A cholesteatoma is where there is an abnormal extension of skin into the middle ear and mastoid air spaces.
Unrecognised and untreated complications include facial nerve weakness, vestibular dysfunction and intracranial invasion.
Usually a cholesteatoma will present with a conductive hearing loss and a foul smelling discharge. It is not unusual for a patient to have been treated for otitis externa for some weeks in primary care, but on direct questioning the patient says that the treatments have not really worked. Pain is often not a feature unless there is bony erosion in advanced disease.
Unlike recurrent otitis externa the discharge tends to be persistent and does not respond well to topical or oral antibiotics. Also a patient with recurrent otitis externa will usually have symptom free periods when a normal tympanic membrane can be seen with the otoscope. Patients who are at risk of developing retraction pockets on the tympanic membrane leading to cholesteatoma may have a history of childhood ventilation tubes or Eustachian tube dysfunction.
Around 90% of patients with a cholesteatoma will have a perforated tympanic membrane. However, this may be difficult to see due to discharge.Therefore microsuction can be very helpful in diagnosis. Most cholesteatomas are in the superior (attic region) and if the edge of the perforation cannot be seen one must have a high index of suspicion. Granulation tissue which arises from the mucosa adjacent to the cholesteatoma may be seen, and there may be visible bleeding.
Bony osteomas in the ear canal may mimic a cholesteatoma, but they are harmless. Scarring on the eardrum, tympanosclerosis, may cause concern. It is usually due to previous otitis media or ventilation tubes. Perforations of the tympanic membrane can also mimic cholesteatoma but they are usually regarded as safe if they do not involve the edge of the membrane and there is no mass or granulation tissue. Malignancy of the ear canal is rare but should be considered if there is gross distortion of the ear canal.
Refer the same day by speaking to an on call ENT surgeon f there is facial nerve weakness, vestibular dysfunction or severe pain.
Ask for an ENT appointment ideally in 2-4 weeks if:
– treatment with antibiotic drops has not resulted in clinical improvement and you cannot see the tympanic membrane.
– there is a perforation where you cannot see the edge of the tympanic membrane
– there is granulation tissue obstructing the view of the eardrum
– the patient has had persistent, particularly foul smelling discharge and there is a conductive hearing loss (remember Webers test refers the sound of the tuning fork to the affected ear)
Be prepared to escalate the appointment if the patient’s clinical condition deteriorates.
The examination of choice is CT scan of the temporal bone. Bone destruction can be seen including that of the ossicular chain. The mainstay of treatment is mastoid surgery to produce a safe dry ear, and also if possible to reconstruct the ossicular chain.
Dr Stephen Brown is a GPSI ENT in Buckinghamshire