登革熱：臨床診斷、處置與防治

Dengue Fever: Clinical Diagnosis, Management and Prevention

登革熱為全球性重要公共衛生議題，每年約有5千萬至1億人罹患登革熱。登革病毒是屬於黃病毒科中的一種RNA病毒，主要藉由埃及斑蚊散佈。
多數人感染登革熱後沒有症狀，部分患者經過3至7天的潛伏期後會驟發症狀，而症狀可以分為三個時期：初始的發燒期（持續3至7天）、退燒期間的關鍵期（持續24至48小時）、與復原期。發燒期的典型症狀包括高燒(≥38.5˚C)、頭痛、嘔吐、關節及肌肉疼痛、斑疹等。少數人經過此發燒期後可能會出現全身性的血管滲漏症候群，甚至發生登革休克症候群。實驗室診斷檢測上，在發燒期間可以用RT-PCR檢測血清中病毒，或是用ELISA或快篩試劑檢測血清中病毒抗原NS1。初步評估中必須注意處於病程階段、警示徵象、水分與循環狀態、以及住院之需要。目前並沒有針對登革熱的抗病毒藥物可以使用，主要是以支持性治療為主，尤其是謹慎的水分補充。病人依據嚴重度分為A、B、C三個族群。A群患者能自行補充足夠水分，不具有危險徵象，可居家追蹤治療；B群為具有警示徵象、有合併潛在疾病或特定社經狀況者，需要住院進行輸液治療；C群為出現嚴重血漿滲漏、出血、或器官損傷的患者，需要緊急治療或是儘速轉院。於任何一位登革熱患者須注意出血跡象，預防創傷性出血，且於需要時盡早輸血。
|登革熱的防治主要是清空並刷洗生活周遭儲水容器以避免病媒蚊孳生。目前疫苗尚在研發中，已經在進行第二至第三期之臨床研究。

Dengue fever is a global public health issue with 50~100 million cases reported per year around the world. Dengue virus is one of the RNA viruses in the Flaviviridae family and mainly transmitted by Aedes aegypti.
Most infected cases are asymptomatic. Sudden onset of symptoms may develop in some patients after a 3~7-day incubation period. There are three stages of the symptoms: an initial febrile phase (lasting for 3 to 7 days), a critical phase around the time of defervescence (lasting for 24 to 48 hours), and a spontaneous recovery phase. During the initial phase, typical symptoms and signs include high temperature (≥ 38.5˚C) accompanied by headache, vomiting, myalgia, joint pain, and a macular rash.
In a minority of these patients, a systemic vascular leak syndrome becomes apparent after the febrile phase, while dengue shock syndrome may also occur. Laboratory diagnosis of dengue is established by detecting the virus in serum with RT-PCR or viral antigen NS1 with ELISA or conducting a rapid test. A clinician should take notice of the current phase in the disease course, presence of warning signs, fluid and hemodynamic status, and the need for hospitalization. Currently, no effective antiviral agents are available for treating dengue infection, and treatment remains supportive, particularly with careful fluid management. Patients are divided to group A, B, and C according in terms of disease severity. A Group A patient able to tolerate adequate volumes of oral fluids and without warning signs may receive home care. A patient with warning signs, co-existing conditions, or certain social circumstances is placed in Group B and should be referred for in-hospital fluid management. Group C patients require emergency treatment and urgent referral when severe plasma leakage, hemorrhage, or organ impairment is identified. Signs of hemorrhage should be noticed in every patient with dengue fever. Proper measures should be taken to prevent traumatic hemorrhage, and blood transfusion should be initiated early if necessary.
Frequent emptying and cleaning by scrubbing of water-storage vessels in our environment continues to be the mainstay of dengue vector control. Dengue vaccine candidates are currently in phase 2-3 clinical trials.