Celiac Disease

Celiac disease is a helper T cell-mediated enteropathy that is triggered by dietary gluten in susceptible individuals (1% of the population). Gluten is the alcohol-soluble protein component of cereals, such as wheat, rye, and barley. Pathologically, there is villous atrophy and crypt hyperplasia in the small bowel.

Most patients respond to a gluten-free diet; however, some patients may be classified as having refractory celiac disease if they continue to have severe symptomatic enteritis that does not respond to at least 6 months of a strict gluten-free diet. Patients with refractory celiac disease are at a higher risk of developing complications (see below).

Refractory celiac disease can be classified as type 1 and type 2. Patients with type 1 refractory celiac disease have a normal intraepithelial lymphocyte phenotype, while those with type 2 have clonal expansion of aberrant intraepithelial lymphocyte populations and are at increased risk for developing lymphoma (enteropathy-associated T-cell lymphoma). Because of this risk of neoplasm (both lymphoma and carcinoma), abdominal pain in patients with celiac disease should increase suspicion of malignancy.

Small bowel series and CT enteroclysis may reveal:

• Reversed jejunoileal fold pattern: Loss of jejunal folds with a compensatory increase in ileal folds (the reverse of the normal pattern). This is the single most reliable sign for the diagnosis of celiac disease.
• Early flocculation: Barium droplets falling out of suspension due to increased secretions. Seen in other malabsorption syndromes. May obscure more specific features of celiac disease.
• Malabsorption: Dilution of contrast in the small bowel.
• Bowel dilatation: Jejunal dilatation > 4 cm; ileal dilatation gt; >3 cm.
• Delayed transit: Small bowel transit time is normally between 45 minutes and 90 minutes, but is significantly delayed in patients with celiac disease.
• Transient intussusception: Non obstructive and transient.

Conventional CT may reveal engorgement of mesenteric vessels and mesenteric adenopathy, the latter of which is more frequently seen in patients with refractory type 2 celiac disease and in patients with enteropathy-associated T-cell lymphoma. Conventional CT is also better at defining dilated loops of bowel than CT enteroclysis. Another suggestive finding is intramural fat deposition in the submucosal layers of the duodenum and jejunum.

Imaging is invaluable in defining the complications of this systemic disease, including:

• Small bowel intussusception: Rarely symptomatic
• Ulcerative jejunoileitis: Multiple benign ulcers of variable depth, predominantly involving the jejunum, but can also involve the colon. Occurs most commonly in patients with type 2 refractory celiac disease. On small-bowel series we may see focal constrictions, a spiculated pattern, or alternating areas of narrowing and dilatation. The clinical presentation may be similar to those of celiac disease complicated by a malignant neoplasm.
• Pneumatosis intestinalis: May reflect dissection of intraluminal gas into the inflamed small-bowel wall without accompanying intraabdominal abnormalities such as ischemic bowel or perforation. Pneumoperitoneum due to subserosal rupture of bubbles may also be seen and should not cause additional concern for rupture or ischemic bowel in isolation from clinical findings.
• Lymphoma: The most common malignant disease complicating celiac disease. This is mostly of T-cell in origin, but B-cell lymphoma of the gastrointestinal tract and extraintestinal lymphoma can also be seen. Typical imaging features include circumferential ulcers with short strictures in the proximal small bowel. Other imaging findings may include a nodular appearance to the bowel, an exophytic mass, or an aneurysmal pattern (cavitary dilatation of the small-bowel lumen and annular wall thickening). Clinically patients may present with abdominal pain and diarrhea despite strict adherence to a gluten-free diet; or bowel perforation, obstruction, and hemorrhage. Lymphoma may also predate clinical recognition of celiac disease.
• Cavitating lymphadenopathy syndrome: Rare complication of celiac disease characterized by cystic changes in mesenteric lymph nodes. On CT, there are cystic mesenteric masses with central low attenuation (fluid or fat) and thin, enhancing rims. Fat-fluid levels, if present, are unique to cavitating lymphadenopathy syndrome. Otherwise, differential considerations for low-attenuation mesenteric masses includes: Mycobacterial infection, Whipple disease, lymphoma, and necrotic metastases (e.g., germ cell tumors).
• Carcinoma: Patients with celiac disease are more susceptible to developing carcinoma of the pharynx, esophagus, duodenum, jejunum, and rectum.
• Hyposplenism: Splenic atrophy is found in up to 50% of adult patients with celiac disease and correlates with the severity of disease.
• Thrombocytosis:
• Thrombocytopenia:
• Venous thromboembolism: Characteristically involving the portal or hepatic veins.
• Leukopenia:
• Immunoglobulin A deficiency:
• Lane-Hamilton syndrome: Idiopathic pulmonary hemosiderosis in association with celiac disease.
• Hepatic disease: Most commonly steatosis, causing laboratory abnormalities. Nodular regenerative hyperplasia may also be seen.
• Biliary disease: Possible association with primary biliary cirrhosis.

References

• Huppert BJ, Farrell MA, Kawashima A, Murray JA. Diagnosis of cavitating mesenteric lymph node syndrome in celiac disease using MRI. AJR Am J Roentgenol. 2004 Nov;183(5):1375-7.
• Lomoschitz F, Schima W, Schober E, Turetschek K, Kaider A, Vogelsang H. Enteroclysis in adult celiac disease: diagnostic value of specific radiographic features. Eur Radiol. 2003 Apr;13(4):890-6. Epub 2002 May 23.
• Nishino M, Patrick JL, Connors JM. Lane-Hamilton syndrome. Radiology. 2010 Mar;254(3):985-8.
• Soyer P, Boudiaf M, Fargeaudou Y, Dray X, Hamzi L, Vahedi K, Lavergne-Slove A, Rymer R. Celiac disease in adults: evaluation with MDCT enteroclysis. AJR Am J Roentgenol. 2008 Nov;191(5):1483-92.