Bulging fontanelle

Background

Neonatal suture anatomy.

• Fontanelles are fibrous, membrane-covered gaps between cranial bones.
• A newborn has six fontanelles: anterior, posterior, two mastoid, and two sphenoid.
  • Anterior and posterior are the most prominent
  • The posterior fontanelle usually closes by 1-2 months of age.
  • The anterior fontanelle usually closes between 7-19 months of age.
• A bulging fontanelle represents increased intracranial pressure, which may be transient and either benign or malignant.
• Meticulous history and physical is essential to guide management of these infants.

Clinical Features

• Bulging fontanelle

Differential Diagnosis

• Meningitis
• Encephalitis
• Meningoencephalitis
• Congestive Heart Failure
• Space-occupying lesions
• Thyroid disorders
• Intracranial Hemorrhage
• Parathyroid disorders
• Brain Abscess
• Diabetic Ketoacidosis
• Hypervitaminosis A
• Anemia
• Lead encephalopathy
• Leukemia
• Inborn errors of metabolism
• Uremia
• Trauma
• Roseola Infantum
• Vaccinations
• Shigella
• Idiopathic Intracranial Hypertension (Pseudotumor Cerebri)
• Dural sinus thrombosis
• Viral syndromes
• Hydrocephalus

Evaluation

• Clinical diagnosis
• Evaluate for underlying etiology
• Standard approach:
  • Head CT
  • LP (if not contraindicated by CT findings) with opening and closing pressures

Management

• Treat underlying pathology
• See elevated ICP