What is the appropriate workup for a patient with altered mental status?

From the Guidelines

The workup for altered mental status should begin with a thorough history and physical examination, focusing on vital signs, neurological assessment, and identifying potential causes, as recommended by the most recent guidelines 1. The initial evaluation should include a comprehensive assessment of the patient's mental status, using validated scales such as the Richmond Agitation Sedation Scale and Glasgow Coma Scale to quantify the severity of symptoms 1. Initial laboratory tests should include:

• Complete blood count
• Comprehensive metabolic panel
• Urinalysis
• Blood glucose
• Arterial blood gases
• Toxicology screen
• Blood cultures if infection is suspected Imaging studies should include a non-contrast head CT to rule out structural abnormalities, followed by MRI if needed for more detailed evaluation 1. Lumbar puncture should be performed if meningitis or encephalitis is suspected, after ruling out increased intracranial pressure. An electroencephalogram (EEG) is valuable for detecting seizure activity, especially in cases of non-convulsive status epilepticus. Additional specialized tests may include:
• Thyroid function tests
• Vitamin B12 and folate levels
• Ammonia levels
• HIV testing
• Autoimmune panels depending on clinical suspicion. The workup should be tailored to the patient's presentation, with attention to common causes like metabolic derangements, infections, toxins, structural lesions, and seizures. Prompt identification and treatment of the underlying cause is essential, as altered mental status represents a medical emergency that can rapidly progress to permanent neurological damage if not addressed quickly 1. It is crucial to consider the potential for delirium, which is a common and serious condition that can be easily missed, especially in elderly patients 1. The economic impact of delirium is significant, with estimated total costs ranging from $38 to $152 billion annually in the United States 1. Therefore, a thorough and timely workup is critical to improve patient outcomes and reduce morbidity and mortality associated with altered mental status.

From the Research

Approach to Altered Mental Status

The approach to a patient with altered mental status (AMS) should be prompt and thorough, as AMS can be a sign of a life-threatening condition 2, 3. The initial evaluation should include a primary survey, followed by a secondary survey with a focus on identifying immediate life-threatening reversible causes 2.

Key Components of the Evaluation

The evaluation of a patient with AMS should include:

• A detailed history and physical exam 2, 4
• Laboratory and radiographic testing to identify potential causes of AMS 2, 3
• Consideration of various etiologies, including:
  • Primary neurologic insults 2, 5
  • Systemic illnesses resulting in end-organ dysfunction of the brain 2, 3
  • Toxicological causes 3, 6
  • Infectious causes 3, 5
  • Endocrine/metabolic causes 3, 5
  • Traumatic causes 3, 6

Systems-Based Approach

A systems-based approach should be used to search for any other life-threatening or reversible causes of AMS 2. This approach should include:

• Evaluation of the patient's airway, breathing, and circulation (ABCs) 2
• Assessment of the patient's neurological status, including level of consciousness and cognitive function 2, 5
• Consideration of the patient's medical history and potential underlying conditions that may be contributing to the AMS 2, 4

Prehospital Care

In the prehospital setting, EMS protocols for AMS vary widely, but should include:

• Patient assessment, including evaluation of airway, breathing, and circulation (ABCs) 6
• Point-of-care tests, such as blood glucose checks 6
• Supplemental oxygen as needed 6
• Consideration of various etiologies, including toxicological and traumatic causes 6