Clinicopathological Features of Telbivudine-Associated Myopathy.
Telbivudine, a thymidine nucleoside analog, is a common therapeutic option for chronic hepatitis B infection. While raised serum creatine kinase is common, myopathy associated with telbivudine is rare. Reports on its myopathological features are few and immunohistochemical analyses of inflammatory cell infiltrates have not been previously described. We describe the clinical, myopathological and immunohistochemical features of four patients who developed myopathy after telbivudine therapy for chronic hepatitis B infection. All four patients presented with progressive proximal muscle weakness, elevation of serum creatine kinase and myopathic changes on electromyography. Muscle biopsies showed myofiber degeneration/necrosis, regeneration, and fibers with cytoplasmic bodies and cytochrome c oxidase deficiency. There was minimal inflammation associated with strong sarcolemmal overexpression of class I major histocompatibility complex (MHC class I). Upon withdrawal of telbivudine, muscle weakness improved in all patients and eventually completely resolved in three. In our series, telbivudine-associated myopathy is characterized by necrotizing myopathy which improved on drug withdrawal. Although the occasional loss of cytochrome c oxidase is consistent with mitochondrial toxicity, the overexpression of MHC class I in all patients could suggest an underlying immune-mediated mechanism which may warrant further investigation.
Division of Neurology, Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.|Department of Pathology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
Tomica
http://orcid.org/0000-0003-1022-1512
T
Ambang
Division of Neurology, Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.|Department of Pathology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
Joo-San
JS
Tan
Department of Medicine, Queen Elizabeth Hospital, Kota Kinabalu, Sabah, Malaysia.
Sheila
S
Ong
Department of Pathology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
Kum-Thong
KT
Wong
Division of Neurology, Department of Medicine, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
Khean-Jin
http://orcid.org/0000-0001-5416-9627
KJ
Goh
D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009135:Muscular Diseases / Q000139:chemically induced* / Q000473:pathology*; D000077712:Telbivudine; D013936:Thymidine / Q000009:adverse effects / Q000031:analogs & derivatives*
D000077712:Telbivudine; D013936:Thymidine