Initial Evaluation and Management of Altered Mental Status
The initial evaluation of a patient with altered mental status should follow a systematic approach focusing on identifying and treating life-threatening conditions immediately, addressing underlying causes, and providing supportive care. 1
Initial Assessment
Vital Signs and Airway Management
- Assess and stabilize ABCs (Airway, Breathing, Circulation)
- Monitor vital signs: temperature, pulse, blood pressure, respiratory rate, oxygen saturation
- Ensure equipment to maintain patent airway is immediately available 2
- Consider intubation for patients with severe altered mental status who cannot protect their airway
Rapid Neurological Assessment
- Glasgow Coma Scale (GCS) assessment
- Pupillary response and size
- Motor function and reflexes
- Signs of meningeal irritation (nuchal rigidity, Kernig's sign, Brudzinski's sign)
- Mental status examination (orientation, attention, memory)
Diagnostic Workup
Initial Laboratory Testing
- Complete blood count
- Basic metabolic panel (electrolytes, BUN, creatinine)
- Liver function tests
- Blood glucose (immediate bedside testing)
- Arterial blood gas (if respiratory compromise)
- Urinalysis
- Blood cultures (if febrile)
- Ammonia levels (if liver disease suspected) 1
Imaging Studies
- CT head without contrast (for patients with trauma, focal neurologic findings, or unexplained altered mental status)
- Consider MRI brain if CT is negative but clinical suspicion remains high
- Chest X-ray to evaluate for pulmonary sources of infection
Additional Testing Based on Clinical Suspicion
- Lumbar puncture (if meningitis/encephalitis suspected and no contraindications)
- Toxicology screen
- Thyroid function tests
- Vitamin B12 levels (especially in elderly)
- EEG (if seizures or non-convulsive status epilepticus suspected)
Management Approach
Four-Pronged Approach 3
Initiate care for altered consciousness
- Ensure adequate oxygenation and perfusion
- Maintain normothermia
- Avoid physical restraints when possible
Seek and treat alternative causes of altered mental status
- Consider common etiologies: neurological (35%), toxicological (23%), systemic/organic (14.5%), infectious (9.1%), endocrine/metabolic (7.9%) 4
Identify and correct precipitating factors
- Infections (UTI, pneumonia, sepsis)
- Metabolic derangements (hyponatremia, hypoglycemia)
- Medication side effects or interactions
- Hypoxia or hypercapnia
Commence empirical treatment
- For suspected hepatic encephalopathy: lactulose (and consider rifaximin if lactulose alone is insufficient) 3
- For suspected status epilepticus: lorazepam 4 mg IV slowly (2 mg/min) for adults; may repeat once after 10-15 minutes if seizures continue 2
- For suspected sepsis: early antibiotics after cultures
- For hypoglycemia: glucose administration
Special Considerations
Drug Toxicity Syndromes
- Recognize patterns of specific toxidromes:
- Serotonin syndrome: agitated delirium, hyperreflexia, clonus, diaphoresis, hyperthermia
- Neuroleptic malignant syndrome: "lead pipe" rigidity, bradyreflexia, hyperthermia
- Anticholinergic poisoning: hot, dry, red skin, mydriasis, dry mucous membranes, altered mental status 3
Hepatic Encephalopathy
- Normal ammonia level calls for diagnostic reevaluation 3
- Identify and correct precipitating factors (infection, GI bleeding, medications)
- Lactulose is the initial treatment of choice 3
Common Pitfalls to Avoid
- Attributing behavioral changes to psychiatric causes without adequate medical workup
- Overreliance on neuroimaging before basic laboratory testing
- Missing atypical presentations of common infections in elderly patients
- Failure to recognize medication side effects or interactions 1
- Neglecting to reassess patients frequently for changes in status
Admission Criteria
- Unexplained altered mental status requiring further workup
- Severe physiological derangements
- Need for close neurological monitoring
- Patients with acute metabolic encephalopathy and aspiration problems should be admitted to ICU 1
By following this systematic approach to evaluation and management, clinicians can effectively identify and treat the underlying causes of altered mental status, potentially reducing morbidity and mortality associated with this condition.