Page 600 - Cote clinical veterinary advisor dogs and cats 4th

272 Distemper, Canine

• CNS infection occurs hematogenously CPV does not cross the blood-brain doses are sometimes advocated for acute
through infected mononuclear cells that barrier, a CDV/CPV ratio that is higher inflammatory CDV encephalitis in older dogs
VetBooks.ir through the olfactory nerve. CDV enters the ○ Severely immunosuppressed patients advocated in the treatment of ODE and
in CSF than in blood suggests CDV
cross the blood-brain barrier or anterograde
without systemic disease. Glucocorticoids are
infection.
CNS through meningeal perivascular spaces,
vaccine-induced CDV, tapered to the lowest
choroid plexus, and ventricular ependymal
cells. Acute CDV encephalomyelitis occurs or those with the noninflammatory effective dose. They are contraindicated for
demyelinating form of CDV may have
systemic disease with mucosal (respiratory,
early in the course of the disease of young normal CSF, often with low CSF protein ocular, GI) signs and any evidence of second-
and immune-deficient dogs, causing a (<5 mg/dL). ary bacterial infections or if CSF analysis
polioencephalomyelitis. • Fluorescent antibody testing shows no signs of inflammation and very
• Full recovery from CDV illness in young ○ Cytologic smears from buffy coat, tonsillar low total protein (≤5 mg/dL).
animals is uncommon but likely produces or conjunctival epithelial scrapings, CSF,
lifelong immunity. bone marrow, urine sediment Possible Complications
• Transplacental infections can result in ○ More rewarding on conjunctival scrapings • Recovery from systemic signs of the disease
abortions or stillbirths. Puppies that survive early in course of the disease may precede development of neurologic signs
transplacental infections can develop neuro- • Polymerase chain reaction (PCR) test for weeks to months later.
logic signs by 6 weeks of age and often have CDV: whole blood, serum, CSF • A possible link has been noted between
lifelong immunodeficiency. • Airway lavage (p. 1073) for cytology and rheumatoid arthritis and CDV.
• Some dogs will continue to shed the virus for culture and susceptibility of secondary
for up to 2 months after infection. bacterial pathogens if indicated by worsening PROGNOSIS & OUTCOME
pneumonia.
DIAGNOSIS • Postmortem testing: immunofluorescent • Development of CNS signs is the most
techniques for frozen samples of tonsils, important negative prognostic factor.
Diagnostic Overview lymph nodes, GI epithelium, spleen, urinary • Dogs with adequate immunity do not
A presumptive diagnosis in a young, unvac- bladder, brain develop clinical signs and clear the virus
cinated dog is based on presentation of clinical within 14 days after infection. The incidence
signs that include oculonasal discharge, vomit- TREATMENT of late-onset CNS signs in these dogs is low.
ing, and/or diarrhea with or without a recent • Dogs with inadequate immunity develop
onset of neurologic signs. Older dogs can Treatment Overview mild to severe systemic signs and frequently
initially present with signs consistent with infec- Treatment includes supportive care, antibiotics develop CNS signs.
tious tracheobronchitis. Clinical confirmation to control secondary bacterial infection, and
typically comes from a blood sample submitted anticonvulsants to control seizures. There is no PEARLS & CONSIDERATIONS
for immunofluorescent antibody testing of medication to eradicate the virus. Suspected or
white blood cells or anti-CDV antibody titers confirmed cases must be kept in isolation to Comments
in cerebrospinal fluid (CSF). prevent spread of this highly contagious virus. • CDV has a worldwide distribution and
most commonly affects puppies and young,
Differential Diagnosis Acute General Treatment unvaccinated adults.
• Canine infectious tracheobronchitis • Broad-spectrum antibiotics (parenterally • Unvaccinated puppies exposed to an infected
• Canine parvoviral enteritis initially) such as ampicillin 22 mg/kg IV dog in the waiting room of a veterinary
• Other CNS diseases of young to middle-aged q 8h or other parenteral antibiotic therapy hospital should be vaccinated at that time
dogs for secondary bacterial infections and usually develop sufficient immunity
• Nebulization and coupage if pneumonia is before the virulent virus produces systemic
Initial Database apparent radiographically signs.
• CBC: absolute lymphopenia; rarely, CDV • Antiemetics (e.g., maropitant 1 mg/kg SQ or • Weimaraners may have an unusual suscep-
inclusions are identified in lymphocytes, 2 mg/kg PO q 24h; dolasetron 0.3-0.6 mg/ tibility to vaccination (see below).
monocytes, neutrophils, or erythrocytes kg IV or SQ q 12-24h; or metoclopramide
• Serum biochemistry profile and urinalysis: 0.2-0.4 mg/kg SQ q 8h), antidiarrheals (e.g., Prevention
varies and nonspecific loperamide 0.1-0.2 mg/kg PO up to q 8h), • Routine vaccination with a modified live
• Thoracic radiographs: interstitial pattern in and GI protectants (e.g., omeprazole 1.0 mg/ canine distemper (ML-CDV) vaccine is
early phases; evidence of bronchopneumonia kg PO q 24h) as needed. indicated in puppies (every 3-4 weeks, begin-
in later stages with secondary bacterial • IV fluid resuscitation to correct dehydration ning at 6 weeks and ending at 16 weeks).
infection and electrolyte disturbances A booster vaccine is given 1 year later and
• Diazepam or midazolam 0.5 mg/kg IV or then periodically (every 3 years).
Advanced or Confirmatory Testing 1 mg/kg per rectum prn up to four times • Vaccination usually confers adequate
• Serum antibody testing: elevated serum in 2 hours if acute seizure control is needed immunity. Immunocompromised dogs or
immunoglobulin M (IgM) titers in unvac- ○ Levetiracetam injectable 30 mg/kg q 8h dogs exposed to a large amount of a highly
cinated dogs confirm recent exposure or if necessary for continued seizure control virulent CDV strain can still develop disease.
current infection (p. 1321). • Serum titers correlate well with level of
• CSF (pp. 1080 and 1323) Chronic Treatment protection and a titer of ≥ 32 has been
○ Elevated CSF protein and lymphocytic • Anticonvulsant therapy (levetiracetam 30 mg/ considered protective (may vary among
pleocytosis are typical. kg PO q 8h or phenobarbital 2-4 mg/kg PO laboratories and from one individual to the
○ Presence of CSF antibody titers to CDV q 12h) for seizure control. Sodium valproate next).
is confirmatory when there is no blood 60-100 mg/kg PO q 8h can be considered in • Vaccine-induced infections are rare and
contamination of the sample. early stages of myoclonus but is ineffective produce only CNS signs.
○ With potential blood contamination of in later stages. • Complications from the vaccine are rare but
the CSF sample, paired samples of CSF • The use of glucocorticoids is controversial. can include hypertrophic osteodystrophy
and serum are tested for CDV and canine Antiinflammatory doses are considered useful (HOD) and juvenile cellulitis. Clinical signs
parvovirus (CPV) antibody titers; because to combat optic neuritis. Immune-suppressive usually develop within 10 days of vaccination

www.ExpertConsult.com