What is the workup and treatment for a patient presenting with diarrhea in an urgent care center?

Workup and Treatment for Diarrhea in an Urgent Care Center

The initial management of diarrhea in an urgent care setting should focus on assessing dehydration severity, identifying red flag symptoms, and providing appropriate rehydration therapy while determining if antimotility agents or antibiotics are indicated. 1

Initial Assessment

Evaluate for Dehydration

• Assess dehydration severity:
  • Mild: <3% weight loss
  • Moderate: 3-9% weight loss
  • Severe: >9% weight loss, altered mental status, poor perfusion 1
• Check vital signs (blood pressure, heart rate)
• Assess urine output (target ≥0.5 ml/kg/h)
• Look for clinical signs: skin turgor, mucous membrane moisture, sunken eyes

Key History Elements

• Onset and duration of diarrhea
• Number and characteristics of stools (watery, bloody, nocturnal)
• Associated symptoms:
  • Fever
  • Abdominal pain/cramping
  • Dizziness or weakness
  • Vomiting
• Medication review (identify diarrhea-inducing agents)
• Dietary history (lactose, alcohol, high-osmolar supplements) 2, 1

Red Flag Symptoms Requiring Urgent Attention

• Bloody diarrhea
• Severe dehydration
• Persistent fever
• Immunocompromised status
• Persistent vomiting preventing oral intake
• High stool output (>10 mL/kg/hour)
• Altered mental status 1, 3

Laboratory and Diagnostic Testing

When to Order Tests

• Reserve diagnostic tests for patients with:
  • Severe dehydration
  • Bloody stools
  • Persistent fever
  • Immunocompromised status
  • Suspected nosocomial infection 3

Recommended Tests

• Stool studies:
  • Standard culture (Salmonella, Shigella, Campylobacter)
  • Consider specific tests for other pathogens based on history
• Complete blood count
• Electrolyte panel
• Consider additional tests based on clinical suspicion 1

Treatment Algorithm

1. Rehydration Therapy

• Mild to Moderate Dehydration:

  • Oral rehydration solution (ORS) with reduced osmolarity (65-70 mEq/L sodium)
  • Target fluid intake: 2200-4000 mL/day for adults
  • Rate must exceed ongoing losses 1

• Severe Dehydration:

  • Immediate IV fluid resuscitation with isotonic saline or balanced salt solution
  • Initial fluid bolus: 20 mL/kg
  • Continue rapid infusion until clinical signs of hypovolemia improve
  • Monitor electrolytes, particularly sodium and potassium 1

2. Dietary Modifications

• Eliminate lactose-containing products
• Avoid alcohol and high-osmolar supplements
• Recommend clear liquids (8-10 large glasses daily)
• Suggest BRAT diet (bananas, rice, applesauce, toast, plain pasta)
• Resume normal diet gradually as symptoms improve 2, 1

3. Pharmacologic Management

Antimotility Agents

• Loperamide:

  • Initial dose: 4 mg
  • Followed by 2 mg every 4 hours or after each unformed stool
  • Maximum daily dose: 16 mg
  • Contraindications: bloody diarrhea, suspected inflammatory diarrhea, ileus, children <2 years, patients with cardiac risk factors 1, 4
  • Discontinue after 12-hour diarrhea-free interval 2

• Cardiac Warning: Avoid loperamide in patients taking medications that prolong QT interval (Class IA/III antiarrhythmics, certain antipsychotics, antibiotics) or with risk factors for QT prolongation 4

Antibiotics

• Consider in:

  • Immunocompromised patients
  • Severe bloody diarrhea with fever
  • Confirmed bacterial pathogen requiring treatment
  • Suspected neutropenic enterocolitis 1

• First-line options based on suspected pathogen:

  • Shigella: Azithromycin
  • Campylobacter: Azithromycin
  • ETEC: TMP-SMX (if susceptible) or Azithromycin
  • Bacterial gastroenteritis: Third-generation cephalosporin or Azithromycin 1

• Avoid antibiotics in E. coli O157:H7 or other Shiga toxin-producing E. coli due to increased risk of hemolytic uremic syndrome 1

4. Special Considerations

• Severe cases: Consider octreotide (100-150 μg SC/IV TID) for severe, refractory diarrhea 2, 1
• Immunocompromised patients: Lower threshold for diagnostic testing and antibiotic treatment 1
• Elderly patients: Use caution with loperamide due to increased risk of cardiac adverse events 4

Discharge Instructions

• Continue fluid replacement
• Follow dietary recommendations
• Monitor for warning signs requiring return:
  • Worsening symptoms despite treatment
  • Development of bloody stools
  • Fever
  • Abdominal distention
  • Symptoms persisting >48 hours 2, 1
• Proper hand hygiene after toilet use and before food preparation 1

Referral Criteria

• Patients with severe dehydration not responding to initial management
• Bloody diarrhea with severe symptoms
• Immunocompromised patients with worsening symptoms
• Persistent symptoms beyond 48 hours despite appropriate management 1, 3