Differential Diagnosis for Altered Mental Status Mnemonic – USMLE Step 2 CS Mnemonics

Differential Diagnosis for Altered Mental Status Mnemonic:

Altered mental status is a common chief complaint among older emergency department patients. Despite the frequency of this complaint, the term “altered mental status” is vague and has several synonyms such as confusion, not acting right, altered behavior, generalized weakness, lethargy, agitation, psychosis, disorientation, inappropriate behavior, inattention, and hallucination. Acute changes in mental status are more concerning and are usually secondary to delirium, stupor, and coma. These forms of acute brain dysfunction are commonly precipitated by an underlying medical illness that can be potentially life-threatening and are associated with a multitude of adverse outcomes. Though stupor and coma are easily identifiable, the clinical presentation of delirium can be subtle and is often missed without actively screening for it. For patients with acute brain dysfunction, the ED evaluation should focus on searching for the underlying etiology. Infection is one of the most common precipitants of delirium, but multiple etiologies may exist concurrently.

Altered Mental Status Differential Diagnosis Mnemonic

Differential Diagnosis for Altered Mental Status Mnemonic

Key Physical Exam for Altered Mental Status:
  • Vital signs including orthostatic vital signs
  • Complete neurologic exam including: DTR’s, CN2-12, motor, sensory, gait
  • Carotid and cardiac exam
  • Lung exam
  • Exam of the lower extremities
Work-up for Altered Mental Status:
  • CBC,
  • Electrolytes,
  • Glucose level,
  • Urine toxicology,
  • Electrocardiogram (ECG),
  • 24 hour holter monitoring,
  • CT of the head,
  • MRI of the brain,
  • Lumbar puncture for CSF analysis,
  • Electroencephalogram (EEG),
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