Posterior reversible encephalopathy syndrome in a patient with multiple myeloma treated with thalidomide

Abstract

Posterior reversible encephalopathy syndrome (PRES) is a clinical-radiologic syndrome presenting with headache, mental status changes and visual disturbances accompanied by typical fi ndings on magnetic resonance imaging (MRI). Th e majority of reported cases have been linked to hypertension or pre-eclampsia; however, a signifi cant number of cases have also been associated with immunosuppressive agents or chemotherapy. We report the second documented case of PRES in association with thalidomide treatment, an agent that has been used in maintenance therapy post-autologous hematopoietic stem cell transplant and in combination fi rstline therapy for multiple myeloma. A 49-year-old woman presented with an episode of involuntary right leg shaking initially lasting 10 min. Upon arrival to the emergency department via the emergency medical services, she had a second episode of involuntary right leg movement lasting approximately 45 min. Intermittent, involuntary leg shaking continued for the fi2 h of her hospital stay and then evolved into a witnessed generalized tonic – clonic seizure with incontinence, loss of consciousness and a post-ictal period. Her seizure was terminated with the administration of lorazepam. Physical examination of the cardiac, respiratory and abdominal systems was unremarkable. Neurologic examination revealed normal cranial nerves including full extraocular movements and visual fi elds. She had slightly decreased power diff usely to the right upper extremity, but full power in her other limbs, and refl exes were 3 throughout. Sensory, cerebellar and gait testing were all normal. Orientation, naming, repetition and memory were all intact. She was normotensive. Fluid-attenuated inversion recovery (FLAIR) sequence MRI demonstrated multiple foci of T2 hyperintensity in the occipital and posterior parietal lobes extending into the medial and superior parietal regions bilaterally, as well as involvement of the deep paracentral white matter. Diff usion weighted imaging was normal (Figure 1). Th e patient ’ s clinical presentation, accompanied by these typical radiologic fi ndings, was considered to be most consistent with PRES. Th e patient ’ s medical history was signifi cant for a T10 plasmacytoma requiring surgical resection, laminectomy and stabilization, 2 years previously. She had received radiotherapy to the area and undergone an autologous hematopoietic stem cell transplant following dexamethasone induction for her concurrent lambda light chain multiple myeloma, performed 1 year prior to presentation. She had been started on maintenance thalidomide following her transplant, and, at the time of her seizure, had been on thalidomide 200 mg daily for approximately 11 months. At presentation, her other medications also included pregabalin, hydromorphone and monthly pamidronate infusions. Within hours of admission to hospital, she developed a fever which was treated with empiric antibiotic therapy, initially cefotaxime and azithromycin, subsequently changed to meropenem. A vesicular rash then developed over her truncal region and was treated with acyclovir. Polymerase chain reaction (PCR) testing of vesicular fl uid later confi rmed the presence of varicella zoster virus. Blood cultures taken prior to the initiation of antibiotic and antiviral therapy were subsequently found to be negative, and a chest radiograph was unremarkable. Lumbar puncture was not done at the time because of the presence of the zoster rash over the lumbosacral area. Th e patient completed a 7-day course of antibiotics and acyclovir and was discharged home with an additional 10 days of oral acyclovir. She was not given steroid therapy. A diff use rash was noted following initiation of dilantin therapy, and she was switched to valproic acid because of concern regarding a dilantin allergic reaction. She was discharged on valproic acid 500 mg twice daily. She did not develop any further seizures or other neurologic events, and her level of consciousness and cognition remained normal during the course of her stay in hospital and thereafter. Th e patient ’ s seizures were not felt to be related to herpes simplex encephalitis (HSE) as they were not typical in origin or character for HSE and were relatively easily controlled. Th e imaging pattern was typical of PRES rather than viral encephalitis, and she did not develop any other neurologic sequelae suggestive of encephalitis. Her myeloma was in