Odd EMG findings.

[PMR 4 MSK]

Young guy, 23, in college, planning to be a professional musician, plays various stinged instruments many hours per day. 6 months to a year of hand cramping, UE variable pains and numbness forearms and hands. Seen by ortho hand surgeon first - opinion is no surgical cause, go see physiatry (smart doc!)

No injuries, no trauma, PMH - nothing. No meds, no allergies, no surgeries. FH neg for similar, just CAD in father. Non-drinker, smokes 1/3 ppd. ROS otherwise normal.

PE on initial presentation 6 months ago - normal cervical exam - full pain-free ROM, non tender, neg spurlings. Normal strength all myotomes, normal reflexes - biceps, triceps and brachirad. No sensory impairment to touch, just feelings of intermitten paresthesias. Tinel's negative at wrists and elbows, Phalen's mildly positive on the left. Tests for epicondylitis normal. Arms non tender, all joints full pain-free ROM. Nothing else focal. Shoulder exams benign as well. He has fine intention tremor bilat hands, not facial or tongue tremors or fasics. Pt mildly anxious, slightly odd affect, but hey, he's an artist.

No improvement with PT, NSAID's or gabapentin to 1800 mg/d. MRI C-spine shows congenital slender canal, mild DDD at C5-6, slight uncovertebral hypertrophy on the left at C5-6 and C6-7, otherwise normal.

I do an EMG about 4 months ago - Median motors and sensories normal through the axilla. Ulnar motors and sensories show mild delays across the elbows - about 47 m/s vs 58 and 61 in forearms for motors, 50 and 52 m/s for sensories across the elbows vs 69 and 62 in the forearms. Radial SNAPs normal. Needle of bilat Delt, Tric, Bic, PT, FDIM and APB's mostly normal, except I note some fasiculations in his right deltoid - just on needle, not visible. I felt he had borderline criteria for cubital tunnel syndrome.

We tried some more PT and Lyrica, still no better. For the hell of it, we inject one of his cubital tunnels - no better. He goes away for a couple months, then comes back 3 weeks ago, with new onset weakness - cant fully extend middle and ring fingers. I recommend we do a more detailed EMG, this time looking at radials. He goes for a second opinion, that doc (also PM&R, in another town, don't know him) agrees with me, and he comes in today for the second EMG.

I do his radials, picking up the EIP with needle in the muscle, stimulating 8 cm prox, antecubital fossa, below spiral groove, above it and Erb's. All latencies, NCVs and amplitudes WNL. I also put the needle in the EDC and stim AC fossa and Below SG, also appear normal.

However, as I'm needling the left EDC, trying to seperate out the digits, I notice some PSWs here and there. Then in the ECU I see one of the most bizzare CRDs I've ever seen - going at about 20 Hz, polyphasic potential (8 - 10 turns), with a leading motor unit that waxes and wanes in size like a common dive bomber, but the polyphasic part doesn't wax or wane - sustained for > 30 seconds. I found it several times in the muscle. Normal MUAP activation otherwise. I find PSWs and some fibs also in the EIP, ECU, deltoid, tricep and a litttle in the bicep, nothing in the forearm flexors or hand (APB, FDIM, ADM). Right side is similar, except no CRD's - just PSWs and fibs in Delt, tric and bic, as well as several of the extensors. All activation patterns are normal. Some increased insertional activity her and ther to complement the PSWs and fibs.

So I get a little more creative and do NCV of proximal muscles - stim Erb's and pickup from Delt, Bic, Tric and Supraspinatus - all amplitudes and latecies normal and similar bilaterally. Cervical paraspinals were normal.

At this point I had to stop, or I was going to give the poor guy an MI - he was having a lot of pain at the end. He took it like a trooper but it was a lot for him.

I'm ordering MRI brain and bilateral brachial plexuses (plexi?). What do you think? Prolonged, slowly developing Parsonage-Turner? Proximal variant of
GBS? MS vs ALS? TOS? Any recs for further W/U. He had some labs by his PCP a few months ago - normal CBC, CMP, TSH.

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[SSdoc33]

Thats a doozy. What strikes me is that needle EMG was essentially normal the first time, then 4 months later has all of these changes. Distribution of findings leads to Dx of a plexopathy b/c there are too many changes in different myotomes and nerves to be a single radic of entrapment.

