34-year-old man • chronic lower back pain • peripheral neuropathy • leg spasms with increasing weakness • Dx?

Abstract

Ch ro nic low er ba ck pa in -Pe rip he ra l ne ur op at hy -Le g sp as m s wi th inc re as ing we ak ne ss THE CASEA 34-year-old man was referred to the sports medicine clinic for evaluation of lumbar radiculopathy. He had a 2-year history of chronic lower back pain that started while he was working on power line towers in Puerto Rico. The back pain was achy, burning, shooting, and stabbing in nature. He had been treated with anti-inflammatories by a company health care provider while in Puerto Rico, but he did not have any imaging done. At that time, he had tingling and burning that radiated down his left leg to his ankle. The patient also had leg spasms-in his left leg more than his right-and needed a cane when walking. His symptoms did not worsen at any particular time of day or with activity. He had no history of eating exotic foods or sustaining any venomous bites/stings. Ultimately, the back pain and leg spasms forced him to leave his job and return home to Louisiana.Upon presentation to the sports medicine clinic, he explained that things had worsened since his return home. The pain and burning in his left leg had increased and were now present in his right leg, as well (bilateral paresthesias). In addition, he said he was feeling anxious (and described symptoms of forgetfulness, confusion, and agitation), was sleeping less, and was experiencing worsening fatigue.Work-ups over the course of the previous 2 years had shed little light on the cause of his symptoms. X-rays of his lumbar spine revealed moderate degenerative changes at L5-S1. A lab work-up was negative and included a complete blood count, testing for HIV and herpes, a hepatitis panel, an antinuclear antibody screen, a C-reactive protein test, and a comprehensive metabolic panel. Thyroid-stimulating hormone, creatine kinase, rapid plasma reagin, and human leukocyte antigen B27 tests were also normal.Magnetic resonance imaging (MRI) revealed a cystic lesion in the right ilium near the sacroiliac joint. A more recent follow-up MRI and computed tomography scan of the pelvis found the cyst to be stable and well marginalized, with no cortical erosion. Attempts at physical therapy had been unsuccessful because of the pain and decreasing muscle strength in his lower extremities. The patient's primary care provider was treating him with meloxicam 15 mg/d and duloxetine 60 mg/d, but that had not provided any relief.