Abstract Details

Title Chloroquine and Hydroxychloroquine Myopathy: Clinical Spectrum and Treatment Outcomes

Topic Neuromuscular and Clinical Neurophysiology (EMG)

Presentation(s) Neuromuscular and Clinical Neurophysiology (EMG) Posters (7:00 AM-5:00 PM)

Poster/Presentation
Number 125

Objective

To describe the full clinical spectrum and treatment outcomes of Chloroquine (CQ)/Hydroxychloroquine (HCQ) myopathy, and the safety profile of these drugs.

Background CQ/HCQ-myopathy has been mostly described as a reversible proximal myopathy. There has been a surge in the use of HCQ during COVID19 raising concerns for a surge in neuromuscular complications.

Design/Methods

We conducted a retrospective chart review of 13 patients presenting with CQ/HCQ myopathy to Mayo Clinic, between April 2000 and 2019. We collected clinical, cardiac, laboratory, histopathologic and treatment data, as well as medication dosages and exposure duration.

Results Median age at presentation was 66 years, 11 patients were females. At onset, patients were on CQ/HCQ for a minimum of 6 months. Diagnosis was often delayed by a median of 6 months. At presentation, 13 patients reported limb weakness, 5 requiring assistance walking. Ten reported dysphagia, often severe, resulting in marked weight loss or aspiration pneumonia. Nine reported respiratory symptoms, which were multifactorial in four, and four reported severe neck weakness. Clinical evaluation showed predominant involvement of one or more of the following: proximal limb muscle weakness (12 patients), dysphagia (9), axial weakness (4), and respiratory failure (5). 10/11 patients had prolonged QT interval, and 4/11 had CQ/HCQ cardiomyopathy. 11 patients had a muscle biopsy showing a myopathy with rimmed vacuoles and marked acid phosphatase reactivity. 10/12 patients markedly improved after discontinuing the medication, but most were left with residual weakness. Higher cumulative dose and longer exposure duration were associated with more severe disability, and more common cardiac and swallow involvement.

Conclusions

CQ/HCQ may result in a myopathy with a wide spectrum of clinical presentation and predilection to swallowing, respiratory and cardiac muscles, mostly in patients exposed for more than 6 months. Once accurately diagnosed, patients usually improve but often fail to return to baseline.

Authors/Disclosures
Elie Naddaf, MD (Mayo Clinic) PRESENTER	Dr. Naddaf has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Klick, Inc. Dr. Naddaf has received personal compensation in the range of $500-$4,999 for serving as a Consultant for WebMD. Dr. Naddaf has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Arcellx. The institution of Dr. Naddaf has received research support from NIAMS. The institution of Dr. Naddaf has received research support from Abcuro. The institution of Dr. Naddaf has received research support from Cabaletta . The institution of Dr. Naddaf has received research support from Arcellx.
Pritikanta Paul, MD (University of California, San Francisco)	The institution of Dr. Paul has received research support from ZS Associates.
	No disclosure on file

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