Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

190 Small Animal Radiolo g y and Ultrasono graphy
P U L M O N A RY I N F I LT R AT E S W I T H E O S I N O P H I L I A
A syndrome has been described in which dogs develop medium to large areas of alveolar
pattern infiltrates (Fig. 2-170). 519-527 In some cases, associated findings may include
lymphadenopathy and a bronchial, fine linear interstitial pattern. Less frequently seen are
pleural effusions and nodular masses. The affected dogs usually have an associated
eosinophilia. The exact cause of the eosinophilia frequently is not determined.
C A R D I O G E N I C A N D N O N C A R D I O G E N I C P U L M O N A RY E D E M A
Pulmonary edema is the flooding of the end–air spaces with fluid. Pulmonary edema can
be subdivided into that caused by left heart failure, cardiogenic pulmonary edema, and that
due to other causes, noncardiogenic pulmonary edema.
Cardiogenic pulmonary edema is the most frequently seen type of pulmonary edema.
It is typified by alveolar pattern infiltrates that are located in the hilar and perihilar areas,
but atypical distributions occasionally can be seen (Figs. 2-171 and 2-172). If particularly
severe, the infiltrates may involve all portions of the lung (Fig. 2-173) and free pleural fluid
may be observed. If radiographed early in the pathogenesis of left heart failure or after successful
treatment, the lesion may be predominately an interstitial pattern infiltrate. The
lesions usually resolve from the periphery toward the hilus, the reverse of their evolution.
There are many causes of noncardiogenic pulmonary edema, including neurologic
problems such as head trauma or seizures, electric shock, severe allergic disease,
advanced uremia, pancreatitis, pulmonary reexpansion, irritating inhalants such as
smoke or heat, near drowning, radiation damage, and acute respiratory distress syndrome.
528-539 The more commonly seen lesions are typically in the dorsal and caudal
portions of the caudal lung lobes and are associated most frequently with electric shock
or seizures (Figs. 2-174 and 2-175). Other types of noncardiogenic edema may be distributed
more diffusely.
N E O P L A S I A
The vast majority of primary and metastatic pulmonary tumors cause interstitial pattern
infiltrates. 540-544 However, there are several uncommon exceptions. These include
Fig. 2-170 A 6-year-old male Whippet was evaluated for cough. An
absolute eosinophilia was present. The dog’s test results for dirofilariasis
were negative. The ventrodorsal radiograph revealed patchy areas
of alveolar pattern infiltrate (arrows) in multiple lung lobes.
Diagnosis: Pulmonary infiltrates with eosinophilia. (From Burk RL:
Radiographic examination of the cardiopulmonary system. Vet Clin
North Am 1983; 13:241.)