Gut2019-08-21T10:02:58+00:00

Amyloid and the Gut

Amyloid involvement in the gastrointestinal tract is most commonly seen in AL amyloidosis but it can occur in all types of systemic amyloidosis and in localized amyloidosis.

The Normal GUT

The gastrointestinal tract includes the tongue, oesophagus, stomach, small and large bowel and liver.

The main role of the gut is to break down the food into small components to enable energy and nutrients to be absorbed into the body and expel the remaining waste as faeces.

What happens when the amyloid protein deposits in the gut?

The pattern of gastrointestinal symptoms varies substantially, not only between the different types of amyloidosis but also within them.

Diffuse infiltration of the amyloid can interfere with normal muscular contractions and the intestine cannot propel its contents adequately.

  • This will predispose it to bacterial overgrowth
  • May result in poor mixing of contents for digestion and absorption
  • If amyloidosis infiltrates the lining of the intestine it may interfere with normal cell function and impede digestion and absorption.

Symptoms

Symptoms are often nonspecific and range from:

  • Nausea
  • Reflux
  • Diarrhea
  • More severe hemorrhage and obstruction
  • Within the liver, amyloidosis represents a fibrotic disease with associated manifestations.

When the amyloid deposits interfere with the guts regular movements making it difficult for nutrients to pass from the gut into the body, symptoms may include:

  • Loss of appetite
  • Nausea/vomiting
  • Weight loss
  • GI bleeding
  • Gastro oesophageal reflux
  • Heartburn
  • Feeling full after a little food
  • Abdominal pain
  • Malabsorption.
  • Diarrhea
  • Constipation
  • Abdominal pain
  • Bleeding (This may appear as black bowel movements as well as bright red blood)
  • Bleeding from oesophageal varices.

Patients receiving chemotherapy and other treatments may experience treatment related symptoms affecting the GUT.

Symptoms from liver involvement may include:

  • Jaundice (Rare)
  • Anorexia
  • Steatorrhea
  • Ascites
  • Splenomegaly

Amyloid deposits can also be found in the tongue resulting in an enlarged rubbery tongue. (macroglossia)

This may affect:

  • Speech
  • Teeth (tongue pushes teeth out or the teeth cut into the enlarged tongue)
  • Eating
  • Difficulty breathing.

Diagnosis

If amyloidosis has already been definitively diagnosed symptoms in the gut may be put down to that disease.

Amyloidosis is sometimes found incidentally at colonoscopy.

A definitive diagnosis of amyloidosis can only be made through:

  • A tissue biopsy. This involves taking a small piece of tissue from the body often the fat pad on the tummy or the lip. Sometimes a more invasive biopsy may be taken from the gut at colonoscopy or other symptomatic part of the gastric system
  • Staining this biopsy with a dye, Congo red, in the laboratory
  • If amyloid is present, the biopsy will appear red under normal light and green (apple-green birefringence) under special polarized light.

Further testing on the biopsy will be performed to identify the type of amyloidosis.

It is imperative to clarify this as treatment is different for each type.

Further tests include:

  • Endoscopy and colonoscopy to see the extent of the amyloid or for diagnostic purposes
  • Amyloid in the gut can be diagnosed incidentally during a colonoscopy or other procedure
  • Radiological evaluation.

Treatment

In all types of amyloidosis, the goals of treatment are the same:

  • To stop or slow the production of the precursor protein
  • To support and preserve the affected organs while treatment is being given
  • To improve quality of life.

There is no “approved” treatment to stop the production of the amyloid protein available anywhere in the world at this time.

There is no “approved” amyloidosis treatment at this time anywhere in the world to stop the production of the abnormal protein amyloid, which deposits in the organs and tissues in all type of amyloidosis.

In AL present treatments have been borrowed from those which have been shown to work in myeloma, also a bone marrow disease. If the treatment reduces the production of the “light chains” there is a chance that organs and tissues affected by the amyloid may improve.

In AA amyloidosis if the underlying inflammatory disease is successfully controlled the production of the amyloid protein SAA may eventually reduce slowly improving organ function.

In ATTRv and ATTRwt a number of treatments are being trialed to stop the production of the protein in the liver and to stabilize the protein TTR in the blood. At this stage TTR stabilizing drugs have been introduced to therapy but these are not available in Australia as yet.
Consider reviewing the individual types of amyloidosis under the Patient and Carers menu heading above.

Because TTR is mainly produced in the liver a liver transplant may be considered in some highly selected ATTR-FAP patients, to try and slow or halt disease progression.

Treatment for amyloidosis affecting the gut is usually none specific and mostly aimed at symptom control which is extremely important, for example:

  • Nutritional and vitamin supplementation if there is malabsorption
  • Treatment for diarrhoea. A colostomy has been recommended in some extreme cases
  • Addressing any resulting infections from treatment related immune compromise
  • Surgical resection may be required in cases of large hemorrhage or obstruction
  • Removal of teeth if tongue becomes too swollen.

Meet the Gastrointestinal Tract!

How your digestive system works – Emma Bryce