TN 7 (08-12)
DI 23022.860 Pelizaeus-Merzbacher Disease--Classic Form
COMPASSIONATE ALLOWANCE INFORMATION
PELIZAEUS-MERZBACHER DISEASE--CLASSIC FORM
Classic PMD; Pelizaeus-Merzbacher Brain Sclerosis; Adult Pelizaeus-Merzbacher Disease; Classic Pelizaeus-Merzbacher Disease
Pelizaeus-Merzbacher Disease (PMD) is a rare, neurodegenerative disorder, and is one of a group of genetic disorders called leukodystrophies affecting the white matter of the brain and spinal cord. There are two main types of PMD: Classic PMD and Connatal PMD (see Connatal PMD template). Pelizaeus-Merzbacher Disease-Classic Form (Classic PMD) is the most common type. Symptoms begin in the first year of life with diminished muscle tone, stridor, poor coordination, involuntary eye movements, and delayed motor development. Other features that may develop over time include difficulties with balance, uncontrolled movements, and spasticity. Epileptic seizures are rare but may occur. While children may learn to walk with the assistance of crutches or a walker, this ability is generally lost by late childhood/adolescence. However, some children with classic PMD never learn to walk. Feeding concerns are less common than in the more severe form of PMD (Connatal). Most children develop language but have some degree of intellectual disability.
DIAGNOSTIC TESTING, PHYSICAL FINDINGS, AND ICD-9-CM CODING
Diagnostic testing: MRI demonstrates symmetric and widespread abnormality of the white matter of the cerebrum, brain stem, and cerebellum.
Physical findings: Individuals with Classic PMD have infantile nystagmus, abnormal muscle tone and spasticity, ataxia, and chorioathetosis.
ONSET AND PROGRESSION
Classic PMD progresses slowly and children generally survive to adulthood. Some children die before the age of 20, while others live much longer.
There is no cure for PMD, and treatment is supportive. Tracheostomy and/or feeding tubes may be necessary to avoid aspiration. Physical therapy, orthotics, and antispasticity medications may aid in motor development, and minimize joint contractures and kyphoscoliosis; orthopedic surgery is sometimes indicated. Developmental therapy and special education help to maximize cognitive achievement, and speech/language therapy aids in language development.
SUGGESTED PROGRAMMATIC ASSESSMENT*
Suggested MER for evaluation:
Clinical history and examination that describes the diagnostic features of the impairment
MRI of the brain showing abnormal white matter (demyelination)
Progress reports of physical therapy, speech/language therapy
Reports of educational evaluations/academic progress
Suggested Listings for Evaluation:
* Adjudicators may, at their discretion, use the Medical Evidence of Record or Listings suggested to evaluate the claim. However, the decision to allow or deny the claim rests with the adjudicator.