Diarrhea

Diarrhea

The bowel frequency of the normal population ranges from three bowel movements per day to one bowel action every third day, and a normal stool consistency ranges from porridge-like to hard and pellety.

The term applied to :  increased stool frequency and loose or watery stools.

Gastroenterologists define diarrhoea as the passage of more than 200 g of stool daily, and measurement of stool volume is helpful.

The most severe symptom in many patients is urgency of defecation, and faecal incontinence is a common event in acute and chronic diarrhoeal illnesses.

 Acute diarrhea  : This is extremely common and usually due to faecal-oral transmission of bacteria, their toxins, viruses or parasites. Infective diarrhoea is usually short-lived and patients who present with a history of diarrhoea lasting more than 10 days rarely have an infective cause. A variety of drugs, including antibiotics, cytotoxic drugs, proton pump inhibitors and NSAIDs, may be responsible for acute diarrhoea.

Chronic or relapsing diarrhea:

The most common cause is irritable bowel syndrome ,which can present with increased frequency of defecation and loose, watery or pellety stools. Diarrhoea rarely occurs at night and is most severe before and after breakfast. At other times the patient is constipated and there are other characteristic symptoms of irritable bowel syndrome. The stool often contains mucus but never blood, and 24-hour stool volume is less than 200 g. Chronic diarrhoea can be disease of the colon or small bowel, or malabsorption. Clinical presentation, examination of the stool, routine blood tests and imaging reveal a diagnosis in many cases.

A series of negative investigations usually implies irritable bowel syndrome but some patients clearly have organic disease and need more extensive investigations.

Colonic diarrhea:

Clinical features: Blood and mucus in stool. Cramping lower abdominal pain.

Some causes:Inflammatory bowel disease. Neoplasia. Ischaemia. Irritable bowel syndrome.

 Investigations: Colonoscopy with biopsies.

Malabsorption:

Clinical features: Steatorrhoea. Undigested food in the stool. Weight loss and nutritional disturbances.

Some causes:

Pancreatic (Chronic pancreatitis, cancer of pancreas, cystic fibrosis).

Enteropathy (Coeliac disease, tropical sprue, lymphoma, lymphangiectasia)

Obstructive Jaundice..

Investigations: (US, CT scan, MRCP, small bowel biopsy, barium follow through).

Small bowel  diarrhea:

Clinical features: Large volume watery stool, abdominal bloating, cramping mid-abdominal pain.

Some causes: VIPoma. Drug induced (NSAIDs, Aminosalicylates, SSRIs).

Investigations: Stool volume, Gut hormone profile, Barium follow through.