長期間の抗菌薬経静脈投与を要した頭蓋底骨髄炎例

Skull-base osteomyelitis occurs as a result of spread of inflammatory disease around the temporal bone into the adjacent skull base, and carries a poor prognosis. Occasionally, patients present with paralysis of the lower cranial nerves, which further worsens the survival. Prolonged intravenous antibiotic therapy for six to eight weeks is needed for treatment. Herein, we present a case of skull-base osteomyelitis caused by Pseudomonas aeruginosa that developed in a 78-year-old male patient with diabetic nephropathy who was under maintenance hemodialysis. He presented to our hospital with the complaints of earache and otorrhea on the left side. Exploratory tympanotomy revealed pus and granulation tissue filling the tympanic cavity and mastoid, and destruction of the tympanic portion of the temporal bone; based on the findings and results of pus culture, we made the diagnosis of skull-base osteomyelitis caused by Pseudomonas aeruginosa. While the osteomyelitis was gradually improving with intravenous meropenem, the patient desired early discharge from the hospital. Therefore, the intravenous antibiotic therapy was switched earlier than intended to oral antimicrobial therapy, which led to progression of the disease, and the patient presented with lower cranial nerve palsies three months after his discharge. He was initiated again on intravenous meropenem. While the osteomyelitis improved gradually with the intravenous antimicrobial therapy for two months, the levels of inflammatory markers, such as the serum c-reactive protein, increased again soon after discontinuation of the intravenous antibiotic therapy. Therefore, we decided to continue the patient on intravenous meropenem every other day administered at the outpatient clinic after dialysis. The treatment was continued for four months after discharge, and the improvement was maintained. We reaffirmed the importance of long-term intravenous antibiotic therapy to treat skull-base osteomyelitis. Intravenous antibiotic administration every other day at the outpatient clinic after dialysis could be a useful treatment strategy to treat skull-base osteomyelitis in patients under maintenance hemodialysis.