Page 416 - Problem-Based Feline Medicine

408 PART 7 SICK CAT WITH SPECIFIC SIGNS

Differential diagnosis These organisms typically produce chronic ulcerating
lesions or masses (abscesses and mycetomas) that are
Differential diagnoses for disseminated mycobacter-
cutaneous or subcutaneous. The lesions have usually
ial infections include multicentric lymphoma, widely
developed at sites of penetrating wounds and have not
metastatic tumors, other pyogranulomatous bacterial
resolved with typical wound treatment. Localized
infections and systemic fungal infections.
infections in other organs and disseminated infections
Differential diagnoses for leprosy include neoplasia, may also occur. Accompanying signs vary with organ
eosinophilic granuloma complex, other chronic bacter- involvement.
ial infections and fungal infections.
Local, regional, generalized peripheral and internal
Differential diagnoses for local or regional atypical lymphadenopathy may occur.
mycobacteriosis include neoplasia, foreign body reac-
Systemic signs may be absent or mild with local cuta-
tion, eosinophilic granuloma complex, panniculitis,
neous and subcutaneous infections. Mild to severe
pansteatitis, other chronic bacterial infections and fun-
signs occur with internal or disseminated infections.
gal infections.
Differentiation is based on cytology, histology and culture.
Diagnosis
Treatment Pyogranulomatous-granulomatous inflammation is
evident on cytology and histology of exudates and
Tuberculosis.
biopsy specimens.
● Notify public health officials. Euthanasia is often
advised because of the zoonotic risk. If treatment is Cytology may reveal Gram-positive bacteria in
attempted, drug doses are provided in the reference macrophages (Rhodococcus equi), mats of Gram-positive
at the end of the chapter. filamentous organisms (Actinomyces sp.), Gram-
positive, weakly acid-fast beaded filamentous organ-
Treatment of leprosy and atypical mycobacteriosis are
isms (Nocardia sp.), or Gram-positive branching
discussed in The Cat With Non-Healing Wounds
filamentous organisms with transverse longitudinal
(page 1086).
divisions resulting in paired rows of coccoid spores
(Dermatophilus congolensis).
Lymph node biopsy reveals hyperplasia or lymph-
(PYO)GRANULOMATOUS BACTERIAL adenitis.
INFECTIONS*
Definitive diagnosis is by culture of the organism
from lesions.
Classical signs
There may be a history of exposure to horses with
● Chronic ulcerating
rhodococcosis.
cutaneous/subcutaneous lesions.
● ± Local, regional or generalized
lymphadenopathy. Differential diagnosis

Eosinophilic granuloma complex, mycobacterial infec-
See main reference, page 1086 (The Cat With Non-
tions, fungal infections, neoplasia, panniculitis and
Healing Wounds).
steatitis.
Differentiation is based on cytology, histology and culture.
Clinical signs

Chronic ulcerating lesions occur with a number of Treatment
bacteria, including Rhodococcus equi, Actinomyces sp.,
Treat the primary disease. See page 1087 (The Cat With
Nocardia sp., and Dermatophilus congolensis.
Non-Healing Wounds).