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Obesity image



AUTHOR: CHERYL A. HOLLOWAY



EDITOR: KATHYRN E. MICHEL



BASIC INFORMATION image



DEFINITION


A chronic relapsing disorder associated with excessive accumulation of body fat, resulting in an increase in body weight beyond the limitation of skeletal and physical requirements. Animals with an accumulation of body fat of more than 20% of their moderate body weight for that species and breed are considered obese.



EPIDEMIOLOGY


SPECIES, AGE, SEX: Any species, both sexes, any age (3 months of age until the end of life)


GENETICS & BREED PREDISPOSITION: Between 30% and 70% of the risk for obesity in dogs is attributable to breed; breeds that are reportedly at increased risk include Labrador retrievers, cairn terriers, cocker spaniels, dachshunds, Shetland sheepdogs, basset hounds, beagles, and cavalier King Charles spaniels.


RISK FACTORS: Genetic predisposition, neutering, multiple pet households, indoor housing, overfeeding, sedentary lifestyle, metabolic disorders


ASSOCIATED CONDITIONS & DISORDERS: Some obese animals may be at increased risk for diabetes, joint problems, muscle tears, hip dysplasia, tracheal collapse, skin and heart disorders, complications during anesthesia and surgery, and reduced life expectancy.



CLINICAL PRESENTATION



HISTORY, CHIEF COMPLAINT



• The most common history collected is of a pet that has gradually been gaining weight over a period of years, and the owner has been unaware of the increase.

• Another common history is of acute weight gain over a period of a few months after the animal was switched to a different diet or started on a new medication; the animal could also have gone through a stressful period or could have developed a metabolic disorder.

PHYSICAL EXAM FINDINGS: A body condition score (BCS) of 5/5 is characterized by the following:


• Ribs and other skeletal prominences are difficult to feel under thick fat cover.

• Fat hangs from the abdomen.

• The tail base is thickened.

• The animal does not have an apparent waist when it is viewed from the side or above.

• The animal is markedly broadened when it is viewed from above.


DIAGNOSIS image



DIAGNOSTIC OVERVIEW


Diagnosis should include identification of conditions that can predispose to or be mistaken for weight gain.



DIFFERENTIAL DIAGNOSIS



• Hypothalamic disorders, hypothyroidism, hyperadrenocorticism (Cushing’s disease), insulinoma, chronic corticosteroid use, and chronic use of some epileptic drugs (phenobarbital) can cause obesity.

• Tumors, edema, and ascites may be confused for obesity.


INITIAL DATABASE



• CBC, serum chemistry panel, urinalysis: clinicians should assess for metabolic diseases that could affect the animal’s weight, such as diabetes mellitus, hyperlipidemia, or hypothyroidism.

• Thyroid function studies (TSH, free T4) are used for evaluating the role of hypothyroidism as a cause of obesity (prevalence of hypothyroidism is less than 1% in dogs; rare in cats).


ADVANCED OR CONFIRMATORY TESTING


Radiographic imaging studies are not specific in the diagnosis of obesity but may provide evidence of the extent of fat accumulation in the periphery and in the abdominal and thoracic compartments.



TREATMENT image



THERAPEUTIC OVERVIEW


The therapeutic goal is to return the animal to a healthy status and resolve complaints. A 10% decrease in body weight reduces the risk of obesity-related diseases in humans and a 1%-2% weight loss per week is a reasonable initial goal for animals.



ACUTE GENERAL TREATMENT


Treatment is aimed at weight reduction and risk-factor modification.


• Clinicians should take an accurate diet history; it provides essential information about the food intake of the pet as well as information about the food itself and the related bond between a pet and owner. An accurate diet history can take 30-60 minutes to collect.

• The clinician should calculate caloric intake from all sources. Caloric content of human foods is available at the U.S. Department of Agriculture’s Web site (http://nal.usda.gov).

• Clinicians should determine weight reduction goal and calories. An initial goal of a 10% weight loss usually is reasonable and can be attained by prescribing an energy deficit of 10 kcal per kilogram of body weight per day through a combination of decreased intake (about 8 kcal/kg/d) and increased activity-induced expenditure (about 2 kcal/kg/d).

