What is the initial workup for a hospitalized patient presenting with drowsiness or altered level of consciousness (aLOC)?

Initial Workup for Drowsiness/Altered Level of Consciousness in Hospitalized Patients

The initial workup for a hospitalized patient with drowsiness or altered level of consciousness (aLOC) should follow a systematic approach focused on airway, breathing, circulation assessment followed by targeted neurological evaluation and laboratory studies to identify potentially life-threatening causes.

Primary Assessment

Immediate Evaluation

• Assess and secure airway, breathing, and circulation (ABC) as the first priority 1
• Check vital signs including heart rate, respiratory rate, blood pressure, temperature, and oxygen saturation 2
• Perform rapid neurological assessment using a validated scale such as:
  • Glasgow Coma Scale (GCS) 2
  • AVPU scale (Alert, Voice, Pain, Unresponsive) 2
  • NIH Stroke Scale (NIHSS) for level of consciousness (0=alert, 1=drowsy, 2=obtunded, 3=coma) 3

Oxygen and Respiratory Support

• Administer supplemental oxygen to patients with altered level of consciousness, respiratory depression, or hypoxemia (oxygen saturation <94%) 2
• Continue oxygen until the patient is alert with no respiratory depression or hypoxemia 2
• Consider continuous pulse oximetry monitoring, especially in patients at increased risk of respiratory compromise 2

Secondary Assessment

Neurological Examination

• Perform a detailed neurological examination including:
  • Pupillary size and reactivity 4
  • Motor responses and strength 4
  • Sensory function 5
  • Cranial nerve function 6
  • Check for focal neurological deficits (e.g., facial droop, arm drift, abnormal speech) 2

Laboratory Studies

• Complete blood count (CBC) 7
• Comprehensive metabolic panel (electrolytes, renal function, liver function) 7
• Arterial blood gas analysis for patients with oxygen saturation <95% on room air or who are unconscious 2
• Blood glucose level (hypoglycemia is a common reversible cause) 7
• Toxicology screen when appropriate 4
• Blood cultures if infection is suspected 7

Imaging Studies

• Brain CT scan to rule out intracranial hemorrhage, stroke, or space-occupying lesions 7
• Consider MRI for more detailed evaluation if CT is negative but clinical suspicion remains high 6

Common Etiologies to Consider

Intracranial Causes

• Cerebrovascular accidents (24.5% of aLOC cases) 7
• Traumatic brain injury (22% of aLOC cases) 7
• Status epilepticus (4% of aLOC cases) 7
• Intracranial pressure changes 4

Extracranial Causes

• Organ failure (22% of aLOC cases) 7
• Infections and sepsis (12.2% of aLOC cases) 7
• Metabolic disturbances:
  • Diabetic emergencies and hypoglycemia (11.6% of aLOC cases) 7
  • Electrolyte abnormalities 4
• Shock (4% of aLOC cases) 7
• Medication effects (especially sedatives, opioids) 2
• Hypoxemia 2

Special Considerations

Monitoring Requirements

• For patients with drowsiness as a sign of potential respiratory depression:
  • Monitor at least once per hour for the first 12 hours 2
  • Continue monitoring based on patient's clinical condition and medications 2
• For patients with severe drowsiness or obtundation:
  • Consider continuous monitoring in a critical care or step-down unit 2
  • Frequent neurological checks to detect deterioration 6

Warning Signs Requiring Immediate Intervention

• Presence of drowsiness is a predictor of impending respiratory failure and may require ventilatory support 2
• Deteriorating level of consciousness on serial assessments 6
• Development of new focal neurological deficits 2
• Abnormal pupillary responses 6
• Declining oxygen saturation despite supplemental oxygen 2

Documentation and Communication

• Clearly document baseline mental status and all changes in level of consciousness 6
• Use validated scoring systems consistently for serial assessments 8
• Communicate findings and concerns promptly to the healthcare team 6

Remember that drowsiness in hospitalized patients can rapidly progress to more severe alterations in consciousness and requires vigilant monitoring and prompt intervention to prevent adverse outcomes.