< Presentation of Case >
A 60-year-old man presented to the out-patient clinic with fever and generalized skin rashes. The patient lived in Penghu and had been in his usual state of health. He travelled to Taipei because the insecticide spray was undertaken in his neighborhood due to the epidemic of dengue fever in October 2011. However, right after he came to Taipei, he developed a fever with a temperature as high as 39℃. He was seen at a local clinic, where a diagnosis of upper respiratory tract infection was made and medications were prescribed. On the same day when he took the medications, he noted that there were red rashes that started from the face and gradually spread to the whole body; furthermore, fever persisted. He also felt headache and retro-orbital pain. Two days later, he sought medical attention at the emergency department of this hospital, where an antihistamine was given.
Three days later, he was seen at an infectious diseases out-patient clinic. He was afebrile, but generalized skin rashes became confluent. The headache persisted but improved than 2 days before. There were no arthralgias or muscle aches. Otherwise, there were no upper respiratory tract symptoms; gastrointestinal symptoms; or urinary frequency, urgency or dysuria.
He was a retired teacher. He had no other history of travel in recent 3 months. He lived with his wife, who did not report similar symptoms. He did not recall any contact with others who had a fever.
On examination, the patient was not ill looking. The temperature was 36.7℃, the pulse, 86 beats per minute, the respiration rate, 14 breaths per minute, and the blood pressure, 136/80 mmHg. The rashes were noted mainly on the trunk and extremities, with the palms and soles spared. The non-blanching rash was measured around 1 mm to 5 mm, some of which had become confluent. There was no eschar. The conjunctiva was neither pale nor edematous. There was no cardiac murmur. The breath sounds were clear without crackles. The abdomen was not tender and the hepatic and spleen were not palpable. The leg was not edematous.
The data of laboratory tests revealed mild leukopenia (3200/mm3) with lymphocyte predominance (55%) and thrombocytopenia (95K/mm3). GOT was 75 U/L and GPT 85 U/L and the bilirubin level was normal. The other data was within normal limits.
On admission, differential diagnosis included dengue fever, scrub typhus, and murine typhus. A blood sample was sent to the Centers for Disease Control, Taiwan. Seven days later, serologic tests for dengue fever were positive, and the results for scrub typhus or murine typhus were negative. Follow-up hemogram revealed that the WBC increased to 5400/mm3 and platelet count to 120K/mm3. GOT was 54 U/L and GPT 43 U/L. He went back to Penghu without complications.
< Discussion >
Dengue fever is the result of infection with dengue virus, a RNA virus that belongs to Flaviviridae family. Patients with dengue fever are frequently noted during the summer time and in the southern part of Taiwan. However, in recent years, cases of dengue fevers are increasingly detected in the northern Taiwan and in fall.
The most common symptoms and signs for dengue fever include fever, generalized skin rashes, retro-orbital pain, muscle aches, and arthralgias. In laboratory examinations, leukopenia and thrombocytopenia are common findings. Mildly elevated aminotransferases are often noted. Most of the time, the skin rashes do not extend to the palms and soles; instead, syphilis or enterovirus infection should be considered when the rashes involve the palms and soles.
The diagnostic methods performed at Taiwan CDC include PCR assays, virus isolation, determination of paired IgG and IgM titers, and detection of NS1 antigen. If the first sample is tested negative, repeat sampling is recommended 8-13 days later. Dengue fever is a hotifiable infectious disease and should be reported to CDC within 24 hours.
The infectious period is one day before and 5 more days after onset of symptoms. During the infectious period, mosquito net should be used to prevent transmission. The treatment is mainly supportive care and clinicians should be alert to the complications such as hemorrhagic dengue fever, which include fever, haemorrhagic manifestations, thrombocytopenia (< 100,000/mm3), and haemoconcentration (haematocrit increase by >20%) . The mortality rate for dengue fever is usually as low as 1% but can be increased to 20% if dengue hemorrhagic fever develops. |
Case Discussion
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