AANEM Connect

Good afternoon,

I'm interested in hearing others' thoughts on this case I have.

25yoM with severe back injury while lifting a heavy object in August but with worsening weakness and clumsiness in his legs thereafter. Exam with preserved reflexes except absent achilles and reduced patellars. 2/5 ankle dorsiflexion, otherwise 4- great toe extension 4+ knee flexion and 5s elsewhere. Romberg with step off and decreased proprioception in toes and patchy temp/LT loss in legs. Normal MRI L-spine x2. I did an EMG/NCS 1 month after injury and found (abnormals bolded):

LUE:

- Median digit 2 SNAP latency 3.9 amplitude 5.2, motor distal latency 5.2, amplitude 8.1

- Ulnar digit 5 SNAP latency 3.9, amplitude 4.6, motor CV 24 across elbow, amplitude 11.6 distally

- Radial SNAP latency 2.6, amplitude 11.6

LLE:

- Sural latency 4.7, amplitude 4.4

- Superficial peroneal latency 3.8, amplitude 6.3

- Peroneal - EDB distal latency 8.0, amplitude 2.6, distal segment CV 34, across fibular head 42

- Tibial AH distal latency 6.7, amplitude 2.8

RLE

- Sural peak latency 5.3, amplitude 5.9

- R superficial peroneal latency 4.2, amplitude 6.6

- R peroneal - EDB latency 7.3, amplitude 1.2, distal segment CV 37, across fibular head 46

- R tibial - AH latency 7.5, ampliotude 1.9, NR at popliteal fossa

I (regretably but due to time constraints did not do any F-waves or H-reflex)

EMG

- L FCR 1+ fibs/positives, 1+ amplitude

- L APB 1+ fibs/positives

- L tib ant 2+ fibs/positive, 2+ amplitude/duration, reduced recruitmet

- L gastroc medial head 2+ fibs/positives, 1+ amplitude/duration

- R tib and 2+ fibs/positives, 1+ amp/duration

- R gastroc medial 2+ fibs/positives, 1+ amp/duration

- Normal: L delt, L biceps, L triceps, L FDI, L vastus, L EIP, R vastus, R lumbar paraspinals

At this point I was concered about a mixed polyneuropathy but also noted the severe ulnar at the elbow and median at the wrist (FCR spontaneous noted...) and sent genetics for HNPP. No M-spike, B12 238 (started supplementation), TSH >16 (started thyroid replacement), A1c 5%.

He deteriorated and became wheelchair bound with 2/5 dorsiflexion, inversion/eversion, and some scattered weakness elsewhere. Reflexes went away even in the uppers. I did an LP and whites were 9 with protein 150-170. Admitted for IVIG 2g/kg. Second outpatient IVIG 1g/kg reflexes returned but strength remained the same, L leg slightly worsening (dorsiflexion/inversion/eversion 1/5).

Genetics returned HNPP positive for heterozygous PMP22 deletion.

So now here I am left with a variety of questions, and I'm wondering the thoughts of the community. Does he have CIDP? There are some arguments for this, but it isn't clean. Could this be a nodopathy justifying Ritux? I'm gearing up to send for the antibodies but haven't pulled the trigger yet. Could this all be HNPP? It seems unlikely, but so is HNPP + an acquired mixed polyneuropathy. It's almost as if the arms look like HNPP and the legs look like an acquired polyneuropathy (maybe DADS-I looking at L peroneal EDB and R sural, but I can't ignore the axon loss).

I will also repeat the EMG after his next dose of IVIG.

Thanks for any thoughts on this complex case!