200 Section - Severe Sciatic Neuropathy with Ischemic Myonecrosis and Delayed Neurologic Symptom after Acute Carbon Monoxide Intoxication

Case Diagnosis: Severe Sciatic Neuropathy with Ischemic Myonecrosis after Acute Carbon Monoxide(CO) Intoxication with Delayed Neurologic Symptom(DNS).
Serial electromyography revealed severe incomplete axonal injury involving the left sciatic, inferior gluteal, and superior gluteal nerves. Hip MRI demonstrated multifocal ischemic myonecrosis of the bilateral gluteal and obturator internus muscles with associated sciatic neuritis.

Case Description: We report a case of a 23-year-old previously healthy male who developed delayed cognitive impairment and severe unilateral peripheral neuropathy approximately four weeks after acute CO intoxication. Initial brain MRI demonstrated restricted diffusion in the bilateral globus pallidus and left temporal periventricular white matter. The patient showed near-complete recovery of cognitive function during the acute phase; however, residual left sciatic neuropathy persisted, and he was discharged for outpatient follow-up.
Despite initial full neurologic recovery, the patient was readmitted approximately four weeks later with executive dysfunction and short-term memory impairment consistent with DNS. Concurrently, he continued to exhibit profound weakness of the left lower extremity without clear clinical worsening.

Discussions: CO poisoning is a cause of hypoxic brain injury and is classically associated with bilateral globus pallidus lesions in radiologic study and DNS.  Central nervous system lesions are well described, while peripheral nervous system involvement, particularly when accompanied by ischemic myonecrosis, remains under-recognized and rarely reported.
This case highlights the potential for combined central and peripheral nervous system injury with concomitant musculoskeletal involvement after CO intoxication and emphasizes the diagnostic value of correlating MRI and electrophysiologic findings.

Conclusions:

Carbon monoxide intoxication can result in combined central and peripheral nervous system injury, including delayed neurologic sequelae and severe axonal peripheral neuropathy with ischemic myonecrosis. Correlation of clinical findings with advanced imaging and electrophysiologic studies is essential for accurate diagnosis and understanding of the underlying pathophysiology. Awareness of these rare but significant complications may improve long-term management and prognosis in patients with CO poisoning.