Odd EMG findings

[PMR 4 MSK]

81 yo female, fell 2.5 months ago, Fx C1 without paralysis, in a halo, Fx left distal radius, treated with casting. post-casting pt c/o burning pain in hand, indicates middle fingers more than the rest, but all involved, up to mid-forearm. referred for EMG.

Strength and reflexes normal throughout BUEs, sensation reduced throughout the whole left hand. Hoffman's negative.

NCV shows left median motor with amplitude around 3 (nl >5) with normal distal onset, reduced NCV in the forearm around 46, normal in the upper arm 54.

Left ulnar motor shows normal onset, normal amplitude, slow NCV in the forearm around 48, normal across the elbow 56.

Right median motor normal distal onset and amplitude, slow NCV forearm 48.

F-waves normal bilateral median, slightly delayed left ulnar.

Left median sensory absent, left ulnar and right median sensories show normal onset, amplitude and NCV.

Needle of the left arm shows CRD's in the biceps and pronator teres - ssustained at about 100Hz or so, not diffuse throughout the muscles - more patchy. Otherwise needle exam benign including deltoid, triceps, FDIM and APB.

I could not do parapspinals due to the halo. I didn't do more due to Medicare restrictions.

My thought is of a polyneuropathy, mild, axonal type with a possible left C6 (vs 7?) radic. But the needle is not conclusive enough. Could a partial central-cord syndrome do this? Any thoughts appreciated.

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[SSdoc33]

81 yo female, fell 2.5 months ago, Fx C1 without paralysis, in a halo, Fx left distal radius, treated with casting. post-casting pt c/o burning pain in hand, indicates middle fingers more than the rest, but all involved, up to mid-forearm. referred for EMG.

Strength and reflexes normal throughout BUEs, sensation reduced throughout the whole left hand. Hoffman's negative.

NCV shows left median motor with amplitude around 3 (nl >5) with normal distal onset, reduced NCV in the forearm around 46, normal in the upper arm 54.

Left ulnar motor shows normal onset, normal amplitude, slow NCV in the forearm around 48, normal across the elbow 56.

Right median motor normal distal onset and amplitude, slow NCV forearm 48.

F-waves normal bilateral median, slightly delayed left ulnar.

Left median sensory absent, left ulnar and right median sensories show normal onset, amplitude and NCV.

Needle of the left arm shows CRD's in the biceps and pronator teres - ssustained at about 100Hz or so, not diffuse throughout the muscles - more patchy. Otherwise needle exam benign including deltoid, triceps, FDIM and APB.

I could not do parapspinals due to the halo. I didn't do more due to Medicare restrictions.

My thought is of a polyneuropathy, mild, axonal type with a possible left C6 (vs 7?) radic. But the needle is not conclusive enough. Could a partial central-cord syndrome do this? Any thoughts appreciated.

those ARE strange findings. doesnt seem to fit perfectly. my though tis that this isnt like a perfect picture that you'd see in a textbook or in an exam.

central cord should not show up with the needle findings peripherally. CRDs imply a chronic nerve injury, and it would be a bit strange to see only those needle findings without PSWs or fibs at 2.5 months. those may have been there and have nothing to do with her injury. she is 81, and may have chronic radiculopathy / cervical stenosis with those findings.

her absent median sensory and decreased ampitude median motor make me think that is a local phenomenon rom her wrist fracture.

f-waves make a plexopathy unlikely, but i guess you cant rule it out completely without the paraspinals.

bottom line is that the CRDs could be a zebra and throw you off. a C6 radic would have a normal median sensory NCS, so the CTS must be real and not part of the radic picture.

 

[Ludicolo]

I think you may have several things going on. Agree it is difficult to lump all of the EDX findings into a common disorder. A pure central cord lesion wouldn’t show anything on EMG, but it is a good thought with regards to her history and symptoms.

The slowing of CVs in the left forearm, coupled with the left median motor and sensory changes, (note normal median motor distal latency), could be consistent with a mixed neurapraxic/axonal median and ulnar injury in the forearm. Possibly related to her casting. I don’t think it represents CTS per se, since the median motor distal latency is normal. With a dropped median sensory response, you would expect to see at least a prolonged motor DL in a severe median neuropathy at the wrist.

The CRDs in the left biceps and PT, the slowness in the right median motor study…not sure. She might have a cervical polyradic, as could be seen in cervical stenosis. She might have a polyneuropathy (don’t know what her lower extremity exam/findings are) with an old left C6 radic. There is probably something else going on, which begs the question – why did she fall in the first place?

 

[PMR 4 MSK]

why did she fall in the first place?

She says her walker got caught at the edge b/w bare floor and carpet - but she fell backwards.