Today we meet Sam, who has chronic proliferative otitis externia.
So what is otitis externia? This is inflammation of the external ear canal and is indicated by head shaking and scratching at the ear. Otitis externia is quite prevalent in small animals and has numerous predisposing conditions and numerous causes.
Predisposing conditions are those that alter the ear canal environment that may allow a primary cause to establish the problem. The types of condition we commonly associate with ear problems are:
- Conformational changes such as dependant ears, narrow canals, hair in the canal
- Moist conditions – humidity, frequent swimming
- Obstructions of the ear – tumours, polyps
- Inappropriate treatments – use of cotton buds, irritant substances applied to ear
- Systemic diseases
Primary causes are the inciting agents or disease the cause otitis externia with or without predisposing factors. These include:
- Infectious Organisms
- Foreign Bodies
- Autoimmune Diseases
These causes incite inflammation which results in increased wax production, secretions, thickening of the canal wall and ulceration of the canal. A pungent odour and thick sticky discharge is the result of this process. In chronic otitis externia proliferative growths develop. This is part of the inflammatory immune response to long standing or repetitive bouts of otitis externia.
Fibrocytes which from fibrous tissue – scar tissue – are deposited in chronic areas to protect the body from ongoing insult however they result in thickening in the canal and ear lobe which are never removed and cause narrowing of the canal diameter.
Sam, which is short for Samantha, is an aged poodle cross. Her Mum and Dad tell us that Sam has had ear problems for many years and slowly the skin of the ear lobe – pinna – change becoming more nodular with proliferative lesions. These lesions started to have an impact a couple of years ago resulting in an inability to be able to resolve otitis externia problems medically. Sam initially responded well with all signs of head shaking and scratching ceasing while on medication however once treatment stoped the problem returned. Eventually the lesions became so severe that Mum could not find the opening of the ear canal to administer the drugs.
When we first saw Sam she was busily shaking her head and trying to scratch at both ears at once. There were copious amounts of black exudate, a foul smell, proliferative tissue and like Mum we could not easily find the ear canal either. Our first step was to try and have a look at the entire length of the canal. This meant that Sam has a short sleep while we irrigated the canal so we could have a good look at them. Fortunately in the left ear about 80% of the canal was normal but unfortunately the right ear was not completely normal. The vertical section of the canal was narrowed by proliferative tissue and the horizontal section of the canal although not show any proliferative tissue was narrowed.
With what we found we knew that if we removed the vertical sections of both canals we stood a good chance of being able to fix Sam’s problems. The technique used is known as a lateral wall resection or Zepp’s operation. This involves the removal of the outer 12 of the vertical section of the canal and establishing a new ear opening at the junction of the vertical and horizontal sections of the ear canal. In other words making a dog’s ear canal into one that resembles our own. This should allow the ear to breathe and drain normal products thus restoring normality to the canal.
Sam’s surgery has progressed well and all surgical areas have healed. There will still to be some problem with material building up in the proliferative tissue but with regular cleaning Sam should no longer have too many problems with her ears.