Differential diagnosis of diarrhea and constipation

	Diagnosis	Sonographic signs
	Common
	Crohn disease	Homogeneous, hypoechoic wall thickening, often i 10 mm; discontinuous pattern of involvement; decreased peristalsis
	Ulcerative colitis	Continuous pattern of involvement with intraluminal wall irregularities (pseudopolyps); wall thickening is less common
	Abdominal tumor	Target pattern, circumscribed wall thickening to 8 mm
	Obstructive lesion	Bidirectional peristalsis; fluid-distended bowel loops
	Chronic pancreatitis, pancreatic insufficiency	Nonhomogeneous parenchyma with coarse, high-level internal echoes (fibrosis, calcification)
	Diverticulitis	Thickened, hypoechoic bowel wall; incomplete acoustic shadow from intraluminal air
	Less common
	Hernia	Hernial sac with wall-thickened bowel loops, gap in the peritoneum
	Rare
	Pseudo-obstruction	Dilated bowel loops, decreased peristalsis, no obstruction of intestinal transit

Conditions that cannot be diagnosed with ultrasound
Common: Viral, bacterial and parasitic bowel disease; Whipple disease; panarteritis nodosa of
the mesenteric vessels; drugs, poisoning, irritable bowel Less common: Lactase deficiency, reflex response to pain, fluid deficiency, electrolyte disorders Rare: Abdominal toxoplasmic lymphangitis, malabsorption syndrome.

intestinal polyps, carcinoid syndrome, hormone-producing tumor, hyper- or
hypothyroidism, food allergy, antibody deficiency syndrome, cystic fibrosis, mesenteric
lymph node tuberculosis.

Sonographic findings:
x Homogeneous, hypoechoic wall thickening, often i 10 mm, affecting a long
segment of the bowel wall; a three-layered wall structure is occasionally seen
x Decreased peristalsis
x Luminal narrowing with prestenotic dilatation
x Discontinuous pattern of involvement
x Involvement of the cecum and terminal ileum
x Frequent lymphadenopathy around affected bowel segments
x Complications can be clearly identified:
– Abscess (hypoechoic to anechoic mass, stationary, with irregular margins)
– Conglomerate mass
– Fistula
– Ascites

Accuracy of sonographic diagnosis: The bowel-wall changes detectable with
ultrasound are not specific for chronic inflammatory bowel disease. However,
the sum of the changes and their distribution pattern, combined with the patient’s
history, provide a very high index of suspicion. The detectable complications will
also suggest the correct diagnosis.

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