Systematic Approach to Pediatric Macrocephaly.

Area of Science:

• Pediatric Radiology
• Neurology
• Medical Imaging

Background:

• Macrocephaly (head circumference > 2 SD above mean) is a frequent pediatric finding, often prompting neuroimaging.
• The differential diagnosis is broad, with many conditions presenting differently in infants versus older children with fused skull sutures.
• The Monroe-Kellie hypothesis explains how intracranial volume changes lead to increased intracranial pressure when skull sutures are closed.

Purpose of the Study:

• To present a practical classification paradigm for evaluating pediatric macrocephaly.
• To highlight the role of various imaging modalities (US, CT, MRI) in diagnosing macrocephaly.
• To emphasize the importance of clinical context, patient age, and imaging findings in diagnosis.

Main Methods:

• Classification of macrocephaly based on the enlarged cranial component: cerebrospinal fluid, blood/vasculature, brain parenchyma, or calvarium.
• Review of common and rare causes of pediatric macrocephaly.
• Correlation of imaging findings with clinical presentation and age.

Main Results:

• Most pediatric macrocephaly cases involve increased cerebrospinal fluid spaces, such as benign enlargement of the subarachnoid space.
• Distinguishing benign conditions from traumatic subdural fluid collections is critical.
• Other causes include hydrocephalus (aqueductal web, hemorrhage, neoplasm) and rare overgrowth/metabolic disorders.

Conclusions:

• A systematic approach to classifying macrocephaly by cranial component aids diagnosis.
• Imaging plays a crucial role in identifying the underlying cause, guiding further management, and potentially prompting genetic testing.
• Accurate diagnosis is essential for differentiating benign conditions from serious pathologies and trauma.