Causes and risk factors
The most common cause of petrositis is a pre-existing suppurative mastoiditis. Common causative organisms include staphylococci, streptococci, and Haemophilus influenzae.
Clinical presentation
Petrositis presents with a classic triad of symptoms – otorrhea, pain, abducens nerve paresis.
Otorrhea – patients have a discharge from the affected ear.
Pain – patients experience pain deep within the eyes, in the forehead, ear, or facial pain in general.
Sixth nerve paresis – patients develop paresis of the abducens nerve. This nerve supplies the lateral rectus muscle, which is responsible for abduction of the eye. Thus paresis of the abducens nerve prevents the outward motion of the affected eye. This leads to diplopia (double vision).
Apart from these typical symptoms, patients may develop certain less commonly occurring symptoms such as fever, loss of consciousness, palsy of any other cranial nerve, and sometimes even coma.
Investigations
Culture and sensitivity testing is carried out on the discharge from the ear. If there is no discharge, then fluid may be obtained from the middle ear via a procedure known as myringotomy.
Blood tests are carried out to detect the complete blood count, blood glucose levels, ESR, and C-reactive protein levels.
Imaging studies such as CT, MRI, or sometimes a bone scan is carried out.
Other tests include audiometry (assessment of hearing) and petrous biopsy.
Treatment
Primary line of treatment for petrositis involves the use of antibiotics. If the infection still persists, then surgical intervention becomes necessary.
Surgery involves the removal of the mastoid (mastoidectomy) in order to drain the petrous temporal bone.
Complications
Petrositis is a dangerous condition since the infection may spread to the brain tissue giving rise to meningitis or even death. Cranial nerve palsy is a frequently occurring complication. Other complications such as spasm of the carotid artery or destruction of the temporal bone may occur.
When to contact a doctor
Contact a doctor as soon as you experience facial pain, ear discharge, or diplopia.
Systems involved
Otology, ophthalmic, CNS
Organs involved
Temporal bone, ear, eyes, brain
