Subdural Hematoma

A patient on warfarin falls at home and seems fine — then deteriorates over the next 48 hours. The slow bleed beneath the dura is what makes subdural hematomas deceptively dangerous.

A subdural hematoma (SDH) is venous bleeding between the dura mater and arachnoid membrane, caused by tearing of bridging veins. Because the source is venous (low pressure), bleeding accumulates gradually — this is the defining feature that separates SDH from arterial bleeds. SDH is classified by timing: acute (symptoms within 24-72 hours), subacute (days to 2-3 weeks), and chronic (weeks to months). Chronic SDH is the classic presentation in older adults and clients on anticoagulants, where brain atrophy stretches bridging veins and even minor trauma causes slow accumulation. Symptoms develop insidiously — progressive headache, personality changes, confusion, unilateral weakness, and eventual decreased LOC. On CT, an acute SDH appears as a crescent-shaped hyperdense collection that conforms to the brain surface, crossing suture lines. Chronic SDH appears hypodense. Nursing priorities include serial neurological checks (GCS trending, pupil reactivity, motor response symmetry, signs of rising ICP such as Cushing's triad) and, for anticoagulated patients, anticipating urgent reversal (e.g., vitamin K, PCC, or FFP for warfarin). High-risk populations include older adults, chronic alcohol users (brain atrophy), and anyone on anticoagulant or antiplatelet therapy.

Key Distinctions

Don't confuse subdural (venous, crescent-shaped, crosses suture lines, gradual onset) with epidural (arterial, lens-shaped, bounded by suture lines, lucid interval then rapid decline). Students often mistake chronic SDH's slow cognitive changes for dementia or delirium — always ask about recent falls. A 'minor' fall in an anticoagulated older adult warrants neurological monitoring that a younger client might not need.

Clinical Pearl

Crescent means subdural, lens means epidural. If the bleed crosses suture lines and the patient is elderly or anticoagulated, think subdural until proven otherwise.