What is the management for an 8-month-old infant with gastroenteritis who now has hematochezia (blood in stool)?

Management of 8-Month-Old with Gastroenteritis and Hematochezia

For an 8-month-old infant with gastroenteritis who develops bloody stools, immediately assess for dehydration and obtain stool testing for Shiga toxin-producing organisms (STEC), Salmonella, Shigella, Campylobacter, and Yersinia, while avoiding antimotility agents and most antibiotics until pathogen identification. 1

Immediate Clinical Assessment

Dehydration Evaluation (Critical First Step)

• Assess dehydration severity as this increases risk of life-threatening illness and death, especially in infants 1
• Look for specific signs by severity level 1:
  • Mild (3-5% deficit): Increased thirst, slightly dry mucous membranes
  • Moderate (6-9% deficit): Loss of skin turgor, skin tenting when pinched, dry mucous membranes
  • Severe (≥10% deficit): Severe lethargy/altered consciousness, prolonged skin tenting (>2 seconds), cool/poorly perfused extremities, decreased capillary refill, rapid deep breathing (acidosis sign)
• Obtain accurate body weight and check for adequate bowel sounds before initiating oral therapy 1
• Visual examination of stool to confirm blood presence 1

Key History Elements

• Duration and frequency of diarrhea 1
• Fever presence (suggests bacterial pathogen requiring workup) 1
• Recent antibiotic exposure (consider C. difficile, though bloody stools are not typical) 1
• Exposure to undercooked meats, unpasteurized dairy, or ill contacts 1
• Travel history or contact with travelers 1

Diagnostic Testing

Mandatory Stool Studies

Obtain stool testing for the following pathogens in this infant with bloody diarrhea 1:

• STEC (Shiga toxin-producing E. coli) - use tests that detect Shiga toxin or genes encoding them, distinguishing O157:H7 from non-O157 strains 1
• Salmonella species 1
• Shigella species 1
• Campylobacter 1
• Yersinia enterocolitica (especially relevant in infants with exposure to pork products) 1

Blood Cultures

Obtain blood cultures in this infant <3 months of age if signs of sepsis are present or if the infant appears systemically ill 1

Laboratory Studies (Selective Use)

• Serum electrolytes only if clinical signs suggest abnormal sodium/potassium concentrations 1
• Hemoglobin/hematocrit if bleeding appears significant 2
• Most cases do not require routine laboratory studies 1

Treatment Approach

Rehydration Strategy

Oral rehydration solution (ORS) is the primary treatment for most infants with gastroenteritis and dehydration 1, 2:

• Use physiologically balanced ORS for mild to moderate dehydration 2
• For severe dehydration (>5% dehydrated, lethargic, hypovolemic): initiate IV boluses of isotonic saline or Ringer's lactate 2
• Goal is normalization of blood pressure and heart rate 1

Nutritional Management

• Do not withhold food - children with severe diarrhea need nutrition to restore digestive function 2
• Resume age-appropriate feeding once rehydration is achieved 1

Critical Medication Avoidance

Do NOT use antidiarrheal agents (loperamide, kaolin-pectin, antimotility drugs) in this infant 1:

• These agents do not reduce diarrhea volume or duration 1
• Serious complications reported including severe abdominal distention and death in children given loperamide 1
• They shift focus away from appropriate fluid/electrolyte therapy 1

Antibiotic Considerations

Hold antibiotics until pathogen identification in most cases 1, 3:

• Pathogens typically associated with bloody diarrhea are detected in less than half of cases, and inappropriate antibiotic use is common 3
• NEVER give antibiotics if STEC is suspected or confirmed - this increases risk of hemolytic uremic syndrome (HUS) 1
• Antibiotics may be beneficial for confirmed Salmonella, Shigella, or Campylobacter only after susceptibility testing 1

Red Flags Requiring Urgent Intervention

Signs of Severe Illness

• Hemodynamic instability despite fluid resuscitation 1
• Signs of sepsis 1
• Altered mental status or severe lethargy 1
• Persistent or worsening bloody diarrhea 1

HUS Surveillance

Monitor for hemolytic uremic syndrome development, especially if STEC is identified 1:

• STEC, particularly those producing Shiga toxin 2, carry higher HUS risk 1
• Shigella dysenteriae type 1 can also cause HUS 1

Common Pitfalls to Avoid

1. Using antidiarrheal medications - can cause life-threatening complications in infants 1
2. Empiric antibiotics before stool testing - inappropriate in most cases and dangerous if STEC present 1, 3
3. Withholding nutrition - delays recovery of digestive function 2
4. Underestimating dehydration severity - use objective clinical signs, not just parental report 1
5. Assuming all bloody diarrhea is bacterial - viral and other causes are common 3