Diarrhea

SOURCE

Source: Fabel PH, Shealy KM. Diarrhea, constipation, and irritable bowel syndrome. In: DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey LM, eds., Pharmacotherapy: A Pathophysiologic Approach. 10th ed. New York, NY: McGraw-Hill; 2017. http://accesspharmacy.mhmedical.com/content.aspx?bookid=1861&sectionid=146059459. Accessed March 14, 2017.

DEFINITION

• Self-limited increase in frequency and decrease in consistency of fecal discharge primarily due to viral, bacterial, or protozoal infection.

ETIOLOGY

• Most common bacterial causes: Shigella, Salmonella, Campylobacter, Staphylococcus, and Escherichia coli

• Most common viral causes: Norwalk and rotavirus.

• Medications (Table 1)

PATHOPHYSIOLOGY

• Imbalance in absorption and secretion of water and electrolytes due to.

  • Change in active ion transport by decreased sodium absorption or increased chloride secretion (secretory diarrhea)

  • Change in intestinal motility caused by.

    • Reduced contact time in small intestine.

    • Premature emptying of colon.

    • Bacterial overgrowth.

  • Increase in luminal osmolarity.

  • Increase in tissue hydrostatic pressure.

PREVENTION

• Initiate isolation techniques in daycare centers and nursing homes to prevent transmission of viral illness.

• Practice strict food handling, sanitation, water, and other environmental hygiene practices to prevent transmission of bacterial, parasitic, and protozoal infections.

• Treat drinking water and limit consumption of fresh vegetables; in addition, prophylactic antibiotics and bismuth subsalicylate may be indicated when traveling.

CLINICAL PRESENTATION

SIGNS AND SYMPTOMS

• Acute diarrheal episodes subside within 72 hours of onset.

• Chronic diarrhea involves frequent attacks over extended periods of time.

• Abrupt onset of.

  • Nausea.

  • Vomiting.

  • Abdominal pain.

  • Headache.

  • Fever.

  • Chills.

  • Malaise.

• Frequent, nonbloody bowel movements over 12–60 hours.

• Pain described as gripping or aching localized to.

  • Hypogastric region.

  • Left or right lower quadrant.

  • Sacral region.

• Chronic diarrhea associated with.

  • Weight loss.

  • Anorexia.

  • Chronic weakness.

• Physical exam demonstrates hyperperistalsis with borborygmi and generalized or local tenderness.

DIAGNOSIS

LABORATORY TESTS

• Stool analysis for microorganisms, blood, mucus, fat, osmolality, pH, electrolyte, and mineral concentration.

• Stool cultures.

• Stool test kits for detecting viruses, particularly rotavirus.

• Antibody serologic testing is nonspecific and not practical.

IMAGING

• Radiographic studies helpful in neoplastic and inflammatory conditions.

DIAGNOSTIC PROCEDURES

• Assess for presence of colitis or cancer through direct endoscopic visualization and biopsy of colon.