Overview
Localized macrodontia, particularly in infants, often manifests as macrocrania due to benign extracerebral fluid collections, primarily subdural or subarachnoid fluid accumulations. These collections are typically asymptomatic and resolve spontaneously without intervention 2.Diagnosis
Key Diagnostic Criteria: Bilateral frontal extracerebral fluid collections observed on imaging.
Recommended Tests:
- CT Scan: Initial imaging modality to identify macrocrania and fluid collections.
- MRI: Superior in differentiating between benign enlargement of subarachnoid spaces and subdural collections, showing distinct fluid layers 1.
Grading:
- Single fluid layer on MRI suggests benign enlargement of subarachnoid spaces.
- Two distinct layers on MRI indicate subdural collections, often with an outer hyperintense layer 1.Management
First-Line Treatment:
- Observation: Asymptomatic patients require longitudinal observation without immediate intervention 2.
Adjunctive Treatments:
- Subdural Drainage: Indicated in symptomatic cases or when collections are hemorrhagic, though spontaneous resolution is common 1.Special Populations
Pediatrics: Benign extracerebral fluid collections are common causes of macrocrania in infants, typically benign and self-limiting 2.Key Recommendations
Perform MRI for definitive differentiation between subarachnoid fluid accumulation and subdural collections in infants with macrocrania (Evidence: Moderate 1).
Observe asymptomatic infants with benign extracerebral fluid collections without immediate intervention (Evidence: Strong 2).
Consider subdural drainage in symptomatic cases or when collections are hemorrhagic, though spontaneous resolution is often observed (Evidence: Moderate 1).References
1 Wilms G, Vanderschueren G, Demaerel PH, Smet MH, Van Calenbergh F, Plets C et al.. CT and MR in infants with pericerebral collections and macrocephaly: benign enlargement of the subarachnoid spaces versus subdural collections. AJNR. American journal of neuroradiology 1993. link
2 Hamza M, Bodensteiner JB, Noorani PA, Barnes PD. Benign extracerebral fluid collections: a cause of macrocrania in infancy. Pediatric neurology 1987. link90021-x)