Coma

Coma can be defined as the absence of consciousness.  It is not a disease itself, but rather a state of being that occurs as a result of a disease.

Many medical conditions can lead to coma.  Metabolic problems such as liver and kidney failure can cause it, as can infections such as meningitis or sepsis.  Coma can result from severe brain trauma or from massive stroke or brain hemorrhage.  It can occur after cardiac arrest or even as a result of a small injury to the brainstem.

A patient in coma cannot respond to stimulation either from the verbal, visual, or tactile spheres.  Primitive reflexes, or pre-programmed automatic responses may occur, but are not purposeful.

The neurologist plays an important role in estimating the prognosis of a patient who is in coma.  Depending on the neurological examination, cause of coma, and duration of coma, the neurologist can counsel a patient's family as to the likelihood and expected degree of recovery.