Page 345 - Feline Cardiology

358 Section K: Heartworm Disease

A
A

Heartworm Disease B

Figure 23.4. Thoracic radiographs (lateral and VD) from a cat
presenting with an acute crisis and pneumonitis following adult
worm death. Patchy interstitial infiltrates and severe pulmonary
arterial enlargement are present.

B

Figure 23.3. Left lateral (A) and ventrodorsal (B) radiographs worm infection (Selcer et al. 1996). This finding was
from a heartworm positive cat. Note the diffuse bronchointersti- corroborated in a study that compared radiographic and
tial pulmonary pattern and the prominent right caudal pulmonary serology findings with pulmonary histology in 120
artery (arrowhead). The cardiac silhouette is unremarkable. shelter cats. The researchers demonstrated that radio-
graphic pulmonary arterial lesions were heartworm
stage-specific and inconsistent predictors of infection
radiographic changes consistent with heartworm disease (Upchurch et al. 2010). Thus, radiographic findings in
are noted in only half of the cats suspected to have cats with heartworm disease are highly variable and
disease on physical examination (Atkins et al. 1998). In dependent on the time postinfection when cats are
another study, only 55% of heartworm antigen-positive presented.
cats had radiographic signs consistent with heartworm Echocardiography is a particularly useful adjunctive
disease (Nelson 2008b); another report showed normal- test in cats in which there is a suspicion of heartworm
ization of peripheral pulmonary artery enlargement in disease despite negative Ag test results. One retrospective
experimentally exposed cats, in spite of active heart- study reported that worms were visible echocardio-