Slimmer's paralysis in a physical trainer with drastic weight fluctuations

Slimmer's paralysis is a peripheral mononeuropathy of the common peroneal (fibular) nerve (CPN/CFN), typically associated with rapid weight loss resulting in loss of subcutaneous fat pad and subsequent neural compression at the fibular head. Here, we describe a young man with a 1-year history of right-sided foot drop, which developed following a rapid intentional weight loss of 11 kg over a period of 15 days. This weight loss was preceded by rapid weight gain over 2 days owing to binge eating. Laboratory parameters for systemic/metabolic disorders were unremarkable. Radiology of the lumbosacral spine was unremarkable. Confounding risk factors included high-intensity training, frequent squatting and stretching. Electrophysiological studies revealed common peroneal (fibular) neuropathy at the fibular head with persistent denervation. This case highlights the diagnostic dilemma between lumbosacral plexopathy/radiculopathy and common peroneal (fibular) neuropathy. Electrophysiological studies and radiological assessment of the lumbosacral spine suggest that neither CPN nor lumbosacral surgical decompression would be beneficial, emphasising the need for tendon transfer.