The contribution of a spinal mechanism in developing peripheral myoclonus: a case report.

Focal myoclonus of peripheral origin, i.e., peripheral myoclonus (PM), is a rare disorder. Although PM always accompanies a lesion in the peripheral nerve, supplying the affected muscles, its mechanism remains unclear. Here we present a patient with focal myoclonus of the thigh muscles following a traumatic lesion in the femoral nerve. Lumbar spinal anesthesia, as well as local anesthetic block of the femoral nerve, completely abolished the patient's myoclonus temporarily. This movement was remarkably diminished after a surgical exploration of the wound with the removal of fibrous tissue beneath the scar and liberation of the femoral nerve. This case suggests the contribution of a spinal relay mechanism in the development of PM, in addition to the contribution of a nerve lesion.

Reversible MR changes in the cat brain after cerebral fat embolism induced by triolein emulsion.

BACKGROUND AND PURPOSE: Clinical cerebral-fat embolism shows both reversible and irreversible changes. We used MR imaging to investigate the reversibility of embolized lesions induced with a fat-emulsion technique and to evaluate the histologic findings. METHODS: A fat emulsion was made with 0.05 mL of triolein and 20 mL of normal saline and vigorous to-and-fro movement through a three-way stopcock. In 50 cats, the internal carotid artery was infused with the fat emulsion. Cats were divided into six groups on the basis of time delay after embolization: 1 hour; 1 and 4 days; and 1, 2, and 3 weeks. MR imaging and histologic examination were performed at these times. RESULTS: Embolized lesions were hyperintense on T2-weighted images, isointense or mildly hyperintense on diffusion-weighted images, isointense on apparent diffusion coefficient maps, and enhancing on gadolinium-enhanced T1-weighted images at 1 hour. These MR imaging findings were less evident at day 1 and reverted to normal after day 4 (isointense on all images). Electron microscopy showed minimal findings in the cortical lesion in groups 1 and 2 (group 1 at 1 hour and group 2 at 1 hour and 1 day). Light microscopic findings revealed evidence of necrosis-small focal gliosis and demyelination in the periventricular white matter-in only one cat. The number of intravascular fat globules was not significantly different between groups, as visualized by oil red O staining. CONCLUSION: Cerebral-fat embolism induced by a triolein emulsion revealed reversible MR findings and minimal histologic findings.