Initial Approach to Altered Mental Status in Hospitalized Patients
The initial approach to a patient with altered mental status in the hospital should follow a four-pronged strategy: 1) initiate appropriate care for altered consciousness, 2) identify and rule out alternative causes of altered mental status, 3) identify and correct precipitating factors, and 4) commence empirical treatment as indicated. 1
Step 1: Initial Assessment and Stabilization
- Airway, Breathing, Circulation (ABC): Ensure airway patency and adequate oxygenation and circulation
- Vital signs: Obtain complete set including temperature, blood pressure, heart rate, respiratory rate, and oxygen saturation
- Glucose check: Immediate bedside glucose measurement to rule out hypoglycemia
- Immediate interventions for life-threatening conditions:
- Administer glucose for hypoglycemia
- Provide oxygen for hypoxia
- Give naloxone if opioid overdose is suspected 2
Step 2: Focused Neurological Assessment
- Level of consciousness: Assess using Glasgow Coma Scale
- Pupillary response: Check size, symmetry, and reactivity
- Focal neurological deficits: Evaluate for lateralizing signs
- Meningeal signs: Check for nuchal rigidity, Kernig's and Brudzinski's signs
- Mental status examination: Orientation, attention, memory, and cognition assessment
Step 3: Diagnostic Workup
First-line Laboratory Tests:
- Complete blood count
- Basic metabolic panel
- Liver function tests
- Urinalysis
- Blood cultures (if febrile)
- Thyroid function tests
- Ammonia levels (if hepatic encephalopathy suspected) 2
Neuroimaging:
- Head CT without IV contrast is usually appropriate as the first-line neuroimaging test in patients with unexplained altered mental status and suspected intracranial pathology 1
- Brain MRI may be more appropriate in certain conditions and when the clinical picture is unclear 1, 2
Additional Testing Based on Clinical Suspicion:
- Lumbar puncture: Consider when CNS infection is suspected, especially with fever without clear source 2
- EEG: Indicated when seizure disorder or non-convulsive status epilepticus is suspected 2
- Toxicology screen: When substance use or toxin exposure is suspected
Step 4: Identify and Manage Common Etiologies
The most common causes of altered mental status include:
- Neurological (35%)
- Toxicological (23%)
- Systemic/organic (14.5%)
- Infectious (9.1%)
- Endocrine/metabolic (7.9%)
- Psychiatric (3.9%)
- Traumatic (2.1%) 2, 3
Hepatic Encephalopathy Management:
- Identify and correct precipitating factors (nearly 90% of patients can be treated with just correction of precipitating factors)
- Consider lactulose as initial treatment
- Consider rifaximin and other antibiotics when appropriate 1
Important Considerations and Pitfalls
- Avoid routine laboratory testing: Targeted rather than routine laboratory testing is recommended as the diagnostic yield of routine testing is low 2
- Consider non-convulsive status epilepticus: This can present as altered mental status without obvious seizure activity and requires EEG for diagnosis 2
- Elderly patients require special attention: They are at higher risk of having abnormal brain imaging, with associated factors including lower Glasgow Coma Scale, presence of lateralizing signs, higher systolic blood pressure, and lower body temperature 2
- Avoid medications that worsen encephalopathy: Benzodiazepines and opioids can exacerbate altered mental status 2
- Normal ammonia levels: In suspected hepatic encephalopathy, a normal ammonia value calls for diagnostic reevaluation 1
- Don't miss delirium: It has a prevalence ranging from 7-35% in the emergency department and is associated with nursing home residence, cognitive impairment, hearing impairment, and history of stroke 2
By following this systematic approach, clinicians can efficiently evaluate and manage patients with altered mental status in the hospital setting, potentially improving outcomes by quickly identifying and treating the underlying cause.