• The clinician should make sure the animal completes the dietary plan.
○ The clinician should create the plan with the owner to increase compliance for completion of the plan.

○ Once the owner and clinician agree to a plan, a schedule of follow-ups must be established to provide coaching and monitor progress.


NUTRITION/DIET



• Therapeutic and over-the-counter (OTC) diets are available that have been formulated to have a low-caloric density and may aid in restricting calories.

• Cases that require a large amount of weight loss may require a therapeutic diet versus an OTC to attain the protein/calorie ratio needed for success.

• In all cases, it is crucial to determine the protein, mineral, and vitamin intake of the diet to ensure that changes will not result in nutrient depletion.


BEHAVIOR/EXERCISE



• The owner should encourage the animal to be active 30 minutes every day if the animal can tolerate this comfortably. This can be achieved with gradual increased increments of 10 minutes of activity per day. The clinician and owner can adjust the time and intensity of the activity according to weight loss and the animal’s enjoyment.

• There are many behavioral solutions that may be presented to the owner and should be a part of every recommendation. See Suggested Reading below.


DRUG INTERACTIONS


Glucocorticoids, phenobarbital



POSSIBLE COMPLICATIONS


Nutrient depletion, increased anesthetic risk, slower wound healing, hepatic lipidosis (cats)



RECOMMENDED MONITORING


The clinician’s first contact with the client occurs 1 week after initial recommendations are made, followed by repeat “check-ins” at 6 weeks, 3 months, 6 months, and 1 year. These appointments permit the clinician to monitor the animal’s BCS and weight progress, make adjustments as needed, and continue to support and motivate the client.



PROGNOSIS AND OUTCOME image


Very good, depending on compliance of owner



PEARLS & CONSIDERATIONS image



COMMENTS



• According to veterinary experience, the critical key to successful obesity therapy is ongoing follow-up and support of the animal and owner’s progress.

• Many clinics are opting to create a “clinic within a clinic“ that is run by the staff and entails a weight management program similar to Weight Watchers for their clients’ pets.


PREVENTION


Starts with puppies/kittens; clinicians should recommend adjusting feeding after spaying/neutering if needed.



TECHNICIAN TIPS



• Assign a “weight loss consultant” to each client. Each time the client calls or comes in, there is consistency in care.

• Provide measuring cups with a line or marker drawn on the cup for desired amount to help with compliance.

• Create a contest to spread the enthusiasm to keep the clients interested.


CLIENT EDUCATION



• Clients should be able to assess and feed according to their pet’s appropriate BCS.

• Every client should know how many kilocalories a pet food cup or can contains.


SUGGESTED READING



Buffington CAT, Holloway C, Abood S. Manual of veterinary dietetics. St Louis: WB Saunders, 2004;109-116.


Nestle Purina Weight Management Program, Nestle Purina Veterinary Resource Center at 1-800-222 VETS (8387).


The Ohio State University Veterinary Hospital Nutrition Support Service. www.nssvet.org.



Obsessive-Compulsive Disorder (OCD)



AUTHOR: SONYA. JUARBE-DIAZ



EDITOR: KAREN. OVERALL



BASIC INFORMATION image



DEFINITION


Mood/behavioral disorders characterized by repetitive, invariant, patterned behaviors which are exaggerated in intensity, frequency, and duration given the inciting stimuli (i.e., expressed out of context). The behavior interferes with health and well-being.



SYNONYMS


Compulsive disorders, stereotypies; include star gazing, air or fly snapping, spinning/tail chasing, and self-mutilation



EPIDEMIOLOGY


SPECIES, AGE, SEX: Dogs and cats of any age


GENETICS & BREED PREDISPOSITION: Dogs: Genetic predisposition is suspected. Anecdotally, certain syndromes are more commonly associated with some breeds:


• Acral lick dermatitis: large and giant dog breeds

• Air/fly snapping, checking (hind quarter area), star gazing: miniature schnauzer

• Flank sucking: Doberman pinscher

• Spinning/tail chasing: German shepherd dog, bull terrier, Parson Russell and Jack Russell terrier

Cats: fabric chewing or ingestion is anecdotally associated with so-called Asian breeds (e.g., Siamese, Tonkanese, Burmese).


