CD DR. CHINTAN DAVE CLINICAL EP 25

@drchintandave

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Why it worked

The content provides a clear, structured, and educational case study on a critical medical condition, using a visually engaging slideshow format. It breaks down complex information into digestible points, making it highly valuable for medical professionals and students.

Summary

This is a medical case challenge presented in a slideshow format, detailing a patient with dyspnea and discussing the diagnosis of myasthenic crisis. It explains the key physiological principles, diagnostic rules, and treatment considerations for neuromuscular respiratory failure.

Structure

1Case presentation: Would you intubate her?
2Six non-pulmonary findings suggesting a diagnosis
3Diagnosis: Myasthenic crisis and its features
4Physiology: Ventilation failure precedes oxygenation failure
5Key Principle: The 20/30/40 rule for respiratory pump failure
6Why saturation misleading: Oximeter measures lung, not pump
7Bulbar weakness as an airway problem
8Drugs that can unmask myasthenia

Original caption

The most common feedback I get is that answers to my case challenges are not easy to find. So for every new case challenge, I will create a carousel explaining the core physiology and teaching points. This case wasn't about the nurse vs resident. They were both looking at the same patient but saw different physiology. The case and your clinical reasoning only makes sense once you line up all the findings and actually reason over them. Neuromuscular Resp failure is often missed because it's a silent resp failure, ie. you don't get the overt resp distress and abdominal paradoxical breathing you typically get, so it's important to look for other signs- outlined in this post. Save for the next time you're seeing a Myasthenia patient! One question for my followers: Is the content in this carousel too dense or too much? I cover a lot of things, would you prefer multiple posts with more bite-sized pearls or longer, denser pearls which you can save as a one-stop-shop for that condition/case/physiology! I'd appreciate your feedback :) #icu #criticalcare #foamed #medicaleducation #doctor

