Presentation on theme: "History A 24-year-old man presents to his GP with a fever. This has been present on and off for 3 days. On the first day he felt a little shaky but by."— Presentation transcript:
History A 24-year-old man presents to his GP with a fever. This has been present on and off for 3 days. On the first day he felt a little shaky but by the third day he felt very unwell with the fever and had a feeling of intense cold with generalized shaking at the same time. He felt very sweaty. The whole episode lasted for 2.5 h, and he felt drained and unwell afterwards. He felt off his food. There is previous history of hepatitis 4 years earlier and he had glandular fever at the age of 18 years. He smokes 15-20 cigarettes each day and occasionally smokes marijuana. He denies any intravenous drug use. He drinks around 14 units of alcohol each week. He has taken no other medication except malaria prophylaxis. He denies any homosexual contacts. He has had a number of heterosexual contacts each year, but says that all had been with protected intercourse. He returned from Nigeria 3 weeks earlier and was finishing off his prophylactic malaria regime. He had been in Nigeria for 6 weeks as part of his job working for an oil company and had no illnesses while he was there.
Examination He looks unwell. His pulse is 94/min, blood pressure 118/72 mmHg. There are no heart murmurs. There are no abnormalities to find in the respiratory system. In the abdomen there is some tenderness in the upper left quadrant of the abdomen. There are no enlarged lymph nodes. Heamoglobin11.1 g/dL13.7-17.7 g/dL MCV97 fL80-99 fL WCC9.4 X 10 9 /L3.9-10.6 X 10 9 /L Neutrophils6.3 X 10 9 /L1.8-7.7 X 10 9 /L Lymphocytes2.9 X 10 9 /L1.0-4.8 X 10 9 /L Platelets112 X 10 9 /L15-440 X 10 9 /L Bilirubin28 mmol/L3-17 mmol/L
. The parasitized destroyed when the schizont ruptures. The material released induces the activation of macrophages and the release of proinflammatory mononuclear cell–derived cytokines, which cause fever and exert other pathologic effects. Temperatures of 40°C damage mature parasites; in untreated infections, the effect of such temperatures is to further synchronize the parasitic cycle, with eventual production of the regular fever spikes and rigors that originally served to characterize the different malarias.
Classic dengue (breakbone fever) begins suddenly with an influenzalike syndrome consisting of fever, malaise, cough, and headache. Severe pains in muscles and joints (breakbone) occur. Enlarged lymph nodes, a maculopapular rash, and leukopenia are common. After a week or so, the symptoms regress but weakness may persist. Although unpleasant, this typical form of dengue is rarely fatal and has few sequelae
dengue hemorrhagic fever is a much more severe disease, with a fatality rate that approaches 10%. The initial picture is the same as classic dengue, but then shock and hemorrhage, especially into the gastrointestinal tract and skin, develop. Dengue hemorrhagic fever occurs particularly in southern Asia, whereas the classic form is found in tropical areas worldwide
Hemorrhagic shock syndrome is due to the production of large amounts of cross-reacting antibody at the time of a second dengue infection. The pathogenesis is as follows: The patient recovers from classic dengue caused by one of the four serotypes, and antibody against that serotype is produced. When the patient is infected with another serotype of dengue virus, an anamnestic, heterotypic response occurs, and large amounts of cross-reacting antibody to the first serotype are produced