Diarrhea means loose, watery
stools which occur frequently. It occurs when the intestines fail to absorb the
liquids or when excess fluid leaks into the lumen.
symptoms that may be associated with diarrhea include abdominal
abdominal cramps, fever, bloating, blood in stool and
fever. Depending on the cause, diarrhea may last for a day to several
days.If diarrhea lasts for less than 2 weeks, it is
acute diarrhea. If it lasts longer than 4 weeks, it is called chronic
The causes of diarrhea include
infection, medications, endocrine-related conditions, digestive disorders or
Diarrhea is a frequent cause of death due to
dehydration among children. Infections are the main cause of diarrhea in
underdeveloped and developing nations.
the Causes of Diarrhea?
The causes of diarrhea
due to bacteria, virus and
parasites can cause diarrhea. The patient gives a history of intake of possible
contaminated food or water and may suffer from vomiting, fever and pain in the
abdomen as well.Bacterial Causes of
Viral Causes of
- Bacteria causing diarrhea are Salmonella,
Shigella, E.coli, Vibrio cholera,
Campylobacter and Clostridium difficile. The type
of stools and associated symptoms may give a clue on the type of infection.
- Vibrio cholerae produces watery
diarrhea and causes severe dehydration.
- Clostridium difficile produces
watery and sometimes bloody stools. The patient may give a history of prior
antibiotic use or hospitalization.
- Shigella produces
dysentery with mucus and/or blood in the
- Some patients with
diarrheal infections with organisms like Salmonella, Campylobacter, Shigella and
Yersinia may develop reactive arthritis where the patient shows features of
arthritis, sore or pink eyes, and inflammation of the
- Infection with enterohemorrhagic E
coli and Shigella can result in kidney failure due to hemolytic uremic
The viral causes of diarrhea include
Norwalk virus, viral hepatitis and Cytomegalovirus. Rotavirus is the common
causative agent of diarrhea among the children. Cytomegalovirus often
causes diarrhea in patients with reduced immunity. Viral diarrhea is usually
self-limiting and does not require
antibiotics.Parasitic Causes of
Cryptosporidium are some of the parasites which cause diarrhea.
dysentery.Diarrhea due to
Diarrhea can be a side effect of almost
all oral medications. There are certain drugs which cause diarrhea by various
Drugs like citrates, sulfates, phosphates,
magnesium containing laxatives and mannitol cause diarrhea due to osmotic water
release into the lumen of the intestine.
- Antibiotics like amoxicillin,
antiarrhythmic drugs like quinine, colchicine,
non-steroidal anti-inflammatory drugs, prostaglandins and biguanides cause
diarrhea due to increased secretion.
- Drugs like
erythromycin, metoclopramide and laxatives cause
diarrhea due to the increased intestinal motility.
like acarbose and
aminoglycosides cause diarrhea due to
- Broad-spectrum antibiotics disturb the
normal gut flora. This leads to the infection with Clostridium
difficile causing pseudomembranous enterocolitis, which causes
A history of intake of the medications should be
obtained from a patient with diarrhea. Diarrhea often reduces when the
medication is stopped and replaced with a different
- Irritable bowel syndrome
(IBS): It is functional diarrhea that can cause watery stools.
IBS causes symptoms of crampy abdominal pain
along with either diarrhea or constipation. The abdominal discomfort is relieved
by defecation. It is more common among women and in developed nations. Emotional
stress, eating and infections exacerbate IBS. The tests are normal in
- Inflammatory Bowel Disease (IBD)
manifests in two forms, ulcerative colitis or Crohn’s disease.
Ulcerative colitis involves colon, rectum and causes diarrhea, blood in stool
and pain in abdomen. Crohn’s disease initially involves ileum and later involves
the whole gastrointestinal system. Crohn’s disease causes diarrhea, pain in the
abdomen and fever.
- Microscopic Colitis
is due to microscopic inflammation of the colon. It causes
intermittent secretory diarrhea.
Diarrhea is seen in intestinal malabsorption conditions like celiac
disease, Whipple’s disease and mesenteric ischemia. Celiac disease is due to the
hypersensitivity of the small intestine to gluten leading to malabsorption.
Malabsorption of fat results in greasy, foul-smelling and difficult to flush
stools. The patient may suffer from other nutrient deficiencies and weight
Intolerance is characterized by an inability of the intestines
to digest lactose due to lack of the enzyme lactase. It causes chronic diarrhea,
bloating and pain in abdomen. Diarrhea improves on avoiding lactose-containing
colon carcinoma and villous adenocarcinoma can cause diarrhea. The patient may
give a history of severe weight loss.
Causes of Diarrhea
- Hyperthyroidism: High
thyroid hormone levels increase the motility of the gut and cause diarrhea.
Other symptoms of hyperthyroidism like increased heart rate, hand tremors and
easy fatigue may be noted in these
- Gastrinoma is a
gastrin-secreting tumor of the pancreas or duodenum. Increased secretion of
gastrin causes excessive release of hydrochloric acid into the gut and increases
the gut motility to cause diarrhea. The patient suffers from stomach ulcers
which do not respond to treatment.
- VIPoma is a tumor in the pancreas.
The tumor secretes excess Vasoactive Intestinal Peptide (VIP) leading to
diarrhea. The tumor results in large volumes of watery stools that can cause
dehydration and electrolyte abnormalities.
Disease is due to adrenal gland insufficiency. Diarrhea is a
common symptom in the patients with Addison’s
- Mastocytosis is a disorder
of the mast cells, which are often involved in allergic and inflammatory
reactions. Diarrhea, abdominal pain, nausea and vomiting are common in
- Carcinoid Syndrome is
seen when the substances like serotonin and kallikrein produced by a carcinoid
tumor are released into systemic circulation. Watery diarrhea is common in
carcinoid syndrome. The patient may also experience episodes of flushing,
wheezing and breathlessness, and skin
Diarrhea is common among patients after
surgeries like gastrectomy (surgical removal of part or all of the stomach),
cholecystectomy (gall bladder removal), vagotomy (removing part of the vagus
nerve) and intestinal resection. A history of prior surgery is obtained from the
patient. The surgical scar may be noted to confirm the cause of the
Diarrhea can also be caused due to anxiety,
excess caffeine and alcohol consumption and radiotherapy.