Osteomyelitis of bilateral great toes: iatrogenic complication of nerve conduction study.

A 16-year-old male with Allgrove’s syndrome presented to a pediatric clinic with bilateral great toe redness, swelling, and purulent drainage of 1-month duration. He had longstanding history of alacramia, achalasia, autonomic disturbances, and Addison’s disease consistent with diagnosis of Allgrove’s syndrome [1]. One year prior to his presentation, he started to develop bilateral lower extremity weakness and bilateral feet pain. For evaluation of sensory motor neuropathy (another complication seen in Allgrove’s syndrome), he had undergone a nerve conduction study 5 weeks ago. No definite abrasion or pre-existing nail bed infection was noted. Skin was disinfected with an alcoholbased solution and disposable surface electrode patches (single patient surface Electrodes, Neuroline 175) were used to record medial and lateral plantar nerve compound action potentials and sural nerve sensory studies. Natus WR-50 bipolar stimulator was used to stimulate standard stimulation points. He refused to complete the study due to pain and needles were not inserted for electromyogram (EMG) portion of the study. Few days after the procedure, he noticed some redness and swelling of both toes. He used hydrogen peroxide and alcohol to keep his toes clean, but the condition worsened over next few weeks. At presentation to the clinic, he had significant swelling, redness, and drainage from left great toe nail bed and a scant amount of drainage was seen from the right great toe. He had some pain with weight bearing but denied fever or any other systemic symptoms. An MRI of distal lower extremity with and without contrast was performed which showed osteomyelitis of great toes as well as surrounding cellulitis and nail infection (Fig. 1). He was started with vancomycin and piperacillin/tazobactam for empiric coverage. Nail bed drainage was cultured and grew staphylococcus aureus. According to sensitivity testing, antibiotics were changed to clindamycin and ciprofloxacin. His blood culture remained negative. Subsequently, he had great improvement with complete recovery with no need for surgical intervention. Nerve conduction study (NCS) is routinely performed in patients with suspected neuromuscular disorders. Other than discomfort during examination and minor bruising, serious complications are rare. Though risk of transmission of infection is less in NCS using electrodes, skin preparation and pressure from electrodes or stimulator during the procedure may occasionally abrade the skin with potential entry of infection [2]. Surface electrodes exposed to blood or body fluids may transmit infection in between patients and this risk is currently minimized by prevalent use of disposable electrodes. In immunocompromised patients such as ours, the risk of infection is significantly higher. Proper cleaning of re-usable electrodes in between usages and adoption of universal precaution may minimize the infection rate. Proper inspection of body part to rule out an abrasion or infected area before the procedure is necessary, especially in areas with higher risk of infection as in feet. This is the first report of iatrogenic bilateral great toe osteomyelitis after nerve conduction study. Underlying peripheral neuropathy, possible pre-existing abrasion, mechanical trauma, immunocomprised state, and delay in seeking of medical care may contribute to this complication. & Debopam Samanta dsamanta@uams.edu