An intracranial hematoma is a pocket of clotted blood inside the skull. It can grow quickly after a head bump or appear days later when a small vein keeps leaking. As the clot expands it squeezes the brain and raises pressure, producing clear warning signals.

The first sign is often a headache that ramps up over minutes to hours. It feels like a steady drum inside the head and is usually worse when lying flat.

Nausea and vomiting can follow the headache without any stomach upset. The vomit may come on suddenly and bring brief relief, then return.

Thinking becomes foggy. The person repeats questions, forgets what day it is, or speaks more slowly than usual. Family usually notice the change first.

Weakness or numbness shows up on one side of the face, arm, or leg. An eyelid may droop, a smile turns crooked, or the hand cannot grip a coffee cup.

Vision can blur or double for seconds. Closing one eye does not clear the double image, and the outer edges of sight may gray out.

Some people hear an internal “whoosh” in time with their heartbeat, especially at night. Raising the head on extra pillows may quiet the noise.

If the clot keeps growing, drowsiness deepens and the person can be hard to wake. This is an emergency.