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Syphilis is a systemic disease caused by the spirochete Treponema pallidum . Otosyphilis is well known as a complication of syphilis. The clinical manifestation of otosyphilis include sensorineural hearing loss, tinnitus and vertigo. The presumptive diagnosis of otosyphilis can be made in patients with these symptoms, positive serology for syphilis and no other known aetiology for the inner ear disturbance. The first-line therapy is high-dose intravenous penicillin. However, this treatment needs hospitalisation and inconvenience of intravenous antibiotic.
Oral doxycycline is one of alternative regimens for treatment of syphilis with less expensive and convenience to use. This drug has been found to be effective in early syphilis. 1 2 It also have been shown to have good distribution into cerebrospinal fluid (CSF). 3 This paper reported the result of doxycycline treatment of otosyphilis with hearing loss that, to our knowledge, has never been reported.
Methods
The study was done at the Out-Patient Department, Srinagarind Hospital, Khon Kaen University. Chart review was done retrospectively in all patients with the diagnosis of otosyphilis and received doxycycline treatment 200 mg orally twice a day for 21 days 4 between 2004 and 2009.
Adult patients (aged >=15 years) who presented with sensorineurol hearing loss (confirmed by audiogram) were studied. Other causes of hearing loss such as Meniere's disease, tumours, trauma, chronic otitis media and toxic substances were excluded. The diagnosis of otosyphilis was confirmed by a positive serum for T pallidum haemagglutination test. We also excluded HIV patients, patients with tinnitus or vertigo, neurological deficit, previous treatment of syphilis, that is, penicillin, or glucocorticoid treatment.
There were two treatment outcomes including clinical outcome and audiogram outcome. Both outcomes were evaluated at approximately 1 year of follow-up and classified as improved, stable or worse. The clinical outcome was the hearing symptom reported by the patient, while the audiogram outcome was the comparison of audiogram reports (initial vs 1 year). The improvement of audiogram was defined if pure tone average threshold at 0.5, 1 or 2 kHz decreased >10 dB or pure tone average threshold decreased >15 dB at any frequency or discrimination score increased >15%.
Data were reported as descriptive statistics. The study protocol was approved by the Khon Kaen University's ethics committee for human research.