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1 Added by Dr. Mahadev Desai on plexusmd.com, August 2015

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Dengue Fever

Dr. Mahadev Desai, MD plexusmd.com/drmahadevdesai

August, 2015

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www.plexusmd.com • [email protected]

http://www.plexusmd.com/drmahadevdesai


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Disclaimer

This presentation is prepared by leading medical experts solely for academic purposes

and intended for reading only by qualified Medical doctors. The objective is to spread

awareness and make clinical management-related information handy for consultants

across specialties and setups. The reader is advised to use own discretion while

relying upon information provided in this presentation and refer more comprehensive

sources if required in a given set of circumstances. This is not a comprehensive note

on the subject – various information may be concised, abbreviated or curtailed to

highlight only the most important aspects in the author’s opinion. PlexusMD and the

author expressly disclaim any liability arising out of the use of the information

provided here.


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Agenda

• Dengue viral infection and Vector

• Spectrum of illness

• Clinical Manifestations

• Critical phase of illness – Day 3 to Day 7

• Classification

• Diagnosis

• Treatment


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Dengue Viral Infection

Vector Virus

Mosquito Female Aedes aegypti • Day-time feeder

• Peak biting in early morning and just before dusk

• Infected humans are the main carriers and multipliers of the virus

Dengue Virus

Flaviviridae family

• Single stranded RNA Virus

• 4 serotypes: DEN1, DEN2, DEN3 and DEN4

• Asian Genotype DEN2 and DEN3 frequently associated with severe disease, usually in

secondary infections

Incubation period: 4 to 7 days


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Range of Illness

Dengue Fever clinical manifestations range from asymptomatic infection to severe shock

Asymptomatic infection

Self-limiting Dengue Fever

Dengue Haemorrhagic Fever

with Shock syndrome

Secondary infection much more riskier Infection by one serotype confers future immunity to that serotype • However no or little cross-immunity for other serotypes • In fact, subsequent infection with another serotype much

more prone to severe disease We have a large pool of Primary Dengue fever patients


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Clinical manifestations of Dengue Fever

Asymptomatic Symptomatic

Undifferentiated fever

Dengue fever

Without haemorrhage

With unusual haemorrhage

Expanded dengue syndrome /

isolated organ involvement

DHF (with plasma leakage)

DHF non-shock DHF with shock DSS


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Revised 2009 classification by WHO


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Clinical manifestations: classic symptoms

Fever lasts for 5 to 7 days

Often high grade

“Saddleback” fever curve seen only in 5-6%

Headache, retro-orbital pain, myalgia, arthralgia ("break-bone fever")

Fever may be followed by a period of marked fatigue that can last for days to weeks

Classic Dengue Fever

Rash

Bleeding manifestations

First 2-3 days: Diffuse flushing may be observed on the face, neck and chest

3rd-4th day: Maculopapular or rubelliform rash appears

End of febrile period/Convalescence period: Generalized rash fades, localized clusters of petechiae over dorsum of feet, legs, hands and arms

Skin itching may be observed

There may be minor to major bleeding manifestations

Dengue is a non-catarrhal viral illness: presence of running nose and cold should lead to

suspicion of alternative diagnosis or mixed infection


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Clinical examination

Rashes on face/limbs/trunk

Tourniquet test for microvascular fragility

Inflate BP cuff on the arm to midway between SBP & DBP for 5 minutes

Examine skin below the cuff for petechiae

>10 petechiae in 1 square inch area is a positive tourniquet test

Oedema, pleural effusion, pericardial effusion, ascites, hepatosplenomegaly


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The critical phase

Day 3-7 days of illness is the critical phase where disease may start resolving or progress rapidly

Fever with other symptoms headache, bodyache may persist or resolve in ensuing days

Progressive leucopenia rapid decrease in platelet counts ± plasma leakage

Patients with increased capillary fragility and leak hypotension shock if not controlled with treatment DSS (dengue shock syndrome)

Bleeding minor to major may occur during the course, is independent of shock


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Course of Dengue illness, the critical phase

Dengue Guidelines for Diagnosis, Treatment , Prevention and Control, WHO 2009


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Red alerts: Signs and symptoms of impending DHF/DSS

Dengue fever (DF) with haemorrhagic manifestations must be differentiated from Dengue Haemorrhagic Fever (DHF)

Abdominal pain precedes onset of plasma leakage in ~ 60% of patients with DHF

Plasma leakage is a result of rapid development of capillary leak, within hours oedema, pleural and pericardial effusions or ascites may develop

Plasma leakage occurs typically 3-7 days after fever onset, coinciding with the resolution of fever/hypothermia and lowest platelet counts

DHF is not a continuum of DF

DHF is characterised by:

• Intense abdominal pain

• Persistent vomiting

• Sudden change from fever to hypothermia

• Marked restlessness or lethargy


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Convalescence in DHF

• Diuresis

• Return of appetite

• Stable vital signs

indications to stop volume replacement

Also frequently observed features are:

• Sinus bradycardia or arrhythmia

• Characteristic dengue confluent petechial rash

• Fatigue

• Convalescence in patients with or without shock is usually short and

uneventful


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Traditional Criteria for grading severity of Dengue infection

Severity Signs/symptoms Comments

Dengue Fever (DF)

• Fever with two or more of following: headache, retro-orbital pain, myalgia, arthralgia

• Leucopenia

• Thrombocytopenia <100,000/cu.mm.

