Celiac disease

Coeliac disease, also known as non-tropical sprue, is a T-cell mediated autoimmune chronic gluten intolerance condition characterised by loss of villi in the proximal small bowel and gastrointestinal malabsorption (sprue).

It should always be considered as a possible underlying aetiology in cases of iron deficiency anaemia of uncertain cause.

Epidemiology

Coeliac disease is relatively common in Caucasians, 1 in 200, but it is extremely rare in Asian or black people. There are two peaks of presentation, small number of patients present early in childhood and the second more common group of patients presents at 3^rd and 4^th decades. 

Clinical presentation

Many patients have paucity of symptoms with no GI upset. However, abdominal pain is considered the most common symptoms. Other findings include:

• iron deficiency anaemia and guaiac-positive stools 
• diarrhoea
• constipation
• malabsorption including fat soluble vitamins
• weight loss

Pathology

Coeliac disease is a chronic autoimmune disease induced in genetically susceptible individuals after ingestion of gluten. Small bowel mucosa is primarily affected (submucosa, muscularis and serosa remain normal), resulting in progressive degrees of villous inflammation and destruction (which starts in duodenum and extends into ilium) with resulting of induction crypt hyperplasia. Loss of villi, which absorbs fluid, and hypertrophy of crypts, which produce fluid, result in fluid excess in the small bowel lumen ⁸.  

The villous atrophy that occurs within the bowel also results in malabsorption of iron, folic acid, calcium and fat soluble vitamin resulting in a variety of signs, some of which may be non-specific.

The gold standard diagnostic test is a duodenal biopsy taken at endoscopy.

Histology

• total villous loss, initially blunting progressing to flattened mucosa
• hyperplasia of the crypts 
• epithelial infiltration with T-cell lymphocytes

Markers

Additionally, serum antibodies may be raised:

• anti-tissue transglutaminase antibody (anti-tTG), IgA
• deamidated gliadin peptide (DGP) antibodies, IgA
• anti-endomysial antibodies (EMA), IgA class
• anti-reticulin antibodies (ARA), IgA class

Quantitative immunoglobulin A (IgA): measures the total level of IgA in the blood to determine if someone is deficient in the IgA class of antibodies. The IgG class of anti-tTG may be ordered for people who have a deficiency of IgA.

Associations

• idiopathic pulmonary haemosiderosis: as part of the Lane Hamilton syndrome ⁴
• dermatitis herpetiformis
• IgA deficiency
• cavitatorycavitary lymph node syndrome
• small bowel lymphoma, in particular enteropathy-associated T cell lymphoma but also other non-Hodgkin lymphomas¹¹
• Down syndrome (trisomy 21)¹²

Radiographic features

Fluoroscopy

Features of small bowel barium studies are not sensitive enough for confident diagnosis, but some changes may be seen:

• small intestinal dilatation due to excess fluid
• dilution of contrast
• multiple non-obstructing intussusception
• jejunoileal fold pattern reversal (including jejunalisation of the ileum)
• moulage sign
• mosaic pattern
• flocculation
• segmentation

CT enteroclysis

Features present on CT enteroclysis may include ^3,6:

• reversed jejunoileal fold pattern: thought to have the highest specificity is considered the most discriminating independent variable for the diagnosis of uncomplicated coeliac disease
• ileal fold thickening
• vascular engorgement
• prominent mesenteric lymph nodes, may cavitate with fluid fat level
• submucosal fat deposition in long standing cases
• other adjunctive features
  • splenic atrophy

Complications

• increased risk of malignant conditions such as small bowel lymphoma(mainly T cell type) and small bowel adenocarcinoma
• ulcerative jejuno ileitis ¹
• increase risk of development of carcinoma of oesophagus
• cavitatory lymph node syndrome^1-2
  • hyposplenism ¹