Rinsho Shinkeigaku (Clinical Neurology)

Original Article

Clinical characteristics of 17 adult patients with epidemic myalgia associated with human parechovirus type 3 infection

Tatsushi Yamakawa, M.D.1), Katsumi Mizuta, M.D.2), Katsurou Kurokawa, M.D.1), Hikaru Nagasawa, M.D.1), Takahiro Yamada, M.D.3), Emiko Suzuki, M.D.4) and Manabu Wada, M.D.1)

1)Department of Neurology, Yamagata Prefectural Central Hospital
2)Department of Microbiology, Yamagata Prefectural Institute of Public Health
3)Department of Emergency Medicine, Yamagata Prefectural Medical Center for Emergency
4)Department of Pediatrics, Yamagata Prefectural Central Hospital

We investigated 17 adult cases (14 males and 3 females) of myalgia induced by human parechovirus type 3 (HPeV3) infection, treated during the summers of 2008, 2011, 2014, and 2016. The patients were aged between 21 and 50 years. The limbs and trunk of all patients were affected, and severe myalgia, muscle weakness, and decreased grip strength were observed. In addition to myalgia and muscle weakness, symptoms included fever in 14 (82%), upper respiratory inflammation in 8 (47%), gastroenteritis in 4 (24%), and scrotal pain in 4 (29% of males) patients. Tendon reflexes were preserved, and serum creatine kinase level increased in all but 1 patient. Spinal MRI was performed for 3 patients, with normal results. Musculoskeletal MRI scans showed abnormal signals in the femoral muscles in 2 of 5 patients. In a nerve conduction test, the frequency of F wave appearance in the median nerve was 40% or less in 5 of 9 patients, and repeater F waves were seen in 2 patients. Of these, 7 patients had infants in their families, and developed fever around the same time; they may have been infected by these infants. All patients recovered within 1-2 weeks. HPeV3 infection is characterized by severe myalgia, and is frequently observed in summer every 2-3 years.
Full Text of this Article in Japanese PDF (1020K)

(CLINICA NEUROL, 57: 485|491, 2017)
key words: human parechovirus type 3, epidemic myalgia, HPeV3-associated myalgia/myositis, HPeV3-M, myositis

(Received: 21-Mar-17)