lunes, 5 de noviembre de 2018

Coeliac Disease Diagnosis

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By Ananya Mandal, MDReviewed by April Cashin-Garbutt, MA (Cantab)

Celiac disease involves inflammation and damage caused to the inner lining of the small intestines due to an autoimmune process.

Classification of celiac disease

Classical celiac disease – this has predominant gastrointestinal symptoms.
Atypical celiac disease – this has mostly non-gastrointestinal symptoms and symptoms if present may be single or less in severity.
Silent celiac disease with no symptoms

Differential diagnosis

Some of the diseases that need to be ruled out while making a diagnosis of celiac disease include:-

Tropical sprue, collagenous sprue and refractory sprue
Enteropathy caused by HIV/AIDS or due to combined immunodeficiency or due to autoimmune enteropathy
Damage to the intestines due to radiation and/or chemotherapy
Graft-versus-host disease after an organ transplant
Chronic ischemia of the gut
Giardiasis
Inflammatory bowel disease like Crohn’s disease
Eosinophilic gastroenteritis
Zollinger–Ellison syndrome
Enteropathy-associated T-cell lymphoma

Diagnostic pathway for detecting celiac disease

Suggested diagnostic pathway for detecting celiac disease includes:–

Detailed history of symptoms and family history of a similar condition. First degree relatives of a patient are more likely to get this condition.
Physical examination including a detailed general survey examining for signs of poor nutrition and anemia
Definitive diagnosis is made on the basis of positive serological tests and endoscopy with biopsy of the lesions in the small intestine.
Serological tests include tests that detect serum antibodies. These are basically classified into two groups based on the target antigens. One group is the Anti-tTG antibody tests and the other is Antigliadin antibody tests. Enzyme-linked immunosorbent assay (ELISA) tests are commonly applied.
The common tests applied are –
- IgA endomysial antibody (IgA EMA) - this test is most specific and sensitive and gives the highest diagnostic accuracy. These antibodies normally bind to the endomysium that is the connective tissue around smooth muscle. The test result is reported simply as positive or negative and if positive is strongly indicative of celiac disease.
- IgA tissue transglutaminase antibody or the IgA tTG - the antigen against which the antiendomysial antibodies are directed is tTG. Thus Anti-tTG antibodies are highly sensitive and specific for the diagnosis of celiac disease.
- IgA antigliadin antibody or the IgA AGA - Gliadins are the major proteins that are present in wheat and are called gluten. Serum antigliadin antibody levels are commonly increased in untreated celiac disease.
- IgG antigliadin antibody or the IgG AGA
Endoscopy with biopsy of the small intestine lesions. The typical findings seen on endoscopy include:-
Scalloped folds, fissures and a mosaic pattern
Smaller size and or disappearing of folds with maximum insufflation
Flattened folds of the inner walls of the small intestines

Intestinal biopsy

Once these abnormalities are detected, an intestinal biopsy is recommended. More than one biopsy is taken from the second or third part of the duodenum. Best samples are obtained with the suction biopsy using a Crosby capsule.

Once the biopsy is mounted on a slide it shows definitive findings under the microscope. The mucosa of the proximal small intestine is affected and the damage shows decreasing intensity towards the distal small intestine.

In more severe cases the damage may extend up to the ileum. In silent cases or asymptomatic cases the damage is mild.