Neurophysiological findings in conus medullaris infarction-a case report and systematic review of the literature.

INTRODUCTION: Conus medullaris infarction (CMI) is a rare vascular phenomenon that has been scarcely reported in the literature. While previous studies have described the clinical and radiological features of CMI, little attention has been paid to its associated neurophysiological findings. METHODS: We present a case of idiopathic CMI and its neurophysiological findings, then present our findings from a systematic review of other reports of CMI with neurophysiological features found via PubMed search. RESULTS: Nine articles describing ten cases of CMI with associated neurophysiological data were found, in addition to our case. Out of all 11 cases, 7 cases (64%) had absent F-waves on the first nerve conduction study (NCS) performed as early as 4 h after onset, 5 of whom demonstrated reappearance of F-waves on subsequent follow-up NCS. Seven patients (64%) had diminished compound muscle action potentials (CMAPs), which was usually detectable on NCS performed between day 8 and day 18 of onset. None of them showed recovery of CMAPs in follow-up studies. Four patients (36%) had absent H-reflexes and two patients (18%) had sensory abnormalities. Electromyography (EMG) was reported in seven patients (64%), showing reduced recruitment as early as day 1 of onset, and denervation potentials as early as 4 weeks after onset. CONCLUSION: Absent F-waves and diminished CMAPs are the most common NCS abnormalities in CMI. Absent F-waves are detectable very early but tend to recover on subsequent NCS, while diminished CMAPs are detectable later but do not seem to resolve. Further research to determine the utility of neurophysiological studies in CMI diagnosis and prognostication is needed.

Piriformis Pyomyositis Presenting as Migratory Hip to Knee Pain: A Case Report.

CASE: The authors report a case of piriformis pyomyositis in a teenage female patient with fever and left hip pain. Her pain migrated to the knee with concurrent near resolution of hip pain. Imaging revealed an abscess in the left piriformis with pus tracking along the sciatic nerve sheath. This was complicated by internal iliac vein thrombosis and an embolus to the lung. Open drainage was performed, followed by outpatient intravenous cloxacillin and oral warfarin, with complete resolution of symptoms. CONCLUSION: Piriformis pyomyositis is a rare condition with varying presentations. The threshold for suspicion should be low even in healthy young individuals.