis)

Signs/Observed Changes in the Pet

  • Sudden closure of the angle between the iris and cornea of the eye (known as “acute angle closure”), leading to blockage of the flow of fluid and subsequent increased pressure within the eye—apparent pain (squinting or spasmodic blinking [known as “blepharospasm”], tenderness about the head, discharge from the eye(s), may be clear or may contain mucus); may note a cloudy or red eye; vision loss usually not noticed unless both eyes are involved
  • Secondary glaucoma—depends on primary disease
  • Inflammation of the iris and other areas in the front part of the eye (uveitis)—may note pain (for many days); red or bloodshot eyes, caused by dilated blood vessels (known as “scleral injection”); and cloudiness due to fluid buildup in the clear part of the eye (known as “corneal edema”)
  • Movement of the lens out of its normal location and into the front part of the eye (known as “anterior lens luxation”)—may note sudden (acute) pain; red or bloodshot eyes (scleral injection); and cloudiness due to fluid buildup in the clear part of the eye (corneal edema); may see lens in the anterior chamber (the front part of the eye, between the cornea and the iris), if corneal edema is not severe
  • Long-term (chronic) inflammation of the iris and other areas in the front part of the eye (uveitis). Enlarged, seemingly painless eye or a dilated pupil is common
  • Eyeball or globe enlargement (known as “buphthalmos”)—may be noticed first by owners

Sudden (Acute) Primary Glaucoma

  • High intraocular pressure (measured by your pet’s veterinarian)
  • Squinting or spasmodic blinking (blepharospasm)
  • Eyeball may recede into back of socket (known as “enophthalmos”)
  • Red or bloodshot eyes (scleral injection)
  • Cloudiness due to fluid buildup in the clear part of the eye (corneal edema)
  • Dilated pupil; the “pupil” is the circular or elliptical opening in the center of the iris of the eye—light passes through the pupil to reach the back part of the eye (known as the “retina”); the “iris” is the colored or pigmented part of the eye—it can be brown, blue, green, or a mixture of colors
  • Vision loss
  • Optic nerve may be depressed or cupped when the back of the eye is evaluated with specialized eye instruments by your pet’s veterinarian; the “optic nerve” is the nerve that runs from the back of the eye to the brain

Long-Term (Chronic) or End-Stage Glaucoma

  • Eyeball or globe enlargement (buphthalmos)
  • Lines that develop on the inner lining of the cornea, the normally clear part of the front of the eye (known as “Descemet’s streaks” or “Haab’s striae”)
  • Partial movement of the lens out of its normal location (known as a “lens subluxation”) with a resultant “crescent” appearing in the area of the iris (known as an “aphakic crescent”)
  • Wasting away or decrease in size of the cells in the optic nerve head (known as “optic nerve head atrophy”); the “optic nerve” is the nerve that runs from the back of the eye to the brain
  • Death of tissue in the retina (known as “retinal necrosis”)—detected increased reflectivity in the back of the eye when the veterinarian performs an examination

Glaucoma Induced by Inflammation of the Iris and Other Areas in the Front Part of the Eye (Uveitis)

  • Elevated intraocular pressure (measured by your pet’s veterinarian)
  • Red or bloodshot eyes (scleral injection)
  • Cloudiness due to fluid buildup in the clear part of the eye (corneal edema)
  • Inflammatory debris in the front part of the eye, between the cornea and the iris (anterior chamber)
  • Constricted or miotic pupil may or may not be seen; the “pupil” is the circular or elliptical opening in the center of the iris of the eye; light passes through the pupil to reach the back part of the eye (known as the “retina”); the “iris” is the colored or pigmented part of the eye—it can be brown, blue, green, or a mixture of colors
  • Scar tissue between the iris and the lens of the eye (known as “posterior synechia”) may or may not be present; the “lens” is the normally clear structure directly behind the iris that focuses light as it moves toward the back part of the eye (retina)
  • Bulging of the iris toward the front of the eye (known as “iris bombé”) may or may not be recent

Causes

  • Primary glaucoma—structural abnormalities of the eye involving the filtration angle (the “filtration angle” is the area where the cornea, sclera, and iris meet; it contains a structure that allows fluid to flow out of the eye, thus maintaining normal pressure within the eye; in primary glaucoma, the structure is abnormal so fluid does not flow adequately and the pressure within the eye increases)
  • Secondary glaucoma—blockage of the flow of aqueous humor out of the eye; the “aqueous humor” is the transparent liquid that fills the front part of the eyeball

Risk Factors

  • Inflammation of the front part of the eye, including the iris (known as “anterior uveitis”)
  • Movement of the lens out of its normal location (lens luxation)
  • Blood in the anterior chamber of the eye (the front part of the eye, between the cornea and the iris; accumulation of blood known as “hyphema”)
  • Tumor or cancer within the eyeball
  • Medications applied to the eye directly to dilate the pupil (known as “mydriatics”)—may lead to sudden (acute) glaucoma in susceptible pets
  • Primary glaucoma in dogs—consider all cases to involve both eyes, even if one eye has normal intraocular pressure at the time of evaluation; a veterinary eye doctor (ophthalmologist) should examine the apparently normal eye for filtration angle abnormalities to determine the risk for future glaucoma

Treatment

Health Care

  • Sudden (acute) glaucoma in dogs—inpatient medical care
  • After discharge from the veterinary hospital—reevaluate every 1–2 days for 1 week to monitor for return of increased intraocular pressure

Surgery

  • Cases with primary glaucoma or glaucoma due to movement of the lens out of its normal location (lens luxation) induced are best treated surgically
  • Primary glaucoma in dogs—less than 10% of affected pets undergoing medical treatment alone will have vision remaining at the end of the first year following diagnosis
  • Various surgical procedures may be performed to increase the flow of aqueous humor out of the eye; to decrease production of aqueous humor in the eye; procedures performed attempt to maintain normal intraocular pressure and vision; the “aqueous humor” is the transparent liquid that fills the front part of the eyeball
  • Surgical removal of lens that has moved forward in the eye (anterior lens luxation) may result in a visual eye, as well as help lower intraocular pressure
  • Blind, painful eyes—surgically remove the eye (known as “enucleation”); may remove the inner parts of the eye surgically, leaving the eyeball and place a prosthesis in the eye (known as “evisceration and intraocular prosthesis implantation”) in some cases

Medications

Medications presented in this section are intended to provide general information about possible treatment. The treatment for a particular condition may evolve as medical advances are made; therefore, the medications should not be considered as all inclusive.

Sudden (Acute) Primary Glaucoma in Dogs

  • Emergency medical treatment may include one or more of the following:
  • Medications applied to the eye directly to cause the pupil to constrict (known as “topical miotics”)—latanoprost 0.005% (Xalatan), travoprost 0.004% (Travatan), or bimatoprost 0.03% (Lumigan); 2% pilocarpine solution; 0.25% demecarium bromide; treatment aimed at improving aqueous outflow
  • Topical beta-adrenergic antagonists—timolol maleate 0.5%, levobunalol 0.5%, betaxolol 0.5%; reduce aqueous humor production; the “aqueous humor” is the transparent liquid that fills the front part of the eyeball
  • Carbonic anhydrase inhibitor (administered by mouth)—methazolamide; reduce production of aqueous humor
  • Carbonic anhydrase inhibitors (applied to the eye directly)—dorzolamide 2% (TruSopt), brinzolamide 1% (Azopt); reduce aqueous humor production
  • Medications to remove fluids from the body (known as “hyperosmotic agents”)—mannitol or glycerin; dehydrate the vitreous humor; the “vitreous” is the clear, gel-like material that fills the back part of the eyeball (between the lens and the retina)

Glaucoma Secondary to Movement of the Lens Out of its Normal Location Toward the Front of the Eye (Anterior Lens Luxation) or Inflammation of the Iris and Other Areas in the Front Part of the Eye (Uveitis) in Dogs

  • Treated like primary glaucoma
  • Medications to cause the pupil to constrict (miotic agents) should not be used
  • Steroids applied to the eye directly (known as “topical steroids”)—used to reduce inflammation if no changes of the cornea (the clear outer layer of the front of the eye) characterized by the presence of ulcers, with or without inflammation (condition known as “ulcerative keratitis”)

Long-Term (Chronic) Smoldering Inflammation of the Iris

  • Steroids applied to the eye directly (topical steroids)
  • Topical beta-blockers; reduce aqueous humor production; the “aqueous humor” is the transparent liquid that fills the front part of the eyeball
  • Carbonic anhydrase inhibitor diuretics or topical carbonic anhydrase inhibitors to reduce production of aqueous humor

Follow-Up Care

Patient Monitoring

  • Intraocular pressure—monitored often and regularly after starting initial therapy; if low intraocular pressure (known as “hypotensive ocular pressure”) is maintained for many weeks, slowly taper drug therapy (as directed by your pet’s veterinarian)
  • Monitor for drug reactions

Preventions and Avoidance

  • Primary glaucoma—consider all cases to involve both eyes, even if one eye has normal intraocular pressure at the time of evaluation; a veterinary eye doctor (ophthalmologist) should examine the apparently normal eye for filtration angle abnormalities to determine the risk for future glaucoma
  • Prophylactic therapy for the apparently unaffected eye—0.25% demecarium bromide or 0.005% latanoprost or 0.5% timolol maleate or 2% dorzolamide; delays onset of glaucoma in second susceptible eye

