Sickle Cell Pain Crisis or SomethingElse? A Painful Journey of a Kidney Transplant Patient

Introduction: Mycophenolate (MMF) is an essential medication in transplant care, yet one should be vigilant of the uncommon adverse effects of such agents. We describe a rare side effect of migratory arthralgias and myalgia related to MMF in a post-renal transplant patient. Case Description: A 44-year-old lady with past medical history of sickle cell trait, type I diabetes mellitus complicated by diabetic nephropathy, status post preemtive live-related kidney transplant in October 2023. She was maintained on a steroid-free regimen with MMF and tacrolimus. Following discharge, she visited the emergency room multiple times with joint pain and swelling at different sites, including the left shoulder and wrist, right thigh and knee. Each time she was diagnosed with sickle cell pain crisis and discharged after symptoms improvement. Tacrolimus levels were within target range, and extensive workup including workup for rheumatological and infectious causes, was unremarkable. An MRI of the leg was performed, which showed extensive muscular edema of distal right thigh, knee, and leg regions with no evidence of avascular necrosis or osteomyelitis (Figure1). These findings prompt us to investigate medication-related adverse effects; hence, MMF was discontinued. Surprisingly, two days later, the patient's symptoms improved significantly. Upon follow-up, three months later, a repeat MRI of the leg showed near total resolution of the right lower limb muscular oedema, with no recurrence of symptoms. Discussion: Migratory polyarthritis with myalgias is a rare and usually forgotten side effect of MMF. In 2002, Bart et al. first described an inflammatory reaction in two patients with Wegner's granulomatosis treated with MMF, characterized by fever, arthralgia and myalgia, these symptom resolved within 48hrs of MMF discontinuation 1. This was followed by several other reports, all of which described a pro-inflammatory reaction in the form of migratory polyarthralgia related to MMF. 2 3,4,5,6 In conclusion, a nephrologist should be informed about rare MMF-related side effects, and early intervention should be considered to prevent long-term complications.