Femoral, femoral cutaneous and obturator nerve compression due to a large psoas and iliacus muscles hematoma: the importance of a good clinical evaluation

Abstract

The lumbar plexus but more specifically, the genitofemoral, femoral, lateral femoral cutaneous and obturator nerve have an intimate relation with the psoas and iliacus muscles. A hematoma on these muscles is a rare event but can cause compression on the aforementioned nerves. This is an atypical case of a 78-year-old woman, with relevant history of chronic pulmonar tromboembolism (PE), hospitalized due to a pulmonar infection with septic shock. Dua to the PE she initiated enoxaparin in therapeutic doses. After one week she developed lumbar pain with an atypical pattern of irradiated pain and sensitivity disorders on the lower limbs. After a challenging diagnostic investigation,  we were able to diagnose a simultaneously femoral, lateral femoral cutaneous and obturator nerve compression, confirmed on electrodiagnostic studies (abundant spontaneous activity in the rectus femoris, lateral vastus and adductor magnus), caused by a spontaneous hematoma on the right psoas, measured on the CT scan, with more proximally with 5.3 x 4.7cm and distally on the thigh with 6.1 x 4.7cm and on the iliacus with 9 x 3.6cm observed on the computed tomography (CT) scan and. With reversion of the hematoma and rehabilitation with physiotherapy the patient had a partial recovery with lesser hypoesthesia, improvements on strength and gait autonomy. This case shows how challenging it can be to make a correct diagnosis and reinforces the importance of a good clinical history and a thorough physical examination to better guide the diagnostic approach.