Possible Complications

  • Blindness
  • Long-term (chronic) eye pain

Expected Course and Prognosis

  • Long-term (chronic) disease that requires constant medical treatment (even with surgical intervention)
  • With medical treatment only—most affected pets ultimately go blind
  • Surgical treatment—better chance of retaining vision longer; most affected pets do not remain visual for more than 2 years after initial diagnosis
  • Secondary glaucoma due to movement of the lens out of its normal location (lens luxation)—may carry a fair prognosis with successful surgical removal of the luxated lens
  • Secondary glaucoma due to anterior uveitis—may carry a fair prognosis with control of inflammation of the iris and other areas in the front part of the eye

Key Points

  • Primary glaucoma is a disease that involves both eyes; over 50% of pets develop glaucoma in the other eye within 8 months without prophylactic therapy
  • 40% or more of dogs will be blind in the affected eye within the first year, no matter what is done medically or surgically

Conjunctivitis

Conjunctivitis – An Overview

  • Inflammation of the moist tissues of the eye (known as the “conjunctiva”); the conjunctiva is the vascularized moist tissue (mucous membrane) that covers the front part of the eyeball or globe, up to the edge of the cornea (known as the “bulbar conjunctiva”) and lines the lids and third eyelid (known as the “palpebral conjunctiva”)

Signalment/Description of Pet

Breed Predilections

  • Breeds susceptible to allergic or immune-mediated skin diseases (such as “atopy”) tend to have more problems with allergic inflammation of the moist tissues of the eye (conjunctivitis) or “dry eye” (known as “keratoconjunctivitis sicca” or KCS); “atopy” is a disease in which the dog is sensitized (or “allergic”) to substances found in the environment (such as pollen) that normally would not cause any health problems

Signs/Observed Changes in Pet

  • Squinting or spasmodic blinking (known as “blepharospasm”)
  • Redness of the moist tissues of the eye (known as “conjunctival hyperemia”)
  • Discharge from the eye(s); may be clear or may contain mucus and/or pus
  • Fluid buildup (known as “edema”) of the moist tissue covering of the eyeball (bulbar conjunctiva), around the cornea (condition known as “chemosis”)
  • Follicle formation; the “follicles” are accumulations of lymphoid tissue located at the moist tissue surface of the third eyelid and the eyelids, causing a “cobblestone” appearance; lymphoid tissue contains lymphocytes, a type of white blood cell that are involved in allergies and response to irritants

Causes

Bacterial Causes

  • Primary condition (that is, not secondary to another condition such as “dry eye” [keratoconjunctivitis sicca or KCS])—rare
  • Newborn inflammation of the moist tissues of the eye (conjunctivitis)—accumulation of discharge, often associated with a bacterial or viral infection; seen before the eyelids separate or open

Viral Causes

  • Canine distemper virus
  • Canine herpesvirus-1
  • Canine adenovirus-2

Immune-Mediated Causes

  • Allergic conjunctivitis—especially in atopic pets; “atopy” is a disease in which the animal is sensitized (or “allergic”) to substances found in the environment (such as pollen) that normally would not cause any health problems
  • Follicular conjunctivitis—inflammation of the moist tissues of the eye (conjunctivitis) characterized by accumulations of lymphoid tissue located at the moist tissue surface of the third eyelid and the eyelids, causing a “cobblestone” appearance; lymphoid tissue contains lymphocytes, a type of white blood cell that are involved in allergies and response to irritants; especially in dogs younger than 18 months of age, secondary to long-term (chronic) antigenic stimulation (that is, the substance to which the immune system is responding and producing antibodies)
  • Plasma-cell conjunctivitis—inflammation of the moist tissues of the eye (conjunctivitis) characterized by the presence of plasma cells (a specialized type of white blood cell; plasma cells are lymphocytes that have been altered to produce immunoglobulin, an immune protein or antibody necessary for fighting disease); especially in German shepherd dogs
  • Related to generalized (systemic) immune-mediated diseases—such as pemphigus, in which the body attacks its own tissues

Cancer or Pseudocancer Causes

  • Tumors involving the moist tissues of the eye (conjunctiva)—rare; include melanoma, hemangioma, hemangiosarcoma, lymphoma, papilloma, and mast-cell tumors
  • Lesions that appear to be cancer, but are not cancerous (known as “pseudocancer”)—inflammation of the border between the cornea (the clear part of the eye, located in the front of the eyeball) and the sclera (the white part of the eye, it is composed of a tough covering that protects the eyeball) characterized by the presence of nodules (condition is known as “nodular episcleritis” [also-called “fibrous histiocytoma,” “ocular nodular granuloma,” and “conjunctival pseudotumor”]; most commonly seen in collies and mixed collies; believed to be immune-mediated; usually appears as a pink mass

Secondary to Disease of the Tissues Surrounding the Eye (Known as “Adnexa,” Such as Eyelids, Third Eyelid, and Tear Glands)

  • Lack of normal tear film (known as “aqueous tear film deficiency”); “dry eye” (KCS)
  • Lid diseases (such as “entropion,” in which the eyelid curls inward, allowing facial hair to rub the eye; “ectropion,” in which the eyelid is turned outward) and lash diseases (such as “distichiasis,” in which two rows of eyelashes are present on a single eyelid; “ectopic cilia,” in which one or more eyelashes grows in an unusual location [may grow through the conjunctiva, leading to irritation of the eye])—may lead to clinical signs of inflammation of the moist tissues of the eye (conjunctivitis)
  • Secondary to blockage of the outflow portion of the drainage system that normally moves tears to the nasal passages (known as the “nasolacrimal system”), such as an obstructed nasolacrimal duct or lack of normal openings on the eyelids into the tear drainage system (known as “imperforate puncta”)

Secondary to Trauma or Environmental Causes

  • Foreign body located in the moist tissues of the eye
  • Irritation from dust, chemicals, or eye medications

Secondary to Other Eye Diseases

  • Disorder of the cornea (the clear outer layer of the front of the eye) characterized by the presence of ulcers, with or without inflammation (condition known as “ulcerative keratitis”)
  • Inflammation of the front part of the eye, including the iris (known as “anterior uveitis”)
  • Disease of the eye, in which the pressure within the eye is increased (known as “glaucoma”)

Other Causes

  • Ligneous conjunctivitis (inflammation of the moist part of the eye, characterized by thick, opaque conjunctiva)—young, female Doberman pinschers

Risk Factors

  • Exposure to dogs with canine distemper virus, herpesvirus-1, or adenovirus-2 infections

Treatment

Health Care

  • Primary—often outpatient
  • Secondary to other diseases (such as inflammation of the front part of the eye, including the iris [anterior uveitis} and corneal ulceration, with or without inflammation [ulcerative keratitis])—may need hospitalization while the underlying problem is diagnosed and treated

Activity

  • Primary—usually no restriction
  • Suspected contact irritant or sudden (acute) allergic disease—prevent (if possible) contact with the agent causing the irritation or allergy
  • Do not expose pets to other dogs to decrease risk of spread of infectious causes (such as canine distemper virus) of inflammation of the moist tissues of the eye (conjunctivitis)

Diet

  • Suspected underlying skin disease and/or food allergy—food elimination diet recommended; “elimination diet” is a diet that does not contain substances that the animal normally eats and is free of additives

Surgery

  • Blockage of the outflow portion of the drainage system that normally moves tears to the nasal passages (known as the “nasolacrimal system”), such as an obstructed nasolacrimal duct—surgical repair is difficult; treatment often not recommended
  • Cancer involving the moist tissues of the eye (“conjunctival cancer”)—may involve surgical removal of the tumor followed by radiation therapy; freezing (known as “cryotherapy”); or heating of the tissues using radiofrequency waves (known as “radiofrequency hyperthermia”); may involve surgical removal of the eyeball and associated tissues (known as “enucleation”), depending on the type of tumor and the extent of involvement

Medications

Medications presented in this section are intended to provide general information about possible treatment. The treatment for a particular condition may evolve as medical advances are made; therefore, the medications should not be considered as all inclusive.

