Confusing case - help??

[SSdoc33]

45 y/o guy, healthy, referred by ortho b/c he cant lift his right arm. this has been going on for 5 years. right shoulder MRI is fine, neck MRI is fine. he also has mild parethesias that he complains about in both hands and very mild in right foot. he has visible fasciculations in right deltoid. clear weakness in abduciton and flexion on right. weak reflexes.

NCS:
bilateral sensory median and radial are absent. ulnars are slow and relatively large for some reason.

MABC normal on right absent on left
LABC normal on left absent on right

motor NCS in UE generally show decet response proximally, but i have trouble finding the more proximal response with some temporal dispersion.

absent RLE sural, tibial motor is fine with ankle stim, but cant get a good pop fossa stim

EMG:
RUE shows big (but not giant) units with polyphasia in deltoid and biceps, and to a lesser extent in most other RUE muscles. there is also some polyphasia in LUE, and tiny bit in some RLE muscles. there is no active denervation anywhere or CRDs. the fasciculations look like a polyphasic unit on needle testing.

ok, what the #$@!$ does this guy have? i dont see any unifying entity or diagnosis here. i suppose he could have some strange peripheral neuropathy, but his presentation is a bit peculiar. also, the sensory findings point away from a strict motor neuron disease. his findings are bilateral and diffuse, so plexopathy seems unlikely. i trust my NCS findings, but something here is askew. dont really know what to do with him. he saw a neurologist about 3 years ago who didnt do much for him either.

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[RUOkie]

Correct me if I misread this, his NCS reveal an assymetric demyelinating polyneuropathy, but the EMG shows polyphasia and chronic denervation changes. You are right, he has something bad. Get a detailed family history (HSMN?) This website http://neuromuscular.wustl.edu/naltbrain.html is a really good resourse

1) Repeat his study and check his BLE and needle A LOT of muscles. Make sure to check thoracic paraspinals and cranial innervated muscles.

2) Do the polyneuropathy lab work with attention towards the rheumatologic stuff. If his ESR is even slightly high, and the redo EDX don't suggest motor neuron disease (the sensory's make that unlikely), then he needs a biopsy to r/o neural vasculitis (mononeuritis multiplex).

3) I don't know where you are, but since the patholgists in my area are so unreliable with nerve biopsies, I send all my nerve biopsies to either the Neuromuscular Center at Washington University, Mayo (MN), or Baylor Neurology (yes, the neurolgists!). If you get it done locally, talk to the patholgist first so that your surgeon preps the tissue properly.

Once you figure it out (or better yet, AS you work him up) keep us apprised.

 

[Ludicolo]

Cool case.

Your asymmetric antebrachial findings scream mononeuritis multiplex.

Your temporal dispersion, conduction block w/ the tibial motor study suggest an acquired demyelinating process, like CIDP.

Look up MADSAM

 

[SSdoc33]

no relevant family history. forgot to mention that he has been having some mild eyelid fasciculations, but no droopy/myasthenia eyes.

i agree with the continued work up with labs, etc.

but when, if ever does something like CIDP present with unilateral shoulder weakness?

some rhematologic nonsense like mononeuritis multiplex does make sense. ill do some digging. fasciculations with mononeuritis multiplex?

what do you guys make of the large amplitude and slow ulnar findings? he was plenty warm

 

[RUOkie]

The very first EMG I did after residency was "r/o tarsal tunnel" from a local ortho doc. 31y/o F with foot numbness. Unfortunately she had a footdrop when she walked into my office. Her EMG showed a mononeuritis multiplex and her labs were normal. Her biopsy showed vasculitis.

On further questioning, I discovered that she had finished 3 days of predinisone for an asthma attack the day before her EMG (which was why her sed rate was normal) On recheck, the sed rate was 210!

 

[PMR 4 MSK]

possible old polymyositis?

 

[Ludicolo]

possible old polymyositis?

That wouldn’t explain the SNAP abnormalities, the temporal dispersion, etc.

SS – I wouldn’t put too much stock in the fascics. They’re a relatively nonspecific finding. If this is something like mononeruitis multiplex, the “large” ulnar sensory responses are probably what he runs normally, i.e. these nerves haven’t been as affected by the disease process. In CIDP variants like MADSAM you can definitely see asymmetric weakness, mimicking a plexopathy. In addition to the rheum w/u, getting a dedicated brachial plexus MRI for this guy wouldn’t be uncalled for. He could always have more than one thing going on.

 

[drusso]

Multifocal motor neuropathy with conduction block? Could check anti-GM1 antibodies.

 

[SSdoc33]

Multifocal motor neuropathy with conduction block? Could check anti-GM1 antibodies.

thought about motor neuron disease, but there were definitely sensory abnormalities. no median or radial SNAPs on either side.

ill run the blood tests, but im not keeping my hopes up. i may try to find a good neurologist, and think about an LP, but i may no tbe able to get a great diagnosis here. frustrating.

im also not sure how far i want to push this. he doesnt have ANY pain, and his condition has been static for almost five years. i might continue the work up if things progress.

 

[latinman]

Please keep us posted. This is an interesting case. I will try to share some of the cool stuff I have also encountered.