RISK FACTORS: Stressful or traumatic event. Lack of a daily routine.


CONTAGION & ZOONOSIS: Characteristically, OCD is not induced in conspecifics (e.g., housemates) by affected individuals.


ASSOCIATED CONDITIONS & DISORDERS: The patient may have multiple diagnoses of other impulsive or anxiety-based disorders.



CLINICAL PRESENTATION



HISTORY, CHIEF COMPLAINT



• Repetitive behavior that is out of context (may have exacerbated over time or begun suddenly).

• Inciting triggers may be identifiable, or the behavior may occur spontaneously.

• Earlier in the course, the owners may have been able to stop the behavior, but that may not be the case at the time of presentation, and the pet may not stop until exhausted.

• The pet may hide (to perform the behavior) or become aggressive when the owners try to stop the behavior or may begin avoiding the owners.

• Distress vocalizations (whining, crying, yowling, or growling) may occur before, during, or after performance of the compulsive behavior.

• When owners do not identify the behavior as abnormal, the chief complaint may refer to damage to self (alopecia, granuloma, weight loss, change in voice, recurring gastrointestinal obstruction due to pica), damage to the home, or altered social interactions.

• Chief complaint may suggest partial seizures or dysphoria.

• With chronicity, some owners may not consider the behavior problematic or abnormal.


PHYSICAL EXAM FINDINGS



• Often unremarkable

• Skin lesions possible with overgrooming/self-mutilation

• Weight loss if near-constant


ETIOLOGY AND PATHOPHYSIOLOGY



• A genetic contribution is suspected.

• In humans, the current hypothesis of OCD involves dysfunction in a neuronal circuit traversing from the orbital frontal cortex to the cingulate gyrus, caudate nucleus and putamen (the striatum), the globus pallidus, thalamus, and back to the frontal cortex.

• Dysfunction involving glutamate and/or gamma-aminobutyric acid (GABA) is a new focus for research.


DIAGNOSIS image



DIAGNOSTIC OVERVIEW


History is the cornerstone of diagnosis: occurrence of repetitive, invariant behaviors that are spontaneous or triggered are difficult or impossible to interrupt and interfere with normal maintenance and social behaviors.



DIFFERENTIAL DIAGNOSIS



• Attention-seeking (behavior occurs only when the owner is present).

• Separation anxiety (behavior occurs only when the owners are absent).

• Cognitive dysfunction (middle aged/geriatric animals that pace or stare)

• Hyperthyroidism (primarily cats)

• Neuropathic pain disorders (e.g., feline hyperesthesia, neck and shoulder hyperesthesia in syringomyelia in the Cavalier King Charles spaniel)

• Degenerative joint disease, anal sac disease, cystitis (excessive licking or hindquarter checking)

• Circling, spinning, and air snapping patients should be evaluated for peripheral or central vestibular disease, psychomotor seizures, or other central nervous system lesions.


INITIAL DATABASE



• CBC, urinalysis, and serum chemistry profile: usually within normal limits (assess for systemic disorders; prior to initiation of medications).

• Dermatologic diagnostic tests (see p. 1248) if skin lesions are a feature.


TREATMENT image



TREATMENT OVERVIEW



• All cases of OCD warrant intervention, which is individualized and based on frequency and severity of clinical signs.

• Treatment usually is a combination of behavioral and environmental modification and psychotropic medication.

• The goal is to minimize—and if possible eliminate—bouts of compulsive behavior and the concomitant anxious states that accompany them.


ACUTE AND CHRONIC TREATMENT



• Owner: identify and eliminate trigger events/situations.

• No punishment should ever be used, since it can heighten anxiety and worsen, not improve, the problem.

• If possible, the pet can be redirected to an alternative and incompatible behavior—such as licking food from a toy instead of licking the skin—if the redirection does not make the pet more anxious.

• The pet should be calmly rewarded for any spontaneous calm behavior.

• Keeping a structured daily routine helps decrease anxiety.