Bacterial Infections

  • Antibiotics based on bacterial culture and sensitivity results
  • Antibiotics may be applied directly to the moist tissues of the eye (“topical treatment”) or may be given by mouth (“systemic treatment”)
  • Initial treatment—broad-spectrum topical antibiotic or specific antibiotic based on results of microscopic examination of discharge and/or conjunctival scraping, while waiting for bacterial culture and sensitivity results; may try treatment based on experience with other cases of conjunctivitis, performing a bacterial culture and sensitivity only if the pet does not respond to selected treatment
  • Topical triple antibiotic or chloramphenicol—if cocci (general type of bacteria) seen on microscopic examination of discharge and/or conjunctival scraping
  • Gentamicin or tobramycin—if rods (general type of bacteria) seen on microscopic examination of discharge and/or conjunctival scraping
  • Ciprofloxacin or other quinolone antibiotics—may be useful for severe bacterial inflammation of the moist tissues of the eye (conjunctivitis)
  • Systemic antibiotics—occasionally indicated, especially for more generalized disease (such as inflammation of the moist tissues of the eye [conjunctivitis] associated with skin infection characterized by the presence of pus [known as “pyoderma”])

New Born Conjunctivitis

  • Depends on severity
  • Topical steroids— applied directly to the moist tissues of the eye; 0.1% dexamethasone; improve clinical signs of allergic, follicular conjunctivitis (characterized by accumulations of lymphoid tissue located at the moist tissue surface of the third eyelid and the eyelids, causing a “cobblestone” appearance), and plasma-cell conjunctivitis (characterized by the presence of plasma cells); improvement often temporary
  • Treatment of any underlying disease (such as atopy) often improves clinical signs; “atopy” is a disease in which the animal is sensitized (or “allergic”) to substances found in the environment (such as pollen) that normally would not cause any health problems
  • Other steroids—1% prednisolone acetate; betamethasone; hydrocortisone

Follow-Up Care

Patient Monitoring

  • Recheck shortly after beginning treatment (at 5–7 days); then recheck as needed

Preventions and Avoidance

  • Treat any underlying disease that may make the eye disease worse—allergic or immune-mediated skin disease; “dry eye” (KCS)
  • Vaccination against canine distemper virus

Expected Course and Prognosis

  • Bacterial infection/inflammation of the moist tissues of the eye (conjunctivitis)—usually resolves with appropriate administration of antibiotics; if an underlying disease is found (such as “dry eye” [KCS]), resolution may depend on appropriate treatment and resolution of the disease
  • Immune-mediated diseases—diseases tend to be controlled, not cured; may require long-term (chronic) treatment with steroids at the lowest dose possible

Key Points

  • If a large amount of discharge is noted, gently clean the eyes before administering treatment
  • If both eye solutions and eye ointments are prescribed, apply the solution(s) before applying the ointment(s)
  • If several eye solutions are prescribed, wait several minutes between treatments
  • Call for instructions if the condition worsens, which indicates that the condition may not be responsive to treatment or may be progressing or that the animal may be having an adverse reaction to a prescribed medication
  • An Elizabethan collar should be placed on the pet, if self-trauma occurs

Cataracts

Cataracts – An Overview

  • Opacity in the lens; the lens is the normally clear structure directly behind the iris (the colored part of the eye) that focuses light as it moves toward the back part of the eye (retina); if opacity is complete, it prevents passage of light to the back part of the eye (retina), leading to blindness in the affected eye
  • “Cataract”—may refer to a lens that is entirely opaque or to a localized opacity within the lens; does not imply cause

Genetics

  • Inheritance has been established for many dog breeds; most common mode of inheritance—autosomal recessive
  • The number of individuals with genetic cataracts varies significantly between breeds; it has been reported to be as high as 10% in some breeds
  • Inheritance has been established in the Himalayan (cat)—autosomal recessive

Signalment/Description of Pet

Breed Predilections

  • Over 135 dog breeds are suspected of having increased likelihood of having hereditary cataracts

Mean Age and Range

  • Depend on cause
  • Cataracts can develop at any age
  • Genetic cataracts can develop as early as 6 months of age

Signs/Observed Changes in Pet

  • Opacity or white appearance of the lens
  • Related to the degree of vision impairment
  • Vision loss may be noticed when cataracts are present in both eyes
  • Cataract caused by diabetes mellitus (sugar diabetes)—may see signs of diabetes, such as increased urination (known as “polyuria”), increased thirst (known as “polydipsia”), and weight loss
  • Cloudiness in the eye (specifically the lens) noticed before vision impairment—may be related to sclerosis, rather than cataract formation; “sclerosis” is a normal aging change in the lens due to changes in the lens fibers, it apparently has little to no effect on vision
  • May be associated with inflammation of the front part of the eye, including the iris (known as “anterior uveitis”)—typically see cloudiness of aqueous humor (the “aqueous humor” is the transparent liquid that fills the front part of the eyeball) due to increased protein content and suspended cellular debris (condition known as “aqueous flare”); scar tissue between the iris and the lens of the eye (known as “synechiae”); and decreased pressure within the eye (known as “low intraocular pressure”)

Causes

  • Heredity—most common cause in dogs
  • Diabetes mellitus (sugar diabetes)
  • Inflammation of the front part of the eye, including the iris (anterior uveitis)—secondary to formation of scar tissue between the iris and the lens of the eye (synechia) or altered aqueous humor (the transparent liquid that fills the front part of the eyeball) composition
  • Trauma—injury to the eye, where something penetrates the outer surface of the eye and disrupts the anterior lens capsule, most commonly a cat-claw injury especially in puppies.
  • Senile—age-related; slowly progressive cataract in senior pets
  • Congenital (present at birth)—inherited cataract; damage to the developing lens or eye while the puppy is in the uterus; may be associated with other congenital eye abnormalities
  • Surgery
  • Toxic substances
  • Radiation
  • Low levels of calcium in the blood (known as “hypocalcemia”)
  • Nutrition—use of unbalanced milk-replacer diet in bottle-fed puppies
  • Electric shock—chewing electrical cords or lightning strike

Risk Factors

  • Genetics
  • Diabetes mellitus (sugar diabetes) in dogs
  • Long-term (chronic) inflammation of the front part of the eye, including the iris (anterior uveitis
  • Progressive retinal atrophy (a group of eye diseases characterized by generalized deterioration of the retina, becoming increasingly worse over time); the “retina” is the back part of the eye; the retina contains the light-sensitive rods and cones and other cells that convert images into signals and send messages to the brain, to allow for vision

Treatment

Activity

  • For safety, blind pets should not be allowed access to an in-ground swimming pool or elevated decks with open railings; use caution near stairs
  • Restrict outside activity to fenced yards or leash-walks

Surgery

  • Phacoemulsification is a surgical procedure in which ultrasonic vibrations are used to fragment and liquefy the lens, in order to remove the lens material; procedure of choice
  • Ideal time for cataract surgery is the immature or early mature cataract stageIntraocular lenses—may be implanted safely at the time of surgery, so the pet will not suffer extreme farsightedness

Medications

Medications presented in this section are intended to provide general information about possible treatment. The treatment for a particular condition may evolve as medical advances are made; therefore, the medications should not be considered as all inclusive.

  • Topical (applied directly to the eye) anti-inflammatory medication is recommended to prevent and treat lens-induced inflammation of the front part of the eye, including the iris (anterior uveitis); topical anti-inflammatory medications include flurbiprofen or diclofenac or a topical steroid, such as prednisolone 1% or dexamethasone 0.1%
  • Topical atropine for lens-induced inflammation of the front part of the eye, including the iris (anterior uveitis)
  • Non-steroidal anti-inflammatory drugs (NSAIDs) administered by mouth (oral administration) are used to treat lens-induced inflammation of the front part of the eye, including the iris (anterior uveitis); examples include carprofen, meloxicam, and tepoxalin

Follow-Up Care

Patient Monitoring

  • Early immature cataracts—monitor regularly for progression of cataracts, in order to select the ideal time for surgery and avoid complications associated with cataracts
  • Post-operative monitoring by the surgeon is critical for success

Preventions and Avoidance

  • Do not breed pets with cataracts

Possible Complications

  • Lens-induced inflammation of the front part of the eye, including the iris (anterior uveitis)
  • Secondary glaucoma (in which the pressure within the eye [intraocular pressure] is increased secondary to inflammation in the front part of the eye)
  • Separation of the back part of the eye (retina) from the underlying, vascular part of the eyeball (known as the “choroid”; condition known as “retinal detachment”)
  • Movement of the lens out of its normal location (known as “lens luxation”)

Expected Course and Prognosis

  • Long-term prognosis following cataract surgery is very good
  • Some pets have increased risk for post-operative complications, such as those with pre-existing inflammation of the front part of the eye, including the iris (anterior uveitis), even if medically controlled; genetic likelihood of developing glaucoma; retinal abnormalities

Key Points

  • Cataract surgery is performed routinely with an overall 80–90% success rate
  • Once the cataract(s) is/are removed, they cannot return
  • Artificial lens implants will restore essentially normal vision
  • Evaluation for surgery should be done early in the course of cataract development to avoid complications that may result in the cataract becoming inoperable, to allow time to plan for the surgery, and, in some cases, to eliminate the need and extra cost for an ultrasound examination of the eye and an evaluation of the electrical responses in the retina (procedure known as an “electroretinogram”)

Osteosarcoma

Osteosarcoma – An Overview

  • Most common primary bone tumor in dogs
  • “Appendicular” is an adjective relating to the limbs; “axial” is an adjective relating to the head and trunk of the body
  • Osteosarcoma typically affects the appendicular skeleton of large- to giant-breed dogs; may be seen in the axial skeleton (composed of skull, spine, ribs, and sternum)
  • Cancerous (malignant) tumor, with spread to the lungs (known as “lung metastases”) in more than 90% of dogs at the time of diagnosis; lung metastases may be microscopic
  • Osteosarcoma may spread to soft tissues, such as the skin, kidney, and liver
  • Osteosarcoma accounts for up to 85% of primary bone tumors in dogs

Genetics

  • Appears to be inherited in giant breeds, such as Scottish deerhounds and Irish wolfhounds
  • Increased likelihood of developing osteosarcoma does occur in some breeds
  • Breed size and rate of maturity may be more important than breed or family line

Signalment/Description of Pet

Breed Predilections

  • large- to giant-breed dogs

Mean Age and Range

  • bimodal peak at 2 years and 7 years; reported as young as 6 months of age.

