Macrocephaly

Macrocephaly is a condition characterized by having an unusually large head. Specifically, this is given as a diagnosis when the child’s head is larger than the 98th percentile. For instance, the head circumference (HC) of Caucasian one-year-olds is typically 17.5 inches; it would then be a red flag if an infant’s HC is 21 inches. Physicians order an imaging test (MRI, ultrasound, or CT scan) when they suspect that the head circumference is unusually large. This is most often harmless; however, it may also be an indication of a brain tumor, hydrocephalus (hyperlink), bleeding, metabolic condition, infection, or a certain syndrome.