• The most successful medications used in the treatment of OCD in people include a number of selective serotonin reuptake inhibitors (SSRIs) and clornipramine, a tricyclic antidepressant (TCA). In dogs and cats, the most commonly used are:
○ Clornipramine (Clomicalm): dogs, 2-3 mg/kg PO q 12 h for a minimum of 16 weeks; cats, 0.5 mg/kg PO q 24 h for a minimum of 16 weeks

○ SSRI drugs (fluoxetine [Prozac, Reconcile]): dogs, 1 mg/kg PO q 24 h for 16 weeks minimum; cats, 0.5 mg/kg PO q 24 h for 16 weeks minimum. Paroxetine (Paxil); dogs, 1 mg/kg PO q 24 h for 16 weeks minimum; cats, 0.25-0.5 mg/kg PO q 24 h for 16 weeks minimum. Sertraline (Zoloft); dogs, 1 mg/kg PO q 24 h for 16 weeks minimum; cats, 0.5 mg/kg PO q 24 h for 16 weeks minimum.

• Very distressed pets may need concomitant use of benzodiazepines (anxiolytic, faster onset of action).
○ Diazepam or oxazepam (oxazepam for cats, obese patients, liver disease), 0.2-0.4 mg/kg PO q 12-24 h; or alprazolam, 0.01-0.025 mg/kg PO q 8-24 h; or clonazepam (dogs), 0.01-0.05 mg/kg PO q 12-24 h for the first 2-3 weeks of treatment. Adjust to ideal dose based on response and lack of adverse (e.g., hepatic) effects. May also be used preemptively when stress or change in routine is anticipated.

• N-methyl-D-aspartate (NMDA) antagonists hold promise as a potential treatment of OCD as single pharmacologic agents or as an adjunct to SSRIs.

• Typically, TCA or SSRI therapy is necessary for longer periods of time than other anxiety-based disorders (months to years, depending upon severity and how long the disorder has been ongoing). Lifelong medication use is not unusual in severe cases.


BEHAVIOR/EXERCISE


Some patients benefit from activities that serve as a controlled outlet for the compulsive behavior (e.g., retrieving, herding, agility, flyball), although they can be too arousing for others; tailor treatment to the individual.



DRUG INTERACTIONS



• TCAs and SSRIs should not be given with monoamine oxidase inhibitors (MAOIs), which are found in many flea and tick collars and dips and in some medications to treat cognitive dysfunction.

• TCAs: use with caution if cardiac arrhythmias, liver or thyroid disorders.

• Use of SSRIs with tramadol, which has a weak serotonin reuptake inhibiting effect, may increase the risk of serotonin syndrome (see p. 1427). Coadministration of fluoxetine, paroxetine, and possibly sertraline may result in decreased plasma concentrations of tramadol’s active demethylated metabolite via inhibition of hepatic P450 enzymes. If their use together is necessary, starting both at reduced doses, titrating each to effect and keeping watch for signs of serotonin syndrome reduces but does not eliminate the risk; the client should be informed and should learn to monitor heart rate for profound increases as one way of assaying an early sign of serotonin syndrome.


POSSIBLE COMPLICATIONS


Paroxetine: avoid in renal disease; anecdotal reports of constipation in cats.



RECOMMENDED MONITORING



• Cats receiving paroxetine: monitor stool consistency (reports of diarrhea)

• Animals that take BZDs require a physical exam every 6 months in most U.S. states. The potential for human abuse of the drugs warrants vigilance regarding refill requests.

• Performing a yearly physical exam, CBC, serum chemistry profile, urinalysis, and thyroid screen (twice yearly in senior and geriatric pets) should be a minimum for animals taking other psychotropic medications.


PROGNOSIS AND OUTCOME image



• Prognosis is highly variable from guarded to very good for management of the clinical signs of OCD, and is contingent upon a number of variables:
○ Time at which treatment is first instituted (the earlier, the better the prognosis)

○ Owner compliance with all (and not just portions) of the treatment recommendations

○ Frequent communication and follow-up between the owner and the clinician, as the treatment plan will need adjustment based on the pet’s response and changing life circumstances

○ Untreated OCD seldom improves and very commonly worsens over time.


