What is the initial workup for a 70-year-old man (YOM) with altered mental status (AMS) found on the ground with an unknown medical history?

Initial Workup for a 70-Year-Old Man with Altered Mental Status Found on the Ground

The initial workup for a 70-year-old man with altered mental status found on the ground should include vital signs assessment, focused neurological examination, laboratory studies (including urinalysis, complete blood count, basic metabolic panel, and liver function tests), and head CT scan after initial stabilization if no clear cause is identified from laboratory tests or if focal neurologic deficits are present. 1

Primary Survey and Immediate Assessment

1. Airway, Breathing, Circulation (ABC) Assessment:

   • Ensure patent airway and adequate oxygenation
   • Monitor vital signs (temperature, blood pressure, heart rate, respiratory rate, oxygen saturation)
   • Assess Glasgow Coma Scale (GCS) score

2. Immediate Interventions:

   • Establish IV access
   • Administer supplemental oxygen if hypoxic
   • Consider naloxone administration if opioid overdose is suspected 2
   • Check blood glucose and treat hypoglycemia if present

Secondary Survey and Diagnostic Workup

Laboratory Testing (First-Line):

• Urinalysis - high yield in elderly patients as UTIs are common causes of delirium 1
• Complete blood count - to assess for infection or anemia
• Basic metabolic panel - to evaluate electrolyte abnormalities, renal function
• Liver function tests - to assess for hepatic encephalopathy
• Blood glucose - to rule out hypo/hyperglycemia

Additional Laboratory Tests (Based on Clinical Suspicion):

• Blood cultures (if febrile)
• Thyroid function tests
• Toxicology screen and blood alcohol level
• Ammonia level (if liver disease suspected)
• Arterial blood gas (if respiratory distress or severe acidosis suspected)

Imaging Studies:

• Head CT scan is appropriate after initial laboratory evaluation if:

  • No clear cause is identified from laboratory tests
  • Focal neurologic deficits are present
  • History suggests trauma
  • Patient is on anticoagulants or has coagulopathy
  • Hypertensive emergency is present
  • Intracranial infection, mass, or elevated intracranial pressure is suspected 3

• Brain MRI may be considered after initial stabilization if:

  • CT is negative or inconclusive but clinical suspicion for intracranial pathology remains high
  • More detailed evaluation of brain parenchyma is needed 3

Additional Diagnostic Tests (Based on Clinical Indication):

• Electrocardiogram (to assess for cardiac causes)
• Chest radiography (to evaluate for pneumonia)
• Electroencephalography (if seizure activity is suspected)
• Lumbar puncture (if meningitis/encephalitis is suspected and no contraindications exist)

Common Etiologies to Consider

1. Neurological:

   • Stroke/TIA
   • Intracranial hemorrhage
   • Seizure (including nonconvulsive status epilepticus)
   • Meningitis/encephalitis

2. Metabolic/Endocrine:

   • Electrolyte abnormalities (hyponatremia, hypernatremia)
   • Hypoglycemia/hyperglycemia
   • Thyroid disorders
   • Hepatic encephalopathy
   • Uremia

3. Infectious:

   • Urinary tract infection (particularly common in elderly)
   • Pneumonia
   • Sepsis
   • CNS infection

4. Toxicological/Pharmacological:

   • Medication side effects or interactions
   • Alcohol intoxication or withdrawal
   • Drug overdose or withdrawal
   • Carbon monoxide poisoning

5. Traumatic:

   • Subdural hematoma (may be chronic in elderly)
   • Traumatic brain injury

Common Pitfalls to Avoid

• Premature diagnostic closure: Don't assume the cause is psychiatric without adequate medical workup 1
• Overreliance on neuroimaging: Basic laboratory testing should precede neuroimaging in most cases 1
• Missing atypical presentations: Elderly patients may present with altered mental status as the only sign of infection 1
• Failure to recognize medication effects: Polypharmacy is common in elderly patients 1
• Inadequate history: When possible, obtain collateral information about baseline mental status, medication use, and recent changes 4

Management Approach

1. Treat identified causes:

   • Antibiotics for infections
   • Correction of electrolyte abnormalities
   • Antidotes for toxins when available
   • Anticonvulsants for seizures

2. Supportive care:

   • Maintain normothermia
   • Ensure adequate oxygenation and perfusion
   • Avoid physical restraints when possible
   • Provide reorientation strategies

3. Disposition:

   • Most patients with unexplained altered mental status require admission for further workup and monitoring
   • Consider ICU admission for patients with severe physiological derangements or those requiring close neurological monitoring

The yield of neuroimaging in altered mental status without focal neurologic deficits is relatively low (11-16.5%), but should not be omitted in elderly patients found on the ground with unknown medical history, as they are at high risk for traumatic brain injury and other intracranial pathologies 1.