Page 384 - Problem-Based Feline Medicine

376 PART 7 SICK CAT WITH SPECIFIC SIGNS

These signs may also be observed in postnatally Differential diagnosis
infected kittens and include:
Rule out diseases associated with affected organs, e.g.,
–A distended abdomen from an enlarged liver
FIP for neurologic and ocular signs.
and/or ascites.
– Icterus from hepatitis or cholangiohepatitis.
– Dyspnea is present in most kittens and cats with Treatment
signs of acute infection.
Clindamycin at 10–12 mg/kg orally q 12 hours for
– Neurologic deficits; continuous vocalization;
4 weeks is usually effective.
excessive sleeping.
● Cats should respond within several days of treat-
– Fever, anorexia, depression often accompanies
ment.
the tissue-specific signs.
● If no response is evident after 3 weeks of antibiotic
Non-fatal extraintestinal disease (chronic, intermit- therapy, reconsider the diagnosis.
tent course). ● The chronic form may recur even after successful
● Cats may have a moderate fever, lethargy and treatment, as drugs tend to suppress replication
depression that waxes and wanes. rather than kill the parasite.
● Hyperesthesia and stiff painful joints or shifting
Other systemic drugs with potential efficacy include
lameness may be evident, presumably due to an
the trimethoprim sulfas combination, doxycycline,
immune-mediated process.
minocycline, azithromycin and clarythromycin.
● Unilateral or bilateral anterior or posterior uveitis
may occur with possible sequelae of lens luxation, Cats with ocular lesions should also be treated with
glaucoma or retinal detachment. corticosteroids, either topically (e.g. topical 0.5%
● Seizures and ataxia may be present if CNS tissues Prednisolone acetate drops applied q 6–12 h) or sys-
are involved. temically to control inflammation and its sequelae
● Rarely, a toxoplasma granuloma (tissue cyst) (glaucoma, lens luxation).
forms in the gastrointestinal tract or pancreas
causing chronic vomiting.
Prognosis
Diagnosis Gastrointestinal disease has a good prognosis,
although it may lead to inflammatory bowel disease in
Clinical signs consistent with toxoplasmosis are sug-
rare cases.
gestive, especially when other causes of the signs have
been ruled out. Acute extraintestinal disease has a guarded to poor
prognosis.
IgM titers > 1:64 and a four-fold increase in
IgG:IgM titers within 2 weeks correlate best with clin- Chronic extraintestinal disease has a fair to good.
ical toxoplasmosis. However, some cats do not develop
detectable IgM titers, and in other cats, positive IgM
Transmission
titers can persist for months to years after infection.
Infection in cats can occur via:
Elevated ocular and CSF titers relative to serum
● The placenta or milk with tachyzoites.
titers in cats with ocular or neurologic signs, respec-
● Ingestion of meat infected with tissue bradyzoites,
tively, are very suggestive. Coefficient values > 1.0 are
e.g., rodents.
highly suspect and > 8.0 strongly suggest local produc-
● Ingestion of sporulated oocysts in food or water.
tion of T. gondii antibodies.
T. gondii has a zoonotic potential. Infection of
Response to therapy for toxoplasmosis is a useful indi-
humans can occur via:
cator of infection.
● Ingestion of undercooked meat containing tissue
Definitive diagnosis requires demonstration of the bradyzoites (most common mode of transmission).
organism in inflamed tissues by histology, immunohis- ● Ingestion of sporulated oocysts from the environ-
tochemistry or polymerase chain reaction assay. ment.