UMEM Educational Pearls

Question

 

A 27 year-old man with history of rheumatoid arthritis presents to the emergency department after ingestion of hydroxychloroquine (20 tablets of 200 mg/tablet). He complains of nausea/vomiting. He appears lethargic. What is the anticipated hydroxychloroquine toxicity and management?

VS: Temp: afebrile, BP: 95/55 mmHg, RR: 23 breaths/min, O2 saturation: 99%

ECG:

 

 

Answer

Signs and symptoms of hydroxychloroquine toxicity includes:

1. Cardiac: Na & K channel blockade, hypotension/shock, ventricular dysrhythmia
2. CNS: CNS depression, seizure
3. Electrolyte: hypokalemia

Patient’s initial ECG showed: QRS: 134 msec; QTc 710 msec. There is also a terminal R wave in aVR. no prior ECG was available.

He experienced intermittent non-sustained V tach.

K was 2.0 mmol/L. other laboratories were normal

 

Management/course:

ED/Hospital day 1:

• The patient was intubated due to lethargy/CNS depression
• NaHCO₃ bolus was administered with narrowing of QRS interval to 128 msec with QTc 639 msec. 
• NaHCO₃ infusion
• Diazepam 1 mg/kg (80 mg IV bolus plus intermittent IV bolus of 6 mg Q2 hrs [total 39 mg])
• Brief requirement of epinephrine infusion at  0.25 mcg/kg/min. 

Hospital day 2:

• QRS: 92 msec; QTc: 474 msec
• Blood pressure normalized

 

Summary

1. Cardiac toxicity (Na and K channel blockade) is the primary feature of hydroxychloroquine toxicity
2. ECG should be obtained to evaluated for evidence of Na channel toxicity – if present, administer NaHCO₃ IV bolus and continous infusion -- and QT prolongation.
3. High dose diazepam: 1-2 mg/kg IV bolus, followed by continous infusion of 1 – 3 mg/kg/24 hour.
4. If hypotensive, epinephrine is the preferred pressor of choice.

References

 

Chai PR et al. Intentional hydroxychloroquine overdose treated with high-dose diazepam: an increasing concern in the COVID-19 pandemic. J Med Toxicol. 2020 PMID: 32514696; PMCID: PMC7278768; DOI: 10.1007/s13181-020-00790-8