What is the appropriate evaluation and management for an 18‑month‑old child who, after seizures have been excluded, wakes at night screaming and demanding leg rubbing?

Evaluate for Restless Legs Syndrome (RLS) and Check Serum Ferritin

This 18-month-old child presenting with nighttime leg discomfort requiring rubbing, after seizures have been excluded, should be evaluated for restless legs syndrome (RLS), with particular attention to iron deficiency as a treatable cause.

Clinical Assessment

The presentation—waking at night screaming with leg discomfort that is relieved by rubbing—fits the diagnostic criteria for RLS in cognitively impaired or young children who cannot verbally describe their symptoms 1. The essential diagnostic features adapted for this age group include:

• Signs of leg discomfort: Rubbing or kneading the legs, groaning while holding lower extremities
• Worse during inactivity: Symptoms occur during periods of rest (nighttime sleep)
• Relief with movement: The child demands leg rubbing, which provides temporary relief
• Circadian pattern: Symptoms occur exclusively or predominantly at night 1

Immediate Diagnostic Workup

Check serum ferritin immediately. Iron deficiency is strongly associated with RLS, and ferritin values less than 50 ng/mL are consistent with RLS diagnosis and indicate need for iron supplementation 1. This is the single most important initial test because it identifies a directly treatable cause.

Additional baseline investigations should include:

• Complete blood count
• Comprehensive metabolic panel
• Thorough neurologic examination to exclude peripheral neuropathy or other neurologic causes 1

Management Algorithm

If Ferritin < 50 ng/mL:

Initiate iron supplementation. While the guidelines primarily address older populations, iron repletion is the cornerstone of treatment for iron-deficiency-associated RLS 1. Consult with pediatric hematology for age-appropriate dosing and formulation.

If Ferritin ≥ 50 ng/mL or Symptoms Persist Despite Iron Repletion:

Consider referral to pediatric sleep medicine or neurology for further evaluation and potential treatment options. While dopaminergic agents (ropinirole, pramipexole) are first-line pharmacologic therapy for RLS in adults 1, their use in an 18-month-old would require specialist guidance given the lack of pediatric data at this age.

Important Differential Considerations

Rule out other causes of nocturnal leg discomfort:

• Growing pains (though typically occur in older children, ages 3-12 years)
• Peripheral neuropathy or radiculopathy (should be evident on neurologic exam) 1
• Atopic dermatitis with nocturnal pruritus (check for skin findings) 2
• Sleep-related movement disorders distinct from RLS

Behavioral and Supportive Measures

While awaiting diagnostic results and regardless of etiology, implement sleep hygiene measures:

• Consistent bedtime routine
• Avoid stimulating activities before bed
• Ensure comfortable sleep environment 3

Critical Pitfall: Do not dismiss this as simply "behavioral" or "attention-seeking." The child's distress is real, and RLS in young children is underdiagnosed because they cannot articulate the characteristic uncomfortable sensations 1. The demand for leg rubbing is a key diagnostic clue that the child has discovered provides relief.

Follow-Up

If iron supplementation is initiated, reassess symptoms and recheck ferritin in 8-12 weeks. Document response to treatment, as improvement with iron repletion supports the diagnosis of RLS. If symptoms persist despite adequate iron repletion or if ferritin is normal initially, specialist referral is warranted for consideration of other treatment modalities and to exclude alternative diagnoses.