Anti-thyroid drugs-related myopathy: is carbimazole the real culprit?
BACKGROUND
Anti-thyroid drugs (ATDs)-related myopathy is rarely reported in literature, but once developed, it can cause significant morbidity to patient.


METHODS
A 28-year old Chinese female was treated with carbimazole (CMZ) for Graves' disease with hyperthyroidism. Two weeks later, she developed myalgia and proximal muscle weakness. Investigations showed evidence of myopathy. CMZ was stopped and rapid improvement of clinical condition and biochemical parameters ensued.


CONCLUSIONS
Rapid decrement of thyroid hormone level is recognized as an important association for anti-thyroid drugs (ATDs)-related myopathy; however, the drug effects on muscle tissue cannot be excluded. Further elucidation of pathophysiology and identification of risk factors are needed. After commencing ATDs, early recognition of this rare condition and close monitoring are the essence of management. Different treatment strategies: dose reduction of ATDs, switching to alternative ATDs, with or without addition of thyroid hormone supplement can be applied depending on clinical situation.
Department of Medicine, Alice Ho Miu Ling Nethersole Hospital, Hong Kong, China.
Chiu Chi
CC
Tsang
Department of Medicine, Alice Ho Miu Ling Nethersole Hospital, Hong Kong, China.
Wai Shan
WS
Hui
Department of Medicine, Alice Ho Miu Ling Nethersole Hospital, Hong Kong, China.
Kwun Man
KM
Lo
Department of Medicine, Alice Ho Miu Ling Nethersole Hospital, Hong Kong, China.
Jonas Hon Ming
JH
Yeung
Department of Medicine, Alice Ho Miu Ling Nethersole Hospital, Hong Kong, China.
Yuk Lun
YL
Cheng
Carbimazole; Creatine Kinase; Graves ‘disease; Hyperthyroidism; Muscular Disease; Myositis