- Clinical science
Diarrheal diseases are very common and, in most cases, self-limiting. Diarrhea is defined either as the presence of more than three bowel movements per day, water content exceeding 75%, or a stool quantity of at least 200–250 g per day. Acute diarrhea lasts for no longer than 14 days and is typically caused by viral or bacterial infection or food poisoning. Chronic diarrhea is often caused by underlying gastrointestinal or endocrinological conditions, such as inflammatory bowel disease or hyperthyroidism. Further symptoms may include fever, bloody stools, abdominal pain, and nausea and vomiting in cases of gastroenteritis. Diagnostic tests for acute diarrhea are usually unnecessary, but they may include CBC, stool samples, or colonoscopy for severe or chronic cases. Most cases of diarrhea only require symptomatic treatment, such as oral rehydration, while severe cases may necessitate administration of antibiotics and hospitalization for IV fluid replacement.
- Diarrhea is present if one of the following criteria is fulfilled:
- Frequent defecation: ≥ three times per day
- Altered stool consistency: water content > 75%
- Increase in stool quantity: more than 200–250 g per day
- Acute diarrhea: lasting ≤ 14 days
- Persistent diarrhea: lasting > 14 days
- Chronic diarrhea: lasting > 30 days
|Helminth infections|| |
Risk factors and disease transmission
- Transmission by direct contact and droplets
- Day care attendance, nursing home residency, hospitalization
- Contaminated food and water (see )
- Animal exposure
|Exudative-inflammatory diarrhea|| |
|Secretory diarrhea|| |
|Osmotic diarrhea|| |
|Motor diarrhea|| || |
The loss of bicarbonate-rich fluid in severe diarrhea may cause non-anion gap metabolic acidosis!
- Acute or chronic diarrhea (see “Definition” above)
- Further possible symptoms
- Disease courses can range from mild to severe with need of hospitalization.
- Infections which typically occur in patients with a history of recent travel
- Very common while traveling in Asian (“Delhi belly”), African, and Latin American countries ("Montezuma's Revenge")
- A major cause of diarrhea among children in developing countries
- May be exudative-inflammatory diarrhea or secretory diarrhea
- Most commonly caused by enterotoxigenic Escherichia coli (ETEC)
- Other pathogens: Campylobacter jejuni, Shigella spp., Salmonella spp., other E. coli strains (e.g., EAEC), protozoa (e.g., Giardia), viral diarrhea (norovirus, rotavirus, astrovirus)
- Definition: self-induced diarrhea, usually by ; often occurs in individuals with
- Most prevalent in women
- Patients are usually employed in the health field.
- History of multiple hospital admissions
- Clinical findings: chronic watery diarrhea without identifiable cause
- Correction of electrolyte disturbances and dehydration
- Referral to psychotherapy
- Clinical features
- Melanosis coli: benign hyperpigmentation of the colonic mucosa caused by anthraquinone abuse
The workup for diarrhea includes a detailed patient history (e.g., recent travel), physical examination, and laboratory tests to assess severe cases.
Laboratory tests are usually not required in acute cases and are instead reserved for diagnosis of severe or chronic disease.
- CBC: may show anemia or leukocytosis
- Stool samples: leukocytes; ova and parasites
- Stool culture
- C. difficile toxin assay
- Colonoscopy: in patients with chronic diarrhea without identifiable cause
- CT: if diverticulitis or IBD is suspected
Since most cases of acute diarrhea are self-limited, treatment is mostly symptomatic, focusing on oral rehydration, and rarely requires medication.
- Rehydration (especially in children)
- Antidiarrheal agents: (e.g., loperamide): may be given in mild to moderate cases; should be avoided if there is fever or blood in stools (indicative of systemic disease)
- Antibiotics: are generally not indicated
- Treatment of the underlying condition in cases of chronic diarrhea