A rare case of malignant otitis externa in a non-diabetic patient By A. E.

SOLIMAN

(Hull, East Yorkshire)

MAUGNANT otitis externa is a rare disease which affects mainly old debilitated diabetic patients and usually the organism responsible for the infection is Pseudomonas aeruginosa. The disease is said to be characterized by an infection starting in the external auditory meatus, especially at the floor, extending inferiorly and anteriorly into the soft tissue at the base of the skull and posteriorly to the mastoid. It may involve the last four cranial nerves at the base of the skull, the bone, the cartilage, the blood vessels and the parotid gland. If this disease is not arrested it may lead to complications such as meningitis, lateral sinus thrombosis, brain abcess and finally death. One of the important signs of malignant otitis externa is that the middle ear compartment is unaffected, the tympanic membrane usually being intact. Pseudomonas aeruginosa is very resistant to the usual methods of treatment, but in most cases it is sensitive to Gentamicin, given intra-muscularly and locally, especially if it is combined with Carbinicillin given intravenously.

Case report A 69-year-old female presented with pain and discharge from both ears for one month. Her general practitioner had prescribed Sofradex ear drops which led to some improvement, but, after a few days, the pain became worse and she came to the out-patient clinic as an emergency. On examination there was a bilateral otitis externa with a fully developed furuncle in the left ear and a generalized inflammation of the right external canal with granulation tissue in the floor. The patient was given Hyd.Nit.Dil. drops. Three weeks later her condition remained unchanged and she was admitted to hospital for daily aural toilet and local application of ear drops. An aural swab showed Pscudomonas aeruginosa, resistant to Ampicillin and Gentamicin but sensitive to Tetracycline, Cephradine and Colistin Sulphate. Her haemoglobin was 11 -6 g per cent. An X-ray showed clear mastoid cells with no evidence of bone destruction. A chest X-ray did not show any significant abnormality. There was no evidence of glycosuria and the blood sugar was 105 mg per 100 ml. As her condition did not improve on Tetracycline given systematically and locally it was decided to examine the ears under general anaesthesia and this confirmed the result of examination in the out-patient clinic. Biopsy of granulations showed non-specific inflammatory cells. A few days later the patient developed right-sided facial palsy with increasing pain over the tip of the right mastoid and otorrhoea. The patient was taken back to the theatre for exploration of the mastoid. It was found that the mastoid tip was absent and in its place was a mass of purulent granulation tissue which extended deeply and medially along the base of the skull. 811

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It was impossible to identify the facial nerve in the soft tissue. The attic and middle ear were not involved. The otorrhoea and the pain over the mastoid persisted and different types of antibiotics, e.g. Tetracycline and Carbenicillin, were used locally and systemically without any improvement in the patient's condition. A few days later the patient developed paralysis of the IX, X, XI and XII cranial nerves on the same side with dysphagia which required a nasogastric tube for feeding. Gradually the general condition of the patient deteriorated until finally she died, four months from the start of the illness. Post-mortem examination

This showed a sub-dural abscess in the right side of the posterior fossa above and medial to the foramen magnum containing thick green pus in addition to a purulent mastoiditis. The swelling had produced some distortion of the right lateral aspect of the pons which could have been the main cause of death. Discussion

Chandler (1968) has described features of malignant otitis externa as the triad of infection by Pseudomonas aeruginosa in elderly patients with diabetes mellitus. He found that the mortality was about 50 per cent in cases with facial nerve palsy and 80 per cent or more when there was multiple cranial nerve involvement. Mawson (1976) and Prasad (1976) have confirmed these findings. Our case is one of the first to be reported in which the typical findings of malignant otitis externa have not been associated with diabetes. The treatment of choice for malignant otitis externa is intra-muscular Gentamicin with intravenous Carbenicillin accompanied by surgical removal of the infected soft tissue. Tn this case the organisms showed resistance to Gentamicin and did not respond to Carbenicillin when given in large doses. The known complications of malignant otitis externa are osteomylitis of the temporal bone, facial nerve palsy and other cranial nerve involvement, meningitis, sigmoid sinus thrombosis, brain abscess and ultimately death. Post-mortem examination in this case showed only a sub-dural abscess which had caused pressure on the pons and resulted in death. This constitutes a new complication to be added to the previous list. Summary A case of an elderly non-diabetic patient suffering from malignant otitis externa is reported. The organisms were resistant to Gentamicin and the cause of death was a sub-dural abscess causing pressure on the pons. Acknowledgements

My thanks are due to Mr. J. S. Martin, for permission to publish this case; to Mr. R. G. Williams, for his help in the presentation of this paper; and to Mrs P. J. Harris, for typing it. REFERENCES CHANDLFR, J. R. (1968) Laryngoscope, 78, 1257. MAWSON, S. R. (1976) Nursing Times, p. 102. PRASAD, U. (1976) Journal of Laryngology and Otology, 90, 963.

A rare case of malignant otitis externa in a non-diabetic patient.

A rare case of malignant otitis externa in a non-diabetic patient By A. E. SOLIMAN (Hull, East Yorkshire) MAUGNANT otitis externa is a rare disease...
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