Predominant Sex

  • no strong indication that a particular sex is more likely to develop osteosarcoma than the other sex

Signs/Observed Changes in Pet

  • Depend on site
  • Signs may be subtle
  • Appendicular skeleton (limbs)—welling, lameness, and pain common
  • Axial skeleton (skull, spine, ribs, sternum)—localized swelling, detectable mass, pain
  • Other complaints—lack of appetite (inappetence) and sluggishness (lethargy)
  • A firm, painful swelling of the affected site common
  • Degree of lameness—varies from mild to non–weight-bearing
  • Buildup of fluid (known as “edema”) around affected area
  • Fractures occurring at the site of weakened bone (known as “pathologic fractures”) are rare

Causes

  • Unknown

Risk Factors

  • Dogs—large- to giant-breed dogs; metallic implants at fracture-repair sites; history of exposure to ionizing radiation
  • Early spay/neuter

Treatment

Health Care

  • Diagnostic evaluation—outpatient
  • Surgery and the first chemotherapy treatment—inpatient
  • Subsequent chemotherapy—outpatient
  • Manage pain, as needed
  • Radiation therapy will decrease pain effectively in dogs

Activity

  • Restricted after surgery, until adequate healing has occurred

Diet

  • Dietary management is not required
  • Weight lost may benefit amputees in general

Surgery

Appendicular Sites (Relating to the Limbs)

  • Amputation of affected limb—limb amputated at the forequarter (including the scapula and shoulder joint) or hip
  • Limb-sparing or salvage therapy—used for osteosarcoma of the distal radius (bone in the lower front leg); available at a limited number of referral hospitals
  • Chemotherapy—recommended after either surgical procedure

Axial Sites (Relating to the Head and Trunk of the Body)

  • Amputation of affected limb—limb amputated at the forequarter (including the scapula and shoulder joint) or hip
  • Limb-sparing or salvage therapy—used for osteosarcoma of the distal radius (bone in the lower front leg); available at a limited number of referral hospitals
  • Chemotherapy—recommended after either surgical procedure

Soft Tissue Sites (Tissues Other than Bone)

  • Amputation of affected limb—limb amputated at the forequarter (including the scapula and shoulder joint) or hip
  • Limb-sparing or salvage therapy—used for osteosarcoma of the distal radius (bone in the lower front leg); available at a limited number of referral hospitals
  • Chemotherapy—recommended after either surgical procedure

Metastasectomy (Surgical Removal of Metastasis)

  • Surgical removal of metastasis to the lungs (known as “pulmonary metastasectomy”)—has been described; indicated in dogs that: (1) had a long disease-free interval (over 300 days) after diagnosis; (2) have only 1–2 detectable lung nodules based on computed tomography scan (CT scan)
  • Inoperable cancer—radiation therapy to control signs and improve the pet’s condition, but not to cure (known as “palliative intent”)
  • Pain management with medications such as nonsteroidal anti-inflammatory drugs (NSAIDs), opiods, or bisphosphonates may improve quality of life and thus prolong survival

Medications

Medications presented in this section are intended to provide general information about possible treatment. The treatment for a particular condition may evolve as medical advances are made; therefore, the medications should not be considered as all inclusive

  • Post-surgical chemotherapy with either platinum-based protocol (cisplatin, carboplatin), or doxorubicin is the current standard of care
  • Palliative medication is intended to improve the pet’s condition and quality of life, it is not a cure for the cancer; these drugs are used to control pain and/or decrease inflammation; options include: aspirin, piroxicam, or other nonsteroidal anti-inflammatory drugs; acetaminophen with or without codeine, tramadol or a fentanyl patch—not all of these drugs can be used in combination; always consult your pet’s veterinarian for the most appropriate pain management for your pet

Follow-Up Care

Patient Monitoring

  • Monitor for reduction of bone-marrow activity (known as “myelosuppression”), resulting in low number of red blood cells, white blood cells, and/or platelets; should have a complete blood count (CBC) performed 7–10 days after chemotherapy
  • Take chest x-rays (radiographs) every 2–3 months after surgery
  • Take x-rays (radiographs) of graft site for cases with limb-sparing or salvage therapy every 2–3 months after surgery, because local recurrence is possible after limb salvage

Possible Complications

  • Spread of cancer (metastasis) to lungs, bone, and soft tissue sites
  • Hypertrophic osteopathy (a bone disorder that causes painful swelling of bone and lameness) with spread of cancer to lungs (lung metastases)
  • Pets that undergo limb-sparing or limb-salvage procedures may develop infections, local recurrence of the cancer, or failure of the surgical implants
  • Amputees rarely show complications secondary to arthritis in the other legs

Expected Course and Prognosis

  • Prognosis is poor; achievable goals should be to relieve discomfort and prolong life
  • Median survival without treatment, with amputation alone, or with palliative radiation therapy alone—approximately 4 months
  • Median survival with surgery and chemotherapy—10 months
  • Osteosarcoma of the lower jaw (known as “mandibular osteosarcoma”)—less aggressive than other sites; 1-year median survival time with surgery alone—71% reported in one study

Key Points

  • The most common primary bone tumor in dogs
  • This disease has an aggressive biologic behavior; therapy should be directed at the painful bone tumor (using either surgery or radiation therapy) as well as at metastatic disease (using chemotherapy)
  • Prognosis is poor; achievable goals should be to relieve discomfort and prolong life
  • Cure is unlikely

Transitional Cell Carcinoma of the Urinary Tract

Transitional Cell Carcinoma of the Urinary Tract – An Overview

  • The urinary tract consists of the kidneys, the ureters (the tubes running from the kidneys to the bladder), the urinary bladder (that collects urine and stores it until the pet urinates), and the urethra (the tube from the bladder to the outside, through which urine flows out of the body)
  • Transitional cell carcinoma is a cancer arising from the transitional epithelium within the kidney, ureters, urinary bladder, urethra, prostate, or vagina; the transitional epithelium is a specialized type of lining in the urinary tract that contracts or stretches in response to the size of the bladder and other organs

Signalment/Description of Pet

Breed Predilections

  • Scottish terriers, West Highland white terriers, Shetland sheepdogs, American Eskimo dogs, and dachshunds; may occur in any breed

Mean Age and Range

  • Dogs—8 years; range, 1–15+ years of age
  • Middle-aged to old, spayed, female small-breed dogs most commonly reported

Predominant Sex

  • Female

Signs/Observed Changes in Pet

  • Similar to those of bacterial urinary tract infection or the presence of stones in the urinary tract (known as “urolithiasis”); for pets showing temporary or no response to appropriate antibiotics, consider transitional cell carcinomaRecurrent straining with slow, painful discharge of urine (known as “stranguria”); abnormal frequent passage of urine (known as “pollakiuria”); blood in the urine (known as “hematuria”); difficulty urinating (known as “dysuria”); inability to control urination or leaking urine (known as “urinary incontinence”); or any combination of these signs
  • Physical examination findings often normal
  • Mass—occasionally may be felt in the abdomen at the location of the urinary bladder
  • Urethral or vaginal transitional cell carcinoma—may be able to feel mass during rectal examination
  • Rarely enlarged intrapelvic or sublumbar lymph nodes—may be able to feel during rectal examination

Causes and Risk Factors

  • Scottish terrier; obesity; environmental carcinogens (substances that cause cancer); long-term (chronic) exposure to certain flea-control products (such as organophosphates or carbamates); and rarely, long-term treatment or a large bolus dose of cyclophosphamide (a chemotherapeutic drug)

Treatment

Health Care

  • Outpatient—stable pets; initial workup generally takes 1–2 days, so hospitalization may be more convenient
  • Seek advice from a veterinary oncologist prior to initiating treatment and consider current recommendations
  • Radiation therapy

Activity

  • Normal

Diet

  • Normal, unless pet also has kidney failure

Surgery

Appendicular Sites (Relating to the Limbs)

  • Surgery for transitional cell carcinoma can be challenging as the tumor easily sheds cancer cells; these cells can be spread into the abdomen during surgery
  • Surgery may result in a cure, if the mass can be removed completely
  • Wide surgical excision (that is, surgically removing the tumor and wide borders of apparently normal tissue) is necessary; up to 50% of the urinary bladder may be removed surgically with minimal loss of function
  • Placement of a catheter from the bladder and exiting through the abdominal wall to allow urine to be removed from the body (procedure known as “tube cystostomy”)—may greatly prolong survival times by bypassing blockage of the urethra (known as “urethral obstruction”)
  • Urethral stenting (placing a medical “tube” inside the urethra) may prolong survival by temporarily relieving blockage of the urethra, and thereby, allowing the pet to urinate

Medications

Medications presented in this section are intended to provide general information about possible treatment. The treatment for a particular condition may evolve as medical advances are made; therefore, the medications should not be considered as all inclusive

