title: Methimazole-induced myositis: a case report and review of the literature.
abstract: Methimazole is an anti-thyroid drug commonly used to treat hyperthyroidism and is a relatively safe medication. Several side effects have been reported and usually develop within 3 months of therapy. Well-known adverse reactions include agranulocytosis, hepatitis, skin eruptions, and musculoskeletal complaints such as myalgia, arthralgia, and arthritis. So far, myositis secondary to carbimazole was described in the context of a lupus-like syndrome or other rare cases of anti-neutrophil cytoplasmic antibodies-associated vasculitis. Methimazole-induced myositis occurring independently of such reactions was rarely stated. We report a patient with hyperthyroidism who, early after therapy with methimazole, developed hepatitis, eosinophilia, and fever that resolved completely after stopping the medication as well as a delayed onset of biopsy-proven eosinophilic myositis and fasciitis of gluteal muscles that resolved eventually without any additional therapy. Therefore, we raise the awareness regarding a rare side effect of methimazole: myositis.
  
  
  CONCLUSIONS
  Several differential diagnoses arise when managing a hyperthyroid patient with muscle complaints.Both hyperthyroidism and methimazole are associated with myositis.Methimazole-induced myositis is a rare clinical entity.Resolution of symptoms may occur after stopping methimazole.
authors.affiliation: Department of Endocrinology Saint Georges University Medical Center, University of Balamand Beirut Lebanon.
authors.forename: R
authors.initials: R
authors.lastname: Bou Khalil
authors.affiliation: Department of Family Medicine Saint Georges University Medical Center, University of Balamand Beirut Lebanon.
authors.forename: M
authors.initials: M
authors.lastname: Abou Salbi
authors.affiliation: Department of Endocrinology Saint Georges University Medical Center, University of Balamand Beirut Lebanon.
authors.forename: S
authors.initials: S
authors.lastname: Sissi
authors.affiliation: Department of Infectious Diseases Saint Georges University Medical Center, University of Balamand Beirut Lebanon.
authors.forename: N
authors.initials: N
authors.lastname: El Kara
authors.affiliation: Department of Infectious Diseases Saint Georges University Medical Center, University of Balamand Beirut Lebanon.
authors.forename: E
authors.initials: E
authors.lastname: Azar
authors.affiliation: Department of General Surgery Saint Georges University Medical Center, University of Balamand Beirut Lebanon.
authors.forename: M
authors.initials: M
authors.lastname: Khoury
authors.affiliation: Department of Family Medicine Saint Georges University Medical Center, University of Balamand Beirut Lebanon.
authors.forename: G
authors.initials: G
authors.lastname: Abdallah
authors.affiliation: Department of Pathology Saint Georges University Medical Center, University of Balamand Beirut Lebanon.
authors.forename: J
authors.initials: J
authors.lastname: Hreiki
authors.affiliation: Department of Gastroenterology Saint Georges University Medical Center, University of Balamand Beirut Lebanon.
authors.forename: S
authors.initials: S
authors.lastname: Farhat