The Journal of Laryngology and Otology January 1992, Vol. 106, pp. 5-6
Malignant external otitis: management policy OSAMA EL-SILIMY,
M.D. (Riyadh, Saudi Arabia)
Malignant external otitis is a progressive pseudomonal infection of the external auditory canal and adjacent structures. In the literature there is no unified policy regarding the management of malignant external otitis. The development of an effective nuclear scanning methpd and antibiotics active against Pseudomonas aeruginosa have helped in formulating our management policy. A review of four years personal experience with this condition is presented. All of our cases were cured from the disease with no fatality. Gallium67 citrate scans showed that antipseudomonal treatment should continue for up to three months.
Progressive osteomyelitis of the temporal bone was first reported by Toulmouche (1838). Meltzer and Kelemen (1959) described a case of progressive pseudomonal osteomyelitis of the temporal bone. Chandler (1968) coined the term 'Malignant External Otitis' when he described 13 cases of pseudomonal external otitis which began in the external auditory canal and mainly affected elderly diabetics. It may spread to the soft tissues and progress to facial nerve palsy, mastoiditis, multiple cranial nerve palsies and death. Gates etal. (1977) reported a mortality rate of 23 per cent if no deep structures were involved, 67 per cent if the facial nerve was involved and 80 per cent if deeper cranial nerves and the jugular vein were involved. Since Chandler's initial description in 1968, this entity has been recognized in its earlier stages with increasing frequency. Cases with malignant external otitis have been described in non-diabetics (John and Hopkins, 1968), in young diabetics (Shamboul, 1983), in patients on cytotoxic drugs (Rubinstein and Ostfeld, 1980) and in infants (Joachims, 1976). A Techneteium" bone scan is a valuable test in diagnosis since results are positive in early cases of osteomyelitis of the temporal bone. Gallium67 citrate serial scans were useful in evaluating the effectiveness of therapy since uptake decreased with control of infection (Lucente et al., 1983). CT scan can replace pluridirectional tomography for the demonstration of bone disease when the central skull base is involved, but neither can be used for following the resolution of central bone destruction (Mendelson and Som, 1983). In the literature there is no unified policy regarding the management of malignant external otitis (Wilson and Pulec, 1971; Joachims, 1976; Chandler, 1977; Strauss and Aer, 1982; Uri etal., 1984; Leggett and Prendergast, 1988). Various treatment modalities have been described, including a wide variety of different parenteral anti-
pseudomonal combinations, local debridement of ear canal, wide surgical excision (Chandler, 1977), the use of hyperbaric oxygen and the use of oral antipseudomonal agents (Scully etal., 1986). There has been improvement in the outcome of the disease due to the availability of new antipseudomonal agents and Gallium67 citrate serial scans. We would like to present 14 cases of malignant external otitis managed by the authors from 1987 through to 1991.
Material and methods
All 14 cases were reviewed retrospectively from patients records. Diagnostic criteria included local invasive Pseudomonus aeruginosa infection beginning in the external auditory canal, penetrating the epithelial barrier and manifesting signs of local subcutaneous tissue invasion . Material for culture was obtained from purulent external ear canal discharge and from material obtained at the time of biopsy of canal granulation. X-rays of skull and mastoid were carried out routinely. A Techneteium99 bone scan was carried out at the time of admission. Gallium67 citrate scan was performed at the start of therapy and at six week intervals. The treatment policy included hospitalization, control of the associated factor, daily ear canal debridement with insertion of Triadocryl ear wick and intravenous piperacillin sodium (Pipril). Most patients were started at the time of admission on one of the new oral Quinolon groups with broad spectrum antibiotic activity, particularly against pseudomonas (noroxin, ciprofloxacin); oral medications was given until the Gallium67 scan reverted to normal. All cases were managed by the authors personally. The aim of the study is to evaluate the results of our management policy.
Department of Otolaryngology, Riyadh National Hospital, P.O. Box 2715, Riyadh 11641, Saudi Arabia. Accepted for publication: 26 September 1991.
O. EL-SILIMY, M. SHARNUBY
Results The average age was 56.8, with a range from 2 to 83 years. Males to females ratio was 2:1 (8:4). Diabetes mellitus was present in 10cases(71.4percent). One case was on immunosuppressive medication, one was on cytotoxic chemotherapy, one was anaemic and suffering from sickle cell trait. In the last patient, all routine investigations failed to find any predisposing factor. Physical examination disclosed discharge and granulation tissue in external canal; Pseudomonas aeruginosa was isolated in all cases. Cranial nerve palsies (facial nerve) were present in three cases (21 per cent). A Techneteium99 bone scan was positive in all 14 cases. Gallium67 citrate scans were positive at the start of the therapy in all nine cases who underwent the tests. X-rays of the skull and mastoids were not helpful. The serial gallium scans were positive for up to three months in four cases. All our cases were cured from the disease. Discussion Malignant external otitis must be treated as a potentially lethal disease which, begins in the external auditory canal and may produce a devastating and invasive infection of the skull. Early diagnosis, adequate local aural treatment and systemic antipseudomonal medication are essential. A Technetium99 scan permits the early detection of osteomyelitis of the temporal bone and skull base before radiological evidence of demineralization has appeared (Gold etal., 1984). However, the bone scan will remain positive for an indefinite period (Parisier and Lucente, 1982). On the other hand, Gallium67 citrate scan revert to normal when the inflammation has ceased (up to 3 months in our cases). We believe that therapy should be maintained until the gallium scan reverts to normal (cold). We do not believe that there is a place for extensive surgery in the management of malignant external otitis. The development of an effective oral antibiotic active against Pseudomonas aeruginosa (Quinolon group) has added a new dimension to the management of malignant external otitis (Scully et al., 1986; Leggett and Prendergast, 1988). Early discharge from hospital and the continuation of the therapy at home, with simple to handle medication until the gallium scan reverts to normal has been achieved with this medication in our cases. Key words: Otitis externa, malignant
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Address for correspondence: MrO. El-Silimy, F.R.C.S., 19 Grange Avenue, Stanmore, Middlesex HA7 2JA, U.K.