[Methicillin-resistant Staphylococcus aureus subdural abscess in an elderly patient with dementia]

A 74-year-old man was admitted to our hospital because of a fever of 38.2 degrees C and drowsiness. Two months before admission, he was admitted to another hospital with the diagnosis of Alzheimer's disease. One week before admission, he had a fever which was judged to be due to pyelonephritis. Because imipenem cilastatin and minocycline were not effective in relieving symptoms, he was transferred to our hospital. Methicillin-resistant Staphylococcus aureus (MRSA) was cultured from the blood, and vancomycin was started on the 5th hospital day. Because of the persistent fever and signs of inflammation, Gallium-scintigraphy was performed, showing abnormal accumulation in the left fronto-parietal region of the brain and the sacral region. Enhanced brain CT revealed a crescentic low density area and a fine, intense line of enhancement in the left fronto-parietal region. An emergency drainage of abscess was performed via single left fronto-parietal burr hole. A slightly yellowish, bloody, purulent fluid was obtained. The subdural space was irrigated with saline containing antibiotics and a drain was inserted. MRSA was cultured from the obtained fluid. The fever gradually subsided and drowsiness disappeared. He had had decubitus ulcer, stage I on the surface, in the sacral region, which later turned out to have unexpectedly deep undermining lesion reaching to periosteum. MRSA was cultured from this decubitus lesion. MRSA which entered into blood stream from the decubitus site might have been implanted in the subdural hematoma. Thus, subdural abscess should be kept in mind as an active differential diagnosis in elderly patients with fever and drowsiness.