1/ #COVID19 Thread: my first case of acute #Hydroxychloroquine intoxication. How do you manage it? Here is what I learned and useful resources I would like to share for your next case, as this presentation may become common. Many thanks to Dr. @PeterRchai for your teaching!
2/ 30yo pt, 12 hrs s/p taking unknown amount #Hydroxychloroquine. Vitals stable. Exam: alert/oriented, but new significant muscle fatigue in upper/lower extremities. CXR wnl. EKG n/f HR 60, QRS 135, QTc 700, NSVT on tele. Labs wnl but K 2.0, Phos 0.6, lactate 3.3, fibrinogen 178.
3/ #Hydroxychloroquine: Na-channel blocker w quinidine-like action. Toxicity onset within 30 min, w risk of: 1) negative chronotropy, 2) wide QRS 3) QT prolongation 4) hypoKalemia 5) Seizures. Avoid treating symptoms w other Na-channel blockers, like lidocaine, keppra, phenytoin.
4/ #Hydroxychloroquine cannot be dialyzed. Consider activated charcoal if ingestion <1 hr ago, otherwise balance risk/benefit of compromising PO route of K, Phos and other electrolyte repletion. While IV repletion possible, speed of repletion may be faster using both routes.
5/ AB-(C): Given myopathy & seizure risk, pt was intubated for airway protection. No common pulmonary toxicity w #Hydroxychloroquine, so ventilation/oxygenation should be easy. But given bicarb drip for wide QRS, monitor hyperventilation-> mixed alkalosis will drive K into cells.
6/ (AB)-C: Hypotension DDx: expect multifactorial mechanism A) distributive from direct #Hydroxychloroquine -induced vasodilation; B) inappropriate bradycardia from negative inotropic effect C) cardiogenic from cardiotox/myopathy. Epinephrine first line for toxicity c/b shock.
7/ Cardiotoxicity. Toxicology recs: IV diazepam drip/bolus (? antiarrhythmic reversal of QTc prolongation), expect polymorphic VT: epinephrine first line (⬆️HR & ⬇️ cardiotox) vs overdrive pacing. Add IV Bicarb drip to narrow QRS, goal <100 ms. If no effect in 1-2 hrs, stop drip.
8/ CNS toxicity: IV diazepam drip/bolus as above, first line given central antagonist and anticonvulsant effect. Ok to add propofol/fentanyl while intubated to further ⬇️ seizure & VT risk. if breakthrough seizure, discuss w Toxicology as a second benzo may be added on top.
9/ Hypokalemia. Mechanism is key: #Hydroxychloroquine causes intracellular shift of K. Replete cautiously and monitor acid/base: as toxicity usually resolves within 24 hours, expect rebound extracellular shift and HYPER kalemia risk. In our case, also replete concurrent low Phos.
10/ Most well-known #Hydroxychloroquine complication from chronic therapy is ophthalmologic toxicity. As a curbside, we learned there is low risk/need for ophthalmologic intervention in the setting of acute toxicity. Any other thoughts @ldallmd?
11/ Hope we will not see many cases of #Hydroxychloroquine toxicity, but if we do, I found this resource very helpful: tinyurl.com. Other thoughts #medtwitter @PeterRchai @WalkerReddMD
@BrighamChiefs @MedTweetorials @runthelistpod @thecurbsiders @Brief_19 @CPSolvers?
@BrighamChiefs @MedTweetorials @runthelistpod @thecurbsiders @Brief_19 @CPSolvers?
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