Osteomyelitis of the skull base, etiology unknown

OSB can occur in the absence of an obvious contiguous source of infection. When a patient has persistent unilateral headache, elevated ESR, and radiographic evidence of a lytic skull-base lesion, the clinician should consider OSB as a potential diagnosis. A baseline gallium scan should be obtained before biopsy, since surgery or trauma can also produce positive results on radionuclide scans. Technetium-phosphate bone scans should also be performed before any surgical manipulation. However, positive results from a gallium or technetium scan in this setting are not conclusive evidence of infection. At biopsy, the otolaryngologist-head and neck surgeon should consider sending a specimen to the microbiology department for culture in addition to the specimen sent for routine pathologic study; this procedure could minimize delay in diagnosis. Establishing the diagnosis in these patients without obvious contiguous infection can be difficult, demanding perseverance and an appropriate index of suspicion. Once the diagnosis is confirmed, intravenous antibiotic therapy should begin immediately. The duration of therapy must be individualized; patients may require from 4 weeks to several months of treatment. Response to therapy is indicated by resolution of symptoms, normalization of ESR, and reversal of abnormalities on radionuclide scans. Serial gallium scans are particularly useful in following response to treatment.