What is the appropriate evaluation and management for a 2-year-old otherwise healthy male with a frontal head contusion and significantly enlarged bilateral cervical, axillary, and inguinal lymphadenopathy (lymph node enlargement) after a fall, without neurological deficits?

Evaluation of a 2-Year-Old with Head Contusion and Generalized Lymphadenopathy

Immediate Head Trauma Assessment

The head contusion requires risk stratification using validated clinical criteria, but given the absence of neurological symptoms, this child falls into a very low-risk category that does not require CT imaging. 1

• This child has a Glasgow Coma Scale of 15, normal mental status, no altered consciousness, no vomiting, no severe mechanism of injury (counter-height fall is not considered severe), and is acting normally per parent 1
• CT head is not indicated as the child meets all PECARN criteria for safe discharge without imaging, with a risk of clinically important traumatic brain injury <0.02% 1
• Continue clinical observation for any signs of deterioration (altered mental status, persistent vomiting, severe headache, neurological changes), which would warrant immediate CT imaging 1

Critical Concern: Generalized Lymphadenopathy

The significantly enlarged bilateral cervical, axillary, and inguinal lymphadenopathy in a 2-year-old is the more concerning finding and requires systematic evaluation, as generalized lymphadenopathy (involving ≥2 non-contiguous regions) often indicates underlying systemic disease. 2, 3

Differential Diagnosis Priority

The generalized nature of lymphadenopathy shifts the differential away from simple reactive adenopathy:

Infectious causes to consider:

• Viral infections (most common cause of generalized lymphadenopathy in children) including EBV, CMV, HIV 2, 3, 4
• Bacterial infections including atypical mycobacteria, cat-scratch disease, toxoplasmosis 4, 5
• Acute bilateral cervical lymphadenitis from viral upper respiratory infection or streptococcal pharyngitis 4, 5

Systemic/malignant causes requiring urgent evaluation:

• Autoimmune Lymphoproliferative Syndrome (ALPS) - characterized by chronic (>6 months) bilateral cervical, axillary, and inguinal lymphadenopathy, which matches this presentation exactly 6
• Chronic Lymphocytic Leukemia (CLL) - typically presents with bilateral cervical, axillary, and inguinal lymphadenopathy 6
• Rosai-Dorfman-Destombes Disease (RDD) - classically presents with bilateral massive painless cervical lymphadenopathy with or without axillary and inguinal involvement 6
• Lymphoma or leukemia (particularly if nodes are hard, matted, or >2 cm) 2, 3

Immediate Workup Required

Laboratory evaluation should include:

• Complete blood count with differential (essential to evaluate for leukemia, lymphoma, or ALPS) 6, 2
• Peripheral blood flow cytometry looking specifically for TCR αβ+ double-negative T cells (DNT cells ≥1.5% of total lymphocytes or 2.5% of T lymphocytes suggests ALPS) 6
• C-reactive protein and erythrocyte sedimentation rate 2
• Comprehensive metabolic panel including LDH 6
• Tuberculosis testing 6, 2
• Consider EBV, CMV, HIV, toxoplasmosis serologies 6, 2

Physical examination specifics:

• Document exact size, consistency (soft vs. hard), mobility, and tenderness of all palpable lymph nodes 2, 3
• Examine for hepatosplenomegaly (present in ALPS, CLL, and RDD) 6
• Look for skin lesions (RDD can have cutaneous manifestations) 6
• Assess for systemic symptoms: fever, night sweats, weight loss (red flags for malignancy) 2, 3

Imaging considerations:

• Ultrasound of affected lymph node regions can provide valuable diagnostic information and guide biopsy if needed 7
• Nodes that are supraclavicular, popliteal, iliac, or epitrochlear >5mm are abnormal and carry higher malignancy risk 3

When to Biopsy

Lymph node biopsy (fine-needle aspiration, core needle, or excisional) is indicated if: 2, 3

• Lymphadenopathy persists beyond 4 weeks without clear infectious etiology 2
• Nodes are >2 cm, hard, matted/fused, or in high-risk locations (supraclavicular) 2, 3
• Systemic symptoms present (fever, night sweats, weight loss) 2, 3
• Laboratory findings suggest malignancy or systemic disease 2

Critical Pitfalls to Avoid

• Do not dismiss generalized lymphadenopathy as "reactive" without thorough evaluation - while most lymphadenopathy in children is benign, the generalized pattern demands systematic workup 2, 3
• Do not give empiric antibiotics without clear evidence of bacterial infection - this can mask underlying malignancy and delay diagnosis 2, 3
• Never use corticosteroids empirically - they can mask histologic diagnosis of lymphoma or other malignancy 2, 3
• Do not obtain CT head for the minor head trauma in this low-risk patient - unnecessary radiation exposure without clinical indication 1

Recommended Management Algorithm

1. Obtain complete blood count with differential and flow cytometry immediately 6, 2
2. If CBC shows abnormalities (blasts, cytopenias, marked lymphocytosis), refer urgently to pediatric hematology/oncology 6
3. If flow cytometry shows elevated DNT cells ≥1.5%, evaluate for ALPS with lymphocyte apoptosis assay and genetic testing 6
4. If initial labs normal but lymphadenopathy persists >4 weeks, proceed to imaging and consider biopsy 2, 3
5. Close follow-up in 2-4 weeks to reassess lymph node size and any new symptoms 2, 3