Acute Dysentery in Children: Causes and Management
Definition and Key Distinction
Dysentery refers specifically to bloody diarrhea with mucus, fever, and abdominal cramps—distinct from watery diarrhea—and requires a different diagnostic and therapeutic approach. 1, 2
Common Causes
Bacterial Pathogens (Most Common)
- Shigella species are the most frequent cause of dysentery worldwide and require specific antimicrobial treatment. 1, 2, 3
- Salmonella and Campylobacter remain important bacterial causes of bloody diarrhea globally. 2, 4
- Shiga toxin-producing E. coli (STEC) is particularly important in industrialized countries and should not be treated with antibiotics due to risk of hemolytic uremic syndrome. 2
Parasitic Pathogens
- Entamoeba histolytica causes amoebic dysentery and must be considered in developing regions, particularly rural or periurban areas, requiring specific antiparasitic therapy. 1, 2
- Other parasites may occasionally cause bloody diarrhea depending on geographic exposure and travel history. 1
Less Common Causes
- Consider Vibrio spp., Aeromonas spp., Plesiomonas spp., Yersinia enterocolitica, Clostridium difficile, Cytomegalovirus, or Schistosoma mansoni based on epidemiological clues and regional endemicity. 2
Initial Assessment
Dehydration Severity Classification
- Mild dehydration (3–5% deficit): Increased thirst, slightly dry mucous membranes. 5
- Moderate dehydration (6–9% deficit): Loss of skin turgor with skin tenting when pinched, dry mucous membranes. 5, 1
- Severe dehydration (≥10% deficit): Severe lethargy or altered consciousness, prolonged skin tenting >2 seconds, cool poorly perfused extremities with delayed capillary refill, rapid deep breathing indicating acidosis. 5, 1
Most Reliable Clinical Indicators
- Capillary refill time is the single most reliable predictor of dehydration in this age group. 5, 1
- Prolonged skin retraction time and decreased peripheral perfusion are more reliable than sunken fontanelle or absent tears. 5
- Obtain body weight immediately to calculate fluid deficit and monitor response. 5, 1
Key Historical Features
- Assess travel history for endemic parasitic infections. 1
- Evaluate age and general appearance—young infants who appear ill may require empiric antibiotics. 1
- Document fever pattern, stool frequency, and presence of blood/mucus. 2, 3
Management Algorithm
Step 1: Immediate Rehydration Based on Severity
Severe Dehydration (≥10% deficit)
- Administer 20 mL/kg boluses of Ringer's lactate or normal saline IV immediately until pulse, perfusion, and mental status normalize. 5, 1
- This is a medical emergency requiring prompt IV access without delay. 5
- Once circulation is restored, transition to oral rehydration solution (ORS) for remaining deficit. 5
Moderate Dehydration (6–9% deficit)
- Administer 100 mL/kg of ORS containing 50–90 mEq/L sodium over 2–4 hours. 5, 6, 1
- If oral intake is not tolerated, consider nasogastric administration at 15 mL/kg/hour. 5
Mild Dehydration (3–5% deficit)
- Administer 50 mL/kg of ORS over 2–4 hours. 5
Step 2: Replace Ongoing Losses
- Give 10 mL/kg of ORS for each additional watery or bloody stool. 5, 1
- Give 2 mL/kg of ORS for each vomiting episode. 5
Step 3: Reassess After 2–4 Hours
- Re-examine skin turgor, mucous membranes, mental status, perfusion, and weight. 5
- If still dehydrated, re-estimate deficit and continue rehydration. 5
- If rehydrated, transition to maintenance phase with continued ORS for ongoing losses. 5
Antimicrobial Therapy Decision Algorithm
When to Treat with Antibiotics
Consider antibiotics when:
- Dysentery (bloody diarrhea) is present with high fever. 5, 1
- Stool cultures confirm Shigella, Salmonella, or other treatable bacterial pathogen. 5, 1
- Patient is immunocompromised or has clinical features of sepsis. 6
- Young infant appears ill. 1
- Watery diarrhea persists >5 days. 5
Critical Exception: STEC
- Do NOT give antibiotics if STEC is suspected or confirmed, as this increases risk of hemolytic uremic syndrome. 2
When Antibiotics Are NOT Indicated
- Most cases of acute watery diarrhea without recent international travel do not require empiric antimicrobials. 6
- Viral gastroenteritis (most common overall cause of diarrhea). 7
Specific Antimicrobial Selection
- Shigella dysentery: Requires specific antimicrobial treatment based on local susceptibility patterns. 1, 3
- Entamoeba histolytica: Requires specific antiparasitic therapy (e.g., metronidazole followed by a luminal agent). 1
- Selection should be guided by stool culture results and local resistance patterns when available. 4
Diagnostic Testing
- Obtain stool culture when dysentery is present, particularly if fever is high or patient appears ill. 1, 2
- Perform stool microscopy for ova and parasites if parasitic infection is suspected based on travel history or exposure. 1
- A single fecal sample studied for etiologic agents is the customary diagnostic approach. 2
- Avoid routine laboratory testing (electrolytes, CBC) in mild-moderate dehydration without specific clinical indications. 5, 1
Nutritional Management
Feeding During and After Rehydration
- Continue breastfeeding throughout the entire illness without any interruption. 5, 6, 1
- Resume age-appropriate diet immediately after rehydration is completed—there is no justification for "bowel rest." 5, 6, 1
- Offer starches, cereals, yogurt, fruits, and vegetables. 5
- Avoid foods high in simple sugars and fats during the acute phase. 5
- Feed every 3–4 hours to maintain nutrition and promote intestinal recovery. 5
Absolute Contraindications
Antimotility Agents
- Antimotility drugs (loperamide) are absolutely contraindicated in all children <18 years due to risks of respiratory depression and serious cardiac adverse reactions. 5, 6, 1
- All anti-diarrheal agents are contraindicated for acute diarrheal disease. 5
Inappropriate Fluids
- Do not use cola drinks, soft drinks, or sports drinks for rehydration—they contain inadequate sodium and excessive osmolality that worsens diarrhea. 5
- Do not use homemade salt-sugar solutions; commercial ORS ensures proper electrolyte composition. 5
Indications for Hospitalization
Admit patients with:
- Severe dehydration (≥10% deficit) or signs of shock. 5, 1
- Altered mental status. 1
- Failure of oral rehydration therapy despite proper technique. 1
- High stool output (>10 mL/kg/hour). 5
- Intractable vomiting preventing fluid intake. 5
Red Flags Requiring Urgent Re-evaluation
Instruct caregivers to return immediately if:
- Fever develops or worsens. 5
- Increased thirst or sunken eyes appear. 5
- Bloody diarrhea develops or worsens. 5
- Many watery stools continue despite treatment. 5
- Child becomes lethargic or difficult to arouse. 5
- Decreased urine output (fewer than 3 wet diapers in 24 hours). 5
Common Pitfalls to Avoid
- Do not delay rehydration while awaiting stool culture results—begin ORS immediately based on clinical assessment. 6
- Do not withhold food or impose "bowel rest"—early feeding improves outcomes and shortens illness duration. 5, 6
- Do not rely solely on sunken fontanelle or absent tears for dehydration assessment—use capillary refill and skin turgor instead. 5
- Do not prescribe empiric antibiotics for uncomplicated watery diarrhea—this promotes resistance without benefit. 6
- Do not give antibiotics for suspected STEC—this increases risk of hemolytic uremic syndrome. 2