There is a spectrum of impaired consciousness that goes from full arousal to complete unresponsiveness. Coma, which is a state of unarousable unresponsiveness is the worst degree of impairment of a patient’s arousal and consciousness.
Words like lethargy, obtunded, and stupor all describe various degrees to which a patient’s arousal is impaired. However, these terms are imprecise. In a clinical setting, it is more useful to describe the patient’s responses to specific stimuli.
What is the difference between being lethargic, obtunded, stuporous, or in a coma?
| Level of Consciousness | Description |
| Clouding of consciousness | The patient has a very mild form of altered mental status in which the patient has inattention and reduced wakefulness. |
| Confusional State | The patient has a more profound deficit than clouding of consciousness that includes disorientation, bewilderment, and difficulty following commands. |
| Lethargy | The patient has severe drowsiness. He/she can be aroused by moderate stimuli, but then drifts back to sleep. |
| Obtundation | “is a state similar to lethargy in which the patient has a lessened interest in the environment, slowed responses to stimulation, and tends to sleep more than normal with drowsiness in between sleep states.” |
| Stupor | Being in stupor means that “only vigorous and repeated stimuli will arouse the patient, and when left undisturbed, the patient will immediately lapse back to the unresponsive state.” |
| Coma | “Coma is a state of unarousable unresponsiveness.” |
Reference
Tindall SC. Level of Consciousness. In: Walker HK, Hall WD, Hurst JW, editors. Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition. Boston: Butterworths; 1990. Chapter 57. Available from: https://www.ncbi.nlm.nih.gov/books/NBK380/