Uncommon side effects of uncommon drug: hydroxychloroquine-induced hypoglycaemia in a patient with multisystem lupus

Aung Naing Myo; Lina Eltayieb; Furhana Hussein; Bashir Mahamud; R Shrestha; A Awan; E Lau; B Bhatt; Dalya Sadulah; A Rameshkumar; M Dram; M Sun; B Hossain; Gideon Mlawa

doi:10.1530/endoabs.110.EP957

JOINT3769

Introduction: Hydroxychloroquine (HCQ) is an antimalarial and immunomodulatory drug commonly used in the treatment of systemic lupus erythematosus (SLE) and other autoimmune conditions. It is generally well-tolerated, with known adverse effects including retinal toxicity, cardiomyopathy, and gastrointestinal symptoms. However, hypoglycemia is a rare but documented side effect of HCQ, potentially due to increased insulin sensitivity and enhanced glucose uptake by peripheral tissues. This case report presents a 28-year-old female with multisystem lupus who developed recurrent hypoglycemic episodes despite no prior history of diabetes. The recognition of HCQ-induced hypoglycemia, along with appropriate medication adjustments, highlights the importance of clinician awareness regarding this uncommon but significant adverse effect.

Case: A 28-year-old female with multisystem lupus, including cardiac, renal, respiratory, and skin involvement, was admitted with right iliac fossa pain and a background of lupus serositis. She was started on HCQ 200mg twice daily on 20/05/23, reduced to 200mg once daily on 30/05/23, and later increased back to 200mg twice daily before being stopped on 06/06/23. The patient exhibited repeated low capillary blood glucose (CBG) readings, particularly from 27/05/23 to 06/06/23, with several episodes below 2.5mmol/L. Severe hypoglycemic episodes: 01/06/23: CBG 1.7–1.8mmol/l04/06/23: CBG 1.3–2.8mmol/lDuring admission, she experienced recurrent hypoglycemic episodes, with capillary blood glucose (CBG) readings as low as 0.7 mmol/lon 06/06/23, despite remaining alert with cold hands. Arterial blood gas (ABG) glucose was normal at 8.9 mmol/L, suggesting falsely low CBG readings due to poor perfusion. Management and Outcome The endocrinology team reviewed her on 31/05/23, and it was suspected that HCQ contributed to the hypoglycemia. Despite ongoing corticosteroid treatment, her blood glucose remained intermittently low. After discontinuing HCQ on 06/06/23, her glucose levels stabilized without further episodes of hypoglycemia.

Discussion: Unexplained hypoglycemia in non-diabetic patients on HCQ should prompt consideration of drug-induced causes. Falsely low CBG readings can occur due to Raynaud’s phenomenon or poor peripheral perfusion, necessitating confirmation with serum glucose or ABG glucose levels. Discontinuation of HCQ led to resolution of hypoglycemia, highlighting the importance of early recognition and appropriate medication adjustment. Multidisciplinary involvement (rheumatology, endocrinology, renal, and cardiology teams) is crucial in complex cases with multisystem involvement.

Conclusion: This case highlights hydroxychloroquine-induced hypoglycemia as a rare but clinically relevant adverse effect. Clinicians should be aware of this possibility, particularly in patients without diabetes who develop unexplained hypoglycemia. Regular blood glucose monitoring and multidisciplinary management are essential for early recognition and intervention.

Endocrine Abstracts

EP957