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Coma (cont.)

What are the causes of Coma?

Generally, coma is commonly a result of trauma, bleeding and/or swelling affecting the brain. Inadequate oxygen or blood sugar (glucose) and various poisons can also directly injure the brain to cause coma.

Trauma

Minor head injuries can cause brief loss of consciousness, but the brain is able to turn itself back on. Similarly, patients with seizures become unconscious - but gradually waken relatively quickly. Those people who cannot respond after head injury usually have had significant force applied to their head and brain.

The skull is a rigid box that protects the brain. Unfortunately, if the brain is injured and begins to swell (edema), there is no room for the additional fluid. This causes the brain to push up against the sides of the skull and it then compresses. Unless the pressure is relieved, the brain will continue to swell until it pushes down onto the brain steam, which then damages the RAS, which subsequently affects blood pressure and breathing control centers.

The affect of trauma on the brain is not predictable. It may or may not cause significant injury. If the brain is shaken, shear injury may occur, where the nerve connections within the brain are damaged. Coma may occur even with a normal CT scan in this situation. Similarly, head trauma may cause swelling of the brain without any bleeding, and coma may be the result.

Head trauma can cause different types of brain injury. The injury can occur to the brain tissue itself or may cause bleeding to occur between the brain and the skull. Computerized Tomography (CT) of the head can identify most bleeding from trauma.

Bleeding (Hemorrhage)

Intracerebral hemorrhage (intra= within + cerebral=brain + hemorrhage=bleeding) may be small, but it is associated swelling that may cause damage.



Next: Epidural, subdural, and subarachnoid hemorrhages »

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