PEARLS & CONSIDERATIONS image



COMMENTS


Repetitive behaviors are commonly thought of by clients as entertaining or as “quirks” in their pet’s personality and seldom understood to be potential early markers of this disease. Many such pets go through their lives suffering greatly while their owners are ignorant of the distress associated with OCDs. Early intervention is a significant factor in the successful treatment of OCDs, but owners seldom talk about behavior during a veterinary visit unless prompted. It is extremely important to incorporate questions about behavior into all wellness and sick exams. “Any behavior that is new, different or peculiar since the last veterinary exam?” is sufficient to open the door and encourage owners to talk about their pet’s behavior.



PREVENTION



• Consider temperament when selecting breeding stock.

• At the onset of any repetitive behaviors, the owners should be instructed to watch for a worsening of signs or any specific triggers that may initiate the behavior. Keeping a diary, written or preferably on video media, is helpful to track onset and progression.


TECHNICIAN TIPS


OCD may create a home situation that is very different and disrupted compared to an owner’s expectations. Support from the entire veterinary staff for identifying and treating this disorder correctly can be rewarding for all and lifesaving for the pet.



CLIENT EDUCATION


Treatment of OCD is never static, often lifelong, and subject to adjustment based on changing conditions. Relapses may occur with treatment discontinuation. Planning in advance of added stressors can help minimize their effect on an OCD patient.



SUGGESTED READING



Overall KL, Dunham AE. Clinical features and outcome in dogs and cats with obsessive-compulsive disorder: 126 cases (1989-2000). J Am Vet Med Assoc. 2002;221:1445-1452.



Ocular Discharge



AUTHOR: CHANTALE L. PINARD



EDITOR: CHERYL L. CULLEN



BASIC INFORMATION image



DEFINITION



• Abnormal secretions on or around the eye(s)

• These secretions can be watery (serous), contain mucus (mucoid), or contain white blood cells, mucus, and bacterial/fungal agents (mucopurulent).

• An abnormal overflow of tears down the face is termed epiphora.


EPIDEMIOLOGY


SPECIES, AGE, SEX: Dogs and cats; variable age of onset depending on cause


GENETICS & BREED PREDISPOSITION: Depends on cause; examples:


• Brachycephalic breeds with medial entropion (see p. 348)

• Breeds predisposed to distichia, ectopic cilia, and trichiasis (see p. 319)

• Breeds predisposed to congenital atresia, ectopia, and/or imperforated lacrimal puncta

• Breeds predisposed to entropion and/or ectropion (see p. 348)

• Dolichocephalic breeds of dogs with narrow skull conformation and deep medial canthal areas (i.e., medial canthal pocket syndrome)

RISK FACTORS: Outdoor animals prone to infectious causes of conjunctivitis (see pp. 237 and 239) and ocular trauma (see p. 249)


CONTAGION & ZOONOSIS: Certain infectious causes of conjunctivitis are contagious (e.g., feline herpesvirus type-1 [FHV-1]) and/or zoonotic (e.g., Chlamydophila spp.).



CLINICAL PRESENTATION



HISTORY, CHIEF COMPLAINT



• Clear, white, to grey mucoid or green-yellow secretions on the eye(s) or eyelids

• Sudden, progressive, or persistent in nature

PHYSICAL EXAM FINDINGS: Unilateral or bilateral serous, mucoid, or mucopurulent ocular secretions with one or more of the following:


• Blepharitis: inflammation of the eyelids (see p. 966)

• Conjunctivitis (see pp. 237 and 239)

• Corneal ulceration (see p. 250)

• Keratoconjunctivitis sicca (KCS; see p. 628)

• Qualitative tear film abnormality (e.g., mucin and/or lipid deficiency; see p. 1076)

• Entropion and/or ectropion

• Distichiasis/ectopic cilia/trichiasis (see p. 319)

• Anterior uveitis (see p. 1151)

• Glaucoma (see p. 448)

• Ocular size abnormalities (see p. 778)

• Orbital disease (see p. 790)

• Congenital anomalies or infection of nasolacrimal system (e.g., dacryocystitis; see online chapter: Dacryocystitis)


