Dengue fever

1. Dengue fever

2. Dengue haemorrhgic fever

3. Plasma leakage is • Selective • Pleural and peritoneal cavities • Transient • Lasts 24-48 hours • Functional

5. Detection of DHF(detection of leakage) At three levels • At the onset of leakage • At hemodynamic instability • Shock

6. Detect leakage Diagnose DHF Prevent Shock Clinical Hematology Radiology

7. Detection: onset of leakage-clinical Potential leaker- • Clinical deterioration with defervescence • Enlarged tender liver Confirmed leaker- • Pleural effusions, free fluid in abdomen

8. Detection of leakage-haematology • White cell count • Platelet count • Haematocrit

9. Timing the onset of critical period platelets WBC Slide- courtesy of Dr Lakkumar Fernando

10. Platelet count • Leakage occurs only after platelets drop below 100,000 mark • A rapid drop of platelet is correlated with severity of leakage • Rise in platelets occur at least `12 hours after the end of leakage phase

11. Haematocrit • Rise towards 20% above baseline considered significant • This may not be seen in patients with • Intravenous fluid replacement • Concomitant bleeding

13. Radiological diagnosis • Ultrasound scan- • Oedema of the gall bladder wall (but seen in dengue fever as well) • Fluid in pleural and/or peritoneal cavities • CXR- right lateral decubitus (when clinically undetectable)

14. Leakage phase-Basic principles of fluid therapy • Leakage is time limited- maximum 48 hours • Not static but dynamic- • Starting with a trickle • Reaching a peak • Then tapering off • Maximum fluid required to counter the resulting hemodynamic instability is M+5% for 48 hours

15. Dynamics of Plasma Leakage

16. Moderate Rapid Slow 24 Hr 48 Hr 0 Hr F R 36 Hr 6 Hr C

17. Basics of fluid therapy • Try and match the dynamics of leakage • Calculate the maximum fluid required for 48 hours with formula • M+5%= in 50 kg adult 4600ml • Use sufficient amounts needed to maintain just adequate intravascular volume and circulation by monitoring the vital signs. • It is not necessary to try and finish M+5%

18. Try and match the leakage • Patients with early leakage • Start with small volumes • Increase the rate gradually to keep hemodynamically stable (pulse pressure >30) with HCT as a guide. Do not try to normalize HCT • Gradually taper off after 24 hours while keeping HCT and vital signs as a guide again

19. Try and match leakage • In a patient presenting with SHOCK leakage will usually end in 24-36 hrs. Try and reduce fluids or stop altogether after 24-36 hrs. • Patients who leak very rapidly with platelet counts dropping sharply usually have relatively shorter period of leaking

20. Keep systolic blood pressure above 100 mmHg • Keep pulse rate below 100/min • Keep pulse pressure above 30 mmHg • Keep UOP above and around 25 ml/hour

21. Fluids used • Crystalloids- normal saline and Hartmann’s solution • Most require only crystalloids • Used in maintenance and as boluses

22. Fluids used • Hyper-oncotic colloid solutions i.edextran and 10% starch. • Use only as boluses (500ml/hour) • Indications • If shock does not respond to crystalloids • When shock detected in a overloaded patient • When heading towards fluid overload with crystalloids only • Maximum doses- • Dextran 30ml/kg/day Starch 50ml/kg/day

23. Iso-oncotic colloids i.e plasma, hemaccel • Not recommended

24. Fluids during end of leaking phase... • If patient is well with stable pulse and blood pressure, do not try to correct the PCV • Re-absorption will start soon and PCV will come down. Observe vital parameters closely

25. Complications of DHF • Too little fluid-profound or prolonged shock • Metabolic acidosis • multiorgan failure • DIC • Too much fluid-fluid overload • Massive effusions- respiratory compromise • Pulmonary oedema • Try to match leak

26. End of leakage (Critical Phase) Not always 48 hours from onset Can be earlier Important to detect More fluid given afterwards can lead to fluid overload

27. End of leakage (Critical Phase) • Clinical improvement • Return of Appetite • Haemodynamic stability (pulse, BP normal) • Diuresis • Stabilization of Hct • Rise in WBC followed by platelet count • Convalescent rash/generalized itching/bradycardia

29. Management of shock • Identify shock • Compensated shock- Pulse pressure <20 tachycardia • Decompensated shock- systolic BP<80,MAP<60 • Profound shock- no pulse, BP • Cause for shock • Leakage • Haemorrhage • Leakage with haemorrhage

30. Leakage causing shock • High haematocrit 20% or more • Treat with appropriate fluid • Compensated shock • Hypotensive shock

31. Haemorrhage causing shock • Normal or low haematocrit • Misdiagnosed earlier as “myocarditis” • Treat with blood

32. Leakage and hemorrhage causing shock • Normal or not so high HCT (equivocal) with shock • HCT drops more than expected after fluid resuscitation • Bring down HCT below 45 with crystalloid then blood

33. Shock not responding to fluid-ABCS • Acidosis-pH<7.35and HCO3 < 15 • Bleeding • Calcium • Sugar

34. Massive effusions, gross ascites • Invariably due to fluid overload • Pleural effusions • Respiratory embarrassment • May need to aspirate • Gross tense ascites • Poor renal and splanchnic circulation • May need to relieve

35. Pitfalls • Shock in early leakage • Rapid leaker • Dehydration in febrile phase • Shock without leakage • Haemorrhage during febrile phase • Leptospirosis

36. Management of shock • Identify shock • Compensated shock- Pulse pressure <20 tachycardia • Decompensated shock- systolic BP<80,MAP<60 • Profound shock- no pulse, BP • Cause for shock • Leakage • Haemorrhage • Leakage with haemorrhage

37. Keep systolic blood pressure above 100 mmHg • Keep pulse rate below 100/min • Keep pulse pressure above 30 mmHg • Keep UOP above and around 25 ml/hour