Microcephalus

This code represents a congenital anomaly characterized by an abnormally small head circumference for the infant's age and sex, typically due to impaired brain development. It often indicates an underlying neurological disorder or genetic condition.

Use this code when documentation clearly states a diagnosis of microcephaly, often identified during prenatal ultrasound or at birth. Supporting documentation should include head circumference measurements falling below the 3rd percentile for gestational age or age-appropriate norms.

• Always review documentation for the underlying cause of microcephaly, if identified, and code it first if it's the primary reason for the encounter.
• Distinguish from craniosynostosis (756.0), which involves premature fusion of cranial sutures, though both can result in an abnormally shaped head.
• Ensure the diagnosis is definitively stated as microcephaly, not just "small head size" without further clinical context.