ETIOLOGY AND PATHOPHYSIOLOGY



• Serous discharge:
○ Corneal mechanical irritation:
▪ Distichiasis/ectopic cilia/trichiasis (see p. 319)

▪ Entropion (see p. 348)

▪ Eyelid agenesis (partial more common than complete): more common in cats

▪ Eyelid neoplasia

○ Blockage of nasolacrimal system, congenital:
▪ Imperforate lacrimal punctum (dorsal and/or ventral lacrimal puncta/punctum not open; common)

▪ Micropunctum (small ventral lacrimal punctum; common)

▪ Nasolacrimal aplasia (lack of opening into nasal cavity; rare)

▪ Obstruction of nasolacrimal duct in dogs by dacryops (cysts originating from lacrimal tissue) or nasal cyst (rare)

○ Blockage of nasolacrimal system, acquired:
▪ Dacryocystitis (inflammation of the nasolacrimal system; see online chapter: Dacryocystitis)

▪ Neoplasia (primary, rare; secondary, more common; e.g., nasal; maxillary sinus)

▪ Foreign body

▪ Trauma to medial canthus/eyelid, involving lacrimal punctum/puncta and/or canaliculus/canaliculi

○ Ocular pain:
▪ Conjunctivitis (see pp. 237, 239)

▪ Simple or indolent corneal ulceration (see p. 250)

▪ Qualitative tear film abnormality (e.g., mucin and/or lipid deficiency; see p. 1076)

▪ Anterior uveitis (see p. 1151)

▪ Glaucoma (see p. 1559)

• Mucoid to mucopurulent discharge:
○ Blepharitis (see p. 966)

○ Conjunctivitis (see pp. 237, 239)

○ KCS (see p. 628)

○ Melting/infected corneal ulceration (see p. 250)

○ Orbital abscess/cellulitis (see p. 790)

○ Dacryocystitis (see p. 280)

○ Nasolacrimal foreign body (e.g., grass awn; parasite)


DIAGNOSIS image



DIAGNOSTIC OVERVIEW


Ocular discharge is apparent on physical examination. The underlying cause should be investigated with a review of the history and physical examination and an ophthalmic examination initially. If the cause is not elucidated, specific ocular tests (some requiring referral) may be warranted.



DIFFERENTIAL DIAGNOSIS



• Ocular discharge with “red eye(s)” is often associated with overproduction of tears (i.e., linked with causes of corneal mechanical irritation, infection or ocular pain).

• Ocular discharge with “quiet eye(s)” (no evidence of ocular pain or eyelid conditions) is often associated with impaired drainage of tears (e.g., congenital or acquired blockage of nasolacrimal system).


INITIAL DATABASE



• Complete ophthalmic examination (see p. 1313), including:
○ Careful examination with magnification of the eyelids

○ Schirmer tear test (dogs: low with KCS; normal 15-25 mm/min; equivocal if 8-15 mm/min)

○ Fluorescein dye application (corneal dye retention with corneal ulceration; dye exiting nares helps confirm patent nasolacrimal system)

○ Intraocular pressure (IOP) (pressures at >30 mm Hg with glaucoma; may be low at <10-15 mm Hg with uveitis; both painful conditions)

• Conjunctival and/or corneal (if infected corneal ulcer) swabs for:
○ Cytologic examination to determine cell type and possible etiology

○ Culture and sensitivity (C&S): aerobic; if needed, anaerobic and fungal

○ PCR: FHV-I, Chlamydophila spp., and Mycoplasma spp.


ADVANCED OR CONFIRMATORY TESTING



• Varies depending on underlying cause

• Blockage of nasolacrimal system can be investigated with nasolacrimal system flush (see online chapter: Dacryocystitis), if no fluorescein dye exits, nares and blockage is suspected. If results are unclear, confirmation is possible with nasal radiographs and a contrast study of the nasolacrimal system. Contrast CT scanning can accurately assess the integrity of the nasolacrimal system.


TREATMENT image



TREATMENT OVERVIEW


Treatment is directed at the underlying cause. If discharge persists, referral to a veterinary ophthalmologist should be considered.



ACUTE GENERAL TREATMENT



• Treat the underlying cause (see Etiology and Pathophysiology section above).

