Dengue

(Dengue fever; Synonyms: Bonecrusher fever, dengue)

Dengue fever is caused by flaviviruses, which are transmitted by mosquitoes. Dengue fever usually leads to an abrupt onset of high fever, headache, myalgia, arthralgia and generalized lymphadenopathy, followed by a rash that occurs at a second temperature rise for a afebrile stage. It can respiratory ailments such. come as cough, sore throat and rhinorrhea. Dengue can cause potentially fatal hemorrhagic fever with bleeding and shock. The diagnosis includes serology and PCR. Treatment is symptomatic and includes, in hemorrhagic dengue fever, an adequate volume replacement therapy.

(See also Overview of infections by Arbovirus, Arena virus and filovirus.)

Dengue fever is caused by flaviviruses, which are transmitted by mosquitoes. Dengue fever usually leads to an abrupt onset of high fever, headache, myalgia, arthralgia and generalized lymphadenopathy, followed by a rash that occurs at a second temperature rise for a afebrile stage. It can respiratory ailments such. come as cough, sore throat and rhinorrhea. Dengue can cause potentially fatal hemorrhagic fever with bleeding and shock. The diagnosis includes serology and PCR. Treatment is symptomatic and includes, in hemorrhagic dengue fever, an adequate volume replacement therapy. (See also Overview of infections by Arbovirus, Arena virus and filovirus.) Dengue is found in tropical regions between the 35th and the 35th northern latitude south. Recently, the incidence has increased in Central and South America. The most common cause in Southeast Asia outbreaks, but they may also in the Caribbean, incl. Puerto Rico and the US Virgin Islands, Australia / Oceania and the Indian subcontinent happen. The annual incidence of dengue cases by returnees of long-distance travel has increased sharply in recent years and is estimated to occur in 2012. worldwide 50-100 million cases with 20,000 deaths in Germany at> 600 cases. The causative agent, a flavivirus 4 serogroups, is transmitted by the bite of gnats of the genus Aedes. The virus circulates in the blood of infected humans for two to seven days; Aedes mosquitoes may acquire the virus when they feed on blood during this period in infected humans. Symptoms and complaints After an incubation period of 3-15 days, it comes to an abrupt fever, chills, headache, retro-orbital pain with double vision, low back pain and malaise. During the first hour, there is extreme pain in the legs and joints, leading to the traditional term “bone crusher fever”. The temperature rises rapidly to up to 40 ° C, with relative bradycardia. Conjunctival involvement and transient redness or a pale-pink colored macular rash (especially on the face) may occur. Often the cervical, epitrochlearen and inguinal lymph nodes are enlarged. The fever and other symptoms persist for 48-96 hours, followed by rapid defervescence with intense sweating. Patients feel for about 24 h relatively well, then it can again come fever ( “Gable roof profile”), characteristically with a lower maximum temperature than the first increase. At the same time a pale maculopapular rash spreads from the torso to the extremities and face. Sore throat, gastrointestinal symptoms (eg., Nausea, vomiting) and hemorrhagic symptoms may occur. Some patients develop dengue hemorrhagic fever Neurological symptoms are rare and can encephalopathy and seizures include; Some patients develop Guillain Barre syndrome. Mild cases of dengue fever, which have no lymphadenopathy usually remit in <72 h. For more severe cases, the Entkräftungsphase can last several weeks. Rarely leads to death. There is a long-term immunity to the infecting strain, whereas the immunity to other strains only lasts for 2-12 months. Diagnosis Serological tests during the acute phase and convalescence Suspected dengue fever, patients who travel to endemic areas or live there if they suddenly develop a fever, severe retro-orbital headache, myalgia and lymphadenopathy, especially in a characteristic rash or recurrent Fever. As part of the investigation should alternative diagnoses, particularly malaria and leptospirosis, are excluded. Diagnostic studies include acute and convalescent serologic tests, antigen detection and PCR of blood. Serological tests include a hemagglutination inhibition, or a complement fixation with paired sera, but there are cross-reactions with other flaviviruses before. An antigen detection is available, and a PCR is conducted usually only in laboratories with special expertise. However, the usefulness of these studies in the context of clinical care arises not only in times of an embossed by DRGs health. Also virus cultures can be created from infected mosquitoes in special laboratories. The wide dissemination of the study in Germany has hitherto failed in mind that returning travelers rarely led the person responsible for their illness mosquito in this sufficiently good condition with them. The blood count may have a leukopenia on the second day of fever. Around the 4th or 5th day may be the leukocyte count between 2000 and 4000 / uL, with only 20-40% granulocytes. In urinalysis, a moderate albuminuria and occasionally cylinder may be present. Thrombocytopenia may also be present. Supportive therapy treatment The treatment of dengue is symptomatic possible. Paracetamol can be used, but NSAIDs, including aspirin, should be avoided as a bleeding risk. Because