Dr. Bari Spielman
Pitting and discoloration of the enamel (white surface coating) of the teeth
Certain diagnostic tests must be performed for a definitive diagnosis of canine distemper and to exclude other disease processes that may cause similar symptoms. A complete history (vaccination status, travel pattern, environment, etc.), description of clinical signs, and thorough physical examination are all important to obtaining a diagnosis.
There are certain characteristic changes that may be apparent on the physical examination that lead to a presumptive diagnosis of canine distemper. These include the following:
Presence of rhythmic jerking of a single muscle or a group of associated muscles, called tics or myoclonus
Abnormally thickened and hard foot pads
Inflammatory changes in the retinas of the eyes that are compatible with distemper
The following tests are recommended to confirm a diagnosis:
A complete blood count (CBC) may reveal a mild lymphopenia (a decrease in the number of lymphocyte white blood cells), particularly during the early stage of infection. Occasionally, thrombocytopenia (decreased platelets) is seen also.
A biochemical profile is usually within normal limits, although it may reveal changes in kidney and/or liver enzymes, electrolytes, blood sugar, and protein levels, depending on the stage of disease and degree of severity of disease present.
A urinalysis is helpful in determining the level of hydration on the patient.
Chest and abdominal X-rays are an important part of any baseline work-up. They may be normal, they may show evidence of pneumonia, and they may help rule out other causes of similar clinical signs.
Your veterinarian may recommend additional tests to exclude or diagnose concurrent conditions. These tests are not always necessary in every case; however, they may be of benefit in certain individuals and are selected on a case-by-case basis. These include the following:
The ultimate diagnosis is based on demonstration of viral antigens (proteins) in scrapings and body fluids such as conjunctival smears, transtracheal washings, urine sediment, buffy coat (layer of white blood cells formed after blood is spun down), and cerebrospinal fluid (CSF). Their absence does not rule out infection, however.
Analysis and testing CSF obtained from individuals exhibiting neurologic signs may be useful in diagnosing distemper. Microscopic analysis of CSF may show increased numbers of lymphocytes and protein. Detection of high antibody titers for distemper in the CSF can provide supportive evidence of an active infection. Comparing the antibody titers found in the CSF to antibody titers found in the serum (blood) may also help support the diagnosis of distemper.
The measurement of antibodies to the distemper virus in blood may be helpful. Dogs that are able to mount an antibody response to the virus usually have titers that increase over a 2- to 4-week time period. A single elevated antibody titer taken at the beginning of the illness may be difficult to interpret, because it could represent antibodies produced by prior vaccination.
Dogs with distemper may need to be hospitalized and must always be kept in isolation to prevent infection of other dogs. Therapy is mainly supportive and symptomatic, as there are no antiviral drugs that are effective against distemper. Because there are several clinical manifestations of distemper, there is no single treatment plan that can be recommended for all dogs. The pet owner whose dog has distemper should also understand that even with the best of care, up to 50 percent of dogs infected with canine distemper succumb to the disease.
Intravenous fluid and electrolyte therapy may be recommended in the patient who has severe gastrointestinal signs, is unable or unwilling to eat, and is dehydrated.
Parenteral (intravenous) nutrition may be indicated in the debilitated patient, especially when protracted vomiting and diarrhea are present.
Administration of antiemetic drugs to stop vomiting may be of benefit.
Antibiotics are indicated to control secondary bacterial infections. Many dogs with severe distemper infections are immunocompromised, which means their immune system is functioning less than optimally, and they are susceptible to other infections.
In dogs that develop seizures, anticonvulsant therapy may be administered.
There is no effective treatment available for the myoclonus or tics that are produced in some dogs by distemper.