巨細胞病毒(Cytomegalovirus，簡稱CMV) 是一種常見的病毒，各年齡層的人口均可能被感染，大部分免疫力正常宿主的初級感染，會產生類似傳染性單核白血球增多症或類似感冒症狀，但鮮少引起嚴重併發症；被感染後的宿主，終生可在血清中測到陽性反應。然而在免疫低下的族群，如接受器官移植及愛滋病患者，CMV 感染症可能產生嚴重的併發症甚至死亡。重症病患是近年來逐漸受到關注的族群，因為這類病患的免疫力雖不若傳統免疫不全病患般的低下，但也可能隨著病情變化，如使用呼吸器、敗血症、反覆輸血等因素，造成相對的免疫低下，進而引起CMV 感染或再活化。本文目的有三：首先，綜合整理重症患者發生CMV 感染症的機制、危險因子和臨床表現；其次，針對舊有及最新發展的CMV 診斷工具，探討重症患者診斷CMV 感染症的臨床實務；最後，針對CMV 感染症之預後、治療藥物的選擇和相關藥物副作用，分析治療CMV 感染症的利弊，試圖提出當前重症患者CMV 感染症的治療原則，並剖析血液篩檢用於高風險病患之臨床價值。透過本文獻回顧，我們希望提供臨床醫師在重症患者之CMV 感染症風險、診斷工具及治療方式的參考。

Cytomegalovirus (CMV) is a common virus which all age groups can be infected with. Primary infection from CMV in an immunocompetent host usually presents itself in the manner of flu-like symptoms or mononucleosis, while severe complications are less common. After CMV infection has been established, seropositivity (i.e., positive anti-CMV IgG) persists throughout one’s lifetime. However, in the populations of immunocompromised hosts, such as those in a post solid organ transplant condition, or those living with Acquired Immunodeficiency Syndrome (AIDS), CMV infection may lead to severe morbidity and mortality. Of note, critically ill patients who do not fulfill the conventional parameters regarding immunodeficiency, have received much attention in recent years. These patients may also experience CMV infection or reactivation due to circumstances such as mechanical ventilation, sepsis or frequent blood transfusions. This review has three primary purposes: first, to give a brief summary of the mechanisms, risk factors and clinical presentation involved in developing CMV infection in critically ill patients; second, to discuss the clinical practice centered around CMV infection in critically ill patients according to both old and newly developed diagnostic tools; and last but not least, to provide a CMV treatment guideline for such critically ill patients, while also evaluating the value of CMV blood screening in high-risk groups based upon prognosis, anti- CMV drug choice and relevant adverse drug reactions. Through this review, we expect to provide a clearer reference which focuses on infection risks, diagnostic tools and treatment choices with regards to CMV infection in critically ill patients.