PMC6195644_01
(A and B) Colonoscopy revealing acute purulent whitish-yellow exudate, edema, and mucosal friability in distal colon. Numerous small superficial ulcers in the proximal colon and multiple round, smooth, soft, and friable nodules in the mid-colon, which are endoscopic features of hemorrhagic nodules, are complementary to radiologic findings of thumbprinting and are highly characteristic of ischemic colitis.
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F1
Colonoscopy performed 3 days after receiving SPS was highly consistent with ischemic colitis in the descending colon to cecum (Figure 1).
Medium-powered hematoxylin and eosin stain of colonic mucosa biopsy showing atrophic crypts (C labels) and crypt dropout in the presence of moderately severe acute inflammation, which are compatible with ischemic colitis. Small sodium polystyrene sulfonate (SPS) crystals are embedded within colonic mucosa (arrows), which are better delineated at higher magnification in the surface inflammatory exudate (inset). The basophilic staining, angulated shape, and non-polarizable behavior of these crystals are characteristic for SPS in the absence of cholestyramine ingestion.
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F2
Histopathology revealed inflamed and ulcerated colonic mucosa and basophilic, non-polarizable, angulated, intramucosal crystals, highly consistent with SPS-induced ischemic colitis (Figure 2).