Intermittent and diffuse pain in the lower limbs that wakes up at night

Specialty: Pediatrics.

• Suspicion of benign growth pain
• nocturnal musculoskeletal pain in children

Why it occurs

• Benign growing pains of childhood (self-limited idiopathic entity with a benign course that affects healthy children between 3 and 12 years of age, characterized by diffuse, deep pain, typically bilateral, located in the thighs, calves or popliteal region, which appears exclusively in the evening or at night, often waking the child, and is associated with days of high physical activity, without causing daytime lameness or limitation)
• Benign joint hypermobility syndromes (mild ligamentous instability that generates overload and fatigue of the tendons and adjacent muscle groups after physical activities)
• Subclinical vitamin D deficiency or nutritional imbalances (empirical association with cramps or nocturnal myalgia)
• Referred pain due to lower extremity length discrepancy or podiatric postural anomalies (severe flat foot valgus that alters the biomechanics of gait).

Initial workup

The clinical diagnosis is based on an exhaustive anamnesis that corroborates the typical criteria and on a rigorously normal osteoarticular and neurological physical examination. In case of diagnostic doubts or red flags: Complete blood count with differential white blood cell count and peripheral blood smear (to rule out childhood leukemias or lymphomas). Determination of erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). Levels of 25-hydroxyvitamin D, calcium, phosphorus and alkaline phosphatase. Plain radiography in AP and lateral projections of the painful extremity (to rule out bone tumors such as osteosarcoma, Ewing sarcoma, osteoid osteoma, or infectious processes such as osteomyelitis or septic arthritis).

Standard management

• The management of choice is based on non-pharmacological support measures — detailed explanation and reassurance to parents, gentle circular local massages with moisturizing cream at bedtime, application of warm local heat using heating pads and passive stretching exercises of the quadriceps, hamstrings and triceps surae muscles before sleeping). Paracetamol (oral analgesic indicated only for acute nocturnal pain attacks that make sleep difficult and do not resolve with massage; dose of 10 to 15 mg/kg orally, maximum every 4-6 hours) or Ibuprofen (effective anti-inflammatory analgesic; dose of 5 to 10 mg/kg orally, taken with food, maximum every 6-8 hours
• Cholecalciferol or Vitamin D3 (specific oral supplementation if associated serum deficiency is documented).