Orphanet Journal of Rare Diseases 2009, 4:8doi:10.
1186/1750-1172-4-8
The electronic version of this article is the complete one and can be found online
at: http://www.ojrd.com/content/4/1/8
Received: 26 November 2008
Accepted: 5 March 2009
Published: 5 March 2009
© 2009 Marchiori et al; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution
License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution,
and reproduction in any medium, provided the original work is properly cited.
Abstract
Dengue hemorrhagic fever is an acute infectious disease caused by dengue virus. We
described the high-resolution CT findings in a 70-year-old male with the disease, which was
diagnosed by clinical examination and confirmed by serological methods. High-resolution CT
demonstrated bilateral areas of consolidation with air bronchogram and ground glass
opacities, as well as small bilateral pleural effusions. Dengue hemorrhagic fever should be
considered in the differential diagnosis of diffuse pulmonary hemorrhage.
Background
Dengue fever (DF) is an acute infectious disease caused by dengue virus (DENV). It is a
mosquito-borne flavivirus that belongs to the family Flaviviridae, and consists of four
distinct serotypes (DENV 1–4) 1. Dengue virus causes disease in humans, including dengue
fever, dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) . The virus is
transmitted to humans by the bite of infected female mosquitoes of the genus Aedes.
Dengue disease has a wide spectrum of clinical signs and symptoms, ranging from
asymptomatic infection to severe and lethal manifestations However, pulmonary
hemorrhage and hemoptysis have been rarely described in the literature .
The prevalence of dengue infection has grown dramatically in recent decades, and the
disease is now endemic in more than 100 countries in Africa, the Americas, the Eastern
Mediterranean, Southeast Asia and the Western Pacific . The global resurgence of dengue is
thought to be due to failure to control the Aedes populations, uncontrolled urbanization,
population growth, climate change, and increasing number of international travelers.
In a review of the literature, we have found only one report describing the high resolution
computed tomography (HRCT) findings in DHF. The purpose of this study was to describe
the high-resolution CT findings in a patient with dengue hemorrhagic fever, who presented
with pulmonary hemorrhage and massive hemoptysis.
Discussion
The clinical presentations of dengue include non-specific febrile illness, dengue fever,
dengue hemorrhagic fever, and dengue shock syndrome. Dengue fever usually presents as
an acute fever with headache, rash, myalgia, retro-orbital pain, arthralgia, prostration,
lymphadenopathy, and leucopenia . In general, laboratorial findings include neutropenia
followed by lymphocytosis, presence of atypical lymphocytes and thrombocytopenia. Virus
can be detected in blood for 4 or 5 days after the onset of symptoms and then disappears
as antibody (immunoglobulin M [IgM]) production increases. In primary infections, IgG
antibody appears within a few days, whereas in secondary infections, the IgG level rises
immediately after the onset of symptoms and remains high in most patients .
Early diagnosis of DV infection is important and can be provisionally established by clinical
observation and easily available laboratory tests. The presence of high fever of acute onset
associated with a positive tourniquet test and hemoconcentration (increase of the
hematocrit of 20% or more) or thrombocytopenia are sufficient to establish a provisional
diagnosis of DHF, but a negative tourniquet test does not rule out dengue infection. Low
platelet counts do not predict clinically significant bleeding in dengue, and DHF or dengue
shock syndrome cases frequently have compensated consumptive coagulopathy that seldom
requires treatment . Therefore, platelet or blood transfusions are only indicated in cases
where coagulopathy causes massive bleeding . Currently, dengue diagnosis is based on
serology, viral isolation and RNA detection. Enzyme-linked immunosorbent assays (ELISA)
are still the most widely used technique for serological diagnosis, but they do not identify
the dengue virus serotype responsible for the current infection .
According to WHO guidelines , our patient showed the criteria for defining a case of DHF,
since he presented all of the following signs and symptoms: fever lasting 2–7 days;
hemorrhagic tendencies, evidenced by the presence of ecchymoses and bleeding from the
respiratory tract (hemoptysis); thrombocytopenia less than 100,000 cells per mm3; and
evidences of plasma leakage, manifested by pleural effusion and hypoproteinaemia. Other
manifestations of dengue fever were also present, including headache, myalgia, arthralgia,
leucopenia and a positive IgM antibody test.
Dengue hemorrhagic fever is characterized by an increase in capillary permeability, which
results in fluid extravasations (pleural effusion, ascites), and haemostatic changes, including
decreased platelet levels near the time of defervescence and hemorrhagic manifestations.
Major hemorrhage is unusual except when in association with profound or prolonged shock .
The liver may be enlarged and serum activity of aminotransferases is usually increased .
DHF can also progress to DSS, which is associated with hypotension caused by severe
plasma leakage
