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Dengue fever

2-7 DAYSConvalescent phase• 2-5 DAYS • Longer in adults

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Dengue haemorrhgic fever

LeakageLasts48 hours2-7 DAYS 2-5 DAYS

Longer in adults

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• Plasma leakage is– Selective

• Pleural and peritoneal cavities

– Transient• Lasts 24-48 hours

– Functional

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transientselective

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Detection of DHF(detection of leakage)

At three levels• At the onset of leakage• At hemodynamic instability• Shock

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• Detect leakage

• Diagnose DHF

• Prevent Shock

• Clinical• Hematology• Radiology

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Detection: onset of leakage-clinical

Potential leaker-• Clinical deterioration with defervescence • Enlarged tender liver

Confirmed leaker-• Pleural effusions, free fluid in abdomen

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Detection of leakage-haematology

• White cell count• Platelet count• Haematocrit

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Timing the onset of critical period

17th 8 am

18th

8 am18th 8 pm

19th

8 am19th

8 pm20th 8 am

20th 8 pm

21st

8 am21st

8 pm

7500

7000

6500

6000

5500

5000

4500

4000

3500

3000

2500

2000

1500

260,000

240,000

220,000

200,000

180,000

160,000

140,000

120,000

100,000

80,000

60,000

40,000

20,000

0

platelets

WBC

Slide- courtesy of Dr Lakkumar Fernando

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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

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Haematocrit

• Rise towards 20% above baseline considered significant

• This may not be seen in patients with– Intravenous fluid replacement– Concomitant bleeding

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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)

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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

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Dynamics of Plasma Leakage

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R0 Hr 24 Hr 48 Hr

F C6 Hr 36 Hr

Rapid SlowModerate

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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%

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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

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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

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• 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

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Fluids used

• Crystalloids- normal saline and Hartmann’s solution – Most require only crystalloids– Used in maintenance and as boluses

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Fluids used

• Hyper-oncotic colloid solutions i.e dextran 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

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

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• 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

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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

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End of leakage (Critical Phase)

Not always 48 hours from onsetCan be earlier

Important to detectMore fluid given afterwards can lead to fluid

overload

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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

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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

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Leakage causing shock

• High haematocrit 20% or more• Treat with appropriate fluid

– Compensated shock– Hypotensive shock

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Haemorrhage causing shock

• Normal or low haematocrit– Misdiagnosed earlier as “myocarditis”

• Treat with blood

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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

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Shock not responding to fluid-ABCS

• Acidosis-pH<7.35and HCO3 < 15• Bleeding• Calcium • Sugar

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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

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Pitfalls

• Shock in early leakage– Rapid leaker– Dehydration in febrile phase

• Shock without leakage– Haemorrhage during febrile phase

• Leptospirosis

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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

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• 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