I posted this in peripheral neuropathy but not sure it really belongs there. I don't have sensory abnormalities on exam.
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[40 yo male, previously healthy and fit/athletic with chronic low back pain/no radicular symptoms.

2 months ago, 'tweaked' neck at gym, no radicular symptoms, slowly resolved with rest, NSAIDs, PT.

1 month ago, *sudden* onset over 24-48 hours of widespread paresthesias in 4 extremities, intermittent, variable, mostly described as 'buzzing' or 'hot/cold' as if limbs falling asleep, unclear distribution, not clearly anatomic/dermatomal, seemingly very sensitive to positioning (ie, legs worse when lying down or sitting but better when standing/walking/running; arms worse when flexed). Over several weeks symptoms came and went with some consolidation in a right ulnar distribution (R 4th and 5th digits, forearm, arm to mid-upper arm including at times parts of the shoulder) and left sciatic distribution. right leg and left arm are variable involved. At times one leg will go completely asleep out of nowhere, for example, when driving.

In addition there has been some very mild weakness in the ulnar distribution, right greater than left, not appreciable on exam but quite obvious in day to day activities - reduced grip strength while exercising, cooking, etc; easy fatigue when writing, cooking; clumsiness when typing. Also some slight soreness in the forearms, the brachioradialis muscles in particular.

A couple of times there has been the scary sensation of a numbness or tingling in the back of the throat, on the right hand side, and in the tongue and even a burning sensation on the face, neck, upper back, right worse than left. This is transient.

Pain is mostly non-existent, not the dominant symptom.

I do not have fasciculations or atrophy.

I did have a mild viral illness just prior to this onset.

I am not 'ill-feeling' but I am more fatigued than usual.

Neuro exam by a qualified neurologist is objectively normal.

MRI brain with/without contrast is normal, read by neurologist and qualified neuroradiologist.

MRI neck with/without is normal.

Chemistry with LFT, ANA, ESR, CK all normal.

nerve conduction studies yesterday: left peroneal/sural normal. Right ulnar shows slowed conduction velocity from axilla to elbow; Left ulnar normal though again some relative slowing from axilla to elbow.

In my mind the distinguishing features of this syndrome are:

1. *sudden* onset;
2. normal neuro exam;
3. multiple mononeuropathy;
4. normal MRI of CNS.

My differential of course wants to exclude really bad things like ALS. Does this?

What else is possible? I have considered atypical presentation of GBS, but with minimal weakness seems unlikely. Vasculitis seems unlikely with negative ANA and ESR. Multifocal motor neuropathy seemed plausible but I understand that causes conduction block rather than conduction slowing. Monoclonal gammopathies?

Thought about adding CBC, serum/protein electorphoresis to labs. Any other suggestions? Would like to avoid LP if not necessary, of course.

thank you for your thoughts,


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I had the acute onset of 'buzzing' like vibrating/limbs falling asleep about 1 month ago, and my NCS shows mild slowing in my ulnar nerves, one side greater than other. I also have very subtle weakness in both hands, very obvious in activities of daily living but not appreciable on exam. I have no fasiculations or atrophy, I can still push heavy objects (ie, at the gym), but I lose grip strength when pulling and I am clumsy and tire rapidly with fine motor movements like handwriting, cooking, typing, etc.

I have a clear diurnal variation, symptoms worsen throughout each day, by about 5 pm I start to develop terrible hot flashes on my face, neck, arms, and legs, exactly like when you take too much niacin. My arms get more and more 'buzzy' and I start to feel shaky throughout. These symptoms are all better in the morning and relatively mild throughout the morning hours.

My neuro exam is objectively normal.

My differential is:

multifocal motor neuropathy without conduction block - but I haven't had pronounced or objective weakness, it is very subtle

ALS - but no fasiculations, no atrophy, and my earlies symptoms were sensory

GBS - but again, must be atypical or very mild because the weakness is quite subtle, and not widespread.

I really want to rule out ALS of course. Does what I've told you (and in the link) rule it out?

thank you

Not necessarily. Conduction block cannot be discerned on many MMN patients, including me. Some official diagnostic checklists don't even require conduction block anymore.

While MMN is typically motor rather than sensory, there can be some sensory involvement. I have developed some numbness after five or 10 years.

While your symptoms don't sound that much like MMN, individual cases vary quite a lot. Weakness can be subtle at first; I initially noticed it when I had trouble tearing open oatmeal packets. Nobody took it seriously until years later when I woke up with sudden loss of thumb extension, followed by three more fingers over the course of eight months.

Unfortunately, there is no definite diagnostic test for either MMN or ALS. One thing that helps distinguish them, though, is upper bulbar involvement. My Mayo Clinic neurologist told me that diagnosing MMN is more of an art than a science. On my first mayo visit I had five solid days of testing, mostly to rule out other things like heavy metals, B12 deficiency and Lyme disease.We have many people in our online groups who have bounced back and forth between MMN and ALS diagnoses, and some who still don't know which they have. While treatment with IVIg can be of diagnostic help, 30% of MMN cases do not respond (including me), and some ALS patients do respond initially to treatment. So even that is not definitive.

There is a whole alphabet soup of common, to uncommon, to incredibly rare neuropathies. Again unfortunately, the average time to diagnosis is 7 to 10 years.

You sound pretty knowledgeable, so perhaps you have a head start. My advice is to see more than one neurologist experienced with rare neuropathies.

thank you very much, I appreciate your thoughts.

Between your initial symptom of trouble tearing open oatmeal packets and the weakness in thumb extension years later, were your symptoms stable, or did they progress? Did you have any sensory symptoms early on?

Actually, the very first thing I noticed was a slight tremor in my left hand. After that I had the grip weakness in my left hand and also fasciculations that started in my upper left quadrant and have since spread throughout pretty much everywhere except my head. I can't remember which of those came first.

I would not characterize my lack of extension in my thumb as "weakness". Trying to lift my thumb is like trying to levitate the dining room table. I feel like a vital line of communication has been completely severed. Despite that, they have never been able to find a true conduction block in me, which is a classical hallmark of MMN, though not strictly required for diagnosis. And since then I have lost extension three more fingers on my left hand.

As for sensory symptoms, those came later. Right now the tip of my left index finger is numb, some of my thumb is numb (which could be from spending too many months in a splint, trying to treat De Quervains tenosynovitis), and I have that ghost-stocking feeling on my left ankle which has been spreading.

One always has to keep in mind that there is a lot of variability in symptoms. This makes comparisons difficult. Most people with a current MMN diagnosis have at some point been told they have ALS.