Reflux of barium into the common bile duct is occasionally seen as a result of rigidity and loss of sphincter control at the vaterian segment. Involvement of the biliary and pancreatic ducts may occasionally occur with strongyloidiasis.

The findings on superior mesenteric arteriography have been reported in two cases: both showed an increase in size of the arteries supplying the duodenum and jejunum, particularly the main trunk of the superior mesenteric artery. It has been postulated that the swollen and edematous intestine may be wedged, at the level of the third part of the duodenum, into the angle formed by the superior mesenteric artery and the aorta, to produce a "superior mesenteric artery syndrome" which is reversible. Autopsy findings in one case seem to support this theory.

In a 1998 report, Hizawa et al used double-contrast barium studies to compare the radiological features of strongyloidiasis with isosporiasis (infection with the parasite Isospora belli) in 5 Japanese patients, 4 of whom had impaired cellular immunity (3 had HTLV-1 infection). All had duodenal biopsy with histological examination, proving strongyloidiasis in 3 patients and isosporiasis in the other two. All had diarrhea clinically, and 3 had weight loss. In both diseases, the duodenum and jejunum were affected and showed similar radiographic changes as the diseases progressed. Three patients with diarrhea of one year or less showed only minimal or irregularly thickened mucosal folds as a result of inflammation. Two patients with chronic disease of 17 and 30 years respectively showed a markedly granular mucosa with effacement of the folds. These chronological differences in the radiographic features appeared to reflect the histological degree of villous atrophy.

Pulmonary Strongyloidiasis

The chest radiograph will be normal in the majority of patients infected with Strongyloides, but those with clinical signs and symptoms of pulmonary strongyloidiasis will usually show abnormal findings on chest radiography or CT scanning. These findings at different stages of the disease have been well documented by Woodring, Halfhill and Reed (1994). During the stage of larval migration from the capillary bed into the alveoli, especially in cases of autoinfection, a foreign body reaction, pneumonitis, and hemorrhage can occur within the lungs. Fine miliary nodulation or diffuse interstitial reticulation will be seen on chest x-rays or CT scans at this stage. As the infection intensifies, there may be bronchopneumonia with scattered, ill-defined, soft alveolar, segmental or even lobar opacities similar to those seen in Löffler's syndrome or eosinophilic pneumonitis (Fig. 13.18). These pulmonary opacities can be chronic and serial radiographs may show their migration through different portions of the lungs, often in a peripheral location and associated with peripheral blood eosinophilia.

Fig. 13.18 Larval phase of strongyloidiasis involving the lungs. (A) Diffuse miliary nodularity and ill-defined patchy consolidation scattered throughout both lungs in a 36-year-old Puerto Rican woman (same patient as in Fig. 13.12). The chest x-ray was taken 2 months before the small bowel series and shows changes in the lungs which can be seen in some patients with strongyloidiasis due to an inflammatory reaction about the developing larvae in the alveoli. There is also right paramediastinal widening which may have been due to lymphadenopathy from the patient's underlying lymphoblastic leukemia. A chest film taken 1 month later showed virtually complete resolution of the scattered areas of pneumonitis. (B) Patchy pneumonitis in the left lung base of a patient from India. The appearance of the pulmonary infiltrate may resemble an acute pneumonitis or pulmonary infarct. This patient had an overwhelming Strongyloides autoinfection and the pulmonary stage of development of the larvae has caused extensive damage to the alveoli with multiple minute hemorrhagic areas due to the trauma of larval migration. These findings were confirmed on autopsy. (C) Hematoxylin-eosin stained section of human lung showing a larva of S. stercoralis in an alveolus. (C. courtesy of Dr. Herman Zaiman).