Delayed Dual Diagnosis of Cerebral Palsy with Underlying Duchenne Muscular Dystrophy in a 5-Year-Old Boy: A Case Report

Case Diagnosis: A 5-year-old boy with previously diagnosed spastic quadriplegic cerebral palsy (CP) due to hypoxic ischemic encephalopathy (HIE) is reassessed for toe walking and diagnosed with Duchenne muscular dystrophy (DMD).

Case Description or Program Description: Prior 12-month physical examination indicated head lag, heel cord contracture, and adductor spasticity, which led to the diagnosis of cerebral palsy (CP). Mild hypertonia observed at 15 months was consistent with CP. Examinations at 22 months noted hypertonia in all extremities, truncal and neck hypotonia, tight hip adductors, and tight heel cords with plantarflexion. Oral baclofen did not improve tone or spasticity. No cognitive deficits were noted on neurologic exam.
Bilateral ankle foot orthosis did not remedy toe walking. Baclofen failed to induce muscle relaxation, indicating need for a new assessment.
Anticipating another child, the mother underwent genetic testing, which revealed carrier status for Duchenne muscular dystrophy (DMD). At 46 months, the patient’s testing revealed a deletion in exons in the DMD gene and creatinine kinase level of 1610 U/L, supporting a DMD diagnosis in addition to CP.

Setting: Outpatient primary care and level 2 pediatric trauma center

Assessment/Results: The patient was diagnosed with CP at 12 months and DMD at 46 months.

Discussion (relevance): CP and DMD can share a presentation of toe walking and lower extremity contracture. CP presents with nonprogressive motor impairments and spasticity produced by upper motor neuron lesions. DMD is a myopathy with progressive muscle loss. Physicians commonly have little cause to seek diagnoses beyond CP when history is consistent with physical exam.
CP aided in overshadowing the patient’s underlying genetic disorder, which might have otherwise been addressed prior to 4 years of age. Early diagnosis in DMD is vital in beginning gene therapy and improving ambulation outcomes.

Conclusions: Multiple illnesses can impact symptomatic presentation, encouraging physicians to consider the sum of a patient’s presentation and additional diagnoses for optimal care.