[snowyday]

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,