DENGUE FEVER. Dr. A. HARIKA DEPT OF PEDIATRICS KIMS, NKP. 2 nd Yr PG

Transcription

1 DENGUE FEVER Dr. A. HARIKA 2 nd Yr PG DEPT OF PEDIATRICS KIMS, NKP

2 OBJECTIVES Introduction Epidemiology Dengue virus Transmission Pathogenesis Clinical features Diagnosis Treatment Prevention

3 INTRODUCTION The word dengue is derived from African word denga, means fever with hemorrhage. According to the WHO, dengue is most rapidly spreading mosquito borne viral disease in the world. The first confirmed case was reported in 1789 by Benjamin Rush, who also coined the term "break bone fever". First epidemic of dengue haemorrhagic fever occurred in Kolkata in 1963.

4 EPIDEMIOLOGY Globally, 2.5 billion people are at risk for dengue infection. WHO estimates 50 million cases per year with case fatality 2.5%. South East Asia & Western Pacific areas are most seriously affected. Without treatment, mortality reaches 40-50%. With ICU facilities, it can be reduced to 1-5%.

5 An arbovirus ssrna Family: Flaviviridae Genus: Flavivirus 4 serotypes: DEN1,2,3 &4 DENGUE VIRUS No cross protection between the serotypes DEN-2 and DEN-3 are frequently associated with severe form of disease

6 VECTOR Female Aedes aegypti, mosquito, is the principal vector and all 4 virus types have been recovered from it. It breeds in stored clean water. The mosquito lives indoors and bites the host during daytime. Other mosquitoes: Aedes albopictus, Aedes polynesiensis and Aedes scutellaris complex. Aedes aegypti Aedes albopictus

7 TRANSMISSION Aedes aegypti has a short flight range 400 M. Therefore infection is spread through the movement of patients with viremia rather than that of the mosquito. The disease is widely prevalent in cities with high population density.

8 PATHOPHYSIOLOGY Release of biological mediators (TNF, IL2, INFγ) and their interaction with the vascular endothelium leads to increase in permeability, gives rise to plasma leakage, leading to hemoconcentration, low pulse pressure and other signs of shock. Disorder in the hemostasis involves thrombocytopenia, vascular changes, and coagulopathy.

9 Dengue is one disease entity with different clinical presentations and often with unpredictable clinical evolution and outcome.

10 CLASSIFICATION

11

12 Step I. Overall assessment 1. History MANAGEMENT 2.Physical examination, including full physical and mental assessment 3.Investigation Step II. Diagnosis, assessment of disease phase and severity

13 Step III. Management Depending on the clinical manifestations and other circumstances, patients may: Be sent home (Group A) Be referred for in-hospital management (Group B) Require emergency treatment and urgent referral (Group C). According to recent WHO guidelines

14 Highly suggestive One of the following 1.NS1 Antigen in febrile phase 2.IgM +ve in a single serum sample 3. IgG +ve in a single serum sample with a high titre of 1280 or greater Confirmative tests One of the following 1.PCR +ve 2.Viral culture +ve 3.IgM seroconversion in paired sera 4.IgG seroconversion in paired sera or fourfold IgG titer increase in paired sera

15 Hemogram USG INVESTIGATIONS Ascites/pleural effusion /organomegaly Gall bladder wall thickness.

16

17 Algorithm for the treatment of compensated shock Obtain baseline HCT Fluid resuscitation with plain isotonic crystalloid 10-15ml/kg/h Yes BOX A IV crystalloids 5-7ml/kg/h for 1-2h; reduced to 3-5ml/kg/h; 2-3ml/kg/h for 2-4h. Monitor HCT 6 th hrly. Reassess for hemodynamic status etc. Is there improvement? Administer 2 nd bolus,10-20 ml/kg/hr in 1hr No HCT high HCT low If there are signs of occult /overt bleeding ; tranfuse with whole blood 20ml/kg or PRBC 10ml /kg If patient is stable for 48 hrs, stop ivf or give maintenance fluids If patient is stable, HCT decreases, go to Box A If patient is unstable, HCT increases Give 3 rd bolus ml/kg/hr for 1 hr If patient improves: go to BOX A If No improvement: consider ionotrops

18 Algorithm for the treatment of hypo-tensive shock Obtain baseline HCT Fluid resuscitation with plain isotonic crystalloid or colloid 20ml/kg/h over 15mins BOX A Yes IV crystalloids 5-7ml/kg/h for 1-2h; reduced to 3-5ml/kg/h; 2-3ml/kg/h for 2-4h. Monitor HCT 6 th hrly. Reassess for hemodynamic status etc. If patient is stable for 48 hrs, stop ivf or give maintenance fluids Is there improvement? Administer 2 nd bolus (colloid)10-20 ml/kg /hr over ½ to 1hr If patient is stable: HCT decreases Reduce ivf to 7-10ml/ kg/hr HCT high No If there are signs of occult /overt bleeding ; transfuse with whole blood 20ml/kg or PRBC 10ml/kg If patient is unstable: HCT increases Give 3 rd bolus ml/kg/hr for 1 hr HCT low If stable go to BOX A If patient improves: go to BOX A If NO improve, consider ionotrops

19 HAEMORRHAGIC COMPLICATIONS Strict bed rest Avoid aspirin or ibuprofen, intramuscular injections. Great care should be taken when inserting a naso- gastric tube Give 5 10ml/kg 5 of Fresh-packed red blood cells or ml/kg of Fresh whole blood.

20 Repeat blood transfusion if there is further blood loss or no appropriate rise in HCT after blood transfusion. Although there is little evidence to support the practice of platelet concentrates and FFP transfusion for severe bleeding, they may be given judiciously.

21 DISCHARGE CRITERIA Clinical No fever for 48 hours. Improvement in clinical status (general well-being, appetite, haemodynamic status, urine output, no respiratory distress). Laboratory Increasing trend of platelet count. Stable haematocrit without intravenous fluids.

22 PREVENTION Avoiding mosquito bites through use of proper insecticides, repellents, body covering with clothing and screening of houses. Proper water storage systems Vaccine against Dengue are under investigation and may emerge as an important weapon to control this unique viral infection in future.

23 TAKE HOME MESSAGE Dengue is one disease, often with unpredictable clinical evolution and outcome. There is no specific treatment for dengue, supportive and aggressive fluid therapy are the cornerstone of management. Intelligent interpretation and appropriate therapy in critical phase reduces mortality.

24 THANK YOU