Page 366 - Feline diagnostic imaging

374 22 Gastrointestinal Disease

(d) (e)

(f)

Figure 22.28 (Continued)

acoustic shadowing. Thickening of the cecal wall was pre- radiopaque than usual due to decreased water content. In a
sent in about two‐thirds of the cats with four cats having study comparing normal cats to cats with megacolon or
a loss of wall layering in the cecum. The ileal wall was obstipation, the ratio of maximal colonic diameter to
thickened in one‐fifth of the cats; the colonic walls were length of L5 was less than 1.28 whereas in cats with mega-
thickened in about one‐third. Altered wall layering of the colon, the ratio exceeded 1.48 [54].
ileum or colon was present in some of these cats.
Enlargement of the cecal lymph nodes was also present in 22.5.4 Infiltrative Disease
18/21 cats in which these nodes could be identified.
Underlying causes of these changes are variable but in Cats with infiltrative disease in the large intestine
this study included acute enteritis, foreign body in the (Figures 22.30 and 22.31) usually present with a history of
cecum or small intestine, pancreatitis, cholangitis, hepa- large bowel diarrhea and include conditions such as
tocellular necrosis, hyperthyroidism, lymphoplasmocytic ulcerative colitis, granulomatous colitis, colonic or rectal
enteritis, and parasitism [53]. neoplasia, and fungal or parafungal disease. Most often,
survey radiographs appear normal. On a barium enema
study, the diameter of the colon is decreased and the colon
22.5.3 Obstipation/Megacolon
appears shortened. Fistulae and strictures may be present.
Causes of obstipation and/or megacolon (Figure 22.29) The wall may be thickened and margins are irregular.
include pelvic fractures, masses in the pelvic region, stric- Sonographically, signs are similar to those seen in the small
ture in the colon, and neuromuscular problems. On radio- intestine when infiltrative disease is present. The intestinal
graphs, the colon is distended. Fecal contents are more wall is thickened and exhibits a loss of wall layering or