In Japan, subdural Hematoma is managed by neurosurgerys. A subdural hematoma is a collection of blood between the dura and the arachnoid membrane covering the brain, most commonly caused by tearing of bridging veins from head injury but also occurring spontaneously in older adults on anticoagulation. It is classified by time course: acute (within 3 days of injury, usually severe high-energy trauma), subacute (3-21 days), and chronic (more than 21 days, often after seemingly minor trauma in older adults).
A subdural hematoma (ICD-10: I62.0 nontraumatic; S06.5 traumatic) is a collection of blood between the dura mater and the arachnoid membrane in the cranial vault. Anatomically distinct from epidural hematoma (between skull and dura) and intracerebral hemorrhage (within brain parenchyma). The most common mechanism is tearing of bridging veins crossing the subdural space from the cerebral cortex to the dural venous sinuses; less commonly arterial bleeding (especially in acute trauma) and rarely spontaneous bleeding from cortical aneurysm rupture. Time-course classification: acute (under 3 days post-injury, with hyperdense blood on CT and often associated brain contusion), subacute (3-21 days, mixed density), and chronic (more than 21 days, hypodense or mixed-density collection with neomembrane formation).
The key symptoms of Subdural Hematoma are: Progressive headache developing over days to weeks (chronic SDH) or rapidly worsening severe headache (acute SDH)., Cognitive decline, confusion, and personality change, often mistaken for dementia or delirium in older adults with chronic SDH., One-sided weakness (hemiparesis), most commonly affecting arm and leg on the side opposite the hematoma., Gait disturbance, frequent falls, and clumsiness — sometimes the first noticed symptom in older adults., Slurred speech, dysphasia, or language comprehension difficulty., Seizures, occurring in 10-15% of patients at presentation or during the course., Drowsiness, lethargy, and altered consciousness, ranging from sleepy but rousable to coma depending on hematoma size and brain compression..
Diagnosis of subdural hematoma is established by emergency non-contrast CT of the head, the first-line imaging modality. Acute SDH appears as a hyperdense crescent-shaped collection along the cerebral convexity, often crossing skull suture lines but not falx cerebri. Subacute SDH appears mixed-density and chronic SDH is hypodense with possible neomembranes producing internal density variation. CT volumes, midline shift, basal cistern compression, contusions, and other intracranial injuries are quantified using the Rotterdam or Marshall scores. MRI is more sensitive for small hematomas, posterior fossa lesions, and dating of mixed-density collections, particularly useful when CT is equivocal or for surgical planning. Clinical assessment includes Glasgow Coma Scale (GCS), pupil examination, motor function, brainstem reflexes, and history of trauma, anticoagulation, falls, and alcohol use. Coagulation studies (PT/INR, aPTT, platelet count, fibrinogen) are obtained urgently in all patients, particularly those on anticoagulation, with specific drug levels or anti-Xa where relevant. In acute presentations, point-of-care viscoelastic testing (TEG/ROTEM) guides reversal. CT angiography is added for atraumatic presentations or with associated subarachnoid hemorrhage to exclude underlying aneurysm or vascular malformation. Acute SDH requires immediate neurosurgical assessment; chronic SDH may be managed less urgently if the patient is neurologically stable, but progressive symptoms warrant prompt surgical planning. Falls assessment and underlying coagulopathy or substance use should be evaluated in parallel with the acute care plan.
Acute subdural hematoma carries 30-day mortality of 40-60% in severely injured patients, dropping to 20-30% in younger patients with smaller hematomas. Functional outcome at 6 months is dichotomous — good recovery or moderate disability in approximately 30%, severe disability or death in 60-70%. Age, initial GCS, pupillary findings, hematoma volume, midline shift, associated injuries, time to surgery, and anticoagulation reversal are the strongest prognostic factors. Chronic subdural hematoma has substantially better outcomes: 80-90% achieve good clinical improvement after surgical drainage; 30-day mortality 5-15%; recurrence rate 10-20% with surgery alone, halved with adjunctive MMA embolization. Cognitive recovery is typically gradual over 3-6 months; many older adults regain prior function. Predictors of poor chronic SDH outcome: very advanced age, severe baseline cognitive impairment, multiple comorbidities, large bilateral hematomas, severe neurological deficit at presentation. Resumption of anticoagulation is associated with substantially better long-term cardiovascular outcomes in atrial fibrillation patients despite slightly higher SDH recurrence — restarted in 70-85% of cases after consensus risk-benefit discussion at 1-4 weeks.
Subdural hematoma always requires neurosurgical evaluation — even apparently small lesions can deteriorate rapidly. Acute SDH is a surgical emergency. Chronic SDH is managed by neurosurgery, often in collaboration with geriatrics, neurology, neurocritical care, and rehabilitation. Comprehensive stroke centers or major neurotrauma centers offer the best outcomes for severe acute SDH.
Find specialists →Acute SDH: hospital stay typically 7-21 days depending on severity; rehabilitation over 3-12 months; cognitive and functional improvements continue up to 2 years post-injury. Chronic SDH burr hole drainage: hospital stay 2-5 days; clinical improvement evident within days to weeks; full CT resolution over 6-12 weeks. Anticoagulation typically resumed 1-4 weeks after surgery in patients with strong indication and stable hematoma. Driving cleared after individual neurological and neurocognitive assessment, typically at 1-3 months minimum.
Graded rehabilitation is essential after SDH treatment. Begin with bed mobility and transfers, advance to standing and walking with supervision, then progressive resistance and balance training. Tai chi and structured falls-prevention programs reduce falls and SDH recurrence in older adults. Avoid contact sports and activities with significant fall or head injury risk until cleared by neurosurgery; in older adults, lifelong avoidance of high-risk activities is often appropriate. Resume routine activity in 4-8 weeks after burr hole drainage; longer (8-16 weeks) after craniotomy or with persistent deficits.
Choose a neurosurgeon at a center with 24/7 emergency neurosurgical coverage, neurocritical care unit, and access to interventional neuroradiology (for MMA embolization). For chronic SDH in older adults, look for combined geriatric and neurosurgery pathways. Verify that the center participates in trauma center accreditation or comprehensive stroke center programs.
Medically reviewed by AIHealz Medical Editorial Board · May 13, 2026
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