Skull Base Osteomyelitis

Malignant otitis externa is an uncommon complication caused by the spread of an outer ear infection commonly seen in people with compromised immunity most often diabetes.
It is often caused by pseudomonas and sometimes by fungus. The infection and inflammation may damage or destroy the bones. When the infection spreads from the ear canal to the nearby tissues and to the skull base, skull base osteomyelitis results.

The hallmark of this disease is pain felt deep inside the ear and not responding to conventional treatment. It is followed by drainage from the ears. It is most commonly associated with hearing loss and sometimes with vertigo and tinnitus. If any of the nerves are involved then palsy is evident.

Patient 1 Symptoms :
She had pain which was not responding to conventional treatment. She was seen earlier at Kerala and an ENT surgeon was treating her for chronic ear discharge. She also had narrowing of EAC due to OE. Since he was not able to manage her she was referred to another topnotch ENT surgeon. The surgeon made the right diagnosis but unfortunately failed to treat her appropriately. She was treated with Ciprofloxacin 250 mg for 4months!!! In spite of her symptoms not coming down she was continued with the same management. It was at this following the Front page coverage the patient came to me for further management which would be discussed in the treatment section.

Patient 2:
Almost same history, both were diabetics. She was seen by a leading surgeon in this part of the country. He was taken up for surgery for ear discharge. His symptoms got worse and his pain increased, even at this time SBO was not suspected and he was being managed conservatively along with an aural solution which was his trademark (Solution withheld since it will reveal his name). I saw the patient and noticed some discharge and since I had high regard I was sure he would have been managed properly and so did little alteration in the medications. When even after a week the pain and discharge did not subside I suspected SBO and it was confirmed. Further discussion in Investigations and treatment section.

Exams and Tests:
There will be pain and tenderness behind the ears. In patient 1 the tenderness was near the mastoid tip and over the mastoids. Otoscopy will generally reveal granulation tissue with external auditory canal being edematous. In patient 1 the external auditory canal was extremely edematous and the TM could not be identified. In patient 2 there was extensive granulation tissue with ear discharge even though it was 3 weeks post Myringoplasty.
Pus/drainage has to be sent for C/S. In patient 1, aural swab did not yield anything and since CT revealed granulations she was taken up for cotical mastoidectomy and the granulations were sent for C/S. The patient was informed that the purpose was not to cure the disease as it was very extensive but to obtain tissue for diagnosis.
In my second patient aural swabs were taken from the discharge/ granulations present.
The purpose of the culture is to look for bacteria or fungi, usually the bacteria Pseudomonas.

In both my patients P.Aeruginosa was isolated. It was resistant to almost all antibiotics. In pt.1 it was sensitive to Amikacin, Imipenem and to Piperacillin+Tazobactum

MRI scan was obtained in both the patients and both had evidence of SBO, it was very extensive in patient 1.

Treatment
A team of multidisciplinary professionals is necessary to treat all of the issues associated with the disease including management of diabetes.
The goal of treatment is to cure the infection. Antibiotics proved to be effective against the microorganism are taken for at least 4 – 6 weeks, sometimes longer. IV route is preferred and a combination of drugs is needed to avoid microbiological resistance.
Antibiotics should be continued until inflammation has gone down which is monitored by way of ESR, patients symptoms and by Tc99/MRI scans. (Though Gallium scans are preferable they are substituted by Tc since each Gallium scan costs about Rs.50,000!!! and is not easily/readily available)