Morphine overinfusion of intrathecal drug administration system under magnetic resonance evaluation for the diagnosis of stroke: a case report

BACKGROUND: Until recently, it is generally considered safe to perform magnetic resonance imaging (MRI) in patients with an intrathecal drug administration system (ITDAS) device. In this study, we presented a case of morphine overdose due to ITDAS malfunction during MRI evaluation for the diagnosis of stroke. CASE PRESENTATION: A 58-year-old woman was referred to the emergency department for left-sided hemiparesis and dysarthria. She had undergone ITDAS implantation 4 years ago because of intractable back pain. Her brain MRI examination did not show any abnormalities except an old hemorrhagic infarction in the right basal ganglia. After MRI was performed, her symptoms completely resolved. Approximately 3 h after the MRI scan, the patient showed progressive stuporous consciousness and decreased respiration with decreased peripheral oxygen saturation of 80%. Initial arterial blood gas analysis revealed respiratory acidosis with hypoxia and hypercapnia. We suspected the opioid overdose for her unconciousness, small and sluggish pupils, and slow respiration. The patient regained consciousness within 3 min after the administration of naloxone with severe anxiety and irritability, without any respiratory symptoms or focal neurological deficits. In the pump interrogation and actual reservoir checks performed 6 h after the MRI scan, there was no significant difference between the expected reservoir volume and actual reservoir volume. Follow-up MRI performed to rule out posterior circulation infarction showed no structural lesions. The patient was eventually discharged without further neurologic or functional deterioration, with diagnosis of transient ischemia attack for initial symptoms of focal neurologic deficits. CONCLUSION: Although both ex vivo and in vivo studies have provided evidence that ITDAS devices are MRI-compatible, the pump is made of titanium and has ferromagnetic components. Since misdiagnosis of overinfusion could lead to mortality, early awareness of overinfusion of the intrathecal drug is needed to all clinicians in case of performing MRI in ITDAS implanted patients.