  • Chemotherapy—piroxicam (Feldene), cisplatin (dogs), mitoxantrone (as single agents or as combination therapy for certain drugs); piroxicam and cisplatin cannot be combined because of kidney toxicity; other agents (doxorubicin or doxorubicin/cyclophosphamide combination) may have activity
  • Antibiotics—administered as necessary for secondary urinary tract infections

Follow-Up Care

Patient Monitoring

  • X-rays (radiographs) using contrast media in the bladder (known as “contrast cystography”) or ultrasound examination—every 6–8 weeks; assess response to treatment and screen for spread of cancer into the lymph nodes (known as “lymph-node metastases”)
  • Chest x-rays(radiographs)—every 2–3 months; detect spread of cancer into the lungs (known as “pulmonary metastatic disease”)

Possible Complications

  • Blockage of the urethra (the tube from the bladder to the outside, through which urine flows out of the body) or ureters (the tubes running from the kidneys to the bladder), and kidney failure
  • Spread of cancer (metastasis) to regional lymph nodes, lungs, or bone
  • Recurrent urinary tract infection
  • Lack of control of urination or urine leakage (urinary incontinence)
  • Reduction of bone-marrow activity (known as “myelosuppression”), resulting in low number of red blood cells, white blood cells, and/or platelets or gastrointestinal toxicity secondary to chemotherapy
  • Gastrointestinal ulceration secondary to piroxicam therapy

Expected Course and Prognosis

  • Long-term prognosis grave
  • Progressive disease probable
  • Median survival—no treatment, 4–6 months; with treatment, 6–12 months

Key Points

  • Long-term prognosis is poor, but control of signs to make the pet more comfortable (known as “palliation”) is often attainable
  • The tumor usually cannot be removed surgically in dogs

Rabies

Rabies – An Overview

A severe, invariably fatal, viral inflammation of the gray matter of the brain (known as “polioencephalitis”) of warm-blooded animals, including humans; “gray matter” is the nerve tissue of the brain that contains the nerve cell bodies.

Signalment/Description of Pet

Species

  • All warm-blooded mammals, including dogs, cats, and people.
  • United States—five strains of rabies virus are found in the skunk, raccoon, coyote, fox, and insectivorous bat populations; all five strains can be transmitted to dogs and cats.

Mean Age and Range

  • None, but adult animals that come in contact with wildlife are at most risk

Signs/Observed Changes in the Pet

  • Quite variable; atypical presentation is the rule rather than the exception
  • Three progressive stages of disease—(1) prodromal stage—early signs of disease; signs may include change in behavior, apprehension, nervousness, seeking solitude; (2) furious stage—signs may include irritability, excitability, avoidance of light (known as “photophobia”), and viciousness (biting, attacking); and (3) paralytic stage—also known as the “dumb form” of rabies; signs may include paralysis of various parts of the body (determined by location of original site of exposure to the rabies virus, such as a bite wound), change in voice (known as “dysphonia”), excessive salivation/drooling, and choking sounds; final signs include coma and death
  • 90% of cats with rabies have the furious form of disease
  • Change in attitude—pet seeks solitude; apprehension, nervousness, anxiety; unusual shyness or aggressiveness
  • Erratic behavior—biting or snapping; licking or chewing at site of wound; biting at cage; wandering and roaming; excitability; irritability; viciousness
  • Disorientation
  • Muscular incoordination; seizures; inability to move voluntarily (known as “paralysis”)
  • Change in tone of bark
  • Excess salivation or frothing
  • Paralysis of the lower jaw (mandible) and voice box or larynx; dropped jaw
  • Inability to swallow
  • Fever
  • Dilated pupils—unresponsive to light; unequal size of the pupils (known as “anisocoria”)

Causes

  • Rabies virus

Risk Factors

  • Exposure to wildlife, especially skunks, raccoons, bats, and foxes
  • Lack of adequate vaccination against rabies
  • Bite or scratch wounds from unvaccinated dogs, cats, or wildlife
  • Exposure to aerosols in bat caves
  • Pets that do not have the ability to develop a normal immune response (known as an “immunocompromised pet”)—use of modified live virus rabies vaccine

Treatment for Rabies

Healthcare

  • Strictly inpatient for pet suspected of being exposed to rabies or having rabies
  • Administer nursing care with extreme caution
  • No treatment for rabies
  • Once the diagnosis is certain, euthanasia is indicated

Activity

  • Confine to secured quarantine area with clearly posted signs indicating suspected rabies
  • Runs or cages should be locked; only designated people should have access
  • Feed and water without opening the cage or run door (in other words, pass food and water bowls into the cage or run through specialized access points designed for such use)

Diet

  • Soft, moist food; most affected pets will not eat

Surgery

  • Generally none
  • Skin biopsy—may help establish diagnosis before death of the pet; diagnosis must be confirmed by identification of rabies virus infection from central nervous system tissue

Follow-Up Care

Patient Monitoring

  • All suspected rabies patients should be isolated securely and monitored for any development of mood change, attitude change, or clinical signs that might suggest the diagnosis.
  • An apparently healthy dog or cat that bites or scratches a person should be monitored for a period of 10 days or according to local or state regulations; if no signs of illness occur in the pet within 10 days, the person has had no exposure to the virus; dogs and cats do not shed the virus for more than 3 days before development of clinical disease.
  • An unvaccinated dog or cat that is bitten or exposed to a known rabid animal must be quarantined for up to 6 months or according to local or state regulations.

Preventions and Avoidance

  • Vaccines (dogs and cats)—vaccinate according to standard recommendations and state and local requirements; all dogs and cats with any potential exposure to wildlife or other dogs and cats; vaccinate after 12 weeks of age; then 12 months later; then every 3 years using a vaccine approved for 3 years’ duration; use only inactivated virus or recombinant vector vaccines for cats.
  • Rabies-free countries—entering dogs and cats are quarantined for long periods, usually 6 months.
  • Disinfection—any contaminated area, cage/run, food dish, water bowl or instruments must be disinfected thoroughly; use a 1:32 dilution (4 ounces per gallon) of household bleach to inactivate the virus quickly.

Possible Complications

  • Paralysis
  • Attitude or behavior changes
  • Death
  • Exposure of rabies virus to other animals or people

Expected Course and Prognosis

  • Prognosis—grave; almost invariably fatal
  • Dogs and cats with clinical infection usually succumb within 1–10 days of onset of clinical signs; often within 3–4 days

Key Points

  • Rabies is a serious, usually fatal infection for the pet; rabies can be spread from animals to people (known as having “zoonotic potential”).
  • Tell your veterinarian about any possible human exposure (such as contact with the pet or other suspected rabid animal or a bite or scratch).
  • Any person possibly exposed to rabies should see a physician immediately.
  • Local public health officials must be notified.

Pemphigus

Pemphigus

BASICS-Overview

  • A group of diseases in which the immune system attacks the skin (known as “auto-immune dermatoses”); auto-immune diseases are ones in which the body produces antibodies against its own tissue; an “antibody” is a protein that is produced by the immune system in response to a specific antigen (a substance that induces an immune response)—when the body is exposed to the antigen (in the case of pemphigus, the antigen is some part of the skin), the antibody responds, resulting in signs of disease.
  • The pemphigus group of diseases is characterized by varying degrees of loss of tissue on the surface of the skin, frequently with inflammation (known as “ulceration”); dried discharge on the surface of a skin lesion (known as a “crust”); and formation of small, raised skin lesions containing pus (known as “pustules”) and blisters or small, circumscribed elevation of the outer layer of the skin filled with clear fluid (known as “vesicles”)
  • Affects the skin and sometimes the moist tissues of the body (known as “mucous membranes”)
  • Forms identified in animals include pemphigus foliaceous, pemphigus erythematosus, pemphigus vulgaris, panepidermal pustular pemphigus/vegetans, canine benign familial chronic pemphigus (Hailey-Hailey disease), and paraneoplastic pemphigus; type of pemphigus based on location of skin lesions and microscopic appearance of skin lesions

Genetics

  • Benign familial chronic pemphigus (Hailey-Hailey disease)—may be a genetic disease

Signalment/Description of Pet

Species

  • Pemphigus foliaceus, erythematosus, and vulgaris—dogs and cats
  • Panepidermal pustular pemphigus—dogs

Breed Predilections

  • Pemphigus foliaceus—Akitas, bearded collies, chow chows, dachshunds, Doberman pinschers, Finnish spitzes, Newfoundlands, and schipperkes
  • Pemphigus erythematosus—collies, German shepherd dogs, and Shetland sheepdogs

