What is the next step in evaluating a patient with altered mental status and generalized weakness, presenting with tachycardia, mild hypoxia, and fever, who is unable to provide additional history?

Undress the Patient for Full Examination Immediately

The next step is to undress the patient for a complete physical examination (Option D), as this is essential to identify life-threatening conditions that may be hidden by clothing in a patient presenting with altered mental status, fever, tachycardia, and hypoxia. 1

Why Full Examination Takes Priority

Critical Hidden Pathology Must Be Excluded First

• Physical examination should firstly assess for the presence of peritonitis and clinical signs such as tachycardia, fever, and hypotension that should not be underestimated in patients with altered mental status and abnormal vital signs 1
• Abnormal vital signs or the general appearance of the patient including facial expression, skin color and temperature, and altered mental activity should alert the clinician that a patient may be in critical conditions 1
• In patients with altered mental status, tachycardia, fever, and hypoxia, hypotension and hypoperfusion signs such as oliguria, acute alteration of mental status, and lactic acidosis are indicative of ongoing organ failure that requires immediate identification 1

What the Full Examination Must Assess

• Skin examination for signs of infection, trauma, injection sites, rashes, or evidence of sepsis (mottled or cyanotic skin, cool extremities, slow capillary refill) 1
• Abdominal examination for distension, peritonitis, or occult pathology that could explain the presentation 1
• All hernia orifices (umbilical, inguinal, femoral) and surgical scars must be carefully examined, as incarcerated hernias or occult abdominal catastrophes can present with altered mental status 1
• Evidence of trauma, bruising, or signs of assault that may not be visible with clothing on 1
• Extremities for edema, injection marks, or signs of deep vein thrombosis 2

Why Other Options Are Premature

Blood Alcohol Level (Option A) - Premature Without Full Assessment

• While toxicology screening may eventually be needed, routine laboratory testing generally is low yield, costly, and unlikely to be of value or affect the disposition or management until the physical examination guides what testing is necessary 1
• Laboratory testing should be obtained on the basis of a patient's history and physical examination rather than routinely 1

Diazepam (Option B) - Dangerous Without Diagnosis

• Administering benzodiazepines before establishing a diagnosis is contraindicated, as medications should be used only when nonpharmacologic treatments are ineffective and after the underlying etiology is identified 3
• The patient's tachycardia and fever could represent sepsis, neuroleptic malignant syndrome, or other conditions where sedation could worsen outcomes 1, 4

Observation in ED (Option C) - Inadequate Initial Response

• Simple observation without a thorough physical examination fails to meet the standard of care for a patient with altered mental status, fever, tachycardia, and hypoxia 1, 3
• Patients presenting with altered mental status should be evaluated for other possible infections and non-infection-related conditions that may explain the clinical presentation before deciding on observation alone 1

Critical Pitfalls to Avoid

• Never assume altered mental status is purely psychiatric or substance-related without a complete physical examination, especially in patients "well known to ED staff" where anchoring bias can lead to missed diagnoses 1
• Poor hygiene and being fully clothed can hide critical findings such as abscesses, necrotizing fasciitis, pressure ulcers, or traumatic injuries 1
• Fever with altered mental status and tachycardia represents potential sepsis or other life-threatening conditions requiring immediate identification of the source 1, 5

Immediate Next Steps After Undressing

• Once the full examination is complete, simultaneously attach cardiac monitor, obtain vital signs, establish IV access, and check oxygen saturation 6
• Provide supplemental oxygen if hypoxemia or respiratory distress is present, as hypoxemia commonly drives tachycardia 1
• Obtain targeted laboratory testing based on physical examination findings, including complete blood count, basic metabolic panel, and lactate if sepsis is suspected 1, 5