Ep156 ED Approach to Acute Motor Weakness

Whenever I pick up a patient in the ED, I’m always delighted to see the chief complaint of weakness. It’s almost as exciting as the chief complaint of dizziness; but not quite as exhilarating as the chief complaint of “weak and dizzy”. In this Part 1 of of our 2 part podcast on weakness, Episode 156 - Approach to Acute Motor Weakness, with the help of EM physician Dr. George Porfiris, the winner of many teaching awards and Dr. Roy Baskind, neurologist at North York General, creator of a brand-new neuro podcast The Encephalopod, we turn the assessment of the weak patient into a satisfying, frustration-free, experience for you by laying out a simple approach and feeding you the key clinical pearls that will help you clinch the diagnosis. This is not about generalized malaise or fatigue from dehydration or anemia or sepsis. This is not about hypoglycemia, polypharmacy, or medication side effects. This is not about the details of stroke, traumatic spinal cord injuries or chronic neurodegenerative disorders, all of which can present with the chief complaint of weakness. What we do in this podcast is throw out the word “weakness” and instead, zero in on the specific symptoms of loss of true neuromuscular strength. We dig into the patterns of decreased true neuromuscular strength and how they can narrow our differential. We discuss some key associated symptoms that will narrow our differential even further. We simplify the distinction between UMN and LMN and see how that can narrow our differential even further. And in the next part of this two part podcast we review the key features of the most emergent muscle weakness diagnoses we need to act on in the ED... Podcast production, sound design & editing by Anton Helman, voice editing by Raymond Cho, sound design by Yuang Chen Written Summary and blog post by Priyank Bhatnagar & Saswata Deb, edited by Anton Helman May, 2021 Cite this podcast as: Helman, A. Porfiris, G. Baskind, R. Episode 156-Acute Weakness. Emergency Medicine Cases. May, 2021. https://emergencymedicinecases.com/acuteweakness. Accessed [date] Go to part 2 of this 2-part podcast on acute motor weakness Recognition and management of respiratory failure associated with neuromuscular disease Tachypnea is a sign of impending respiratory compromise in the patient with neuromuscular disease Patients with neuromuscular disease are at particularly high risk of respiratory failure, given the propensity for altered mental status and diaphragmatic and/or accessory respiratory muscle weakness. Tachypnea often presents sooner than, and may herald other signs of, impending respiratory failure. It is prudent for the ED physician to look for the following when assessing the airway status of patient with motor power loss: * Abnormal or poor mentation * Difficulty with speech or weak voice * Drooling or other indication of difficulty handling secretions * Inability or difficulty lifting their head off the stretcher * Weak, rapid, or shallow breaths or use of accessory muscles Pitfall: A common pitfall is to assume that the cause of tachypnea in a patient with suspected neuromuscular disorder with a normal oxygen saturation is due to acidemia only. Tachypnea is often a sign of impending respiratory compromise in these patients due to neuromuscular compromise that may require a definitive airway. When to intubate the patient with suspected neuromuscular disease: Neck flexor weakness and the “20/30/40 rule” In addition to tachypnea, impending respiratory compromise can be heralded by decreased neck flexion strength, as it has shared innervation with the diaphragm.