Workup and Treatment of Diarrhea
The appropriate workup for diarrhea should first classify the condition as uncomplicated or complicated, with initial management focusing on rehydration, dietary modifications, and antimotility agents for uncomplicated cases, while complicated cases require more aggressive intervention including stool studies, IV fluids, and possible antimicrobial therapy. 1
Initial Assessment
Classification of Diarrhea
- Uncomplicated diarrhea: Grade 1-2 diarrhea with no complicating factors
- Complicated diarrhea: Any of the following:
- Grade 3-4 diarrhea
- Moderate to severe cramping
- Grade 2 or higher nausea/vomiting
- Decreased performance status
- Fever, sepsis, neutropenia
- Frank bleeding
- Dehydration 2
Key History Elements
- Duration of symptoms (acute vs. chronic)
- Stool characteristics (watery, bloody, fatty)
- Frequency and volume
- Presence of nocturnal diarrhea
- Associated symptoms (fever, abdominal pain, weight loss)
- Recent travel, antibiotic use, or dietary changes
- Immunocompromised status 1
Diagnostic Workup
For Uncomplicated Diarrhea
- Laboratory testing generally not required
- Routine stool cultures not recommended 3
For Complicated Diarrhea
- Complete blood count
- Electrolyte profile
- Stool studies:
Treatment Approach
Rehydration Therapy (First Priority)
- Mild to moderate dehydration: Oral rehydration solution (ORS)
- Reduced osmolarity ORS (65-70 mEq/L sodium, 75-90 mmol/L glucose)
- Preparation: 3.5g NaCl, 2.5g NaHCO₃, 1.5g KCl, 20g glucose per liter of clean water 1
- Severe dehydration: Intravenous fluids
- Ringer's lactate preferred as it better corrects metabolic acidosis 1
Dietary Management
- Continue age-appropriate diet during or immediately after rehydration
- Follow BRAT diet (Bananas, Rice, Applesauce, Toast)
- Avoid spicy foods, coffee, alcohol, and foods high in simple sugars and fats
- Eliminate all lactose-containing products and high-osmolar dietary supplements 2, 1
Pharmacologic Treatment
For Uncomplicated Diarrhea
- Antimotility agents:
- Avoid antimotility agents in patients with bloody diarrhea 1
For Persistent Uncomplicated Diarrhea (>24 hours on standard loperamide)
- Increase loperamide to 2 mg every 2 hours
- Consider oral antibiotics as prophylaxis for infection 2
For Complicated Diarrhea
- Hospitalization or intensive outpatient management
- Intravenous fluids
- Octreotide: 100-150 μg SC TID or IV (25-50 μg/hr) if severely dehydrated
- Dose escalation up to 500 μg TID until diarrhea is controlled 2
- Antimicrobial therapy based on suspected pathogen:
- Adults: Fluoroquinolone (e.g., ciprofloxacin) or azithromycin
- Children: Third-generation cephalosporin or azithromycin 1
Special Considerations
Neutropenic Enterocolitis
- Broad-spectrum antibiotics covering enteric gram-negative, gram-positive, and anaerobic organisms
- G-CSF administration
- Nasogastric decompression
- IV fluids and bowel rest
- Avoid antimotility agents 2
Chronic Diarrhea (>4 weeks)
- Further categorize as watery, fatty, or inflammatory
- Consider specialized testing:
- Anti-tissue transglutaminase IgA and total IgA for celiac disease
- Fecal calprotectin or lactoferrin for inflammatory conditions
- Fecal fat for malabsorption 5
Monitoring and Follow-up
- Reassess hydration status regularly
- Evaluate patients after 48-72 hours of treatment
- Consider alternative diagnoses if no improvement occurs
- Monitor electrolytes in patients with underlying conditions 1
Prevention
- Proper hand hygiene
- Safe food preparation
- Access to clean water
- Appropriate vaccinations 3
Remember that most cases of acute diarrhea are self-limiting and do not require extensive diagnostic workup. The focus should be on preventing and treating dehydration while identifying patients who need more aggressive management due to complicating factors or underlying conditions.