This block they introduced something called neuroscience nights, which happens about once a week. It's mainly geared to those who want to learn about basic neuroscience research. We read several papers and have a discussion with an expert in the field. Last week, the neuroscience night was on channelopathies (specifically hypokalemic periodic paralysis). Channelopathies are a family of diseases caused by mutations in ion channel genes, such as myotonia, seizures, headaches, dyskinesia, episodic ataxia. This correlated well with my journal club presentation, since that, too, was a channelopathy. I think it's great that they encourage more learning about techniques of investigation, critical thinking, and basic science stuff.
(Image: Voltage gated sodium 1.4 channel, marked with mutation locations leading to channelopathies)
Hey.. the craziest thing!! my oral exam today (5/7) was a case on Hypokalemic Periodic Paralysis - I had read your blog earlier and wish I had put that as one of my DDx. My case was a 17 yo female with cc: sudden onset weakness overnight, to the point where she couldn't stand up. So at that point, my hypotheses were UMN (stroke, tumor, encephalitis) LMN (autoimmune polyneuropathy, MS, Guilliane-Barre), NMJ (botulism and MG) and Other (B12, hyperthyroidism, decreased perfusion and drugs).
ReplyDeleteAfter that, I got pg 2 of the exam which had her HPI - said she had these weakness episodes once or twice before. SH: child in foster care, no FH available, PE: nonremarkable vitals, HEENT, Chest, Heart, Ab, Skin exam. Neuro exam: MMS AxO3, CN nerves normal except some weakness in facial, tongue and neck muscles. Weak grip, arms and legs at 3+/5. Decreased reflexes but intact fine touch, vibration, propioception. Cognitive function “low normal.”
At that point, I ruled out UMN (no +Babinski, spasticity, or hyperreflexia). I ordered a CBC, met panel, and nerve conduction tests. I anticipated MG because of distal extremity involvement, and ordered empiric testing – physostigmine?. It turns out that "the chem machine was broken and met panel was unavailable, CBC unremarkable, and ECG shows a very small T wave with normal rate and rhythm." As I picked learning objectives, my examiner hinted that the broken chem machine and the “small T wave” are good leads to follow up on (which also implies that my MG hunch was off). When I went home, I googled for “T wave flattening” and “weakness” and the first thing I saw was Hypokalemic Periodic Paralysis!!! So yeah, this must be the answer to the case!!