P.073 Transient osteoporosis of the hip during pregnancy associated with EMG signs of acute regional denervation

Abstract

Background: Transient osteoporosis is an infrequent musculoskeletal condition most often seen in middle-aged males, but can rarely present during late pregnancy in females. Patients present with sudden onset of severe joint pain. MRI typically shows T2 hypersignals and bone marrow edema. Abnormal neurophysiological findings have only rarely been described in the literature. Methods: Case report Results: A 35-year old patient presented at 34 weeks of pregnancy with acute onset of right hip and leg pain. MRI showed marked T2 hypersignals in the head of the femur with distal extension and bone marrow edema pathognomonic of transient osteoporosis. Neurophysiological studies showed normal nerve conductions of the lower extremities, but fibrillation potentials and positive sharp waves were found acutely in proximal muscles of the affected extremity and not limited to a single nerve territory. Inflammatory markers were unremarkable. Treatment was conservative with rest and reduction of weight bearing and pain resolved in the hip, but recurred in the ipsilateral knee several months after delivery suggesting evolution toward regional migratory osteoporosis. Conclusions: Transient osteoporosis of the hip may be associated with EMG signs of denervation that could suggest a contributing neurogenic mechanism. Their prevalence may be underestimated and we suggest considering serial EMG studies in its investigation.