Rare neurological complication in an adolescent with kidney failure secondary to systemic lupus erythematosus: Questions

Abstract

A 15-year-old female with kidney failure on intermittent hemodialysis secondary to Class IV lupus nephritis presented to the emergency department with progressively worsening right lower extremity pain. Pain started 2 weeks prior to presentation and was initially dull and throbbing, localized to her right hip and anterior thigh. Over the course of the next 2 weeks, the pain evolved to a shooting and burning sensation originating in her lower back and radiating into her right anterior thigh, knee, anterior leg, ankle, and dorsum of foot. Pain intensity was 10/10 and to the point she was unable to bear weight. She denied any recent trauma, falls, fever, illness, headache, nausea, vomiting, blurry vision, dizziness, or rashes. She started chronic hemodialysis 3 weeks prior to presentation, having reached kidney failure with her most recent lupus flare. Her lupus flare management included rituximab 375 mg/m weekly for 4 weeks, mycophenolate mofetil 1 g twice a day, and methylprednisone pulse 1 g × 3 days at flare onset and again with each weekly rituximab infusion. Her oral prednisone was decreased recently from 60 to 40 mg daily. Other medications included hydroxychloroquine, amlodipine, labetalol, clonidine, atorvastatin, erythropoietin alpha, calcium carbonate, calcitriol, cholecalciferol, and lansoprazole. Immunizations were up to date for age. An outpatient evaluation of her leg pain included hip X-rays and Doppler ultrasounds of the lower extremity, iliac, and inferior vena cava vessels, which were normal. She had been referred to physical therapy; however, she had not yet started due to progressive worsening of her pain. She was referred from the outpatient hemodialysis unit to the emergency department. In the emergency department, her vital signs were temperature 37.0 °C, heart rate 104 bpm, blood pressure 197/112 mmHg, and respiratory rate 20 per minute. Physical exam was notable for patient being in painful distress laying on her left side. Her right hip was held in flexion and external rotation with no erythema, edema, or rash noted. With active range of motion of the right hip, pain was elicited in her hip that radiated along the lateral aspect of the thigh. She had tenderness to palpation along the lateral thigh and decreased muscle strength in several muscle groups including iliopsoas, quadriceps, hamstrings, and tibialis anterior compared to the left side. She had decreased sensation to light touch along the tibial nerve distribution but had intact distal pulses and normal capillary refill. Her spine exam was notable for tenderness to palpation of the right lumbar paraspinal muscles, but no spinal deformities or step-offs were noted. While in the emergency department her blood pressures ranged from 159 to 197/84 to 112 mmHg. X-ray of the right femur showed “serpiginous increased densities noted in the distal femur, suspicious for bone infarcts,” but no fractures or dislocations. X-ray of the hip and pelvis showed no evidence of avascular necrosis or osseous abnormalities. Ultrasound of the lower extremity with Doppler did not show joint effusion or deep vein thrombosis. Complete blood count showed an elevated white blood cell count of 19.01 K/cu mm, hemoglobin of 9.0 mg/dL, normocytic mean corpuscular volume of 85.7 fL, platelets 170 k/cu mm, neutrophil percentage 88.2%, and lymphocyte The answers to these questions can be found at http://dx.doi.org/10.1007/ s00467-021-05200-x