Skip to main content

Clinical course


The characteristic symptoms of dengue are sudden-onset fever, headache (typically located behind the eyes), muscle and joint pains, and a rash. The alternative name for dengue, "break-bone fever", comes from the associated muscle and joint pains.[1][7] The course of infection is divided into three phases: febrile, critical, and recovery.[8]

The febrile phase involves high fever, often over 40 °C (104 °F), and is associated with generalized pain and a headache; this usually lasts two to seven days.[7][8] At this stage, a rash occurs in approximately 50–80% of those with symptoms.[7][9] It occurs in the first or second day of symptoms as flushed skin, or later in the course of illness (days 4–7), as a measles-like rash.[9][10] Some petechiae (small red spots that do not disappear when the skin is pressed, which are caused by broken capillaries) can appear at this point,[8] as may some mild bleeding from the mucous membranes of the mouth and nose.[5][7] The fever itself is classically biphasic in nature, breaking and then returning for one or two days, although there is wide variation in how often this pattern actually happens.[10][11]

In some people, the disease proceeds to a critical phase, which follows the resolution of the high fever and typically lasts one to two days.[8] During this phase there may be significant fluid accumulation in the chest and abdominal cavity due to increased capillary permeability and leakage. This leads to depletion of fluid from the circulation and decreased blood supply to vital organs.[8] During this phase, organ dysfunction and severe bleeding, typically from the gastrointestinal tract, may occur.[5][8] Shock (dengue shock syndrome) and hemorrhage (dengue hemorrhagic fever) occur in less than 5% of all cases of dengue,[5] however those who have previously been infected with other serotypes of dengue virus ("secondary infection") are at an increased risk.[5][12]

The recovery phase occurs next, with resorption of the leaked fluid into the bloodstream.[8] This usually lasts two to three days.[5] The improvement is often striking, but there may be severe itching and a slow heart rate.[5][8] During this stage, a fluid overload state may occur; if it affects the brain, it may cause a reduced level of consciousness or seizures.

Comments

Post a Comment

Popular posts from this blog

Laboratory tests

Dengue fever may be diagnosed by microbiological laboratory testing.[23] This can be done by virus isolation in cell cultures, nucleic acid detection by PCR, viral antigen detection or specific antibodies (serology).[13][25] Virus isolation and nucleic acid detection are more accurate than antigen detection, but these tests are not widely available due to their greater cost.[25] All tests may be negative in the early stages of the disease.[5][13] These laboratory tests are only of diagnostic value during the acute phase of the illness with the exception of serology. Tests for dengue virus-specific antibodies, types IgG and IgM, can be useful in confirming a diagnosis in the later stages of the infection. Both IgG and IgM are produced after 5–7 days. The highest levels (titres) of IgM are detected following a primary infection, but IgM is also produced in secondary and tertiary infections. The IgM becomes undetectable 30–90 days after a primary infection, but earlier following re-inf...
Post a Comment
Read more

Diagnosis

The diagnosis of dengue is typically made clinically, on the basis of reported symptoms and physical examination; this applies especially in endemic areas.[1] However, early disease can be difficult to differentiate from other viral infections.[5] A probable diagnosis is based on the findings of fever plus two of the following: nausea and vomiting, rash, generalized pains, low white blood cell count, positive tourniquet test, or any warning sign (see table) in someone who lives in an endemic area.[23] Warning signs typically occur before the onset of severe dengue.[8] The tourniquet test, which is particularly useful in settings where no laboratory investigations are readily available, involves the application of a blood pressure cuff for five minutes, followed by the counting of any petechial hemorrhages; a higher number makes a diagnosis of dengue more likely.[8] It can be difficult to distinguish dengue fever and chikungunya, a similar viral infection that shares many symptoms and ...
Post a Comment
Read more

Research

Research efforts to prevent and treat dengue include various means of vector control,[43] vaccine development, and antiviral drugs.[27] With regards to vector control, a number of novel methods have been used to reduce mosquito numbers with some success including the placement of the guppy (Poecilia reticulata) or copepods in standing water to eat the mosquito larvae.[43] There are ongoing programs working on a dengue vaccine to cover all four serotypes.[27] One of the concerns is that a vaccine could increase the risk of severe disease through antibody-dependent enhancement.[44] The ideal vaccine is safe, effective after one or two injections, covers all serotypes, does not contribute to ADE, is easily transported and stored, and is both affordable and cost-effective.[44] As of 2009, a number of vaccines were undergoing testing.[13][33][44] It is hoped that the first products will be commercially available by 2015.[27] Apart from attempts to control the spread of the Aedes mosq...
Post a Comment
Read more