Finger/wrist drop - possible MMN with conduction block

[ruuku]

Hi,

I am a 24 year-old white male. For the past 10 months or so, I've had slowly progressing finger and wrist drop in my left hand. So fas as I can tell, all my other limbs are normal.

I'm told that the symptoms affect only my radial nerve, and I have no sensory symptoms (though I do feel the odd tingling across my hand, which lasts for a minute or so).

I had nerve conduction studies done last week, and the guestimate of the guy who performed them is a "strong possibility" of multifocal motor neuropathy with conduction block.

Another possibility, which he regards as unlikely, is compression of my radial nerve. The reason he thinks it's unlikely is that I have no sensory involvement.

The plan seems to be to start me on the immune drugs, and give me a confirmed diagnosis if I respond to them.

My questions are:
- what is the prognosis, assuming successful treatment?
- are there any plausible alternatives to MMN with conduction block?

Thanks,
Ruuku

[CCF-Neuro-M.D.-SH]

First of all, keep in mind that I am unable to diagnose you because I am unable to examine you, this forum is for educational purposes.
    Multifocal Motor Neuropathy (MMN) with conduction block is an immune related disorder that generally responds well to treatment.  This is a pure motor syndrome and presents with asymmetric weakness and atrophy, usually of an arm/hand.  This condition is most often diagnosed by EMG and nerve conduction studies, but is also associated with positive GM1 antibodies that help to differentiate this disorder from other similar disorders such as ALS, compression, CIDP etc.  The treatment consists of IVIG (often very effective) and cyclophosphamide.  The clinical presentation that you describe sounds consistent with MMN with conduction block.  I would recommend sending the anti-GM1 antibody test and a trial of IVIG (intravenous immune globulin) followed by cyclophosphamide is needed.  
I hope this has been helpful.

[mike1105]

i personally would not start on any drugs without knowing the cause of the problem, and without a diagnosis. immune issues can be tested for.