Page 324 - Small Animal Internal Medicine, 6th Edition

296 PART II Respiratory System Disorders

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A B

C

FIG 20.11
Multiple pulmonary nodules are easily visible on the lateral radiograph (A) from a cat
with a 1-year history of cough and recent episodes of respiratory distress with wheezing.
Nodules do not obviously extend to the chest wall as seen on the ventrodorsal
radiograph. (B) However, a 1-cm mass was found on ultrasonographic examination of the
right thorax; (C) a red line has been positioned between ultrasound markers to indicate
site of measurement. An ultrasound-guided aspirate was performed. The presence of
eosinophils in the aspirate prompted the performance of fecal examinations for pulmonary
parasites, and a diagnosis of paragonimiasis was made through identification of
characteristic ova.

during image exposure. For unstable patients for which PARASITOLOGY
results of a noncontrast enhanced CT are considered to
be critical, heavy sedation and physical restraints can Parasites involving the lower respiratory tract are identified
be used. by direct observation, blood tests, cytologic analysis of respi­
ratory tract specimens, or fecal examination. Oslerus osleri
reside in nodules near the carina, which can be identified
NUCLEAR IMAGING bronchoscopically. Rarely, other parasites may be seen. Blood
tests are often used to diagnose heartworm disease (see
Mucociliary clearance can be measured by placing a drop Chapter 10).
of technetium­labeled albumin at the carina and observ­ Larvae that may be present in fluid from tracheal or bron­
ing its movement with a gamma camera to assist in the chial washings include O. osleri, Aelurostrongylus abstrusus
diagnosis of ciliary dyskinesia. Nuclear imaging can be (Fig. 20.12, A), and Crenosoma vulpis (Fig. 20.12, B). Eggs
used for the relatively noninvasive measurement of pul­ that may be present include those of Capillaria (Eucoleus)
monary perfusion and ventilation, valuable for the diag­ aerophila and Paragonimus kellicotti (Fig. 20.12, C and D).
nosis of pulmonary thromboembolism. Restrictions for Larvated eggs or larvae from Filaroides hirthi or Aelurostron-
handling radioisotopes and the need for specialized record­ gylus milksi can be present but are rarely associated with
ing equipment limit the availability of these tools to specialty clinical signs. The more common organisms are described in
centers. Table 20.1.