OverviewA tense or bulging fontanelle occurs when fluid accumulates in the skull cavity or when pressure increases in the brain. Common causes are hydrocephalus or increased intracranial pressure due to illness.
Update Date 2/21/2013
Updated by: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by A.D.A.M. Health Solutions, Ebix, Inc., Editorial Team: David Zieve, MD, MHA, Bethanne Black, Stephanie Slon, and Nissi Wang.