Mononeuritis multiplex vs. HPNN

[Borisgoodenough]

I'm male, age 51. About 5 months ago, after (voluntarily) losing 30 pounds on a low-carb, hi protein diet, I started awakening with numb / tingling fingers. Since then, it's progressed to  regular (but intermittent) sensory loss in parts of all four distal limbs, with slight muscular weakening, plus some muscular and joint soreness (especially shoulders / upper arms). My health is fine otherwise.

After arm EMG/NCVs, a neurologist diagnosed mononeuritis multiplex (both wrists & elbows). Lab tests all  normal -- Chest X-Ray, CBC, Differential, HbA1C, Blood Glucose, Blood B12, Glycohemoglobin, Sed rate, BUN, ANA, C3 & C4 complement, rheumatoid factor, Hep B antigen, protein electrophoresis, Lyme disease, ANCA, C-Reactive, immunoglobulin GAM, creatinine.  Also been examined by a rheumatologist.

My neurologist says it is "most likely" HPNN, with some chance of still-undetected vasculitis.  He wants to wait to see what happens for another month, then possibly do a nerve biopsy.  He recommends against the genetic test for HPNN, saying it is not that reliable. He also declined to do MRIs (cranial or spinal) or a lumbar puncture because he says the problems aren't in the CNS.

I'm not happy just waiting to see what happens, as my symptoms are definitely progressing.

Questions:
(1) What addition tests (including HPNN genetic, MRI, LP, or others) would you recommend now?  
(2) Is the HPNN test reliable?
(3) Is HPNN likely to present as almost-simultaneously appearing symptoms in multiple limbs?
(4) Suggestions for other possible diagnoses?

Thanks!

[ricdmc313]

A related discussion, Left hand has lost muscle mass - basically caved in.  Right hand okay was started.

[Borisgoodenough]

That's HNPP -- not HPNN.

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

Don't want to disagree with the neurologist as they have had the advantage of examining you and reviewing your test results. But doesn't sound too typical of HNPP. As you pointed out, it's symmetric in all limbs which is not really characteristic of that particular disease.  I agree that it's probably not in the central nervous system (brain and spine), but protein level in a spinal tap can often be helpful when evaluating a progressive peripheral neuropathy like this one. The EMG is EXTREMELY important in your case and should be done by a formally trained physician or at a major academic or clinical center with a neuromuscular specialist. If the results point to demyelination of the nerves, this shortens the list of things it could be to diseases such as chronic inflammatory demyelinating polyneuropathy and all of its variants. Also There are diseases that are linked genetically to HNPP like Charcot Marie Tooth which may be what your doc was talking about?? That's a hereditary neuropathy that can be checked for in the blood and on EMG.  This and HNPP are linked to Chr 17. The test may not be 100%, but in patients that I suspect these diseases, it's worth checking.

As you are "not happy just waiting" I recommend a second opinion by a neuromuscular specialist. If you are nearby, Drs. SHields and Levin are excellent specialists here at the clinic who will be happy to see you. GOod luck,.