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CD DR. CHINTAN DAVE CLINICAL EP 25 BEDSIDE PHYSIOLOGY CASE CHALLENGE - 61F, THREE DAYS OF DYSPNEA Would you intubate her? Lungs clear. Chest Xray clean. She is saturating 97% and she cannot hold her head off the pillow. SpO2 97% pCO2 58 FVC 1.1 L NIF -24 @DRCHINTANDAVE SWIPE → 02/14 CD DR. CHINTAN DAVE WHAT THE BEDSIDE GAVE YOU Six findings, none of them pulmonary VOICE Soft, fading through the afternoon EYES Heavy lids, diplopia by evening COUNT TEST Reaches 12 in a single breath SWALLOW Coughs on water, repeated choking NECK Head off the pillow < 3 SECONDS TIMING "She always looks worse at night" Chest exam is clear. CXR shows only low lung volumes. VBG: pH 7.31, pCO2 58. @DRCHINTANDAVE SWIPE → 03/14 CD DR. CHINTAN DAVE ANSWER - D Myasthenic crisis Impending neuromuscular respiratory failure - a clinical diagnosis, not a test result. 01 Fatigable ptosis and diplopia, worse at night 02 Bulbar failure: choking, weak voice, secretions 03 pCO2 58 behind a normal pulse oximeter 04 Ciprofloxacin and magnesium, both triggers 05 Neurology referral pending for droopy eyelids @DRCHINTANDAVE SWIPE → 04/14 CD DR. CHINTAN DAVE THE PHYSIOLOGY Ventilation fails first Oxygenation is a membrane problem. Her membrane is fine. Ventilation is a muscle problem. Her muscles are failing. So CO2 rises for hours while the sat reads 97%. Hypoxemia is the last thing to go wrong! @DRCHINTANDAVE SWIPE → 05/14 CD DR. CHINTAN DAVE KEY PRINCIPLE The 20/30/40 rule Three bedside thresholds that say the respiratory pump is failing, long before the saturation moves. 20 FVC below 20 mL/kg Vital capacity - the volume she can still move 30 NIF weaker than -30 cmH₂O Inspiratory strength - the muscle that fills the lung 40 PEMax below 40 cmH₂O Expiratory strength - the cough that clears secretions She breaches the first two, and PEMax was never checked. A single effort-dependent value proves nothing - trend them frequently (q1h or q2h). @DRCHINTANDAVE SWIPE → 06/14 CD DR. CHINTAN DAVE WHY THE SAT MISLEADS The oximeter measures the lung, not the pump Supplemental oxygen holds the saturation up while tidal volume quietly falls. CO2 retention is the first measurable failure and it needs a blood gas to see. By the time she desaturates, the reserve is already gone. TELLS YOU LITTLE SpO2, oxygen requirement, chest film TELLS YOU EVERYTHING pCO2, single-breath count, neck flexion, secretions @DRCHINTANDAVE SWIPE → 07/14 CD DR. CHINTAN DAVE BULBAR WEAKNESS A swallowing problem is an airway problem SECRETIONS She can no longer clear what she makes. COUGH Expiratory muscle weakness makes it useless. VOICE A weakening voice is a weakening airway. CONSEQUENCE Aspiration arrives before fatigue does. Bulbar failure alone justifies intubation, whatever the respiratory numbers say. @DRCHINTANDAVE SWIPE → 08/14 CD DR. CHINTAN DAVE SHE WAS GIVEN BOTH Drugs that unmask myasthenia FLUOROQUINOLONES Ciprofloxacin - started 5 days ago for UTI MAGNESIUM IV in the ER for presumed bronchospasm MACROLIDES Azithromycin, erythromycin AMINOGLYCOSIDES Gentamicin, tobramycin BETA-BLOCKERS Including topical ophthalmic drops NM BLOCKERS Profound, prolonged sensitivity @DRCHINTANDAVE SWIPE → 09/14 CD DR. CHINTAN DAVE THE DECISION BiPAP or intubate? BiPAP MAY BUY TIME Early hypercapnia, intact bulbar function, protected airway, a reversible trigger already being treated, and a nurse at the bedside. INTUBATE HER Bulbar failure with aspiration, secretions she can't clear, a voice still fading, neck flexor weakness, and deterioration over hours. She has every feature in the right-hand column. A controlled ICU intubation beats a crash airway on the ward, every time. Avoid depolarising and non-depolarising agents where you can; if you paralyse, expect an exaggerated and prolonged response. @DRCHINTANDAVE SWIPE → 10/14 CD DR. CHINTAN DAVE ONCE THE AIRWAY IS SECURED Treating the crisis 01 Find the trigger. Infection is the commonest; drugs are the most missed. 02 IVIG 2 g/kg over 2-5 days, or plasma exchange. Comparable efficacy - choose on severity, access and comorbidity. 03 Hold pyridostigmine in most intubated patients - it floods the airway with secretions. Restart as mechanics recover. 04 Start corticosteroids once support is in place, expecting transient early worsening. 05 Extubate on mechanics and secretion control, not on gas exchange alone. @DRCHINTANDAVE SWIPE → 11/14 CD DR. CHINTAN DAVE THE ICU MISTAKE Watching her overnight Serial numbers get checked once a shift instead of every few hours. A poor-effort NIF gets recorded as reassurance. Sedatives and opioids are given to a patient with no reserve. The team waits for a saturation that only falls at the very end. Every one of these turns a planned intubation into a peri-arrest airway at 3am. @DRCHINTANDAVE SWIPE → 12/14 CD DR. CHINTAN DAVE TAKE THIS TO THE BEDSIDE In neuromuscular disease, never ask how well the lungs are oxygenating. Ask how much longer the muscles can keep working. Myasthenia, Guillain-Barré, ALS, brainstem disease - the question is the same, and it is answered at the bedside. @DRCHINTANDAVE SWIPE → 13/14 CD DR. CHINTAN DAVE EVIDENCE Where this comes from 01 Narayanswami P, Sanders DB, et al. International consensus guidance for management of myasthenia gravis: 2020 update. Neurology. 2021. 02 Wendell LC, Levine JM. Myasthenic crisis. The Neurohospitalist. 2011. 03 Damian MS, Widjicks EFM. The clinical management of neuromuscular disorders in intensive care. Neuromuscular Disorders. 2019. 04 Rabinstein AA, Widjicks EFM. Warning signs of imminent respiratory failure in neurological patients. Seminars in Neurology. 2003. 05 Gajdos P, Chevret S, Toyka KV. Plasma exchange for generalised Myasthenia gravis. Cochrane Database of Systematic Reviews. 2002. 06 Sheikh S, Alvi U, Soliven B, Rezania K. Drugs that induce or cause deterioration of myasthenia gravis. Journal of Clinical Medicine. 2021. @DRCHINTANDAVE SWIPE → 14/14 CD DR. CHINTAN DAVE TAKE-HOME Ask how long the muscles can keep working That question is the difference between a planned intubation and an arrest. SAVE THIS SHARE WITH YOUR TEAM FOLLOW @DRCHINTANDAVE BEDSIDE PHYSIOLOGY EP 25 EDUCATIONAL ONLY, NOT MEDICAL ADVICE @DRCHINTANDAVE