What is the most likely cause of a patient's symptoms of anxiety, agitation, hypertension, and urinary retention after discontinuation of dexmedetomidine (dexmedetomidine) following a bowel resection surgery?

Dexmedetomidine Withdrawal

This patient is experiencing dexmedetomidine withdrawal, which typically manifests within 24-48 hours of discontinuation following prolonged infusions (>7 days), presenting with agitation, tachycardia, hypertension, diaphoresis, and confusion—all of which are present in this case. 1

Clinical Reasoning

The timeline and symptom constellation strongly support dexmedetomidine withdrawal:

• Duration of exposure: The patient received dexmedetomidine for approximately 5 days (started 2 days post-admission, continued through surgery 5 days later, then discontinued after extubation) 1
• Timing of symptoms: Withdrawal symptoms appeared the evening after discontinuation, consistent with the 24-48 hour window when withdrawal typically occurs 1
• Classic withdrawal presentation: The patient exhibits the cardinal features of alpha-2 agonist withdrawal—agitation, confusion, tachycardia (HR 134), hypertension (160/92), and diaphoresis 1, 2

Why Other Diagnoses Are Less Likely

Urinary retention does not explain the systemic hyperadrenergic state (tachycardia, hypertension, diaphoresis) or altered mental status. While 350 mL of retained urine is present, this is a consequence of his agitated state and catheter removal, not the primary cause of his symptoms. 1

Opioid withdrawal is unlikely because:

• He is receiving PCA hydromorphone with adequate pain control 1
• Opioid withdrawal presents with mydriasis, lacrimation, rhinorrhea, and GI symptoms (cramping, diarrhea)—none of which are described 1
• The hyperadrenergic state is more severe than typical opioid withdrawal 2

Propofol infusion syndrome is excluded by:

• Normal laboratory studies (PRIS causes metabolic acidosis, hyperkalemia, elevated creatinine kinase, and cardiac dysfunction) 1
• Propofol was discontinued days earlier 1
• PRIS typically occurs with high-dose, prolonged infusions (>48-72 hours at >5 mg/kg/hr) 1

Acute ischemic stroke would present with focal neurological deficits, not diffuse agitation with preserved motor function (attempting to get out of bed). The confusion is global, not focal. 1

Management Approach

Immediate intervention for dexmedetomidine withdrawal:

• Restart dexmedetomidine at the previous effective dose (typically 0.2-0.7 μg/kg/hour) to rapidly control symptoms 1, 2
• Alternative if dexmedetomidine unavailable: Clonidine 0.1-0.2 mg PO/IV every 6-8 hours can effectively treat withdrawal symptoms as both are alpha-2 agonists 3, 2
• Adjunctive therapy: Beta-blockers may be needed for persistent tachycardia and hypertension (53.7% of withdrawal patients required additional beta-blockers in one study) 2

Weaning protocol once symptoms stabilize:

• For infusions lasting 7-14 days, reduce dexmedetomidine dose by 10-20% every 24-48 hours 1
• Monitor vital signs frequently during weaning 1
• If withdrawal symptoms recur, slow the weaning process or return to the previous effective dose 1

Critical Pitfalls to Avoid

• Abrupt discontinuation of dexmedetomidine after prolonged use (>7 days) significantly increases withdrawal risk—35.5% incidence in one study 2
• Misattributing symptoms to ICU delirium or other causes delays appropriate treatment 2
• Inadequate monitoring: Rebound hypertension was the most common withdrawal sign (87% of cases), requiring vigilant blood pressure monitoring 2
• Failure to recognize risk factors: Patients receiving dexmedetomidine for >7 days require gradual weaning, not abrupt cessation 1

Supporting Evidence

In a retrospective study of 152 ICU patients on dexmedetomidine ≥72 hours, 35.5% developed withdrawal syndrome defined as ≥2 criteria (positive CAM-ICU, RASS ≥+2, hypertension, tachycardia) within 24 hours of discontinuation. 2 Rebound hypertension occurred in 87% of withdrawal cases, and 29.6% required reinitiation of dexmedetomidine. 2

Case reports document severe withdrawal manifestations including posterior reversible encephalopathy syndrome from hypertensive crisis following abrupt dexmedetomidine cessation. 4 Clonidine has proven effective in treating dexmedetomidine withdrawal, even in patients with prolonged exposure (>7 days). 3