• Blockage of nasolacrimal system: treat the primary lesion causing the obstruction (may be difficult to diagnose; if so, consult a veterinary ophthalmologist).


CHRONIC TREATMENT


May be required with certain diseases (e.g., KCS)



POSSIBLE COMPLICATIONS



• Conjunctivitis due to FHV-1 may lead to symblepharon (adhesions of conjunctiva to surrounding tissues), KCS, ulcerative keratitis, and stromal keratitis (see p. 524).

• Chronic epiphora can lead to localized facial dermatitis at the medial canthus.


RECOMMENDED MONITORING


Varies depending on the underlying



PROGNOSIS AND OUTCOME image


Prognosis is guarded to excellent depending on the underlying cause.



PEARLS & CONSIDERATIONS image



COMMENTS



• Clinicians should perform routine aerobic bacterial C&S tests and submit them in cases of mucopurulent discharge to identify the implicated bacterium or fungus.

• Fungal infections are rare causes of ocular discharge in cats and dogs.

• Serous ocular discharge in cats is common with FHV-1.

• A thorough examination of the ENTIRE conjunctival sac, including dorsally throughout the dorsal surface of the globe and ventrally on both sides of the third eyelid, is necessary to identify any retained foreign material.


CLIENT EDUCATION


At the first sign of abnormal ocular discharge in their pets, owners should consult their veterinarian.



SUGGESTED READING



Gerding PA, Kakoma I. Microbiology of the canine and feline eye. Vet Clin North Am Small Anim Pract. 1990;20:615.


Pena MT, Leiva M. Canine conjunctivitis and blepharitis. Vet Clin North Am Small Anim Pract. 2008;38:233-249.



Ocular Size Abnormalities



AUTHOR: CHANTALE L. PINARD



EDITOR: CHERYL L. CULLEN



BASIC INFORMATION image



DEFINITION



• Buphthalmos: a larger than normal globe; may be congenital or acquired and is a result of current or past glaucoma

• Microphthalmos: a smaller than normal globe; a congenital condition sometimes associated with other ocular anomalies

• Phthisis bulbi: a shrunken globe; a condition acquired as a result of chronic ocular inflammation (e.g., uveitis or severe ocular trauma)

• May occur in one or both eyes


SYNONYMS


Buphthalmia (buphthalmos), microphthalmia (microphthalmos)



EPIDEMIOLOGY



SPECIES, AGE, SEX



• Buphthalmos may occur, and microphthalmos does occur, congenitally.

• Phthisis bulbi: no age predisposition


GENETICS & BREED PREDISPOSITION



• Buphthalmos secondary to glaucoma (see p. 448) is inherited in several breeds.

• Microphthalmos is inherited in miniature schnauzers, Australian shepherds, collies, Shetland sheepdogs, and Doberman pinschers.


ASSOCIATED CONDITIONS & DISORDERS



• Buphthalmos can be associated with:
○ Lagophthalmos (incomplete closure of the eyelids) with or without secondary corneal ulceration (see p. 250)

○ Lens subluxation/luxation (see p. 644)

○ Intraocular neoplasia (see p. 620)

• Microphthalmos is associated with:
○ Other congenital ocular anomalies, including cataracts (see p. 181) and retinal dysplasia/folds

○ Collie eye anomaly, including choroidal hypoplasia with or without optic nerve coloboma, staphyloma, retinal detachment, and intraocular hemorrhage

• Phthisis bulbi is associated with:
○ Untreated or poorly responsive ocular inflammation (e.g., uveitis or severe ocular trauma)

○ Variable systemic abnormalities depending on cause of uveitis (see p. 1151)


CLINICAL PRESENTATION


HISTORY, CHIEF COMPLAINT: Condition is most likely unilateral but can also occur bilaterally.


