What is the medical evaluation for a 20-month-old boy with delayed walking?

Medical Evaluation for a 20-Month-Old Boy Who Is Not Walking

A comprehensive medical evaluation for a 20-month-old boy who is not walking should include a thorough neuromotor examination, developmental screening, laboratory testing, neuroimaging, and immediate referral to early intervention services while the diagnostic workup is ongoing. 1, 2

Initial Assessment

History Taking

• Obtain detailed developmental history focusing on:
  • Delayed acquisition of other motor milestones
  • Any regression of previously acquired skills
  • Strength, coordination, and endurance issues
  • Family history of neuromuscular disorders or developmental delays 1

Physical and Neurological Examination

• Complete physical examination with special attention to:
  • Growth parameters (height, weight, head circumference)
  • Muscle tone, bulk, and strength
  • Deep tendon reflexes
  • Joint flexibility and range of motion
  • Observation of spontaneous motor function
  • Presence of Gower's sign (using arms to "climb up" the body when rising from floor) 1, 2

Red Flags to Identify

• Motor red flags:
  • Not rolling to both sides by 9 months
  • Not sitting well without support by 9 months
  • Lack of motor symmetry
  • Persistent primitive reflexes
  • Early handedness before 18 months 2
• Consider Duchenne muscular dystrophy (DMD) if:
  • Not walking by >16-18 months
  • Gower's sign present (especially in boys <5 years old)
  • Family history of DMD 1

Diagnostic Testing

Laboratory Studies

• Serum creatine kinase (CK) - especially important to rule out muscular dystrophies
• Complete blood count
• Comprehensive metabolic panel including liver function tests (AST, ALT)
• Thyroid function tests
• Vitamin D, calcium, phosphorus levels (to rule out rickets) 1, 3

Neuroimaging

• Brain MRI with T1-weighted, T2-weighted sequences, diffusion-weighted imaging, and FLAIR imaging if:
  • Abnormal neurological examination
  • Microcephaly or macrocephaly
  • Global developmental delay 2, 4
• MRI has a diagnostic yield of 55% for global developmental delay 2

Genetic Testing

• First-line: Chromosomal microarray
• Consider whole exome sequencing if microarray is negative
• Targeted genetic testing if a specific syndrome is suspected 2
• For suspected DMD:
  • Dystrophin deletion/duplication testing
  • If negative, genetic sequencing
  • Consider muscle biopsy if genetic testing is inconclusive 1

Referrals and Intervention

Immediate Referrals

• Early Intervention Program (for children 0-3 years) - should be initiated even while diagnostic workup is ongoing 1, 2
• Pediatric neurology
• Developmental pediatrics
• Physical therapy and occupational therapy 2

Specialist Consultations Based on Findings

• Medical genetics if genetic etiology suspected
• Orthopedics if structural abnormalities present
• Physiatrist for rehabilitation planning 1

Follow-up and Management

• Schedule early return visit (before next well-child check) to review test results and monitor progress 1
• Develop a comprehensive management plan with measurable outcomes
• Identify the child as having special health care needs and initiate chronic condition management
• Coordinate care between specialists and therapists
• Provide family support and education about the condition and expected developmental trajectory 1, 2

Common Pitfalls to Avoid

• Delaying therapy while awaiting a definitive diagnosis - early intervention should begin immediately 2
• Overlooking rickets as a treatable cause of delayed walking 3
• Failing to consider DMD in boys with both motor and cognitive delays 5
• Not performing a complete neurological examination, including observation of walking (if previously ambulant) 6
• Attributing delayed walking solely to cognitive delay without considering neuromuscular causes 5

Remember that up to 16% of children have at least one developmental delay, and early identification and intervention are crucial for improving outcomes 2.