Page 373 - Small Animal Internal Medicine, 6th Edition

CHAPTER 22 Disorders of the Pulmonary Parenchyma and Vasculature 345

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A B

FIG 22.2
The operculated ova from Spirometra tapeworms (A) can be misdiagnosed as
Paragonimus ova (B). The Spirometra ova are smaller and paler than the yellow-brown
Paragonimus ova. Most notably, Paragonimus ova have a distinctly visible shoulder
(arrow) at the operculated end. (Courtesy James R. Flowers.)

specimens should be examined in suspected cases because possible heartworm disease. Eosinophilic inflammation may
the eggs are not always present. A presumptive diagnosis is be apparent in peripheral blood and airway specimens.
necessary in some cases. Note that ova from the tapeworm A definitive diagnosis is made through identification of
Spirometra spp. can be mistakenly identified as ova from larvae, which may be present in fecal specimens prepared
Paragonimus (Fig. 22.2). using the Baermann technique (see Fig. 20.12, A) or in
Fenbendazole is used to treat paragonimiasis at the same airway specimens obtained by tracheal washing or bron-
dosage as that recommended for the treatment of capillaria- choalveolar lavage. Fecal Baermann examination is most
sis. Alternatively, praziquantel can be used at a dosage of sensitive for the detection of organisms, although multiple
23 mg/kg orally every 8 hours for 3 days. fecal specimens should be examined in suspected cases
Thoracocentesis should be used to stabilize the condition because organisms are shed intermittently. Airway speci-
of animals with pneumothorax. If air continues to accumu- mens are often negative for organisms, despite infection, and
late within the pleural space, however, it may be necessary stained squash preparations of mucus are recommended to
to place a chest tube and perform suction until the leak has increase sensitivity (Lacorcia et al., 2009).
been sealed (see Chapter 24). Surgical intervention is rarely Cats should be treated with fenbendazole at the same
required. dosage as that used for the treatment of capillariasis. In one
Thoracic radiographs and periodic fecal examinations study, the dosage of 50 mg/kg orally every 24 hours for 15
should be used to monitor the response to treatment. Treat- days was effective in eliminating infection in all four cats
ment may have to be repeated in some cases. The prognosis treated (Grandi et al., 2005). In contrast with a previous re-
is excellent. port, ivermectin (0.4 mg/kg, administered subcutaneously)
was not effective in one cat. Thoracic radiographs and peri-
AELUROSTRONGYLUS ABSTRUSUS odic fecal examinations are used to monitor the response to
Aelurostrongylus abstrusus is a small worm that infects the treatment. Treatment may have to be repeated in some cases.
small airways and pulmonary parenchyma of cats. Snails Antiinflammatory therapy with glucocorticoids alone
or slugs serve as intermediate hosts. Most cats with infec- often causes the clinical signs to resolve. However, eliminat-
tion have no clinical signs. Those cats that do are usually ing the underlying parasitic disease is a preferable treatment
young. Clinical signs are those of bronchitis. Abnormalities goal, and glucocorticoid therapy may interfere with the effec-
seen on radiographs may also reflect bronchitis, although tiveness of antiparasitic drugs. Bronchodilators may provide
a diffuse miliary or nodular interstitial pattern is present symptomatic relief and presumably do so without interfer-
in some cats. Pulmonary arterial enlargement can occur, ence with antiparasitic drug action. The prognosis in animals
making this disease a differential diagnosis in cats with with the infection is excellent.