Monomelic Amyotropy (MMA)

I'm a 43-yr old caucasian male and my neurologist is looking into whether I have this rare disease.

A little background. I had a total right hip replacement in 1998 and in 2007 began experiencing weakness and atrophy (and sometimes fairly intense pain when I slipped or sneezed) in my upper right thigh. In February 2010, my ortho doc did my annual x-ray checkup on the hip and said the prosthesis is still in great shape. I told him about the weakness and he ordered physical therapy and, if that didn't help, a visit to a neurologist. Well, 3 months of PT didn't help and so off I went to the neurologist 3 weeks ago. I had an EMG, which was clear, but my doc said that a dormant form of MMA can bypass EMG detection and only be detected by a brain MRI and/or an MRI of the cervical spine. The brain MRI came back clear and I just had the MRI of the cervical spine. I understand that an MRI of the affected area (upper thigh) would be useless due to the titanium prosthesis in there, but I'm wondering why they're also not looking at the lumbar spine area. Any insight into this disease or whether I may have it would be appreciated. Thanks!

[Christopher R Newey, DO]

Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with a doctor.

Without the ability to examine and obtain a history, I can not tell you what the exact cause of the symptoms is. However I will try to provide you with some useful information.

Monomelic amyotrophy is a condition of degeneration of motor nerves of a limb. I agree that imaging of the lower back may be useful. You should continue working with your neurologist. A repeat EMG may be an option. Monomelic amyotrophy is diagnosed clinically and by EMG findings of active and chronic denervation without sensory abnormalities.

It is difficult to say if you have it or not since I do not have the ability to evaluate you myself. Some diagnoses do take time to confirm.

Thank you for this opportunity to answer your questions, I hope you find the information I have provided useful, good luck.