The Overlap between Fibromyalgia Syndrome and Myotonia Congenita.
BACKGROUND
Fibromyalgia syndrome (FMS) is a complex disorder characterized by chronic widespread pain (CWP), multiple areas of tenderness, sleep disturbance, fatigue, and mood or cognitive dysfunction. Myotonia congenita (MC) is an inherited myopathic disorder that is caused by mutations in the gene encoding the skeletal muscle chloride channel, which can infrequently manifest as generalized muscle cramps or myalgia.


METHODS
The first case was a 33-year-old woman who complained of CWP and chronic headache occurring during pregnancy, and the second case was a 37-year-old man with CWP and depression who suffered from cold-induced muscle cramps. These two patients were initially diagnosed with FMS by rheumatologists, based on CWP of longer than 3 months duration and mechanical tenderness in specific body regions. However, these two FMS patients were subsequently also diagnosed with MC.


CONCLUSIONS
These two cases are the first report of an overlap of CWP between FMS and MC.
Department of Neurology, Chonnam National University Medical School, Gwangju, Korea.; Department of Neurology, Chonnam National University Hwasun Hospital, Hwasun, Korea.
Tai Seung
TS
Nam
Department of Biomedical Sciences, Chonnam National University Medical School, Gwangju, Korea.
Seok Yong
SY
Choi
Department of Rheumatology, Chonnam National University Medical School, Gwangju, Korea.
Dong Jin
DJ
Park
Department of Rheumatology, Chonnam National University Medical School, Gwangju, Korea.
Shin Seok
SS
Lee
Department of Pediatrics, Chonnam National University Medical School, Gwangju, Korea.
Young Ok
YO
Kim
Department of Neurology, Chonnam National University Medical School, Gwangju, Korea. mkkim@jnu.ac.kr.
Myeong Kyu
MK
Kim
chronic pain; fibromyalgia; myotonia congenita