Typhlitis (Neutropenic Enterocolitis)

Background

• Classic setting: Neutropenic patients after chemotherapy with cytotoxic drugs
• Most common malignancies: AML and ALL (more so than other cancers)
• More frequent in children than adults
• Key pathogens: Gram-negative organisms and Clostridium septicum, which can cause rapidly progressive septicemia (Harrison's, p. 2194; Bailey & Love, p. 1363)

Diagnosis

Treatment

• Broad-spectrum antibiotics targeting gram-negative organisms and anaerobes (e.g., piperacillin-tazobactam ± metronidazole; coverage for C. septicum is important)
• Bowel rest — NPO with IV fluids and nutritional support
• Haematopoietic growth factors (G-CSF/GM-CSF) to accelerate neutrophil recovery
• Supportive care: IV fluids, blood products as needed, electrolyte management

• Rarely indicated (Bailey & Love, p. 1363)
• Reserved for complications:
  • Perforation or imminent perforation
  • Uncontrolled hemorrhage
  • Clinical deterioration despite maximal medical therapy
  • Development of an abscess requiring drainage

Key Points

• Gram-negative or clostridial septicemia can be rapidly progressive — early antibiotic initiation is critical
• Mortality is significant; prompt recognition and treatment are essential
• Recovery of neutrophil counts (spontaneously or with growth factors) is a major determinant of outcome
• Differential includes appendicitis, C. difficile colitis, CMV colitis, and ischemic colitis — CT imaging helps distinguish

Sources: Harrison's Principles of Internal Medicine, 21st Edition (p. 2194); Bailey and Love's Short Practice of Surgery, 28th Edition (p. 1363)

Pneumonia in Children

What it is

Common causes by age

• Infants/preschool: mostly viral (RSV, influenza, parainfluenza, adenovirus, hMPV)
• School age/adolescents: increasing Mycoplasma pneumoniae and Streptococcus pneumoniae
• Severe disease/complications can involve Staph aureus or mixed infection

Typical clinical features

• Fever
• Cough
• Fast breathing (tachypnea)
• Respiratory distress (retractions, nasal flaring, grunting)
• Crackles or reduced breath sounds
• Chest/abdominal pain, poor feeding, lethargy (especially in younger children)

Diagnosis

• Primarily clinical, supported by chest imaging when needed.
• Chest X-ray may help confirm pneumonia but does not reliably distinguish viral vs bacterial etiology alone (Laboratory Diagnosis of Respiratory Viruses, p. 4).
• Consider:
  • CBC, CRP, procalcitonin (can improve diagnostic confidence, but not perfect etiology discrimination)
  • Blood culture in severe/hospitalized cases
  • Pleural fluid culture if effusion/empyema is present (Pediatric HIV OI guideline, p. 32)
  • Viral PCR panels where available

Treatment (practical approach)

1) Outpatient, mild disease

• Supportive care: fluids, antipyretics, nasal clearance
• If bacterial CAP suspected:
  • Amoxicillin is first-line in many guidelines
• If atypical pneumonia suspected in older child:
  • Azithromycin (or equivalent macrolide)

2) Inpatient criteria (typical)

• Hypoxemia (SpO₂ < 90 to 92%)
• Moderate to severe respiratory distress
• Dehydration/poor oral intake
• Toxic appearance, apnea, altered mental status
• Significant comorbidity (chronic lung disease, congenital heart disease, immunocompromise)
• Failed outpatient therapy or concern for complications

3) Inpatient therapy

• Oxygen as needed
• IV fluids and monitoring
• Empiric IV antibiotics based on severity/local resistance:
  • Ampicillin/penicillin G or ceftriaxone/cefotaxime
  • Add anti-staphylococcal coverage (for severe necrotizing disease/empyema risk)
• Escalate/de-escalate based on culture and clinical response

Complications to watch for

• Parapneumonic effusion/empyema
• Necrotizing pneumonia/lung abscess
• Sepsis
• Respiratory failure
• SIADH/dehydration

When urgent care is needed

• Fast/labored breathing, chest indrawing, cyanosis
• Persistent high fever with lethargy
• Inability to drink, vomiting everything, reduced urine
• O₂ saturation low or worsening symptoms after 48 to 72 hours of treatment

Example pediatric CXR pattern

Typhlitis: Treatment Duration

General principles:

Key rule:

1. Fever resolves
2. Abdominal symptoms resolve
3. Neutrophil count recovers
4. Imaging shows resolution or significant improvement

Surgical escalation if no improvement by 48–72 hours of conservative management, especially if:

• Perforation or clinical deterioration
• Uncontrolled bleeding
• Persistent sepsis despite antibiotics

Sources: Bailey & Love's Short Practice of Surgery, 28th Ed. (p. 1363); Harrison's Principles of Internal Medicine, 21st Ed. (p. 2194)