Page 408 - Problem-Based Feline Medicine

400 PART 7 SICK CAT WITH SPECIFIC SIGNS

Mild to marked lymphadenopathy and various associ- to hyperplasia from a cause other than retroviral infec-
ated signs may occur with other FIV-associated dis- tion.
orders (e.g. neoplasia and fungal infection).
A FeLV antigen test may be used to rule-out FeLV
● In the terminal phase of FIV infection, appropri-
infection.
ate lymphadenopathy due to hyperplasia may not
occur in response to secondary infection because of Generalized lymphadenopathy is a more prominent
marked follicular involution. feature of FIV, compared to FeLV, infection.

Diagnosis
Treatment
FIV antibody test (ELISA, RIM, FA, western blot).
Treat neoplasia, infection, skin disease or immune-
● Antibody is usually detectable within 2 months of
mediated disease as discussed elsewhere.
infection, but may take up to 6 months, therefore
a negative test should be repeated. There is no specific treatment for lymphadenopathy
that is not due to these conditions.
PCR test for FIV DNA. The sensitivity of PCR for viral
DNA compared to antibody tests is not known. It Supportive care as needed.
should be noted that PCR testing has not been stan-
dardized and is more likely to give false-positive Prognosis
results than antibody tests if the laboratory does not
maintain the highest standards of quality control. Lymphadenopathy is not a distinct disorder in FIV-
positive cats, but rather a marker of the symptomatic
During the acute phase, lymph node biopsy reveals
phases of infection. There is no specific prognosis
marked follicular hyperplasia with or without dys-
attached to lymphadenopathy, except that disappear-
plasia, and less intense parafollicular hyperplasia.
ance during the chronic symptomatic phase correlates
During the chronic symptomatic phase, lymph node with progression to terminal illness.
biopsy reveals follicular hyperplasia with or without
Prognosis is determined by other FIV-associated disor-
follicular involution, follicular plasmacytosis, and vari-
ders.
able erythrophagocytosis by macrophages. These
changes are not specific for FIV infection. Lymph node
histology progresses from follicular hyperplasia, PARASITIC, IMMUNOLOGIC AND
through mixed hyperplasia/involution, to follicular MISCELLANEOUS SKIN DISORDERS**
involution, corresponding to generalized lymphadeno-
pathy, AIDS-related complex and terminal AIDS.
Classical signs
Neutropenia and lymphopenia are common hemato-
● Skin lesions typical of the primary disease
logic abnormalities in symptomatic cats.
(e.g. miliary dermatitis).
● ± Mild to marked lymphadenopathy.
Differential diagnosis
Lymphoma, metastatic lymphadenopathy, atypical See The Cat With Miliary Dermatitis (page 1022), The
hyperplasia and possibly hyperplasia from other Cat With Skin Lumps and Bumps (page 1067) and The
causes may be distinguished from FIV-induced hyper- Cat With Non-healing Wounds (page 1081).
plasia by lymph node histology.
Lymphoma may be present at other sites – e.g. bone Clinical signs
marrow, liver or spleen.
Mild to marked lymphadenopathy may be present
A primary tumor should be identifiable with metas- with disorders of the skin and subcutis, especially
tastic lymphadenopathy. chronic ones, but it is not the salient feature.
Signs of infections, skin diseases or immune-mediated Mandibular lymphadenopathy may be present with
disorders should be present if lymphadenopathy is due acne, mosquito bite hypersensitivity, notoedric mange,