Signs/Observed Changes in the Pet

Pemphigus Foliaceus

  • Scales (accumulations of surface skin cells, such as seen in dandruff); crusts (dried discharge on the surface of skin lesions); pustules (raised skin lesions containing pus); superficial loss of skin tissue (known as “erosions”); reddened skin (known as “erythema”); hair loss (known as “alopecia”); circular patterns of hair loss (alopecia) bordered by scales or surface peeling of the skin (pattern is known as an “epidermal collarette”); and thickening of the skin (known as “hyperkeratosis”) of the footpads with furrows or slits (known as “fissures”)
  • Occasional blisters (vesicles) are transient
  • Common involvement—head, ears, and footpads; often becomes generalized
  • Lesions involving the moist tissues of the body (mucous membranes) and areas where the moist tissues of the body contact the skin, such as the lips (areas known as “mucocutaneous junctions”) are uncommon
  • Cats—nipple and nailbed involvement are common
  • Sometimes enlarged lymph nodes (known as “lymphadenopathy”), fluid buildup in the skin (known as “edema”), depression, fever, and lameness (if footpads involved) may be present; however, pets are often in good health
  • Variable pain and itchiness (known as “pruritus”)
  • Secondary bacterial infection is possible

Pemphigus Erythematosus

  • Same signs as for pemphigus foliaceus
  • Lesions usually confined to head, face, and footpads
  • Loss of pigment of the moist tissues (mucous membranes) and skin (known as “mucocutaneous depigmentation”) more common than with other forms of pemphigus; loss of pigment may precede crusting

Pemphigus Vulgaris

  • Pemphigus; loss of pigment may precede crusting
  • Ulcers of the mouth are frequent, and may precede skin lesions
  • Ulcerative lesions; superficial loss of skin tissue (erosions); circular patterns of hair loss (alopecia) bordered by scales or surface peeling of the skin (pattern is called epidermal collarettes), blisters, and crusts (dried discharge on the surface of skin lesions)
  • More severe than pemphigus foliaceus and pemphigus erythematosus
  • Affects moist tissues of the body (mucous membranes), areas where the moist tissues of the body contact the skin, such as the lips (mucocutaneous junctions), and skin; may become generalized
  • Area under the front legs and between the rear legs (known as the “axillae and groin”) often involved
  • Positive Nikolsky sign (new or extended erosive lesion created when lateral pressure is applied to the skin near an existing lesion)
  • Variable itchiness (pruritus) and pain
  • Lack of appetite (known as “anorexia”), depression, and fever
  • Secondary bacterial infections are common

Panepidermal Pustular Pemphigus

  • Pustule (raised skin lesion containing pus) groups become masses that ooze
  • Involvement of the mouth has not been seen
  • No systemic illness

Causes

  • Undetermined—genetics and a possible triggering event (such as a viral infection or medication)

Risk Factors

  • Undetermined

Treatment

Health Care

  • Initial inpatient supportive therapy for severely affected pets
  • Outpatient treatment with initial frequent hospital visits (every 1–3 weeks); taper to every 1–3 months when remission is achieved and the pet is on a maintenance medical regimen
  • Severely affected pets may require antibiotics and hydrotherapy/soaks

Diet

  • Low-fat—to avoid inflammation of the pancreas (known as “pancreatitis”), which can be a side effect of steroids and (possibly) azathioprine therapy

Surgery

  • Surgical biopsy of the skin lesion and the skin surrounding the lesions

Medications

Medications presented in this section are intended to provide general information about possible treatment. The treatment for a particular condition may evolve as medical advances are made; therefore, the medications should not be considered as all inclusive

Pemphigus Foliaceus and Pemphigus Vulgaris

  • Steroids—prednisone or prednisolone
  • Chemotherapeutic drugs and other drugs to decrease the immune response—more than half of pets require medications other than steroids to decrease the immune response; these drugs generally work in conjunction with prednisone, allowing reduction in dose and side effects of the steroid; examples include azathioprine, chlorambucil, cyclophosphamide, cyclosporine, and dapsone
  • Gold-salt treatment or chrysotherapy—gold salts are used to decrease inflammation and the immune response; often used in conjunction with prednisone; such as auranofin

Pemphigus Erythematosus and Panepidermal Pustular Pemphigus

  • Steroids—prednisone or prednisolone administered by mouth
  • Steroids administered by application directly to the skin (known as “topical steroids) may be sufficient in mild cases

Alternative Steroids

  • Use instead of prednisone, if undesirable side effects to prednisone or poor response occur
  • Methylprednisolone—for pets that tolerate prednisone poorly
  • Triamcinolone
  • Steroid pulse therapy—methylprednisolone sodium succinate administered intravenously for 3 consecutive days to induce remission; limited application

Topical Steroids (Administered to the Skin Directly)

  • Hydrocortisone cream
  • More potent topical steroids—0.1% betamethasone, fluocinolone, or 0.1% triamcinonide

Miscellaneous Medications

  • Tetracycline and niacinamide

Follow-Up Care

  • Monitor response to therapy

Monitor for medication side effects—routine bloodwork (complete blood count [CBC] and serum biochemistry), especially pets on high doses of steroids, chemotherapeutic drugs, or gold-salt treatment; check every 1–3 weeks, then every 1–3 months when in remission

Prevention and Avoidance

  • Pet should avoid the sun, because ultraviolet (UV) light may worsen the lesions

Possible Complications

  • Depend on type of pemphigus
  • Secondary infections
  • Side effects of medications may affect quality of life
  • Pemphigus foliaceus and pemphigus vulgaris may be fatal, if untreated (especially pemphigus vulgaris)

Expected Course and Prognosis

  • Treatment with steroids and chemotherapeutic drugs and medications to decrease the immune response is needed
  • Pets may require medication for life
  • Monitoring is necessary
  • Side effects of medications may affect quality of life
  • May be fatal, if untreated (especially pemphigus vulgaris)
  • Secondary infections cause morbidity and possible mortality (especially pemphigus vulgaris)

Pemphigus Erythematosus and Panepidermal Pustular Pemphigus

  • Relatively benign and self-limiting
  • Steroids administered by mouth eventually may be tapered to low maintenance doses; may be stopped in some pets (as directed by your pet’s veterinarian)
  • Skin disorder (known as “dermatosis”) develops, if untreated; generalized (systemic) signs are rare
  • Prognosis fair

Key Points

  • A group of diseases in which the immune system attacks the skin (known as “auto-immune dermatoses”)
  • Pet should avoid the sun, because ultraviolet (UV) light may worsen lesions

Lyme Disease

Lyme Disease – An Overview

  • One of the most common tick-transmitted diseases in the world.
  • Caused by spirochete species of the Borrelia burgdorferi group (such as B. burgdorferi, B. afzelii, B. garinii).
  • Dominant clinical feature (dogs)—recurrent lameness due to inflammation of the joints (known as “arthritis”); sometimes lack of appetite (known as “anorexia”) and depression; may develop kidney and rarely heart or nervous system disease.
  • Reported in people, dogs, horses, and occasionally in cats.
  • Also known as “Lyme borreliosis” or “borreliosis”.
  • Experimentally, young dogs (puppies) appear to be more susceptible to disease than do adult dogs

Genetics

  • Certain dog breeds (such as the Bernese mountain dog) are reported to develop severe kidney failure following infection with Borrelia.

Signs/Observed Changes in the Pet

  • Recurrent lameness due to inflammation of the joints (arthritis).
  • In studies, sudden (acute) form lasts for only 3–4 days; recurs days to weeks later in the same or in other legs (known as “shifting-leg lameness,” characterized by lameness in one leg, then that leg appears to be normal and another leg is involved); one or more joints may be swollen and warm; a pain response is elicited by feeling the joint; responds well to antibiotic treatment.
  • Affected dogs may refuse to walk or stand or may walk stiffly, with an arched back, and be sensitive to touch.
  • Long-term (chronic) inflammation of several joints, in which the bones around the joints are not destroyed (known as “non-erosive polyarthritis”) is found in pets with prolonged infection without adequate treatment; may persist despite antibiotic therapy.
  • Fever, lack of appetite (anorexia) and depression may accompany inflammation of the joints (arthritis).
  • Superficial lymph nodes close to the site of the infecting tick bite may be swollen.
  • Kidneys—reported glomerulonephritis with immune-complex deposition in the glomeruli leading to fatal kidney disease; “glomerulonephritis” is inflammation and accompanying dysfunction of glomeruli (plural of glomerulus) of the kidney; each kidney is composed of thousands of nephrons (the functional units of the kidney, each consisting of the glomerulus [a tuft of blood capillaries—the “blood filter”] and a series of tubes and ducts, through which the filtered fluid flows, as urine is produced); inflammation most commonly is due to the presence of immune complexes in the glomerulus.
  • Kidneys—loss of protein through the kidneys (condition known as “protein-losing nephropathy”) with resulting low levels of albumin (the type of protein lost through the kidneys) in the blood (condition known as “hypoalbuminemia”).
  • Kidney failure (signs include vomiting; diarrhea; lack of appetite [anorexia]; weight loss; increased urination [known as “polyuria”] and increased thirst [known as “polydipsia”]; fluid buildup in the tissues, especially the legs and under the skin [known as “peripheral edema”] or fluid buildup in the abdomen [known as “ascites”]).
  • Heart abnormalities—reported, but rare; include complete heart block.
  • Nervous system complications—rare.

Causes

  • Borrelia burgdorferi—transmitted by slow-feeding, hard-shelled tick species of the genus Ixodes (such as Ixodes scapularis [the deer tick], Ixodes pacificus, Ixodes ricinus, Ixodes persulcatus).
  • Infection—only after a tick (nymph or adult female) carrying Borrelia has been attached to the host for at least 18 hours.

