Online ISSN: 2187-2988 Print ISSN: 0911-1794
特定非営利活動法人日本小児循環器学会 Japanese Society of Pediatric Cardiology and Cardiac Surgery
Pediatric Cardiology and Cardiac Surgery 38(3): 180-185 (2022)

症例報告Case Report

血液検査値の異常のみから新型コロナウイルスワクチン接種後心筋炎の診断に至った小児例A Pediatric Case of Myocarditis after Coronavirus Disease 2019 Vaccination Diagnosed Only from Blood Tests

東京大学医学部附属病院小児科Department of Pediatrics, The University of Tokyo Hospital ◇ Tokyo, Japan

受付日:2022年2月9日Received: February 9, 2022
受理日:2022年7月10日Accepted: July 10, 2022
発行日:2022年8月1日Published: August 1, 2022

メッセンジャーRNA (mRNA)新型コロナウイルスワクチンの副反応の一つとして心筋炎が知られているが,その診断方法は確立していない.今回血液検査値の異常から診断に至った小児例を経験したため報告する.症例は生来健康な13歳男児で,2回目のmRNA新型コロナウイルスワクチン(BNT162b2)接種後である.接種2日後に強い胸痛を自覚し,同日近医を受診した.受診時には胸痛以外の身体所見の異常を認めなかった.心電図検査や心臓超音波検査等の他の検査では異常を認めなかったが,血液検査において心筋逸脱酵素の上昇を認め,心筋炎と診断した.無治療で経過を観察したところ,症状・心筋逸脱酵素の上昇は改善した.経過を通して,急性期の検査所見の異常は血液検査値のみであった.3回目以降の追加接種や低年齢児へのワクチンの適応拡大により,今後ワクチン接種後心筋炎患者は増加すると推測される.ワクチン接種に伴う心筋炎の正確な頻度,長期予後を明らかにするために,血液検査まで含めた積極的な検査による診断と症例の蓄積が望まれる.

Myocarditis is a known adverse reaction against messenger RNA (mRNA) coronavirus disease 2019 (COVID-19) vaccines, but the method for the diagnosis of postvaccination myocarditis has not been established. We report a child case of postvaccination myocarditis, which was diagnosed by abnormal blood test results alone. The patient was a previously healthy 13-year-old boy who received the second dose of mRNA COVID-19 vaccine (BNT162b2). Two days after vaccination, he experienced chest pain. He was taken to the hospital on the same day, but no abnormal physical findings were noted. Electrocardiogram and echocardiogram were both normal, but cardiac enzymes were elevated. We diagnosed him with postvaccination myocarditis. The symptoms and elevation of cardiac enzymes improved with no medical treatment. Throughout the disease course, only abnormal blood test values were noted on the acute phase; therefore, the diagnosis could not be confirmed. The incidence of postvaccination myocarditis is expected to increase with the increase in the vaccinations to younger age groups and additional vaccinations. To estimate the exact frequency and long-term prognosis of postvaccination myocarditis, accumulation of cases through proactive investigation, including blood tests, are desirable.

Key words: myocarditis; vaccine; COVID-19; coronavirus

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