Medical Director Carilion Clinic Roanoke, Virginia, United States
Case Diagnosis: 72-year-old male with suspected morphine toxicity in the context of an acute kidney injury requiring hemodialysis.
Case Description: The patient presented with right great toe gangrene and right superficial femoral artery occlusion, necessitating a right popliteal artery bypass and transmetatarsal amputation. His postoperative course was complicated by acute renal failure and hypoxic respiratory failure, leading to hemodialysis initiation. To manage uncontrolled postoperative pain, morphine was introduced. Following this, the patient exhibited cognitive changes including drowsiness, disinterest, and depressive features, raising concern for morphine toxicity from renal impairment. The patient’s worsening cognitive state prompted evaluations by palliative care and psychiatry who deemed him incapacitated and unable to make medical decisions. After four days of morphine use, its discontinuation led to cognitive improvements. He demonstrated improved alertness and engagement with therapy and was discharged to a skilled nursing facility a few days later.
Discussions: Morphine toxicity in patients with renal failure is a recognized but often overlooked issue. The kidneys play a crucial role in metabolizing and excreting morphine’s active metabolites. When renal function is impaired or dialysis is started, these metabolites accumulate and may cause serious adverse effects including sedation, cognitive dysfunction, and respiratory depression. Our patient’s cognitive decline on morphine therapy and subsequent improvement after its discontinuation suggest morphine toxicity as a contributing factor. Although morphine was prescribed for uncontrolled pain in our patient, his case demonstrates the importance of closely monitoring for signs of opioid-related adverse effects when managing pain in older patients with kidney impairment.
Conclusions: Morphine toxicity should be considered in patients with renal failure or on dialysis who exhibit cognitive decline or excessive sedation. This case highlights the necessity of careful opioid selection and continuous monitoring in such patients. Further research is needed to establish clear guidelines for the safe use of opioids in patients with renal impairment.