Risk Factors

  • Roaming in tick-infested environment, where Lyme borreliosis is common (known as an “endemic area”)

Treatment for Lyme Disease

  • Outpatient
  • Keep pet warm and dry

Activity

  • Reduced activity advisable until clinical signs improve

Diet

  • No change needed

Surgery

  • Tapping the joint and removing joint fluid (known as “aspiration of synovial fluid”) may be considered for diagnostic purposes

Medications

Medications presented in this section are intended to provide general information about possible treatment. The treatment for a particular condition may evolve as medical advances are made; therefore, the medications should not be considered as all inclusive:

  • Most commonly used antibiotics—doxycycline, amoxicillin, or azithromycin.
  • Doxycycline—preferred in pets that have both Borrelia and Anaplasma phagocytophilum infections at the same time (Anaplasma is another tick-borne agent that causes disease).
  • Antibiotics do not eliminate the infection; consequently, persistent infection with a very low bacterial burden remains; treatment significantly improves clinical signs and disease.
  • Recommended treatment period—4 weeks.
  • Steroids—initially may cause signs to improve; may cover up or mask effects of antibiotics for diagnostic purposes; may increase clinical signs later by decreasing the ability of the pet to develop a normal immune response (known as “immunosuppression”).
  • Nonsteroidal pain medications—use judiciously to avoid covering up or masking signs; use only as directed by your pet’s veterinarian.

Follow-Up Care

Patient Monitoring

  • Improvement in sudden (acute) inflammation of the joints caused by Borrelia (known as “Lyme arthritis”) should be seen within 2–5 days of antibiotic treatment.
  • If no improvement within 2–5 days or is signs worsen, consider a different diagnosis.

Preventions and Avoidance

  • Mechanical removal of ticks—groom pets daily; discuss appropriate technique for removing ticks from your pet with the veterinarian.
  • Prevention of tick attachment—products to kill ticks (known as “acaricides”) and tick repellents are available commercially as spot-on topical products, sprays or collars; any such product should be used only according to label directions (do not use permethrin on cats).
  • Vaccines—are available commercially for dogs; talk to your pet’s veterinarian about the vaccine and vaccination protocols.
  • Tick population control in the environment—restricted to small areas; limited success by reducing deer and/or rodent population.

Possible Complications

  • Fatal kidney failure
  • Heart block
  • Central nervous system disorders

Expected Course and Prognosis

  • Recovery from sudden (acute) lameness expected 2–5 days after initiation of antibiotic treatment.
  • Disease may be recurrent with intervals of weeks to months; responds again to antibiotic treatment.

Key Points

  • Treatment of Lyme disease requires regular administration of antibiotics as prescribed by your pet’s veterinarian.
  • Prevent tick attachment—products to kill ticks (acaricides) and tick repellents are available commercially; any such product should be used only according to label directions (do not use permethrin on cats).
  • Diagnosis of Lyme disease (Lyme borreliosis) in a pet increases the risk to people living in the same area, as the people may be infected with Borreliaif they come into contact with ticks in the environment; they too should prevent tick attachment to themselves and should inform their personal physician of the pet’s diagnosis if they become ill.

Canine Leptospirosis

Leptospirosis – An Overview

  • “Leptospirosis” is caused by disease-causing members of the bacterial genus Leptospira.
  • Sudden (acute) and long-term (chronic) diseases of dogs (mainly inflammation of the kidney [known as “nephritis”] and inflammation of the liver [known as “hepatitis”]) and other animals, including cats, although rarely.
  • Dogs—serovars causing disease vary by geographic region, recent serovars of concern in the United States include Leptospira grippotyphosa,Leptospira autumnalis, and Leptospira pomona; “serovars” are subdivisions of a species that are different from other strains.
  • Dogs—ideally vaccines should include representative serovars found in the geographic region where the dog lives.
  • Young dogs—more likely to exhibit severe disease.
  • Old dogs with adequate protection from vaccinations—seldom exhibit clinical disease, unless exposed to a serovar not in the vaccine.

Signs/Observed Changes in the Pet

  • Vary with age and immune status of the pet, environmental factors that affect Leptospira survival, and disease-causing nature of the infecting serovar
  • May have no clinical signs.

Very Sudden (Peracute) Disease to Disease with Signs over a Moderate Amount of Time (Known as “Subacute Disease”)

  • Fever
  • Sore muscles
  • Stiffness
  • Shivering
  • Weakness
  • Lack of appetite (known as “anorexia”)
  • Depression
  • Vomiting
  • Rapid dehydration
  • Diarrhea—with or without blood
  • Yellowish discoloration to the gums and other tissues of the body (known as “jaundice” or “icterus”)
  • Spontaneous cough
  • Difficulty breathing (known as “dyspnea”)
  • Increased thirst (known as “polydipsia”) and increased urination (known as “polyuria”) progressing to production of no urine (known as “anuria”)
  • Bloody vaginal discharge
  • Death—without clinical signs

Very Sudden (Peracute) to Sudden (Acute) Disease

  • Rapid breathing (known as “tachypnea”)
  • Rapid, irregular pulse
  • Poor blood flow in the capillaries (smallest blood vessels; condition known as “poor capillary perfusion”)
  • Vomiting blood (known as “hematemesis”)
  • Passage of blood in the bowel movement or stool (known as “hematochezia”)
  • Black tarry stools, due to the presence of digested blood (known as “melena”)
  • Bleeding in the nose and nasal passages (known as “epistaxis” or a “nosebleed”)
  • Widespread small, pinpoint areas of bleeding (known as “petechia”); bruises or purplish patches under the skin, due to bleeding (known as “ecchymoses”)
  • Reluctance to move, overly sensitive to pain or touch (known as “hyperesthesia”) along the spine, stiff gait
  • Inflammation of the moist tissues of the eyes (known as “conjunctivitis”)
  • Inflammation of the nose (known as “rhinitis”)
  • Blood in the urine (known as “hematuria”)
  • Mildly enlarged lymph nodes (known as “lymphadenopathy”)

Long-Term (Chronic) Disease

  • May have no apparent illness
  • Fever of unknown origin
  • Increased thirst (polydipsia) and increased urination (polyuria)—long-term (chronic) kidney failure

Causes

  • Dogs—Leptospira canicola, Leptospira icterohaemorrhagiae, Leptospira pomona, Leptospira grippotyphosa, Leptospira copenhagenii, Leptospira australis, Leptospira autumnalis, Leptospira ballum, and Leptospira bataviae
  • Cats—Leptospira canicola, Leptospira grippotyphosa, Leptospira pomona, and Leptospira bataviae

Risk Factors

Transmission

  • Direct—host-to-host contact via infected urine, postabortion discharge, infected fetus/ discharge, and sexual contact (semen).
  • Indirect—exposure (via urine) to a contaminated environment (such as vegetation, soil, food, water, bedding) under conditions in whichLeptospira can survive.
  • Disease agent—Leptospira serovar, each with its own disease-causing factors, infectious dose, and route of exposure.
  • Leptospirosis in companion animals often is the result of spillover from disease occurring in wildlife (many different types of mammals) in the area; wildlife may act as “hosts” and maintain the different serovars.

Host Factors

  • Vaccine—protection is serovar-specific; prevents clinical disease as a result of specific serovar; may not prevent kidney colonization of Leptospiraand subsequent shedding of the bacteria in the urine; serovars not included in the vaccine may infect and cause disease in vaccinated pet.
  • Outdoor pets or hunting dogs—exposure of moist tissues of the body (mucous membranes) to water; exposure of abraded or water-softened skin increases risk of infection.

Environmental Factors

  • Warm and moist environment; wet season (high rainfall areas) of temperate regions; low-lying areas (marshy, muddy, irrigated); warm humid climates of tropical and subtropical regions.
  • Environmental temperature range—7–10 dg C (44.6–50 dg F) to 34–36 dg C (93–96 dg F).
  • Water—organism survives better in stagnant than in flowing water; neutral or slightly alkaline pH.
  • Organism survives 180 days in wet soil and longer in standing water.
  • Dense animal population—kennels and urban settings; increases chances of urine exposure.
  • Exposure to rodents and other wildlife.

Treatment

Health Care

  • Sudden (acute) severe disease—inpatient; extent of supportive therapy depends on severity of disease; kidney failure requires closely monitored, medically induced increased production of urine (known as “diuresis”).
  • Dehydration and shock—intravenous fluids (such as lactated Ringer’s solution).
  • Severe bleeding—blood transfusion may be needed in association with treatment for the blood-clotting disorder, known as “disseminated intravascular coagulopathy” or DIC.
  • Production of only small amounts of urine (known as “oliguria”) or no urine (known as “anuria”)—initially rehydrate; then give medications to increase production of urine (known as “diuretics”); peritoneal dialysis (a type of dialysis in which fluids are put into the abdomen and the lining of the abdomen [known as the “peritoneum”] acts as a filter to remove waste products from the blood; after a certain amount of time, the fluids and waste products are removed from the abdomen) may be necessary.

Activity

  • Suddenly (acutely) ill pets and pets with the presence of bacteria in their blood (known as “bacteremia”) or generalized disease caused by the spread of bacteria in the blood (known as “septicemia” or “blood poisoning”)—restricted activity; cage rest; monitoring; and warmth.

