What causes leg cramping in children?

Common Causes of Leg Cramping in Children

Leg cramps in children are most commonly benign and self-limited, with idiopathic nocturnal leg cramps being the most frequent type. 1 However, several underlying conditions can cause leg cramping that requires attention.

Primary Causes

• Idiopathic nocturnal leg cramps - Most common form, typically affecting children 8 years and older, with peak incidence at 16-18 years 2
• Exercise-associated muscle cramps - Related to muscle fatigue and altered neuromuscular control during or after physical activity 3
• Dehydration and electrolyte imbalances - Particularly hypocalcemia, which can cause muscle cramping and irritability 4

Medical Conditions Associated with Leg Cramps

Neurological Causes

• Restless Legs Syndrome (RLS) - Characterized by an urge to move the legs, usually accompanied by uncomfortable sensations that worsen during rest and improve with movement 4
• Tethered cord syndrome - Can present with leg pain that varies in character (dull, aching, sharp, or electrical) and may be aggravated by walking or running 4
• Peripheral neuropathy - May cause cramping sensations, particularly in older children 4

Musculoskeletal Causes

• Growing pains - Common non-specific lower leg/foot pains that may be associated with pes planovalgus 4
• Juvenile idiopathic arthritis - Can present with cramping pain, often polyarticular and sometimes associated with IgA deficiency 4
• Trauma or stress fractures - May present as cramping pain, especially with activity 4

Metabolic/Systemic Causes

• Hypocalcemia - Common in children with Williams syndrome and other conditions, contributing to muscle cramps 4
• Vitamin D deficiency - Can lead to muscle cramping and weakness 4
• Hypomagnesemia - May trigger seizures or muscle cramping 4

Diagnostic Approach

• Age consideration - Nocturnal leg cramps are typically not present in children under 8 years of age 2
• Frequency assessment - Most affected children (81.6%) experience leg cramps only 1-4 times per year 2
• Duration evaluation - Normal duration is typically less than 2 minutes, with residual tenderness present in approximately 30% of affected children 2
• Localization - Cramps are usually unilateral (98.9%) and may involve the ipsilateral foot (18.9%) 2
• Timing - Most children (73%) experience leg cramps while asleep 2

Red Flags Requiring Further Investigation

• Persistent or worsening symptoms - May indicate an underlying condition such as tethered cord syndrome 4
• Daytime symptoms - Could suggest conditions other than typical nocturnal leg cramps 4
• Associated neurological symptoms - Such as sensory deficits, muscle weakness, or gait abnormalities 4
• Systemic symptoms - Fever, weight loss, or other constitutional symptoms may suggest inflammatory conditions 4
• Abnormal physical findings - Limited range of motion, limp, or abnormal muscle movements like myokymia 5

Management Considerations

• Stretching - Symptomatic treatment consists of stretching the affected calf muscle by forcible dorsiflexion of the foot 1
• Hydration and electrolyte balance - Ensuring adequate hydration and normal electrolyte levels, particularly calcium and magnesium 4, 3
• Evaluation for underlying conditions - When cramps are frequent, severe, or associated with other symptoms 4
• Orthotic support - May benefit children with non-specific lower leg/foot pains associated with pes planovalgus 4

Remember that while most leg cramps in children are benign, persistent or unusual patterns of cramping warrant further investigation to rule out underlying conditions that may affect morbidity, mortality, or quality of life.