Sometimes, no cause can be found. Prevention is related to the cause. For instance, avoiding alcohol can prevent cases due to alcohol abuse. Safer sex practices can prevent many cases due to HIV . Many cases cannot be prevented.
Diagnosis starts with a history and physical exam.
This may be all that is needed to make a diagnosis. In other cases, further testing is needed. Blood tests can help diagnose hormone imbalances, HIV , diabetes , and other conditions. If multiple sclerosis is suspected, a special x-ray test of the brain, called a cranial MRI , may be ordered. In some cases, a test called electromyography , or EMG, is ordered.