Dengue Haemorrhagic Fever – I (DHF-I)

Criteria of DF +

• Haemorrhagic manifestations +ve Tourniquet Test, purpura, petechiae, ecchymoses at venipuncture site

• Evidence of plasma leakage Haematocrit rise ≥ 20%, pleural effusion, ascites

Dengue Haemorrhagic Fever – II

Criteria of DHF-I +

• Evidence of spontaneous bleeding Epistaxis, Melena

• Abdominal pain

Dengue Haemorrhagic Fever – III (DSS)

Criteria of DHF-II +

• Circulatory failure Weak rapid pulse, narrow PP

Dengue Haemorrhagic Fever – IV (DSS)

Criteria of DHF-III +

• Profound shock with undetectable pulse & BP


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Patients at high risk

Infants and the elderly

Pregnancy, women having menstruation or abnormal vaginal bleeding

Hemolytic diseases e.g. G-6PD deficiency, Thalassemia…

Chronic diseases e.g. DM, HBP, asthma, IHD, CRF, Cirrhosis..

Peptic ulcer disease

Patients on steroid or NSAID


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Complications

Bleeding

DIC

Shock Metabolic acidosis

ARDS (acute respiratory distress syndrome)

MODS (multi-organ disorder syndrome)

Iatrogenic: fluid over-load, CHF, electrolyte disturbances


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Differential diagnosis

‘Viral’ infections: Measles, Rubella, Yellow Fever & CCHF

Influenza illness

Malaria

Typhoid fever

Leptospirosis

Always consider co-existing other infections e.g. Gram negative infection, Malaria, Typhoid fever…


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Investigations

First visit/First week

Hb, Platelet count, TC, DC activated lymphocytes

Haematocrit (HCT)

Urinalysis: RBCs

Dengue antigen (NS1)

Dengue serology : IgG, IgM by ELISA

SGPT (ALT): normal values negative predictive value

Prothrombin Time (PT), APTT

Daily CBC, Platelet counts till platelet counts start rising and HCT normalized, then s.o.s.


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Investigations: Dengue Antigen NS1

Dengue virus has 7 non-structural (NS) protein genes

Appearance of NS1 coincides with viremia

NS1 antigen helps in early diagnosis (day 1 to 5)

Sensitivity decreases after 5 days

High circulating levels of the dengue virus NS1 early in dengue illness

correlate with the development of dengue hemorrhagic fever

Libraty DH et al, J Infect Dis. 2002;186(8):1165-8. J Infect Dis. 2002;186(8):1165-8.


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Investigations: Dengue antibodies

Dengue IgM by ELISA

Dengue IgG byELISA

HI (Haemaglutination Inhibition) antibodies: not used

Primary Dengue infection

• Higher titre of IgM

• Insignificant titre of IgG

Secondary Dengue infection

• Higher titre of IgM

• Higher titre of IgG in 1st week


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Treatment: Dengue infection

Just optimum treatment No under treatment

No over treatment

IV fluids

Platelet transfusion

Prophylactic IV fluids before haemoconcentration

Platelet transfusion only on basis of platelet counts

Vision without action is a daydream

Action without vision is a nightmare


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Treatment: Dengue fever

Symptomatic & supportive: avoid NSAID

Watchful for s/s of DHF, repeated Tourniquet test

Most cases can be managed on OPD basis (under supervision) ORS/fruit juices & plenty of fluids, IV if vomiting

Monitor critical period fever to hypothermia, lowest platelet counts

Daily HCT/Hemoglobin & platelet counts


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Treatment: Severe DHF and DSS

Early hospitalization & intensive monitoring

Initiate IV therapy crystalloid : 6 ml/kg/hour for 1-2 hrs

If improvement If no improvement

Reduce IV drip rate to 3 ml/kg/hr

further improvement

Discontinue IV after 24 hours

↑ IV to 10 ml/kg/hr for 2 hrs

improvement

Reduce to 6 ml/kg/hr 3 ml/kg/hr

Discontinue after 24h

No improvement Unstable vitals

Get Haematocrit done

See next page


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Treatment: Severe DHF and DSS (contd.)

No improvement Unstable vitals

Get Haematocrit done

Haematocrit rises Haematocrit falls with

unstable vitals

IV colloid Dextran40/ Haemmacel

10 ml/kg/hr for 1 hour

further improvement

Change to crystalloid reducing 10 ml 6 ml 3ml

BT10 ml/kg/hr

Discontinue after 24h

improvement

Change to crystalloid reducing 10 ml 6 ml 3ml

Discontinue after 24-48h


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Treatment: Severe DHF and DSS (contd.)

Aggressive IV fluids given during shock state will get reabsorbed & may cause fluid

overload & pulmonary edema

IV fluids usually not given beyond 24-48 hrs

Indications of Platelet transfusion

• No role of prophylactic transfusion

• May be given when platelet counts <10,000/cumm

• When bleeding & coagulopathy whole blood (fresh)/PCV (if volume overload),

platelets + FFP


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Aedes aegypti breeding prevention is the easiest and most successful preventive measure

Anti-viral drugs and Vaccine are under trial and development for years...

Our hopes largely rest on reducing population of Aedes Mosquitoes; we must educate patient & relatives for eradication of Breeding places for A. aegypti

Air coolers Coconut shells Disposable cups Construction sites Rubber tyres

About the Author:

Dr. Desai, an Editorial Board Member at PlexusMD, is a senior Physician with over 30 years of teaching experience. He has been the Editor of Gujarat Medical Journal and chaired numerous Scientific sessions. He is currently HOD of Medicine at Ahmedabad Dental College.

Dr. Mahadev T. Desai, MD Consultant Physician Ahmedabad Connect at: plexusmd.com/drmahadevdesai Email: [email protected]

Thank You

http://www.plexusmd.com/drmahadevdesai

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