I have to believe that the music and his posture while playing are the culprit. TOS is a good thought, but you'd think that'd effect mainly the lower trunk / cord. it may be a bit late for this, but sensory studies of the MABC and LABC may belp in pinpointing exactly where the problem is. A sustained scalene contraction for hours a day while playing may be enough to pinch the nerves in the brachial plexus as they filter out into the arm. parsonage turner seems like a long shot, as does MRI of the contralateral plexus and brain. let us know how it turns out.

 

[caedmon]

There was a presentation at the AAPM&R this past fall of a patient who was an athlete who while weight training would get intermittent hand numbness/weakness etc. (dont' remember all the details), but was found to have a chronic exertional compartment syndrome of the flexor compartment- apparently no other cases in the literature.

I guess there is a possibility of an extensor compartment syndrome. Although there are some changes more proximally, I'm not sure what EMG changes whould show, but I guess six hours of day of mad strumming may lead to some changes. Was he having symptoms in both hands or one moreso than the other. It wouls be interesting to know which hand plays where on the instrument. If all turns up negative, could try compartment pressure testing.

Probably unlikely, just some thoughts.

I guess other muscle diseases would be a consideration (paramyotonia).

 

[Myofascist]

The interesting thing is the normality of the NCS with so many findings on needle exam. This makes me think of a muscle problem. I wonder if the weakness in finger extension is actually stiffness and that this could be a myotonia (myotonic dystrophy type I or sodium channel myotonia congenita) with abnormalities typically seen in forearm extensors and normal CMAPs. Maybe checking a CK and muscle biopsy. Are the symptoms worsened with after music playing? Any frontal baldness?

 

[PMR 4 MSK]

intersting thought on myotonic dystrophy, but the hands were normal previously on EMG and it's pretty much universally a distal first problem - no myotonic patterns, except you could argue the CRD, but that was just one muscle. No clinical myotonia - can open an relax hands at will, but still a good thought - possible later than usualy presentation. No frontal baldness. No Hx of MD in the family.

While writing this last night I thought, "Damn! I shoulda done M&L ABCs."

 

[melancholy]

intersting thought on myotonic dystrophy, but the hands were normal previously on EMG and it's pretty much universally a distal first problem - no myotonic patterns, except you could argue the CRD, but that was just one muscle. No clinical myotonia - can open an relax hands at will, but still a good thought - possible later than usualy presentation. No frontal baldness. No Hx of MD in the family.

While writing this last night I thought, "Damn! I shoulda done M&L ABCs."

Cool case. Yeah, myotonics tend to have characteristic "look" and affect to them. Doesn't sound like MMD, however I agree with Myofascist that a CK would be useful to see if there is some myopathic or inflammatory component to this.

Was there any other change on the repeat physical examination other than weakness with extension of the 3rd and 4th digits?

Had the patient changed his activity level, style of playing, choice of instruments over the past year? (thinking of the scalenes mentioned by SSDoc33) I'd think with proper therapy sessions, there would possibly be some change for the better rather than his symptoms appearing to worsen. (Assuming he has been compliant with trying to adjust his lifestyle)

 

[PMR 4 MSK]

Cool case. Yeah, myotonics tend to have characteristic "look" and affect to them. Doesn't sound like MMD, however I agree with Myofascist that a CK would be useful to see if there is some myopathic or inflammatory component to this.

Was there any other change on the repeat physical examination other than weakness with extension of the 3rd and 4th digits?

Had the patient changed his activity level, style of playing, choice of instruments over the past year? (thinking of the scalenes mentioned by SSDoc33) I'd think with proper therapy sessions, there would possibly be some change for the better rather than his symptoms appearing to worsen. (Assuming he has been compliant with trying to adjust his lifestyle)

Actually, he's taken this semester off due to not being able to play long enough for classes. No other new symptoms except his hand tremors seem a little worse, but may just be anxiety.

 

[neglect]

Agree with plexus imaging, because hopefully that's it. On the second NCV were there any sensory abnormalities?

If not, then I agreee: it may be early ALS. I've only had one ALS patient (out of about 5 that I brought from history to EMG) who met EMG criteria for it. I find the exam more useful than the EMG for ALs, so obviously if he has reflexes in the arm with fibs, then it doesn't bode well.

This doesn't sound like a myopathy to me.

 

[drusso]

I'm ordering MRI brain and bilateral brachial plexuses (plexi?). What do you think? Prolonged, slowly developing Parsonage-Turner? Proximal variant of
GBS? MS vs ALS? TOS? Any recs for further W/U. He had some labs by his PCP a few months ago - normal CBC, CMP, TSH.

