Acquired Microcephaly: Causes, Patterns, Motor and IQ Effects, and Associated Growth Changes

OBJECTIVES: The goals were to identify and to classify causes and growth patterns of acquired (or progressive) microcephaly and to look for hypothesized correlations between causes, growth patterns, and developmental quotient/IQ. METHODS: Fifty-one children (24 boys), 0.7 to 11.3 years of age, with early occipitofrontal circumference measurements above and later ones below the second percentile (SD: -2.03) were studied through retrospective note and growth chart review, with formal assessments of developmental quotient or IQ (n = 34). RESULTS: Causes were classifiable into 5 groups as follows: idiopathic, familial, syndromic, symptomatic, and mixed. Four patterns of head growth were identified, as follows: type A, initial decrease from the normal range to below the second percentile, followed by growth below and parallel to the second percentile; type B, continued decrease away from the second percentile; type C, decrease below the normal range, with partial later recovery; type D, insufficient data. For 12 children, there were accompanying decreases in weight percentiles and for 5 of these in height percentiles as well. Infants with lower head circumference z scores at the end of the study also had lower z scores for final weight and final length. There was no correlation between causal group and growth pattern. Developmental quotient/IQ values were mostly <100 and did not correlate with head circumference z score, cause, or pattern. CONCLUSIONS: The classification of causal groups and growth patterns should aid clinical management. Neither cause nor pattern predicted outcomes. The associations with poor weight gain and body growth deserve further study. Pediatrics 2009; 124: 590-595