DR.S.M. JOSHI MEDICAL OFFICER AND FACULTY MEMBER H.F.W.T.C.THANE
Dengue fever is Caused by Virus spread by Aedes Egypti mosquitoes . Globally 2.5-3billion people are estimated to be at risk of infection with Dengue Diseases. It mainly affects children. The case fatality ranges from <1%- 1%(average5%) It is characterized by Fever, headache, muscle and joint pains, rash, nausea ,and vomiting. some infection results in dengue heamorraghagic fever can threaten patient’s life.
DF and DHF are caused by four dengue viruses-DEN 1, DEN2, DEN3, DEN4which are closely related antigenically. Infection with one serotype provides life long immunity to that virus but not to others. Dengue viruses are maintained in urban transmission cycle in tropical and subtropical areas . Dengue viruses are transmitted from person to person by Aedes mosquitoes of the subgenus stegomyia .
Ae. Aegypti breeds entirely in domestic man made water receptacles found in and around household, construction sites, factories, coconut shells, over head tanks ,septic tanks. Under the optimal conditions the life cycle of aquatic stage of the Ae. Aegypti can be short as seven days. Female of Ae. Aegypti is highly anthrofillic with two periods of biting activity several hours after daybreak and in the afternoon several hours before dusk.
Ae. Aegypti prefer rest in dark,humid,secluded places inside houses,or buildings,bedrooms,closets, bathrooms,kitchen. Secondary dengue infection is a risk factor for DHF. Viremia is usually present at the time of or just before the onset of symtoms and lasts on average of five days after the onset of illness. Transmission Cycle Female mosquito bite for meal person with febrile illness mosquito infected transmission in another person onset of disease .
Pathphysiological changes occur mainly in following two manners. 1) Plasma Leakage:-Increased vascular permeability resulting in plasma leakage,hypovolemiaand shock.DHF appers unique is that selective leakage of plasma into pleura and peritoneal cavities.The period of leakage is short-24-48 hours. 2) Heamorrahgic manifestations:-Abnormal heamostasis due to vasculopathy,thrombocytopenia, coagulopathy leading to various ) heamorrahgic manifestations. Clinical manifestations:- depends on age,immune status of host,and the virus strain. In infants it may develop as simple febrile illness indistiguishable from other viral infections.
DIAGNOSIS:-In acute DF episode Total WBC-Normal at onset of fever, leucopenia develops through the febrile period, Platelet Count:- usually normal Serum Biochemistry-Normal Liver Enzymes-may be elevated. In acute DHF episode:- Total WBC-leucopenia develops through the febrile period, Platelet Count:- Thrombocytopenia is constant finding in DHF< 1,00,000/cu/mmof blood is usually found between 5-8day of ilness. Heamoconcentration is constant finding in DHF Transient Albuminurea is sometimes observed. Occult Blood:- is often found in stools.
Management of DF Fever:- Is mainly symptomatic and supportive. 1-bed rest in Acute phase. 2-Antipyretics and Analgesics for control of fever and pain 3-.oral fluid and electrolyte therepy for excessive sweating and vomiting. Management of DHF Fever:- Antipyretics and Analgesics for control of fever and pain simmilar as DF. oral fluid and electrolyte therapy for excessive sweating and vomiting. IV fluid therapy to control plasma loss and impending shock. like Iv Colloid, Crystalloid, blood transfusion