In an 83‑year‑old man 4 days after hip surgery who is now disoriented and agitated but has no focal neurologic deficits, normal labs, mild fever, and a history of atrial fibrillation, Parkinson disease, hyperthyroidism and hypertension, which should be ordered now: a bedside swallow evaluation, serum total thyroxine level, head CT, or electroencephalogram?

Postoperative Delirium Management in Elderly Hip Surgery Patient

Direct Answer

Order a head CT now to exclude acute intracranial pathology (subdural hematoma, stroke) in this elderly postoperative patient with new-onset disorientation and agitation, especially given his atrial fibrillation and anticoagulation history. 1

Clinical Reasoning and Differential Diagnosis

This 83-year-old man presents with postoperative delirium 4 days after hip surgery. The key diagnostic challenge is distinguishing between common postoperative delirium and life-threatening alternative diagnoses that require immediate intervention.

Critical Red Flags Requiring Neuroimaging

• Atrial fibrillation with anticoagulation history creates significant stroke and intracranial hemorrhage risk, making head CT essential before attributing symptoms solely to delirium 1
• Postoperative setting with recent anticoagulation interruption (rivaroxaban held perioperatively) increases thrombotic stroke risk 1
• New-onset confusion in elderly patient warrants exclusion of subdural hematoma, particularly given fall risk and recent surgery 1
• Fever (100.4°F) with altered mental status requires ruling out structural causes before attributing to infection alone 1

Why Head CT Takes Priority

The European Society of Cardiology and American Heart Association guidelines emphasize that any patient with altered consciousness and cardiovascular risk factors requires brain imaging to exclude stroke or hemorrhage before pursuing other diagnoses. 1 In this patient with atrial fibrillation, the stroke risk is substantial, and missing an acute stroke would be catastrophic.

Why Other Options Are Less Urgent

Swallow Evaluation (Option A)

• While aspiration risk exists postoperatively, swallow evaluation should follow exclusion of acute neurological emergencies 1
• The patient's agitation and disorientation would make bedside swallow assessment unreliable and potentially dangerous 1
• This can be safely deferred until mental status is clarified

Serum Total Thyroxine (Option B)

• Hyperthyroidism does not cause acute delirium in the postoperative setting 2, 3
• The patient is already on levothyroxine for known hyperthyroidism, suggesting treated disease 3
• Thyroid storm would present with severe tachycardia (>140 bpm), hyperthermia (>104°F), and cardiovascular instability—none of which are present (HR 87, temp 100.4°F) 2
• Iatrogenic hyperthyroidism from levothyroxine does not cause acute confusion but rather chronic symptoms like atrial fibrillation 4, 5

Electroencephalogram (Option D)

• EEG is indicated when seizures are suspected as the cause of altered consciousness, typically with witnessed convulsive activity, post-ictal confusion, or focal neurological deficits 1
• This patient has no focal motor deficits and normal reflexes, making seizure less likely 1
• Non-convulsive status epilepticus should be considered only after structural lesions are excluded 1

Systematic Approach to Postoperative Delirium

Step 1: Exclude Life-Threatening Causes (Do This First)

• Order head CT immediately to rule out:
  • Ischemic stroke (given atrial fibrillation) 1
  • Subdural hematoma (elderly, fall risk, anticoagulation) 1
  • Intracranial hemorrhage 1

Step 2: Assess for Reversible Medical Causes

• Review current medications for delirium-inducing agents (opioids, benzodiazepines, anticholinergics) 1
• Check for infection: Obtain urinalysis, chest X-ray if not already done, blood cultures 1
• Evaluate metabolic derangements: The provided labs show BUN 25, creatinine 1.2 (mild renal impairment), which could contribute 1
• Assess for urinary retention requiring catheterization 1
• Evaluate pain control: Inadequate analgesia causes agitation, but excessive opioids cause delirium 1

Step 3: Consider Parkinson's Disease-Specific Issues

• Carbidopa-levodopa withdrawal can cause acute confusion and should be restarted immediately if held 6, 7
• Orthostatic hypotension from Parkinson's disease may worsen postoperatively, contributing to confusion 6, 7
• The patient's "brisk reflexes" are atypical for Parkinson's disease and raise concern for upper motor neuron pathology (another reason for urgent CT) 7

Step 4: Address Hyperthyroidism and Atrial Fibrillation

• Restart rivaroxaban once bleeding risk is acceptable (typically postoperative day 2-3 for hip surgery) 1, 2
• Verify levothyroxine dosing is appropriate, but do not attribute acute delirium to thyroid dysfunction 3, 4
• Beta-blockers for rate control if atrial fibrillation becomes rapid 2

Common Pitfalls to Avoid

• Do not attribute all postoperative confusion to "routine delirium" in patients with stroke risk factors—this delays diagnosis of treatable conditions 1
• Do not order EEG before head CT in patients without witnessed seizure activity 1
• Do not delay neuroimaging to obtain thyroid function tests in acute confusion—thyroid disorders do not cause sudden delirium 3, 4
• Do not forget to restart Parkinson's medications as soon as oral intake resumes, as withdrawal exacerbates confusion 6, 7
• Do not overlook medication-induced delirium from opioid analgesics, which are commonly used postoperatively 1

Immediate Management Algorithm

1. Order head CT without contrast now 1
2. While awaiting CT, ensure patient safety: bed alarm, fall precautions, avoid physical restraints 1
3. Review and optimize medications: restart carbidopa-levodopa if held, minimize opioids and benzodiazepines 1, 6
4. Treat reversible causes: supplemental oxygen if hypoxemic, warming if hypothermic, catheterization if urinary retention 1
5. If CT is negative, proceed with infection workup and consider EEG only if seizure suspected 1

The priority is head CT to exclude stroke or intracranial hemorrhage before pursuing other diagnostic avenues. 1

{"question": "An [AGE]-year-old man 4 days after hip surgery with atrial fibrillation, Parkinson's disease, hyperthyroidism, and hypertension who underwent radioactive iodine therapy, on usual medications levothyroxine, rivaroxaban, carbidopa-levodopa, and losartan. Temperature is 100.4°F, respiratory rate [VALUE], blood pressure [VALUE], pulse [VALUE]. Patient is non-hypoxemic, awake but disoriented with rigidity and brisk reflexes, no motor deficits in extremities. Heart sounds normal, abdomen soft and tender due to vomiting on postoperative day 1. NPO status, on intravenous fluids for management. Now disoriented and agitated. Hematocrit 44, leukocyte count 12,000, platelet 251,000, BUN 25, creatinine 1.2, GFR >60, serum total bilirubin 1.1, liver function normal. Blood cultures obtained, chest X-ray shows low volume, no infiltrate. Patient on intravenous fluids, analgesics, and antibiotics as needed. Also on rivaroxaban; other medications on hold. Which of the following should you order now: A) swallow evaluation, B) serum total thyroxine level, C) head CT, D) electroencephalogram?"}