Diet

  • Severely ill pets—often have lack of appetite (anorexia); provide nutrition through intravenous feeding for prolonged anorexia.

Medications

Medications presented in this section are intended to provide general information about possible treatment. The treatment for a particular condition may evolve as medical advances are made; therefore, the medications should not be considered as all inclusive:

  • Procaine penicillin G—an antibiotic; administer until kidney function returns to normal
  • Dihydrostreptomycin—an antibiotic; administer for 2 weeks to eliminate organism from kidney tissues; try streptomycin if no kidney failure (drug not available everywhere)
  • Doxycycline—an antibiotic; administer for 2 weeks; use alone to clear Leptospira from the blood and urine
  • Ampicillin or amoxicillin—antibiotics; may be used instead of penicillin; administer for 2 weeks
  • Erythromycin—an antibiotic

Follow-Up Care

Patient Monitoring

  • Monitor bloodwork and urinalysis for kidney function and monitor bloodwork for liver function and electrolytes.
  • Monitor bloodwork (blood urea nitrogen [BUN] and serum creatinine) and urine specific gravity in dogs with kidney failure for indication of prognosis.

Preventions and Avoidance

  • Vaccine (dogs)—whole-cell bacterin vaccines contain the serovars Leptospira canicola and Leptospira icterohaemorrhagiae (some also now includeLeptospira pomona and Leptospira grippotyphosa); promotes immunity to these serovars and protection from overt clinical disease; serovar specific; does not promote protection against other serovars present in nature; may not prevent colonization of the kidneys of Leptospira, resulting in a long-term (chronic) carrier state; a “carrier state” is one in which the animal has no signs of disease, but harbors Leptospira and can transmit it to other animals.
  • Newer subunit vaccine contains the serovars Leptospira pomona, Leptospira icterohaemorrhagiae, Leptospira grippotyphosa, and Leptospira canicola; claims are made that the vaccine provides protection from clinical disease and prevents kidney colonization of Leptospira.
  • Vaccines—vaccinate dogs per current label recommendations; bacteria-induced immunity lasts only 6–8 months and is serovar specific (no cross-protection outside of the serogroup); revaccination at least yearly; vaccinate dogs at risk (such as dogs that hunt, show dogs, and dogs with access to water/ponds) every 4–6 months, especially in areas where Leptospira is found (known as “endemic areas”); the veterinarian will assess the risk of exposure and will recommend a vaccination protocol for your pet.
  • Kennels—strict sanitation to avoid contact with infected urine; control rodents; monitor and remove carrier dogs until treated; isolate affected dogs during treatment; “carrier dogs” are infected, but have no signs of disease—they harbor Leptospira and can transmit it to other animals.
  • Activity—limit access to marshy/muddy areas, ponds, low-lying areas with stagnant surface water, heavily irrigated pastures, and access to wildlife.

Possible Complications

  • Blood-clotting disorder (disseminated intravascular coagulopathy)
  • Liver and/or kidney dysfunction may be permanent
  • Inflammation of the iris and other areas in the front part of the eye (known as “uveitis”)
  • Abortion

Expected Course and Prognosis

  • Most infections are subclinical or long-term (chronic); a “subclinical infection” is one in which the animal is infected, but has no signs of disease.
  • Prognosis guarded for sudden (acute) severe disease.

Key Points

  • Leptospirosis has zoonotic potential from contaminated urine of affected dogs and their environment; “zoonotic diseases” can be passed from animals to people.

Canine Distemper

Canine Distemper – An Overview

  • Distemper is a contagious disease that appears suddenly (acute) or over a moderate amount of time (known as “subacute”), characterized by fever and a variety of signs involving the eyes, central nervous system, and respiratory, urogenital, and gastrointestinal tracts; often a fatal disease
  • Caused by the canine distemper virus
  • Affects many different species of the order Carnivora (dogs, fox, wolves, hyenas, weasels, ferrets, mink, raccoons, skunks and civets); mortality rate varies greatly among species
  • Young dogs, especially unvaccinated, dogs are more susceptible to infection than are adults

Signs of Distemper/Observed Changes in the Dog

  • Fever—first fever occurs 3–6 days after infection, may go undetected; second fever several days later (and intermittent thereafter), usually associated with discharge from the nose and eyes, depression, and lack of appetite (known as “anorexia”)
  • Gastrointestinal and/or respiratory signs follow, often enhanced by secondary bacterial infection.
  • Central nervous system signs—occur in many infected dogs; often, but not always, after generalized (systemic) disease; depends on the virus strain; either sudden (acute) gray or white matter disease (“gray matter” is the nerve tissue of the brain and spinal cord that contains the nerve cell bodies; “white matter” is the part of the brain and spinal cord that contains nerve fibers covered with myelin, a fatty covering that increases conduction of nerve impulses).
  • Gray-matter disease—affects the brain and spinal cord; may cause inflammation of the meninges (the membranes covering the brain and spinal cord; inflammation of the meninges known as “meningitis”), seizures, stupor, hysteria, and wobbly, uncoordinated or “drunken” appearing gait or movement (known as “ataxia”); dogs may die in 2–3 weeks; some dogs recover (associated with prompt immune response), while others progress to develop white-matter disease; “gray matter” is the nerve tissue of the brain and spinal cord that contains the nerve cell bodies; “white matter” is the part of the brain and spinal cord that contains nerve fibers covered with myelin, a fatty covering that increases conduction of nerve impulses.
  • White-matter disease—variable signs of disease involving multiple locations of the central nervous system; commonly see weakness and wobbly, uncoordinated or “drunken” appearing gait or movement (ataxia) secondary to spinal cord disease; occasionally may see twitching or contraction of a group of muscles (known as “myoclonus”); some dogs die 4–5 weeks after initial infection; some dogs may recover with minimal central nervous system injury.
  • Inflammation of the optic nerve (the nerve that runs from the back of the eye to the brain; condition known as “optic neuritis”) and lesions in the back of the eye (known as the “retina”) may occur.
  • Hardening of the footpads (known as “hyperkeratosis”) and nose—some virus strains; but relatively uncommon.
  • Abnormal development of the enamel layer of the teeth (known as “enamel hypoplasia”) after neonatal infection is common.

Risk Factors

  • Contact of animals that have not been vaccinated or have not responded to vaccinations with animals that are infected with canine distemper virus (dogs or wild carnivores)

Treatment for Distemper

  • Inpatient treatment in isolation, to prevent infection of other dogs
  • Supportive treatment, including intravenous fluids—cases with lack of appetite (anorexia) and diarrhea
  • Once fever and secondary bacterial infections are controlled, pets usually begin to eat again
  • Carefully clean away discharges from the nose and eyes

Activity

  • Limited

Diet

  • Depends on the extent of gastrointestinal involvement

Medications for Distemper

Medications presented in this section are intended to provide general information about possible treatment. The treatment for a particular condition may evolve as medical advances are made; therefore, the medications should not be considered as all inclusive:

  • Antiviral drugs—none known to be effective in treating canine distemper viral infections.
  • Antibiotics—to reduce secondary bacterial infection, because canine distemper virus decreases the ability of the dog to develop a normal immune response (known as “immunosuppression”).
  • Medication to control seizures (known as “anticonvulsant therapy”)—phenobarbital, potassium bromide.

Follow-Up Care

Patient Monitoring

  • Monitor for signs of pneumonia or dehydration from diarrhea in the sudden (acute) phase of the disease
  • Monitor for central nervous system signs, because seizures often follow

Preventions and Avoidance

  • Routine vaccination against canine distemper virus is key to prevention and avoidance; series of vaccinations administered initially followed by periodic booster vaccinations, as directed by your pet’s veterinarian
  • Avoid infection of puppies by isolation to prevent infection from wildlife (such as raccoons, fox, skunks) or from canine distemper virus-infected dogs

Possible Complications

  • Secondary bacterial infections, frequently involve the respiratory and gastrointestinal systems
  • Possibility of occurrence of central nervous system signs for 2–3 months after discharge from the eyes and nose has subsided
  • Seizures
  • Death

Expected Course and Prognosis

  • Depending on the strain of virus and the individual host response—dog may be infected, but have no signs of disease (known as a “subclinical infection”) or have signs of disease involving various areas of the body; the infection may be fatal or non-fatal.
  • Mild central nervous system signs—pet may recover; twitching or contraction of a group of muscles (myoclonus) may continue for several months or indefinitely.
  • Death—2 weeks–3 months after infection; mortality rate approximately 50%.
  • Euthanasia—owner may elect euthanasia, if or when nervous system signs develop; indicated when uncontrollable seizures occur.
  • Fully recovered dogs are not carriers, as they do not shed canine distemper virus.

Key Points

  • Mortality rate is about 50%
  • Dogs that appear to recover from early signs (such as discharge from the eyes and nose) may later develop fatal central nervous system signs
  • Fully recovered dogs are not carriers, as they do not shed canine distemper virus
  • Routine vaccination against canine distemper virus is key to prevention and avoidance; series of vaccinations administered initially followed by periodic booster vaccinations, as directed by your pet’s veterinarian