Subdural hemorrhage

Background

Anatomy of the meninges

Can present as acute (<14 days) and chronic (>14 days)
Both types are caused by sudden acceleration-deceleration of the brain with resultant shearing of the bridging veins.
- Blood pools between the dura mater and arachnoid
Patients with extreme atrophy are at increased risk (elderly, alcoholics)
- Patients less than 2 years old are also at increased risk
SDH are often associated with other brain injuries

Patients with acute SDH generally will present unconscious after a severe trauma
Patients with chronic SDH generally present with altered mental status or vague complaints
High index of suspicion warranted in the aforementioned groups of patients at increased risk with any history of head trauma regardless of severity

Intra-axial
- Hemorrhagic stroke (Spontaneous intracerebral hemorrhage)
- Traumatic intracerebral hemorrhage
Extra-axial
- Epidural hemorrhage
- Subdural hemorrhage
- Subarachnoid hemorrhage (aneurysmal intracranial hemorrhage)

Large left-sided frontal-parietal subdural hematoma with associated midline shift.

Consider brain CT (rule out intracranial hemorrhage)
- Use validated decision rule to determine need
- Avoid CT in patients with minor head injury who are at low risk based on validated decision rules.^[1]
Consider cervical and/or facial CT
Noncontrast CT Brain is the gold standard
- Acute SDH will show as a hyperdense (white) collection with a crescent-shaped appearance
- Chronic SDH will show as a hypodense (dark grey/black) collection in a crescent-shape
- Contrasted studies are useful in distinguishing acute, subacute, and chronic

See Head trauma (main)
Emergent neurosurgical evacuation
- Operative intervention generally for patients with focal findings, >10mm hematoma, midline shift > 5mm, signs of increased intracranial pressure (ICP)^[2] ^[3]
Management of ICP
- Head of bed to 30 degrees
- Short-term use of hyperventilation
- Hyperosmolar agents (Mannitol, 3% saline)
Reversal of anticoagulation
Treat and prevent hypotension and hypoxia
- Associated with significantly increased mortality^[4]
Emergency Department Burr hole, if indicated

↑ Choosing wisely ACEP
↑ Bullock MR, et al. Surgical management of acute subdural hematomas. Neurosurgery. 2006; 58(3):S16-24
↑ Evans JA, et al. A simple tool to identify elderly patients with a surgically important acute subdural haematoma. Injury. 2015 Jan;46(91):76-9
↑ Chesnut, R.M., Marshall, L.F., Klauber, M.R., Blunt, B.A., Baldwin, N., Eisenberg, H.M., Jane, J.A., Marmarou, A. and Foulkes, M.A. (1993) ‘THE ROLE OF SECONDARY BRAIN INJURY IN DETERMINING OUTCOME FROM SEVERE HEAD INJURY’, The Journal of Trauma: Injury, Infection, and Critical Care, 34(2), pp. 216–222.