NEW YORK (Reuters Health) – New guidelines issued jointly by the American Academy of Neurology and the Child Neurology Society point out that children with microcephaly are at increased risk for epilepsy, cerebral palsy, and mental retardation and, therefore, screening for these disorders should be considered.

According to a report in the September 15th issue of Neurology, by Dr. Stephen Ashwal, from Loma Linda University School of Medicine, California, and members of both societies, roughly 25,000 infants in the US are diagnosed annually with microcephaly, defined as a head circumference more than 2 standard deviations below average for age and gender.

Neuroimaging can detect abnormalities in 43% to 80% of cases and genetic causes are reported in 15.5% to 53.3% of cases, the authors report. Metabolic disorders are seen in about 1% of patients.

Neurologic disorders are common in these children, the report indicates. Epilepsy, cerebral palsy, mental retardation, and ophthalmologic disorders were seen in roughly 40%, 20%, 50%, and 20%-50% of children, respectively.

Relative to milder microcephaly (2 to 3 standard deviations below the mean), severe microcephaly (more than 3 standard deviations) increases the likelihood of imaging abnormalities and more severe developmental impairments.

To generate guidelines for the evaluation of children with microcephaly, the researchers used a 4-tiered scheme to classify the strength of each recommendation: A (strongest), B, C, or U (weakest, insufficient data).

Only two level A recommendations were made: –Perform serial head circumference measurements in children with cerebral palsy as they are at increased risk for developing microcephaly. –In children with microcephaly, periodically assess development and academic achievement to determine the need for further testing and rehabilitation.

The other recommendations, all level C, include: –Consider neuroimaging to identify structural causes in children with microcephaly. –Consider genetic testing in children who have clinical/radiologic abnormalities suggesting a specific diagnosis or who have no apparent acquired cause for their microcephaly. –Consider screening for cerebral palsy, epilepsy, and sensory deficits in children with microcephaly, and consider educating caregivers about how to recognize clinical seizures.

The authors conclude, “Further study is needed regarding the yield of diagnostic testing in children with microcephaly.”

Reference:
Neurology 2009;73:887-897.