From the Guidelines
A comprehensive inpatient workup for altered mental status should begin with a thorough history, physical examination, and vital signs assessment to identify immediate life-threatening causes, as recommended by the most recent guidelines 1. Initial laboratory tests should include complete blood count, comprehensive metabolic panel, urinalysis, blood glucose, arterial blood gases, toxicology screen, and blood cultures if infection is suspected. Neuroimaging with CT or MRI of the brain is essential to rule out structural abnormalities, as stated in the 2024 update of the ACR Appropriateness Criteria for altered mental status, coma, delirium, and psychosis 1. Additional studies should include electroencephalogram to detect seizure activity, lumbar puncture if meningitis or encephalitis is suspected (after ruling out increased intracranial pressure), and specific tests based on clinical suspicion such as ammonia levels for hepatic encephalopathy, thyroid function tests, vitamin B12 levels, and HIV testing. Medication review is crucial as many drugs can cause altered mental status, particularly in elderly patients, as highlighted in the AASLD practice guidance on acute-on-chronic liver failure and the management of critically ill patients with cirrhosis 1. The workup should follow the mnemonic "AEIOU TIPS":
- Alcohol/drugs
- Endocrine/Electrolytes
- Infection
- Oxygen (hypoxia)
- Uremia
- Trauma
- Intracranial processes
- Psychogenic
- Seizures/Stroke. This systematic approach ensures comprehensive evaluation of the multiple potential causes of altered mental status, allowing for prompt diagnosis and appropriate treatment to prevent further neurological deterioration, as emphasized in the EASL clinical practice guidelines on the management of hepatic encephalopathy 1.
Some key points to consider in the workup include:
- Identifying alternative causes of neuropsychiatric impairment to improve prognostic accuracy and treatment outcomes, as recommended by the EASL clinical practice guidelines 1
- Ruling out medical conditions that may present with psychotic symptoms, such as endocrine disorders, autoimmune diseases, and infections, as stated in the ACR Appropriateness Criteria for altered mental status, coma, delirium, and psychosis 1
- Considering the potential for coexisting disorders, such as infections, hyponatremia, and renal dysfunction, that may worsen the mental status, as highlighted in the AASLD practice guidance on acute-on-chronic liver failure and the management of critically ill patients with cirrhosis 1.
By following this comprehensive approach, clinicians can ensure that patients with altered mental status receive prompt and effective diagnosis and treatment, improving outcomes and reducing morbidity and mortality, as emphasized in the clinical policy for the initial approach to patients presenting with altered mental status 1.
From the Research
Comprehensive Inpatient Workup for Altered Mental Status (AMS)
The comprehensive inpatient workup for a patient with altered mental status (AMS) involves a systematic approach to identify the underlying cause of the condition. The following steps are recommended:
- A thorough history and physical examination to guide diagnostic testing 2, 3, 4
- Laboratory testing, chest radiography, and electrocardiography to diagnose infections, metabolic disturbances, toxins, and systemic conditions 2, 3, 5
- Neuroimaging with computed tomography or magnetic resonance imaging to evaluate for intracranial pathology 2, 4
- Lumbar puncture and electroencephalography as important diagnostic tests in the evaluation of AMS 2, 4
- A systems-based approach to search for life-threatening or reversible causes 3
Diagnostic Considerations
The differential diagnosis for AMS is broad and includes:
- Primary central nervous system insults 2, 5
- Systemic infections 2, 3, 5
- Metabolic disturbances 2, 3, 5
- Toxin exposure 2, 5
- Medications 2, 5
- Chronic systemic diseases 2
- Psychiatric conditions 2, 5
- Delirium, especially in older people who are hospitalized 2, 6
Management and Treatment
The management and treatment of AMS depend on the underlying cause. The following are recommended:
- Identify and treat reversible causes of AMS 2
- Nonpharmacologic interventions are preferred to medications to control patient behaviors that threaten themselves or others 2
- Physical restraints should rarely be used and only for the shortest time possible 2
- Medications should be used only when nonpharmacologic treatments are ineffective 2