Overview
External hydrocephalus refers to an abnormal accumulation of cerebrospinal fluid (CSF) in the extra-axial spaces, often presenting with enlarged subdural fluid collections. This condition can be associated with transplacental anti-Ro antibodies and may predispose infants to subdural bleeding, complicating diagnosis and management 12.Diagnosis
Clinical Presentation: Progressive head circumference increase, absence of encephalopathy, and lack of retinal hemorrhages 1.
Imaging: CT or MRI showing bilateral subdural fluid collections consistent with chronic subdural hematomas or effusions 1.
Laboratory Tests: Positive anti-Ro antibody testing in infants with maternal history of Sjögren's syndrome 1.
Differential Diagnosis: Exclude non-accidental head injury (NAHI) through thorough child protection investigations 1.Management
Monitoring: Regular head circumference measurements and neuroimaging to assess progression 1.
Conservative Approach: Often no specific pharmacological treatment; management focuses on supportive care and monitoring 1.
Surgical Intervention: Consideration for CSF diversion procedures (e.g., ventriculoperitoneal shunt) in cases of significant neurological compromise 1.Special Populations
Pediatrics: Increased risk of subdural bleeding after minor head trauma in infants with benign external hydrocephalus 2.
Maternal Factors: Infants born to mothers with Sjögren's syndrome and positive anti-Ro antibodies are at higher risk 1.Key Recommendations
Investigate Anti-Ro Antibodies: Screen infants with unexplained subdural fluid collections for anti-Ro antibodies, especially if maternal history suggests Sjögren's syndrome (Evidence: Moderate) 1.
Exclude Non-Accidental Injury: Conduct thorough child protection investigations to rule out NAHI in infants presenting with subdural hematomas (Evidence: Moderate) 1.
Consider Imaging Predictive Models: Use theoretical models to predict predisposition towards extra-axial hemorrhage in infants with benign external hydrocephalus post-minor trauma (Evidence: Weak) 2.References
1 Edwards RJ, Allport TD, Stoodley NG, O'Callaghan F, Lock RJ, Carter MR et al.. External hydrocephalus and subdural bleeding in infancy associated with transplacental anti-Ro antibodies. Archives of disease in childhood 2012. link
2 Papasian NC, Frim DM. A theoretical model of benign external hydrocephalus that predicts a predisposition towards extra-axial hemorrhage after minor head trauma. Pediatric neurosurgery 2000. link