What is a hallmark symptom of a patient with an acute subdural hematoma?

An acute subdural hematoma is characterized by the accumulation of blood between the dura mater and the brain, typically resulting from a traumatic injury. A hallmark symptom of this condition is a decreased level of consciousness. Following the injury, patients may present with confusion, drowsiness, or a reduced ability to respond, reflecting the impact of increased intracranial pressure and brain displacement caused by the hematoma.

In contrast, a brief loss of consciousness might suggest a simpler concussion rather than the more severe effects associated with an acute subdural hematoma. The presence of a persistent lucid phase is more commonly associated with epidural hematomas, where patients may initially feel fine before deteriorating. Immediate recovery of function may occur in some mild head injuries but is not characteristic of the significant and often progressive neurological decline associated with an acute subdural hematoma. Thus, a decreased level of consciousness is a key and classic symptom associated with this condition.