What are the symptoms and treatment options for mesenteric adenitis in pediatric patients?

Pediatric Mesenteric Adenitis: Clinical Presentation and Management

Clinical Presentation

Mesenteric adenitis in children typically presents with right lower quadrant abdominal pain, fever, and often a longer duration of symptoms before presentation compared to acute appendicitis, making clinical differentiation challenging but critical. 1, 2

Key Symptoms

• Abdominal pain: Localized right lower quadrant pain is the hallmark symptom, though less severe and more diffuse than appendicitis 1, 3
• Fever: Often present, with temperatures that can reach 40°C 3
• Gastrointestinal symptoms: Diarrhea may accompany the pain, particularly when associated with infectious etiologies like Salmonella 3
• Duration: Children with mesenteric adenitis typically have longer symptom duration (mean 2.4 days) before emergency department presentation compared to appendicitis (1.4 days) 2
• Multiple presentations: These patients often present to the emergency department multiple times (mean 1.3 visits) before diagnosis 2

Clinical Examination Findings

• Less severe peritoneal signs: Unlike appendicitis, classic abdominal findings (guarding, rebound tenderness) are significantly less common (20% vs 72% in appendicitis) 2
• Absence of pain migration: Migration of pain from periumbilical to right lower quadrant is rare (7% vs 28% in appendicitis) 2
• Less frequent vomiting: Vomiting occurs in only 34% of mesenteric adenitis cases compared to 62% in appendicitis 2

Laboratory Findings

• Lower white blood cell count: Mean WBC is 10.16 × 10³/dL compared to 15.8 × 10³/dL in appendicitis 2
• Lymphocyte predominance: Differential shows 24.6% lymphocytes versus 13% in appendicitis 2
• Lower inflammatory markers: C-reactive protein levels are significantly lower (0.48 mg/dL vs 1.6 mg/dL in appendicitis) 2

Diagnostic Approach

The American Academy of Pediatrics recommends using ultrasound as first-line imaging when imaging is indicated, avoiding radiation exposure. 4

Imaging Characteristics

• Ultrasound findings: Marked mesenteric adenopathy with normal appendix visualization 3
• Point-of-care ultrasound (POCUS): Can reliably identify mesenteric adenitis with high interobserver agreement (κ = 0.83 between experienced physicians, κ = 0.76 between novice and experienced) 5
• Lymph node size: Interestingly, no significant clinical difference exists between small and large lymph nodes, suggesting enlargement is a non-specific finding 2

Red Flags Requiring Escalation

The American Academy of Pediatrics recommends immediate escalation of care when gastrointestinal bleeding, bilious or persistent forceful vomiting, fever with localized right lower quadrant pain, severe or progressive pain, abdominal tenderness, distension, or guarding, weight loss or failure to thrive, or signs of dehydration are present. 4

Treatment Approach

Primary Mesenteric Adenitis (Most Common)

All patients with primary mesenteric adenitis respond well to supportive care alone. 1

• Symptomatic management: Pain control with oral NSAIDs for mild-to-moderate pain without contraindications 4
• Hydration: Maintain adequate fluid intake 1
• Observation: Symptoms typically resolve within 2 days with supportive care 3
• Follow-up imaging: Resolution of adenopathy on follow-up ultrasound confirms diagnosis 3

Secondary Mesenteric Adenitis

When secondary causes are identified, treatment should target the primary etiology. 1

• Infectious workup: Stool cultures should be obtained when diarrhea is present 3
• Salmonella considerations: Unlike Yersinia-associated cases common in Western countries, Salmonella enterica (particularly in regions like Taiwan) carries risk for serious systemic complications including meningitis and septic arthritis, requiring specific attention 3
• Antibiotic consideration: The Infectious Diseases Society of America recommends avoiding routine prescription of broad-spectrum antibiotics for children with fever and abdominal pain when there is low suspicion of complicated infection 4, 6

Complicated Primary Mesenteric Adenitis

Patients with complications require management directed at the specific complication identified. 1

Critical Clinical Pitfalls to Avoid

• Withholding pain medication: The American Academy of Pediatrics advises never withholding pain medication while awaiting diagnosis, as this outdated practice causes unnecessary suffering and impairs examination quality 4
• Overuse of antibiotics: Routine broad-spectrum antibiotics are not indicated for uncomplicated mesenteric adenitis 4, 6
• Relying solely on clinical diagnosis: Ultrasound should be performed in equivocal cases, as clinical evaluation alone cannot accurately distinguish mesenteric adenitis from appendicitis (positive predictive value of clinical diagnosis only 62%) 7
• Ignoring geographic epidemiology: Be aware that infectious etiologies vary by region, with Salmonella carrying higher complication risks than Yersinia 3

Expected Clinical Course

• Resolution timeframe: Pain and fever typically subside within 2 days of supportive care 3
• Follow-up: Four-week clinical follow-up shows favorable outcomes in the vast majority of cases, with surgical abdomen developing in less than 3% 5
• Imaging resolution: Follow-up sonography demonstrates resolution of adenopathy, confirming the self-limited nature of the condition 3