What is the appropriate workup for acute diarrhea?

From the Guidelines

The workup for acute diarrhea should begin with a thorough history and physical examination to determine severity and likely etiology, with a focus on assessing dehydration status and identifying alarm features. For mild to moderate cases without alarm features (fever >38.5°C, bloody stool, severe abdominal pain, dehydration, immunocompromised state, or age >70 years with significant comorbidities), supportive care is the mainstay of treatment. This includes oral rehydration with electrolyte solutions, such as reduced osmolarity oral rehydration solution (ORS), which is recommended as the first-line therapy for mild to moderate dehydration in infants, children, and adults with acute diarrhea from any cause 1.

Key Considerations

• Oral rehydration solutions are effective in correcting dehydration and should be used until clinical dehydration is corrected 1.
• Nasogastric administration of ORS may be considered in infants, children, and adults with moderate dehydration who cannot tolerate oral intake 1.
• Isotonic intravenous fluids, such as lactated Ringer’s and normal saline solution, should be administered when there is severe dehydration, shock, or altered mental status and failure of ORS therapy 1.
• Maintenance fluids should be administered to replace ongoing losses in stools, and ORS should be used until diarrhea and vomiting are resolved 1.
• Laboratory testing is generally unnecessary for uncomplicated cases that resolve within 7 days, but may be considered for severe cases or those with alarm features, and should include complete blood count, basic metabolic panel, stool studies, and possibly inflammatory markers.
• Empiric antibiotic therapy may be considered for travelers' diarrhea, bloody diarrhea, or immunocompromised patients, but should be guided by stool studies and clinical judgment 1.

Treatment Approach

• For mild to moderate cases, supportive care with oral rehydration and symptomatic relief with antimotility agents like loperamide may be sufficient 1.
• For severe cases or those with alarm features, a more comprehensive diagnostic workup and targeted treatment approach may be necessary.
• The underlying pathophysiology of acute diarrhea typically involves either inflammatory processes from invasive pathogens or toxin-mediated effects causing secretory diarrhea, which guides the approach to diagnosis and management.

From the FDA Drug Label

Patients should receive appropriate fluid and electrolyte replacement as needed Acute Diarrhea Adults and Pediatric Patients 13 Years and Older: The recommended initial dose is 4 mg (two capsules) followed by 2 mg (one capsule) after each unformed stool. The maximum daily dose is 16 mg (eight capsules). Clinical improvement is usually observed within 48 hours

The workup for acute diarrhea should include fluid and electrolyte replacement as needed. The treatment with loperamide hydrochloride capsules can be initiated with a dose of 4 mg (two capsules) for adults and pediatric patients 13 years and older, followed by 2 mg (one capsule) after each unformed stool, with a maximum daily dose of 16 mg (eight capsules) 2. Clinical improvement is usually observed within 48 hours.

From the Research

Acute Diarrhea Workup

• The workup for acute diarrhea typically involves assessing the patient's hydration status and electrolyte balance 3, 4.
• Oral rehydration solutions (ORS) are commonly used to treat mild to moderate dehydration in patients with acute diarrhea 3, 5, 6.
• The World Health Organization (WHO) recommends the use of a standard ORS containing 75 mmol/L of sodium and 75 mmol/L of glucose 3.
• Various modifications to the standard ORS have been developed, including hypo-osmolar and hyperosmolar solutions, rice-based ORS, and zinc supplementation 3, 7.
• The choice of ORS depends on the patient's age, severity of dehydration, and underlying medical conditions 5, 4, 6.

Laboratory Tests

• Laboratory tests may be ordered to assess the patient's electrolyte balance, renal function, and stool culture 4.
• Tests may include:
  • Electrolyte panel (sodium, potassium, chloride)
  • Renal function tests (creatinine, urea)
  • Stool culture and sensitivity
  • Complete blood count (CBC)

Treatment

• Treatment for acute diarrhea typically involves oral rehydration therapy (ORT) with an ORS 3, 5, 6.
• Intravenous fluids may be necessary for patients with severe dehydration or those who are unable to tolerate ORT 4.
• Antibiotics may be prescribed if a bacterial infection is suspected or confirmed 4.
• Dietary changes, such as avoiding lactose or spicy foods, may also be recommended 6.