Embolic stroke associated with injection of buprenorphine tablets.

BACKGROUND: Drug users who crush, dissolve, and inject buprenorphine tablets parenterally may be at risk of severe thromboembolic complications or death. We describe patients with neurologic complications after injecting buprenorphine tablets. METHODS: Brain MRI including diffusion-weighted imaging (DWI) in patients admitted to the neurologic department after injecting buprenorphine tablets were reviewed. RESULTS: Seven men had neurologic complications after buprenorphine tablet injection. In 5 patients, multiple small scattered hyperintense lesions were detected on DWI in the cortex, white matter, and basal ganglia of the cerebral hemisphere; one patient had a single small lesion. The side of MRI abnormality corresponded to the side of needle marks on the neck except in one patient who had bilateral injections. One patient, who denied injecting into the neck, had DWI abnormalities in the middle cerebral artery territory on one side and occlusion of the ipsilateral internal carotid artery. CONCLUSIONS: Buprenorphine tablets can be intentionally or inadvertently injected into the carotid artery, causing a characteristic appearance on diffusion-weighted imaging, consistent with embolic cerebral infarction.

Magnetic resonance spectroscopy in adult-onset citrullinemia: elevated glutamine levels in comatose patients.

BACKGROUND: Adult-onset type II citrullinemia is an inborn error of urea cycle metabolism that can lead to hyperammonemic encephalopathy and coma. However, type II citrullinemia is rare outside Japan, and diagnosis and treatment can be delayed. Magnetic resonance spectroscopy may be a useful adjunct to magnetic resonance imaging, and has been applied to noninvasively study chemical metabolism in the human brain. PATIENTS: We describe 2 patients with type II citrullinemia who presented with episodic postprandial somnolence and coma. Diffusion-weighted magnetic resonance imaging showed bilaterally symmetrical signal abnormalities of the insular cortex and cingulate gyrus. On magnetic resonance spectroscopy, glutamine and glutamate levels were elevated, and choline and myo-inositol levels were decreased. The diagnosis of citrullinemia was confirmed based on elevated plasma ammonia and citrulline levels. CONCLUSION: Characteristic features found at the time of magnetic resonance imaging and magnetic resonance spectroscopy may be helpful for early diagnosis of type II citrullinemia in adult patients who present with hyperammonemic encephalopathy and coma.