Bacterial overgrowth, (increased bacterial content in
the small intestine) commonly occurs after resection of the ileocecal
valve (Fig. 9). It causes inflammation of the intestinal mucosa, and breaks
down bile salts so that they are inactive in fat absorption, resulting
in the malabsorption of nutrients.
Figure 9 –
Reflux of Colonic Bacteria
After Resection of the Ileocecal Valve
When there is an excessive amount of bacteria in the
ileum, bile acids are broken down, thus reducing the amount of bile acids.
Since fat must combine with bile acids in order to be absorbed, a reduction
in the amount of bile acid results in unabsorbed fat. The unabsorbed fat
passes into the colon, where it causes steatorrhea (fat in the stool).
Bacterial overgrowth also disrupts the normal absorption
of vitamin B12, which takes place in the last section of the ileum. The
bacteria metabolize vitamin B12, making it unavailable for normal absorption.
Individuals with this complication can develop vitamin B12 deficiency,
which is characterized by pernicious anemia and neurological changes.
The disturbances caused by bacterial overgrowth may
also result in malabsorbed carbohydrates. This eventually leads to bacterial
production of a substance called D-lactate that is absorbed from the colon,
but can only be metabolized to a limited extent by humans. The metabolized
D-lactate is excreted through the kidneys in the urine. Occasionally,
the absorbed D-lactate that cannot be metabolized accumulates in the body.
This leads to the development of metabolic acidosis, a condition with
characteristic neurological symptoms, such as the appearance of inebriation,
even though blood alcohol levels are normal.
This information
is provided as a general educational service
and is not intended to recommend any particular treatment plan
or to replace the advice of physicians. It is important that patients
seek and rely on the advice of a healthcare professional
about their individual medical conditions.
