Myasthenia gravis is a neuromuscular transmission disorder characterized by weakness of the cranial and skeletal muscles, however, neuropathies are extremely rare. In this case report we present a case of a 61-year-old man diagnosed Myasthenia gravis who came to our attention due to a 1 week of acute deep pain [NPRS 8/10] in the anterior and medial right knee which occurred during walking [NPRS 8/10] or stair climbing [NPRS 9/10]. A complete medical record and clinical examination based on physical exploration and ultrasound assessment confirmed a infrapatellar saphenous neuralgia. Therapeutic interventions included Percutaneous nerve electrical stimulation combined with pain neuroscience education, neural mobilization of the saphenous nerve and quadriceps resistance exercises. After 4 weeks, pain intensity [NRPS = 1/10], knee functionality [OKS = 41/48] and lower limb functionality [LLFI = 80%] were notably improved, nevertheless, fatigue [RPE = 2/10] was similar than baseline. At 2 months of follow-up, the effect on intensity of pain NRPS [0/10] and functionality OKS [40/48] and LLFI [82%] was maintained, however, no significant clinical changes were detected on perceived fatigue RPE Scale [2/10]. Despite the important methodological limitations of this study, our case report highlights the efficacy of percutaneous electrical nerve stimulation combined with physical agents modalities for pain and functionality of infrapatellar saphenous neuralgia in the context of Myasthenia gravis.
Keywords: Myasthenia gravis; PENS; neuralgia; saphenous nerve.