Coma

Excerpt

Coma reflects brain failure that may occur from a process originating in the central nervous system or may reflect a systemic metabolic process. Causes of coma range from easily correctable metabolic abnormalities to catastrophic life-threatening mass lesions. The provider must engage in resuscitation and diagnostic steps simultaneously.

Coma is defined as a state of deep unconsciousness, an eyes-closed unresponsive state. Coma is usually a transitory state though it may last for an indefinite or even prolonged period. Alerting and arousal functions of the brain are affected as well as awareness and the content of consciousness. Brief loss of consciousness with full return to alertness defines syncope.

There are gradations of altered mental status that range from mild confusion to conditions described as lethargy, stupor, and obtundation. Though the terms may be clearly defined in the literature, they are often misused leading to miscommunications. Lethargy indicates a defect in attention with only minimally reduced wakefulness. Obtundation refers to more blunted awareness and lessened response to the environment. Stupor describes a deeper unresponsive state from which the patient can be only transiently aroused with vigorous stimulation. Providers should determine a patient’s response to stimulation and describe that response rather than use terms or jargon that may be imprecise. Coma grading scales may provide of simplified manner to track the level of consciousness of a patient over time and may aid in identifying trends.

The first goal of the clinician is to stabilize the comatose patient and diagnose and treat any reversible causes of coma such as hypoglycemia. Further evaluation follows that will identify a likely cause of coma or do the initial critical sorting into structural or nonstructural causes of coma.