What is the appropriate management for a patient presenting with acute watery diarrhea?

Management of Acute Watery Diarrhea

Oral rehydration therapy (ORS) is the cornerstone of treatment for acute watery diarrhea, with immediate assessment of dehydration severity guiding the volume and route of fluid replacement. 1

Immediate Assessment of Dehydration Severity

Categorize dehydration by examining:

• Skin turgor (prolonged tenting indicates severe dehydration) 1
• Mucous membranes (dry indicates dehydration) 1
• Mental status (lethargy or altered consciousness signals severe dehydration) 1
• Capillary refill time (>2 seconds suggests poor perfusion) 1
• Pulse quality and blood pressure (weak/absent pulse indicates shock) 1

Classification:

• Mild dehydration: 3-5% fluid deficit 1, 2
• Moderate dehydration: 6-9% fluid deficit 1, 2
• Severe dehydration: ≥10% fluid deficit, shock, or near-shock 1, 2

Rehydration Protocol Based on Severity

Mild Dehydration (3-5% deficit)

• Administer 50 mL/kg of ORS over 2-4 hours 1, 2
• Use ORS containing 50-90 mEq/L sodium 1
• Give small volumes initially (5-10 mL every 1-2 minutes using a spoon or syringe), then gradually increase as tolerated 1, 2
• Common pitfall: Allowing a thirsty patient to drink large volumes rapidly worsens vomiting 1, 2

Moderate Dehydration (6-9% deficit)

• Administer 100 mL/kg of ORS over 2-4 hours 1, 2
• Use the same small-volume technique as for mild dehydration 1, 2
• Reassess hydration status after 2-4 hours 1, 2

Severe Dehydration (≥10% deficit, shock)

• This is a medical emergency requiring immediate IV rehydration 1, 2
• Give 20 mL/kg boluses of Ringer's lactate or normal saline until pulse, perfusion, and mental status normalize 1, 2
• May require two IV lines or alternate access (venous cutdown, femoral vein, intraosseous) 1
• Once consciousness returns, transition to ORS to complete remaining fluid deficit 1, 2

Managing Concurrent Vomiting

More than 90% of vomiting patients can be successfully rehydrated orally when proper technique is used 1:

• Start with 5 mL (1 teaspoon) every 1-2 minutes 1, 2
• Gradually increase volume as vomiting diminishes 1, 2
• Use a spoon, syringe, or medicine dropper—never allow ad libitum drinking from a cup 1, 2
• If oral intake fails despite proper technique, consider nasogastric administration of ORS 1, 2

Replacement of Ongoing Losses

After initial rehydration, replace continuing losses:

• 10 mL/kg of ORS for each watery stool 1, 2
• 2 mL/kg of ORS for each vomiting episode 1, 2
• Continue replacement until diarrhea and vomiting resolve 2

Nutritional Management

Resume age-appropriate diet immediately after rehydration is achieved—do not delay feeding 1, 2:

• Continue breastfeeding throughout the illness without interruption 2
• Resume full-strength formula immediately for bottle-fed infants 2
• Recommended foods: starches, cereals, yogurt, fruits, vegetables 2
• Avoid: foods high in simple sugars (soft drinks, undiluted fruit juice, presweetened cereals) and high-fat foods 2
• The BRAT diet may be used briefly but should not be prolonged due to insufficient energy and protein 2

When Antibiotics Are NOT Indicated

Routine antibiotics are not indicated for typical acute watery diarrhea 2, 3, 4:

• Most cases are viral and self-limited 3, 4
• Antibiotics do not reduce duration or severity in uncomplicated watery diarrhea 4

When to Consider Antibiotics

Antibiotics should be considered only when 2, 5:

• Bloody diarrhea (dysentery) is present 1, 2
• High fever accompanies diarrhea 2
• Watery diarrhea persists >5 days 2
• Stool culture identifies a treatable pathogen 2
• Severe illness with signs of sepsis 2, 3

For dysentery or febrile diarrhea, azithromycin is the preferred empiric antibiotic (single dose 1,000 mg for adults) 5

Absolutely Contraindicated Medications

Antimotility agents (loperamide) are absolutely contraindicated in: 2, 6

• All children <18 years of age (risk of respiratory depression, cardiac arrest, ileus, and death) 2, 6
• Any patient with bloody diarrhea (risk of toxic megacolon) 2, 6
• Patients with fever suggesting inflammatory diarrhea 6
• High-dose use in adults (risk of QT prolongation, torsades de pointes, cardiac arrest) 6

Warning Signs Requiring Immediate Medical Attention

Seek immediate care for 1, 2:

• Bloody diarrhea (may require antimicrobial treatment) 1, 2
• Severe dehydration with shock or near-shock 1, 2
• Intractable vomiting preventing oral rehydration 1, 2
• High stool output (>10 mL/kg/hour) 1, 2
• Decreased urine output 2
• Lethargy or altered consciousness 2

Adjunctive Therapies

• Ondansetron may be given to children >4 years with vomiting to facilitate ORS tolerance, but only after adequate hydration is achieved 2
• Zinc supplementation reduces diarrhea duration in children 6 months to 5 years in areas with high zinc deficiency prevalence 2
• Probiotics may reduce symptom severity and duration in immunocompetent patients (weak recommendation) 2, 4

Common Pitfalls to Avoid

• Do not use sports drinks, fruit juices, or soft drinks for rehydration—they lack adequate sodium and have excessive osmolality 2
• Do not delay rehydration while awaiting diagnostic test results 2
• Do not prescribe routine stool cultures for uncomplicated watery diarrhea 3, 4
• Do not restrict diet during or after rehydration 2
• Do not mix ORS packets with incorrect water volumes—provide detailed written instructions 2