Bulging fontanelle
Pathophysiology
Fontanelles are fibrous membrane-covered gaps between cranial bones. A newborn has six fontanelles: anterior, posterior, two mastoid, and two sphenoid. The most prominent are the anterior and posterior fontanelles
A bulging fontanelle represents increased intracranial pressure, which may be transient, benign, or malignant. The most commonly considered etiologies include meningitis, space-occupying lesion, cerebral edema, and hemorrhage (spontaneous, non-accidental, or traumatic). A meticulous history and physical is essential to guide management of these infants.
- The posterior fontanelle usually closes by 1-2 months of age.
- The anterior fontanelle usually closes between 7-19 months of age.
Differential Diagnosis
- Meningo-encephalitis
- Congestive heart failure
- Space-occupying lesions
- Thyroid disroders
- Intracranial hemorrhage
- Parathyroid disorders
- Brain abscess
- Diabetic ketoacidosis
- Intracranial hemorrhage
- Hypervitaminosis A
- Anemia
- Lead encephalopathy
- Leukemia
- Inborn errors of metabolism
- Uremia
- Trauma
- Roseola
- Vaccinations
- Shigella
- Benign Intracranial hypertension
- Dural sinus thrombosis
- Viral syndromes
Sources
Baqui AH, de Francisco A, Arifeen SE, Siddique AK, Sack RB. Bulging fontanelle after supplementation with 25,000 IU of vitamin A in infancy using immunization contacts. Acta Paediatr. 1995 Aug;84(8):863-6.
Beri S, Hussain N. Bulging fontanelle in febrile infants: lumbar puncture is mandatory. [Letter]. Arch Dis Child. 2011; 96 (1):109.
Biswas AC, Molla MA, Al-Moslem K. A baby with bulging anterior fontanelle. Lancet. 2000; 356(9224):132.
Long SS. Transient bulging fontanelle after immunization. J Pediatr. 2005; 147(5):A3
Opfer K. The bulging fontanelle. Lancet. 1963 Jan 12;1(7272):116.
Silver W, Kuskin L, Goldenberg L. Bulging anterior fontanelle. Sign of congestive heart failure in infants. Clin Pediatr (Phila). 1970 Jan;9(1):42-3.
Shacham S, Kozer E, Bahat H, Mordish Y, Goldman M. Bulging fontanelle in febrile infants: is lumbar puncture mandatory? Arch Dis Child. 2009;94:690–692.