• Buphthalmos: enlargement of globe during first few months of life (i.e., congenital glaucoma); progressive enlargement of globe and “red eye” (see p. 448)

• Microphthalmos: small eye from birth

• Phthisis bulbi: progressive shrinkage of globe following a “red eye” (see p. 967)


PHYSICAL EXAM FINDINGS



• Buphthalmos: larger globe and signs of glaucoma, including:
○ Red eye (congested conjunctival and scleral blood vessels)

○ Diffuse corneal edema with possible striae (white streaks in the cornea from breaks in Descemet’s membrane)

○ Corneal vascularization if eyelids cannot close over the enlarged globe (i.e., lagophthalmos)

○ Fixed and dilated pupil

○ Lens subluxation/luxation (see p. 644)

○ Blindness

• Microphthalmos: smaller globe and the following:
○ Enophthalmos (caudal displacement of the eye) (see p. 790)

○ Prolapsed third eyelid (see p. 1089)

○ Other intraocular abnormalities (cataracts, retinal folds/dysplasia)

○ ± Small palpebral fissure (i.e., small opening between the eyelids) or entropion and/or conjunctivitis if eyelids are normal length despite small eye

○ Vision may be normal, reduced, or absent.

• Phthisis bulbi: shrunken globe and the following:
○ Enophthalmos (caudal displacement of the eye; see p. 790)

○ Prolapsed third eyelid

○ Corneal edema; deep corneal vascularization

○ ± Entropion, conjunctivitis, posterior synechiae, cataract, iris atrophy

○ Vision typically reduced or absent


ETIOLOGY AND PATHOPHYSIOLOGY



• Buphthalmos: result of untreated or poorly managed glaucoma

• Microphthalmos: congenital deficiency of optic vesicle or failure of normal growth and expansion of optic cup; inherited condition

• Phthisis bulbi: acquired condition that possibly follows chronic intraocular inflammation (see pp. 1151, 448, and 249)


DIAGNOSIS image



DIAGNOSTIC OVERVIEW


The definitive diagnosis depends on the general appearance of the ocular globe and signalment of the patient.



DIFFERENTIAL DIAGNOSIS



• Buphthalmos: exophthalmos (forward displacement of the globe; see p. 790)

• Microphthalmos, phthisis bulbi: ruptured globe (see p. 249)


INITIAL DATABASE



• Complete ophthalmic examination, including:
○ Measurement of intraocular pressure (IOP): may be elevated (>30 mm Hg, indicating uncontrolled glaucoma), or normal (chronic glaucoma) with buphthalmos; typically low (<10-15 mm Hg) with phthisis bulbi.

○ Fluorescein dye application with buphthalmos (there may be positive dye retention, such as with a corneal ulcer)

○ Neuroophthalmic exam (see p. 1313) to assess vision (e.g., menace response)

• Additional tests vary depending on underlying cause


ADVANCED OR CONFIRMATORY TESTING



• Buphthalmos: ocular ultrasound if corneal or ocular media opacification precludes evaluation of intraocular structures (e.g., assess lens for cataracts and globe for intraocular mass)

• Ocular histopathologic examination if enucleation is performed due to blindness and ocular pain (common with buphthalmos)


TREATMENT image



THERAPEUTIC OVERVIEW


The management of ocular pain is paramount, independent of the appearance of the globe. Unfortunately, pain control may require enucleation for several patients. No treatment may be required if ocular size abnormalities are not accompanied by evidence of discomfort, inflammation, or elevated IOP.



ACUTE GENERAL TREATMENT



• For buphthalmos (for treatment options, see Glaucoma, p. 1151); if the animal’s globe is blind and if glaucoma remains medically uncontrolled, options include:
○ Enucleation, evisceration with intraocular prosthesis, or chemical ablation of blind eyes with chronic primary glaucoma (see p. 1151); chemical ablation is not recommended in cats

○ Enucleation of eyes with intraocular neoplasia

○ Enucleation of eyes with congenital glaucoma

• For microphthalmos: enucleation is warranted if eye is blind and entropion or chronic conjunctivitis occurs.

• For phthisis bulbi: treatment of underlying uveitis and advise enucleation if eye is blind and entropion or chronic conjunctivitis occurs.


PROGNOSIS AND OUTCOME image



• Prognosis for vision is grave in cases of buphthalmos and advanced phthisis bulbi.
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Jul 24, 2016 | Posted by in SMALL ANIMAL | Comments Off on O

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