Foot drop after a suicide attempt

Abstract

Sciatic neuropathy with denervation and myonecrosisA 33-year-old male presented with a 2-month history of left foot drop, starting upon waking up 3 days after a suicide attempt with ingestion of high doses of phenobarbital, clonazepam, and alcohol. Painful left drop foot, trophic changes in the lower extremities, and bilateral Achilles areflexia were noted. Magnetic resonance neurography (MRN) of the lumbosacral plexus and left thigh showed thickening and signal intensity (SI) abnormality in the left sciatic nerve along the pelvic outlet and proximal thigh (Fig. 1). Denervation of the lumbosacral plexus affecting the quadratus femoris, piriformis, obturator, and adductor muscles with areas without contrast enhancement consistent with myonecrosis was seen on the pelvis, while denervation of the hamstring muscles related to sciatic neuropathy was seen on the thigh (Fig. 2). Electroneuromyography showed complete motor and sensitive axonal impairment of the left peroneal nerve, partial impairment of the left tibial nerve (with reinnervation), and partial impairment of the left femoral nerve.A compressive-ischemic mechanism after a long-term sideways position during unconsciousness was indicated as the cause of the clinical and imaging findings in this case. Sciatic neuropathy is the second most common cause in the legs, after peroneal neuropathy, and may be caused by acute or chronic compression, stretching, ischemia, laceration, or toxic injury (injections) as well as iatrogenic lesions (hip arthroplasty). Increased pressure on the nerve can cause injury either directly or indirectly as a result of compression of the vasa nervorum if the ischemia is prolonged, which was the most likely mechanism in our case [1,2]. The sciatic nerve derives from the fourth and fifth lumbar and first and second sacral roots, coursing down deeper to the piriformis muscle with anatomical variations. It continues posteromedially to the hip and distally deep in the thigh before dividing into the tibial and common peroneal nerves above the popliteal fossa [2,3].MR imaging patterns vary depending on the muscle denervation stage: acute and subacutely denervated muscles show high SI on fluid-sensitive images and normal SI on T1-weighted images; in chronic denervation, muscle atrophy and fatty infiltration demonstrate high SI on T1-weighted images in association with volume loss [4]. On the other hand, myonecrosis is revealed by high SI on T1-weighted images, heterogeneously high SI on T2-weighted images, and rim enhancement on contrastenhanced images [5]. A possible overlap of denervation No related papers from the same study have been published or submitted.The case presentation can be found at