I found this very interesting and wanted to pass it on... Michelle
For the people who have had BP for many months and are still waiting for full recovery, the final paragraph starting with 'an aside' may provide renewed hope.
It's by a chap called Todd who specialises in facial therapy at Pittsburgh University.
The reason for the difference in speed of recovery, and in some cases, incomplete recovery, has to do with the nature of peripheral nerve injuries (BP is a peripheral nerve injury involving the facial nerve).
I have on my bulletin board a chart that lists the different degrees of injury:
1st degree is termed 'neuopraxia' and it is simple compression of the nerve without morphologic changes.
This means the nerve itself is intact, but simply in a state of shock, if you will.
In this case the nerve does not have to regrow/regenerate... once the shocks wears off the nerve is back to normal, which usually takes 1-8 weeks.
Luckily, this is the majority of BP cases.
2nd degree injury is termed 'axonotmesis' (try saying that 3 times in a row), here the axons (nerve fibers) are lost, but the tube they are running through is left intact, making the regrowth of the axons process much easier (and faster).
These people will take 1-6 months to recover (please don't quote me, this is inexact) and may have small residuals (signs of incomplete recovery, i.e. weakness and synkinesis).
3rd degree is called 'neurotmesis' and involves both the axons and the tubes (made of myelin, the essential ingredient for nerve regrowth, which you don't have in spinal cord or brain nerves - which is why spinal cord injuries and strokes are more permanent ).
The whole nerve has to regenerate from site of injury (actually back to the previous junction, called 'node of ranvier') and recovery is always incomplete with synkinesis. Recovery isn't usually seen starting until 2-4 months and can take up to 18-24 months.
An aside: I was just discussing this with my colleague, Jessie, and we both now are recognizing evidence in some of our longer term patients of nerve recovery much longer out than 24 months.
The only logical explanation (we think) is that the nerve fibers that did recover to a particular muscle in the face (even if only a very few) must be 'sprouting collaterals' to cover more of the surface of the muscle, allowing it to regain contractile ability even at a very late date.
Need seems to drive the brain to find a way to push that peripheral nerve to do this. Need comes from attempted use and this is why we take a much longer view of the recovery process (and rehabilitation) than many others in medicine, and particularly in the insurance industry... (but that is a whole different cup of worms).
Now to finish up with your real question (I think), what determines the degree of injury?
No easy answer to that I'm afraid. Sorry. It certainly seems to help to get on steroids and anti-viral meds. as soon as possible.
The wild card of course is those who have much rarer conditions that cause facial palsy, such as Lyme disease, or otitis media (a bad ear infection), or many others.
It is your physician's job to rule out these other diagnoses and it is important for you to ask questions of your doctor about your symptoms, especially if not typical.
Hope my long winded explantion is a help. The best of luck to you!
I hope that this is of interest.
