Kennedy disease misdiagnosed as polymyositis: a case report.
BACKGROUND
Polymyositis is an immune-mediated myopathy with clinical features of proximal muscle weakness. Dysphagia and neck flexor weakness can develop along with respiratory muscle weakness as the disease progresses. Kennedy disease or X-linked spinobulbar muscular atrophy is a rare X-linked recessive disorder with clinical features of slowly progressive atrophy and weakness of limb and bulbar muscles. These two disorders may have overlapping clinical manifestations.


METHODS
We present the case of a 52-year-old Filipino man with chronic weakness involving his proximal muscle groups who carried the diagnosis of polymyositis and was refractory to multiple immunomodulatory therapies. Further neurologic examination and history taking along with selective serologic and electrodiagnostic studies instead confirmed the diagnosis of Kennedy disease.


CONCLUSIONS
Distinction between polymyositis and Kennedy disease may be difficult given the potential overlapping clinical manifestations. However, with careful neurological history taking, examination, and selective serologic plus electrodiagnostic investigations the correct diagnosis may be made, thus sparing the patient ineffective therapy. One must always be sure of the diagnosis of polymyositis before it's classified as refractory.
Medical Director PIH Health Stroke Program, University of Southern California Keck School of Medicine, Los Angeles County Medical Center, 12401 Washington Blvd, Whittier, California 90602, USA. rison@usc.edu.
Grigor M
GM
Harutunian
Said R
SR
Beydoun
Richard A
RA
Rison
D055534:Bulbo-Spinal Atrophy, X-Linked / Q000150:complications / Q000175:diagnosis* / Q000235:genetics; D003937:Diagnosis, Differential; D003951:Diagnostic Errors; D006801:Humans; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000150:complications; D017285:Polymyositis / Q000175:diagnosis*