Myopathic changes associated with severe acute respiratory syndrome: a postmortem case series.
BACKGROUND
The March 2003 outbreak of the severe acute respiratory syndrome (SARS) resulted in significant morbidity and mortality. Muscle weakness and elevated serum creatine kinase levels are commonly encountered in patients with SARS. However, the nature and cause of myopathy associated with a SARS infection are unknown because, to our knowledge, there has been no report of histological or postmortem examination of the skeletal muscle from SARS-infected patients.


OBJECTIVE
To determine the exact nature of the myopathy associated with SARS.


METHODS
Postmortem skeletal muscles from 8 consecutive patients who died of SARS in March 2003 were studied under light and electron microscopy as well as immunohistochemistry.


RESULTS
Focal myofiber necrosis was identified in 4 of 8 cases. Macrophage infiltration and regenerative fiber were scanty. All 4 patients treated with a steroid had significant myofiber atrophy. In situ hybridization for coronavirus was negative in all subjects. Viral cultures for coronavirus and examination for viral particles under electron microscopy were performed in 2 patients. The viral culture yielded no organisms and there were no viral particles seen on electron microscopic examination.


CONCLUSIONS
There is a spectrum of myopathic changes associated with a SARS infection. Focal myofiber necrosis is common and possibly is immune mediated. Critical illness myopathy and superimposed steroid myopathy may also play an important role in SARS.
Leung
Thomas W
TW
Department of Medicine and Therapeutics, Prince of Wales Hospital, Chinese University of Hong Kong, Shatin, Hong Kong. drtleung@cuhk.edu.hk
Wong
Ka Sing
KS
Hui
Andrew C
AC
To
Ka Fai
KF
Lai
Sik To
ST
Ng
Wai Fu
WF
Ng
Ho Keung
HK
D000328:Adult; D000368:Aged; D001344:Autopsy; D003402:Creatine Kinase / Q000097:blood; D005260:Female; D006801:Humans; D008264:Macrophages; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D018908:Muscle Weakness / Q000209:etiology*; D018482:Muscle, Skeletal / Q000473:pathology*; D009220:Myositis / Q000209:etiology; D009336:Necrosis; D045169:Severe Acute Respiratory Syndrome / Q000150:complications*
D003402:Creatine Kinase