aspirin increases the risk of Reye's syndrome, it should be avoided in children. Prevention people in endemic areas should try to avoid mosquito bites. The certainly most effective prevention for Central Europeans is the absence of avoidable travel to endemic areas. To prevent further transmission by mosquitoes, dengue patient should remain in the endemic areas until resolution of fever the second thrust under a mosquito net. Various possible vaccines are currently in development. A vaccine was licensed in Mexico in December 2015 for use in people aged 9-45 years who live in endemic areas. Key points The dengue virus is transmitted by the bite of mosquitoes of the genus Aedes. Dengue fever typically causes sudden fever, severe retro-orbital headache, myalgia, lymphadenopathy, a characteristic rash and extreme pain in the legs and joints during the first hours. Dengue fever can potentially lethal hemorrhagic fever with bleeding and shock cause (dengue hemorrhagic fever). Walk out of dengue fever when patients living in endemic areas or have traveled there, have typical symptoms; Diagnose by serological testing, antigen assay or PCR of blood. Dengue hemorrhagic fever (Philippinisches-, Thailändisches- or Southeast Asian hemorrhagic fever, dengue shock syndrome) dengue hemorrhagic fever (DHF) is a clinical variant that occurs <10 years, especially in children who are in dengue -Endemiegebieten live. DHF is demanding an earlier infection with the dengue virus. DHF is an immunopathological disease; Existing from an earlier event dengue virus antibody immune complexes trigger a massive release of vasoactive mediators by macrophages. The mediators increase vascular permeability, causing vascular leakage, hemorrhagic manifestations, hemoconcentration and severe bruising, which can lead to circulatory collapse (hence the synonym dengue shock syndrome). DHF symptoms and discomfort often begins with abrupt fever and headache and is initially indistinguishable from a classical dengue. Warning signs that predict a possible development of severe dengue, severe stomach pain and sensitivity include Persistent vomiting hematemesis nosebleeds or bleeding from the gums black, tarry stools (melena) edema lethargy, confusion. Restlessness hepatomegaly, pleural effusion or ascites Significant change in temperature (fever to hypothermia) 2-6 days after onset of the disease can quickly establish a state of shock and a progressive symptoms. Bleeding tendencies manifest themselves as follows: Normally as purpura, petechiae, or bruising at the injection sites sometimes as hematemesis, melena, or epistaxis occasionally as subarachnoid hemorrhage bronchopneumonia with or without bilateral pneumonic infiltrates is frequent. Myocarditis can occur. Mortality is usually in <1% in clinical centers with experience, but can otherwise up to 30% betragen.Diagnose Clinical diagnosis, medical history of a previous dengue fever, possibly confirmed by laboratory criteria Suspected DHF is in children under the defined clinical diagnostic criteria of WHO: Sudden fever that stays high for 2 to 7 days hemorrhagic manifestations hepatomegaly the hemorrhagic manifestations include at least one positive tourniquet test and petechiae, purpura, bruising, bleeding gums, hematemesis or melena. The tourniquet test is carried out by using a blood pressure cuff is inflated over 15 minutes to a value between the systolic and diastolic blood pressure value. The number of petechiae, which form in a circle having a diameter of 2.5 cm is counted; > 20 petechiae talk of increased capillary fragility. It should have a blood count, coagulation tests, liver function tests and dengue serology. Abnormalities of the coagulation include thrombocytopenia (platelets ? 100,000 / ul) A prolonged PT prolonged activated partial thromboplastin fibrinogen Decreased Increased amount of fibrin may occur a hypoproteinemia, light proteinuria and AST. “Complement fixation” antibody titers against flaviviruses are generally high (demonstration of 4-fold or greater change in reciprocal IgG or IgM antibody titers to ? 1 dengue virus antigens in serum pairs). The suspicion of a disease is (Hk increase of ? 20%) in patients with clinical findings according to WHO criteria plus thrombocytopenia (? 100,000 / ul) or hemoconcentration (see the CDC’sDengue virus: Clinical Guidance) .Therapie Supportive treatment patients DHF to maintain a balanced fluid status usually require intensive medical treatment. Both hypovolemia (which can lead to shock) and hyperhydration (which can cause acute respiratory failure syndrome) should be avoided. The urinary excretion, as well as the degree of hemoconcentration can be used to monitor the intravascular volume. Previously known antivirals were the result not verbessern.Wichtige points dengue hemorrhagic fever (DHF) occurs mainly in children <10 years who live in areas where dengue is endemic. A previous infection with the dengue virus is required. DHF may initially resemble the dengue fever, but certain findings (z. B. severe abdominal pain and tenderness, persistent vomiting, hematemesis, epistaxis, melena) show the possible development to severe dengue. The diagnosis is made based on specific clinical and laboratory criteria. Maintaining Euvolemia is crucial. For more information CDC: Dengue virus: Clinical Guidance

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