These tend to be more severe medical illnesses. Malabsorption is the
inability to absorb food, mostly in the small bowel but also due to the
pancreas. Causes include:
►Celiac disease (intolerance to gluten, a wheat product)
►Lactose intolerance (Intolerance to milk sugar, common in
non-Europeans)
►Fructose malabsorption
►Pernicious anemia (impaired bowel function due to the inability to
absorb vitamin B12)
►Loss of pancreatic secretions (may be due to cystic fibrosis or
pancreatitis)
►Short bowel syndrome (surgically removed bowel)
►Radiation fibrosis (usually following cancer treatment)
►Other drugs such as chemotherapy.
Treatment:
Treating the underlying condition (celiac disease, food allergy,
bacterial dysbiosis, etc.) usually resolves the diarrhea.
The two overlapping types here are of unknown origin:
►Ulcerative colitis: is marked by chronic
bloody diarrhea and inflammation mostly affects the distal colon near
the rectum.
►Crohn's disease: typically affects fairly well demarcated segments of
bowel in the colon and often affects the end of the small bowel.
Definition:
Abdominal discomfort or pain relieved by defecation and unusual stool
(diarrhea or constipation or both) or stool frequency, for at least 3
days a week over the previous 3 months. IBS symptoms: can be present in patients with a variety of conditions
including food allergies, infective diarrhea, celiac, and inflammatory
bowel diseases.
IBS can cause visceral hypersensitivity. While there is no direct
treatment for undifferentiated IBS, symptoms, including diarrhea, can
sometimes be managed through a combination of dietary changes, soluble
fiber supplements, and/or medications.
►Ischemic bowel disease: This usually affects older people and can
be due to blocked arteries.
►Bowel cancer: Some (but not all) bowel cancers may have associated
diarrhea. Cancer of the large colon is most common.
►Hormone-secreting tumors: some hormones (e.g. serotonin) can cause
diarrhea if excreted in excess (usually from a tumor).
►Bile salt diarrhea: excess bile salt entering the colon rather than
being absorbed at the end of the small intestine can cause diarrhea,
typically shortly after eating. Bile salt diarrhea is a possible
side-effect of
gallbladder removal. It is usually treated with
cholestyramine, a Bile
acid sequestrant.
►Other (alcohol, microscopic colitis, radiation, surgery)
Diarrhea is caused by infections or illnesses that either lead to
excess production of fluids or prevent absorption of fluids. Also,
certain substances in the colon, such as fats and
bile acids, can
interfere with water absorption and cause diarrhea. In addition, rapid
passage of material through the colon can also do the same.
Diarrhea occurs because more fluid passes through the large intestine
(colon) than that organ can absorb. As a rule, the colon can absorb
several times more fluid than is required on a daily basis. However,
when this reserve capacity is overwhelmed, diarrhea occurs.
To expel the contents of the lower digestive tract, the fluidity of the
contents of the small and large intestines is increased.
Active transport of Na+ back into the gut initiates a reverse sodium
transport. This causes both Cl- and HCO3 to follow passively, as well as
water.
Now in the intestines, the water dilutes toxins as well as triggering
contractions of the intestine due to increase in intestinal distension.
These contractions push the contents of the lower GI tract towards and
out of the anal canal.
Symptoms related to any diarrheal illness are often those associated
with any injury to the gastrointestinal tract, such as fever, nausea,
vomiting, and abdominal pain. All or none of these may be present
depending on the disease causing the diarrhea. The number of bowel
movements can vary up to 20 or more per day. In some patients, blood or
pus is present in the stool. Bowel movements may be difficult to flush
(float) or contain undigested food material.
Proper hygiene and food handling techniques will prevent many cases.
Traveler's diarrhea can be avoided by use of Pepto-Bismol and/or
antibiotics, if necessary. The most important action is to prevent the
complications of Dehydration.
There are some measures that can prevent diarrhea. Patients who are
receiving abdominal radiation therapy can be put into certain positions
to minimize exposure of healthy intestines to radiation. Diarrhea caused
by chemotherapy cannot be prevented; however, the administration of
atropine during treatment with irinotecanmay prevent diarrhea. Patients
should stop taking dietary supplements, as these can cause diarrhea. There are many dietary changes that can be made to prevent or reduce
diarrhea. Foods to avoid include:
►whole grain breads and cereals
►canned
onions,
corn, olives, pickles, and Brussels sprouts
