AANEM Connect

Hello all, I am hoping for some help with diagnosis and management from people much smarter than I am with this complicated (and long) EMG/NCS and case I encountered recently.  The background is a 57 year old patient who had started lamotrigine for mood related issues.  After about 2 weeks she developed diffuse hives for 4-5 days.  She stopped the lamotrigine and used diphenhydramine and topical creams for treatment.  She then woke up one day with trouble using her hands a day or two after the hives resolved.  She also reported numbness in her hands.  She had bad pain in her shoulders and upper back.  The pain lasted about 2 weeks.  She had Xrays of her cervical spine that showed mild degenerative changes.  EMG/NCS performed prior to formal neurological consultation and about 2.5 weeks after onset of the weakness showed normal sensory responses in the bilateral median, ulnar, and radial nerves, and reduced amplitudes of the bilateral median and ulnar motor responses (right median 2.1 mV, left median 1.7 mV, right ulnar 2.1 mV, left ulnar 1.4 mV) and right radial (2.5 mV) without evidence of conduction block or LEMS and with normal distal latencies and conduction velocities.  Left peroneal motor response was normal (latency of 4.5 ms and amplitude 4.7 mV).  Needle exam showed a few fibs and PSWs in the bilateral FDIs and the left pronator teres.  Reduced recruitment of normal units was found in the bilateral FDI, FPL, PT, EDC, and left EIP and right APB, with normal proximal muscles and paraspinals.  Neuro consult performed the next day confirmed the history of an abrupt onset of symptoms (no weakness prior to the lamotrigine and hives) and found 4/5 strength in the bilateral triceps, deltoids, wrist flexion, wrist extension, 3/5 in bilateral finger abduction and flexion and 4+/5 in bilateral finger extension.  Reflexes were normal throughout.  Sensory exam revealed patchy decrease in temperature in the distal forearms and hands symmetrically with normal modalities otherwise.  She was started on a 10 day tapering course of prednisone (60 mg for 5 days then quick taper).  MRI cervical spine and brachial plexus ordered and performed about 4-5 weeks after symptom onset.  These showed T2/STIR hyperintensity in the bilateral T1 and possibly right C7 without clear enhancement (though post contrast images were degraded by artifact).  MRI C spine showed multilevel degenerative disc disease, C5-6 canal stenosis without cord compression and patchy T2 hyperintensity at C5-6 possibly extending to C6-7 without enhancement - radiologist opined that this could be from remote trauma from a disc herniation that resolved or from demyelination.  Lab testing was unremarkable (HIV, SPEP, immunofixation, Sjogren's antibodies, ACE, light chains, celiac panel, B1, ESR, CRP, TSH, B12, CMP - ANA or ANCA were not sent). Lumbar puncture then performed - WBC -2, RBC-21, no differential performed, protein 36.5, glucose 71, negative HSV and CMV and negative gram stain and culture, oligoclonal bands were not sent.  Repeat EMG/NCS performed 8 weeks after initial test (patient reported maybe very minimal improvement in subjective numbness and weakness in the right hand though exam showed no changes) showed again normal sensory responses in the arms bilaterally, left median motor amplitude 3.1 mV, right median 1.5 mV, with normal distal latencies (less than 4.4 ms), left ulnar 1.9 mV and right ulnar 3.5 mV (with minimally prolonged distal latencies 3.5-3.7 ms) and left radial 3.3 mV and right radial 3.7 mV (normal distal latencies 2.7 ms) with no evidence of conduction block or LEMS.  Needle exam showed more insertional and spontaenous activity with expected neuropathic changes (larger units with polyphasia and increased duration) in the motor units in the bilateral FDI, EIP and pronator teres.  Proximal muscles were normal.  Repeat MRI brachial plexus is pending.  I am sorry for the long presentation but this is complicated and I wanted to present as clear a picture as I could.  Thank you!