Management of Subdural Hygroma

Diagnostic Evaluation

The American Academy of Neurology recommends MRI of the brain with intravenous contrast and whole spine MRI as first-line investigations to identify subdural hygroma and investigate for spontaneous intracranial hypotension (SIH) as the underlying cause, in patients with suspected subdural hygroma 2, 1
Brain MRI protocol should include T2-weighted sequences, FLAIR, T2*-weighted gradient echo or susceptibility-weighted imaging, and pre/post-contrast 3D volumetric T1-weighted acquisitions to detect pachymeningeal enhancement and venous engorgement, with a strength of evidence level of high 2
Spine MRI should include fat-suppressed T2-weighted sequences (STIR), high-resolution heavily T2-weighted 3D sequences (CISS, FIESTA, or equivalent), and axial imaging of select spinal segments to identify CSF leaks, with a moderate level of evidence 2

The American College of Neurology recommends epidural blood patch (EBP) as the initial treatment for subdural hygromas associated with spontaneous intracranial hypotension, with a high level of evidence 1
Patients with SIH and subdural collections require referral to a specialist neuroscience center for multidisciplinary team discussion, particularly if first-line treatments fail or there is rapid clinical deterioration, with a moderate level of evidence 2, 1
The specialist center must have neuroradiological expertise, practitioners skilled in epidural blood patching, expertise in targeted patching, and surgical capability to repair spinal CSF leaks, with a high level of evidence 2

Patients able to care for themselves should be referred within 2-4 weeks depending on symptom severity and mental health impact, with a moderate level of evidence 2
Patients unable to care for themselves but with available help require referral within 48 hours, with a high level of evidence 2
Emergency admission is indicated for patients unable to care for themselves without help, or those with subdural hematoma with mass effect requiring urgent tertiary neuroscience center referral, with a high level of evidence 2

After EBP for SIH-related subdural hygromas, patients should maintain supine position with head elevated as comfortable, and advise lying flat as much as possible for 1-3 days, with a moderate level of evidence 1
Minimize bending, straining, stretching, and other activities for 4-6 weeks post-procedure, with a moderate level of evidence 1
Consider thromboprophylaxis during immobilization periods, with a low level of evidence 1

Do not delay neuroimaging when subdural hygroma is suspected, as this can miss underlying pathology requiring urgent intervention, with a high level of evidence 3
Avoid overlooking the need to identify and treat underlying CSF leaks, as persistent leaks can lead to complications including superficial siderosis, with a high level of evidence 1
Be vigilant for cerebral venous thrombosis in cases associated with SIH, as this represents a serious complication, with a moderate level of evidence 1