Malabsorption and Coeliac Disease

Objectives

  1. Recognise the clinical features of coeliac disease
  2. Describe the pathogenesis of coeliac disease
  3. Understand how coeliac disease is diagnosed
  1. Recognise the histological features of coeliac disease
  2. Describe the complications of coeliac disease
  3. List other forms of malabsorption

Good reference site:

 

What is Celiac Disease?

Coeliac disease also known as coeliac sprue is the most common form of malabsorption in Ireland. Autoimmune.

  • Immune-mediated enteropathy (git disease) triggered by the ingestion of gluten containing cereals (wheat, rye, barley)
  • In genetically predisposed individuals

 

What is a “Sprue?”

a channel through which metal or plastic is poured into a mould. The metal then harden in the channel and fills up, to become an arm that holds the molded item.

Coeliac Sprue: Is then named so because the “villi-pockets” are filled up with hyperplasia cells and the channel hence no long exist.

 

Incidence:

  • 1:190 in Derry
  • 1:128 in Sardinia
  • 1:200 in central Europe
  • 1:100 Galway – (highest) in the world
  • Nearly 1% of population

 

Clinical Features

Adults generally present between ages 30 – 60

  • Spectrum of gluten sensitivities
    • Latent coeliac disease:
      • positive TTG serology without villous atrophy
      • (may have increased IELs – intraepithelial lymphocytes)
    • Silent coeliac disease:
      • positive TTG serology and villous atrophy without symptoms
  • Clinical Coeliac disease
    • Clinical manifestation: Intestinal vs Extraintestinal
Intestinal Manifestation

  • Abdominal distension: nothing is being absorbed
  • Abdominal pain
  • Anorexia
  • Diarrhoea or constipation
  • Steatorrhoea: fatty feces

(stools won’t flush)

  • Failure to thrive in children(malnutrition)
  • Weight loss(adults)
  • Fatigue
 Extraintestinal Manifestation

  • Arthritis/joint pain
  • Osteoporosis
  • Autoimmune thyroid disease
  • Hyposplenism
  • Iron-deficiency anaemia: malabsorption( hypochromic)
  • Mix of iron and folate deficiency
  • Short stature and pubertal delay in children
  • Dermatitis herpetiformis: itchy blistering of the skin(AI disease giant epidermis)
  • Lymphocytic gastritis and lymphocytic colitis
  • Lymphocytic infiltrate of colon epithelia

Pathogenesis

Coeliac Disease

Gliadin ingestion results in activation of gliadin-reactive T cells in the intestine. These Celiac Disease 4 T (CD4T) cells are hypothesized to provide immunologic help to B cells to produce TG autoantibodies, in addition to promoting a favorable cytokine milieu to help drive the celiac disease process. Gliadin ingestion is also directly toxic to the enterocytes, resulting in IL-15 release and subsequent upregulation of MIC-A on the enterocyte surface. Infiltrating intraepithelial lymphocytes also differentiate in the presence of IL-15 into lymphocyte-activated killer cells that are cytolytic to enterocytes through the NKG2D/MIC-A interaction. (From Hum Immunol. 2006 Mar;67(3):204-7. Epub 2006 Mar 31)

 

Diagnostics

Diagnosis of celiac disease is usually first suggested by the presence of TG autoantibodies, but established by biopsy of the small intestine by upper intestinal endoscopy. Histology will show some degree of villous atrophy and crypt hyperplasia. Intraepithelial lymphocytes are typically seen in celiac disease lesion, but their presence alone is insufficient to diagnose celiac disease.

  • Serological Testing

 

Histological Features

  1. Villous atrophy, crypt hyperplasia, increased plasma cells in lamina propria
  2. Increased intraepithelial lymphocytes (IELs)
  3. Presence of CD3+, CD8+ T cells

Normal vs Coeliac Disease:

Villous atrophy, crypt hyperplasia, increased plasma cells in lamina propria

 

Complications

  1. Refractory coeliac disease
  2. Enteropathy-associated T cell lymphoma (EATL)
  3. Small bowel adenocarcinoma

Refractory coeliac disease
is defined by persistent or recurrent malabsorptive symptoms and villous atrophy despite strict adherence to a gluten-free diet (GFD) for at least 6–12 months in the absence of other causes of non-responsive treated celiac disease (CD) and overt malignancy.

Type 1: polyclonal expansion of T cells

  • Much more straightforward

Type 2: monoclonal expansion of T cells; risk for development of EATL (enteropathy-associated t-cell lymphoma)

  • Phenotypcially abnormal population of t-cells

Why is Type 2 more severe a state?

EATL (enteropathy-associated t-cell lymphoma)
is a very rare type of non-Hodgkin lymphoma (NHL). It may also be called enteropathy-type T-cell lymphoma or intestinal T-cell lymphoma. It is a fast-growing (aggressive) T-cell lymphoma.

  • Develops in jejunum or ileum
  • Often a history of refractory coeliac disease; some patients no history coeliac disease
    • Not always: might be silent celiac

Presentation:

  • Abdominal pain
  • (frequently) Intestinal perforation (CI chemo)
  • Often multifocal disease

Prognosis: very poor; median survival 10 months

 

 

Other Forms of Malabsorption

 

  1. Giardia lamblia infection (https://www.healthline.com/health/giardiasis)
  1. Tropical sprue: bacterial overgrowth (https://www.healthline.com/health/tropical-sprue)
  1. Whipple disease (https://www.healthline.com/health/whipples-disease)
    1. Gram positive actinomycete, proliferating in macrophages
  1. Collagenous sprue (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3088692/)
  1. Disaccharidase (lactase) deficiency (https://education.questdiagnostics.com/insights/24)
    1. Osmotic diarrhea from unabsorbed lactose

 

 

 

Summary

Coeliac disease relatively common in Ireland, especially in the West of Ireland

Gluten-sensitivity in genetically predisposed individual

Must see positive serology and characteristic histological features on duodenal biopsy for diagnosis

Lifelong gluten-free diet required

Most serious complication is EATL