What could cause fibrillations and positive sharp waves on an
Probably nerve fibers injury.
Hello and welcome to "Ask a Doctor" service.
I have read your query and here is my advice.
The main cause for fibrillation and positive sharp waves on an EMG is nerve fibers injury.
The causes of the nerve injury may be entrapment syndromes, nerve root compression, axonal injury, etc.
In order to be correct about the diagnosis, these EMG findings should be evaluated in the clinical setting.
Hope you found the answer helpful.
Let me know if I can assist you further.