Macrocephaly

Macrocephaly is a clinical and radiological term that refers to a generalized increase in the size of the cranial vault.

Terminology

This slightly differs from the term megalencephaly which means an increase in the size of the brain parenchyma. 

Epidemiology

• content pending

Clinical presentation

In some individuals a large head is normal or something that is familial.

However in others it is related to a syndrome, and other features may be present, see long list of causes below. 

Pathology

Etiology

In an infant it can result from a wide range of causes:

• congenital hydrocephalus: this, in turn, can result from a multitude of causes

• hydranencephaly: the choroid still forms CSF

• subdural fluid collection

• neurofibromatosis type 1

• achondroplasia

• hypochondroplasia

• thanatophoric dysplasia

• tuberous sclerosis complex

• metabolic storage diseases, e.g. mucopolysaccharidoses

• Alexander disease

• Greig syndrome

• Gorlin-Goltz syndrome

• Ruvalcaba syndrome

• Canavan disease ³

• cranio-cerebello-cardiac (CCC) syndrome

• Sotos syndrome

• Bannayan–Riley–Ruvalcaba syndrome (BRRS) ¹

• arterial tortuosity syndrome

• Weaver syndrome

• fragile X syndrome

• Noonan syndrome

• Costello syndrome

• LEOPARD syndrome

Radiographic features

Some define the condition on skull radiography when the head circumference is more than two standard deviations above the mean or exceeds the 97^th percentile by at least 5 mm ^4-7.

See also

• benign enlargement of the subarachnoid spaces in infancy as a benign cause of macrocephaly

• fetal macrocephaly