at: inbox

Neurology - Altered Mental Status - Fast Facts | NEJM Resident 360

Patients admitted to the hospital are often confused. Sorting out the etiology of altered mental status (AMS) and treating reversible causes can shorten length of stay and reduce the risk of further complications.

Altered mental status is a term that is used to describe a range of patient levels of mentation from mild inattention to complete unresponsiveness. If your patient’s mental status is altered, be specific when you are describing the alteration to colleagues, consultants, and in the medical record: Is the patient somnolent, or just answering questions inappropriately? Is the patient protecting his or her airway? Being specific about the mental status helps you and your team determine how urgently the patient needs to be worked up and treated.

Delirium

Delirium is the subacute fluctuating change in mental state usually due to reversible causes. Delirium is common: 30% of older adults hospitalized on a medical unit and 10% to 50% of older adults undergoing surgery will experience delirium. Delirium is most common in older adults, but can also affect middle-aged patients with severe illness in the hospital and ICU. For more on delirium in the elderly and in the ICU see the NEJM Resident 360 Geriatrics and Critical Care rotation guides.

Common Causes of AMS

Delirium is not the only type of AMS in hospitalized patients. If the AMS is acute in onset, persistent (non-fluctuating), or associated with impairment in consciousness, it may not be delirium. The table below summarizes some of the common causes of AMS to consider in hospitalized patients. However, most patients do not require the entire workup described. Begin your evaluation with a focused history, physical, and review of recent events, then determine appropriate next steps depending on the acuity and severity of AMS.

Always begin with a brief assessment of the patient’s general status and vital signs: bradycardia, tachyarrhythmia, hypotension, and acute hypertension can all precipitate altered mental status. All these conditions are emergencies and must be treated first. In patients with otherwise normal vital signs, consider the following other causes of AMS:

Note: Some research indicates a high rate of abnormal EEGs in hospitalized patients undergoing evaluation for AMS, suggesting that EEGs may be underutilized as a diagnostic tool for AMS.

The references cited in Reviews and Guidelines will help guide the urgency and intensity of AMS workup.

inbox