Page 418 - Problem-Based Feline Medicine

410 PART 7 SICK CAT WITH SPECIFIC SIGNS

Differential diagnosis Lymph node cytology reveals hyperplasia; histology
reveals multifocal necrosis.
For a cat presented for lymphadenopathy, differential
diagnoses include lymphoma and most chronic causes The organism, a small Gram-negative coccobacilli, is
of hyperplasia. difficult to see on routine cytology and Gram-stain.
● FA test of air-dried smears of tissues or exudate
Differentiation is based on cytology, histology and
helps identify the organism.
culture.
The organism may be cultured from an aspirate of
lymph node, bone marrow (not blood), or other tissue.
Treatment
● Not all laboratories will attempt culture and special
See page 1067 (The Cat With Skin Lumps and Bumps). media is required – check before submitting.
A single titer ~ 1:80 gives a presumptive diagnosis,
TULAREMIA* while acute (as early as possible once illness is
detected) and convalescent (14 days later) antibody
Classical signs titers demonstrating a four-fold rise give a confirma-
tory diagnosis. Titers are useful to confirm a zoonotic
● Acute high fever.
disease when treatment is based on a tentative diag-
● Peripheral and internal lymphadenopathy
nosis.
See main reference, page 382 (The Pyrexic Cat).
Differential diagnosis
Clinical signs
Other acute viral, bacterial, fungal and parasitic (e.g.
Signs appear within 2–7 days of infection with toxoplasmosis) infectious processes.
Francisella tularensis subsp. tularensis or palaearctica. ● These are distinguished on the basis of exposure
risk, serologic testing and organism identification.
High fever (> 40˚C), lethargy, inappetence, dehydration.
● Acute Gram-negative bacteremia, e.g. secondary to
Moderate to marked painful lymphadenopathy due myelosuppression, is not usually associated with
to lymphadenitis is common; site of infection affects lymphadenopathy.
distribution:
● Cats exposed by mouthing or ingesting a rabbit
Treatment
or rabbit tick will have initial mandibular, cervical
or mesenteric lymphadenopathy. Treat early on the basis of tentative diagnosis.
● Cats exposed by a mosquito, tick bite or innocu-
Antibiotics (optimal treatment is not known).
lation will have initial lymphadenopathy in the
● Recommended antibiotics include tetracycline,
node draining the region.
doxycycline, chloramphenicol, streptomycin and
Other variable signs include multifocal white oral ulcers, gentamicin at standard recommended doses.
abdominal pain, hepatosplenomegaly, vomiting and diar- Fluoroquinolones have been effective experimen-
rhea. tally.
● Localized tularemia causing a chronically draining ● Recommended duration of therapy is 7–14 days.
subcutaneous mass has also been reported. ● Use parenteral treatment initially to minimize
contact of nursing personnel with oral cavity. Use
Diagnosis follow-up treatment with oral antibiotics to min-
imize hospitalization and aminoglycoside toxi-
History of exposure to wild rabbits (North America,
coses.
F. tularensis tularensis).
Treat animal for ticks.
History of exposure to infected rodents, ticks and mos-
quitoes, or contaminated soil and water (Northern Highly zoonotic from tissues and ticks – strict isolation
hemisphere, F. tularensis palaearctica). and barrier nursing procedures must be followed.