Did you get median and ulnar F-waves?

 

[PMR 4 MSK]

Did you get median and ulnar F-waves?

On the first EMG - F- waves all normal. All sensories normal too, except, as above, I did not test antebrachials.

 

[olafa]

Just to add more fuel to the fire, I wonder about the vascular component of his pathology.
Are certain postions exacerbating. With chonic positioning and overuse vasculular endofibrosis can occur causing ischemia to the distal areas from the occlussion. Can be difficult to diagnose and is inderdiagnosed in many athletes.
UE arteriogram - done in the exacerbating postion may help.

If is is vascular smoking definately doesn't help.
Any other elicit social habits that are common to many muscians?

 

[PMR 4 MSK]

Got the brain and brachial plexus MRI results today - all normal.

Hmmmmmmmmmmmmmmmmmm???????

Time to punt. I'm sending him for a neurologists opinion.

 

[aaddnl]

This is Parsonage-Turner syndrome. The neurologist will should confirm the diagnosis.

 

[Myofascist]

Parsonage-Turner???? Initial presentation of hand cramping for 6 mnths doesnt sound like Parsonage-Turner to me. And how is the Neurologist going to confirm it?

 

[aaddnl]

his initial presentation with hand cramping and arm paresthesias doesnt rule out parsonage-turner. these were probably early sx that may/may not have been related to his brachial plexitis. parsonage-turner comes on subacutely, so this is not inconsistent.

the age, sex, history of a job with constant arm and hand activity (classically a mechanic, but guitarist fits) and bilateral involvement, along w/ electrodiagnostic findings all fit very well with parsonage-turner, much better than any of those other diagnoses.

 

[neglect]

his initial presentation with hand cramping and arm paresthesias doesnt rule out parsonage-turner. these were probably early sx that may/may not have been related to his brachial plexitis. parsonage-turner comes on subacutely, so this is not inconsistent.

the age, sex, history of a job with constant arm and hand activity (classically a mechanic, but guitarist fits) and bilateral involvement, along w/ electrodiagnostic findings all fit very well with parsonage-turner, much better than any of those other diagnoses.

I agree. Because what else could it be? Paresthesias go strongly against ALS.

Did the plexus MRI get done with contrast?

 

[PMR 4 MSK]

I agree. Because what else could it be? Paresthesias go strongly against ALS.

Did the plexus MRI get done with contrast?

No, the radiologist didn't think that would help

 

[neglect]

No, the radiologist didn't think that would help

It sure would if the plexus enhances! Then plexitis is the dx and he would need treatment.

 

[aaddnl]

Got the brain and brachial plexus MRI results today - all normal.

Hmmmmmmmmmmmmmmmmmm???????

Time to punt. I'm sending him for a neurologists opinion.

sending him to a neurologist. (Smart Doc!)

parsonage-turner is the diagnosis. now he can be diagnosed and treated properly. orthopod should have sent him to a neurologist in the first place.

 

[aaddnl]

Parsonage-Turner???? Initial presentation of hand cramping for 6 mnths doesnt sound like Parsonage-Turner to me. And how is the Neurologist going to confirm it?

clinically, with the history and physical exam.

 

[PMR 4 MSK]

So I get the Neurologist's report today. She has no diagnosis yet, but wants to repeat the EMG. Can you say no trust?

 

[Myofascist]

sending him to a neurologist. (Smart Doc!)

parsonage-turner is the diagnosis. now he can be diagnosed and treated properly. orthopod should have sent him to a neurologist in the first place.

Wow, I hope you aren't as arrogant with your patients... Oh wait you're a neurologist, I forgot. Keep up the good diagnosing.

 

[neglect]

Wow, I hope you aren't as arrogant with your patients... Oh wait you're a neurologist, I forgot. Keep up the good diagnosing.

This case does have treatment if the diagnosis is brachial plexitis. It seems that perhaps this episode cannot be treated with steroids, but if he is diagnosed, then his nearly certain future episodes could be.

 

[PMR 4 MSK]

So I get the neurologist's EMG report back today - almost identical to mine, same basic numbers, same needle exam, same Dx distally - cubital tunnel syn. Also puts in diagnosis of "muopathy" although I'm guessing that should be myopathy. I didn't really think it was myopathic as the MUAPs were pretty normal and the recruitment pattern was normal.

I'll post more when I know more.

aaddnl - what an @$$hole!

 

[aaddnl]

ok