DENGUE

Presented by:Lt SaroshDengue – derived from Swahili ki denga pepo

CASE DEFINITION

A probable case is an acute febrile illness with 2 or more following features:• Headache• Retro orbital pain• Myalgia• Arthralgia• Nausea vomiting• Rash• Heamorrhagic manifestation• Supportive serology

A confirmed case is with virus isolation, demonstration of 4 fold increase in antibody titre, IgM & IgG antibody positivity, demonstration of dengue antigen by immunochemistry or PCR

992- Chinese Encyclopedia –water poison

1780- Philadelphia “break-bone fever”- Benjamin Rush

Dengue Fever has a long history…

Spread of the vector and the disease go hand in hand

Transatlantic Slave Trade

World War IIhttp://neatorama.cachefly.net/images/2007-09/world-war-2.jpg

EPIDEMIOLOGY

Global situation

WHO –

Disease is now endemic in more than

100 countries in Africa, the Americas,

the Eastern Mediterranean, South - East

Asia and the Western Pacific.

Pathophysiology

VECTOR

AGENT

ENVIRONMENT

Dengue Virus

Flavi Virus

Serotypes 1-5

Post - monsoon period

High temperature and high humidity..

Areas friendly for mosquito breeding

Human behaviour, climate and movement of humans

Day time biter Mosquito

breeding area

Aedes aegypti

Disease process

Infected female Mosquito bites human

Extrinsic incubation period 8-10 days

Mosquito acquire virus from infected person

Virus circulate in humans 2-7 days

Transovarian transmission Maintains virus in nature

Humans are only main Host of virus

Transmission of disease

Phases

Febrile phase

Critical phase

Recovery phase / Severe phase

ACUTE VIREMIA

FEBRILE PHASE

CAP PERMEABILITYPLATELETS

WBCs

A B

B USUALLYPRECEDES A

RECOVERY PHASE

WORSENS DUETO PLASMA LEAK

CRITICAL VOLLOSS

DIC

SEVERE H’AGEHEMATOCRIT

METAB ACIDOSIS

ORGANIMPAIRMENT

Febrilephase

Critical phase

HEMATOCRIT

IF PATIENT SURVIVES CRITICAL PHASE

SITUATION IMPROVES

REABS OF FLUID IMPROVES WELLBEING

HEMODYNAMICSSTABILISES

Recovery phase

Severe dengue

Hypovolemia worsens

Hypovolemic Shock

Compensatory

Systolic pressure normal Pulse pressure narrows

Tachycardia Peripheral vasoconstriction Cold extDelayed cap refil

Hypovolemic Shock

Decompensatory

Prolonged hypotensive Shock & Hypoxia

Vascular permeability progresses

Multi Organ FailureDIC Acidosis

Patient with severe dengue may have coagulation abnormalities but usually not sufficient to cause

major bleeding

Major bleeding usually assoc with prolonged shock along With thrombocytopenia, hypoxia and acidosis leading to

Multi Organ Failure

CLINICAL FEATURES

Clinical spectrum Undifferentiated fever

Dengue fever

Dengue hemorrhagic fever

Dengue shock syndrome

SEARO – REVISED

Undifferentiated fever

Dengue fever

Dengue hemorrhagic fever

Expanded dengue syndrome

Undifferentiated Fever May be the most common manifestation

of dengue

Commonly diagnosed as viral fever

Dengue guidelines for diagnosis, treatment, prevention and control, WHO, 2009

Classical Dengue Fever Prodrome

2 days malaise and headache

Acute onset (Febrile phase) Fever, continuous/saddleback(break on 4/5th day) Backache,arthralgia,generalized musculoskeletal pains

(“break bone fever”) Pain on eye movement Anorexia, nausea, vomiting, Depression, prostration Relative bradycardia, postural hypotension Lymphadenopathy, hepatosplenomegaly

Probable Dengue

Live in /travel to dengue endemic area. Fever and 2 of the following:

• Nausea, vomiting • Rash • Aches and pains • Tourniquet test positive • Leukopenia

Laboratory-confirmed dengueDengue guidelines for diagnosis, treatment, prevention and control, WHO, 2009

Warning signs

Clinical • Abdominal pain or tenderness • Persistent vomiting • Clinical fluid accumulation • Mucosal bleed • Lethargy, restlessness • Liver enlargment >2 cm

Laboratory: Increase in hematocrit concurrent with rapid decrease in platelet count

Dengue guidelines for diagnosis, treatment, prevention and control, WHO, 2009

SEVERE DENGUE

Severe dengue is defined by one or more of the following: plasma leakage that may lead to shock

(dengue shock) and/or fluid accumulation, with or without respiratory distress, and/or

severe bleeding, and/or severe organ impairment.

Severe Dengue

Severe plasma leakage leading to: • Shock (DSS) • Fluid accumulation with respiratory distress

Severe bleeding Severe organ involvement

• Liver: AST or ALT >=1000 • CNS: Impaired consciousness • Heart and other organs

Dengue guidelines for diagnosis, treatment, prevention and control, WHO, 2009

Dengue Hemorrhagic Fever Fever: 2-7 days Hemorrhagic

tendencies Thromboctopenia

<100000/mm3 Plasma leakage

Clinical Case Definition for Dengue Shock Syndrome

All criteria of DHF, plus Evidence of circulatory failure

manifested indirectly by all of the following: Rapid and weak pulse Narrow pulse pressure (<20 mm Hg) OR

hypotension (<90mmHg) Cold, clammy skin and altered mental

status

Dengue guidelines for diagnosis, treatment, prevention and control, WHO, 2009

Unusual Presentationsof Severe Dengue Fever

Differentials

LABORATORY EVALUATION AND

SUPPORT

INVESTIGATIONS

Etiological Diagnosis

Severity of illness and guide to

management

Investigations: Etiological Diagnosis Antigen detection

Antibody detection

Virus isolation and characterisation

Viral nucleic acid detection

General time line of a primary infection from virus isolation to detection of IgM & IgG

Rapid test for NS1 Antigen, IgM & IgG

Primary infection IgM antibodies

detectable in 50% by days 3-5 80% by day 5 99% by day 10

Anti-dengue serum IgG - Low titers at the end of 1st week Detectable after several months, and probably

even for life

Secondary infection Antibody titres rise rapidly and react

broadly against many flaviviruses.

The dominant immunoglobulin isotype is IgG

To distinguish primary and secondary dengue infections

IgM/IgG antibody ratios Haemagglutination-inhibition test (HI)

Investigations: Severity of illness

Complete Blood Count Leucopenia Thrombocytopeni

a Rising Hematocrit

- Plasma leakage/critical phase of the disease

Additional tests LFT RFT Plasma Glucose Serum electrolytes,

bicarbonate/ lactate

Cardiac enzymes urine specific

gravity/microscopy

Interpretation of Dengue Diagnostic Tests

Highly suggestive Confirmed

One of the following:

1. IgM +ve in a single serum sample

2. IgG +ve in a single serum sample with HI titre of 1280 or greater

One of the following:

1. NS1 Ag detection

2. PCR + ve

3. Virus culture +ve

3. IgM seroconversion in paired sera

4. IgG seroconversion in paired sera OR fourfold IgG titer increase in paired sera

Summary of Diagnostic tests

MANAGEMENT

Group A – OPD management

1. Able to tolerate adequate volumes of oral fluids

2. Pass urine at least once every six hours3. Do not have any of the warning signs,

particularly when fever subsides

Daily review for disease

Group B – Requires Admission These include patients with

Warning signs Comorbidities Social circumstances

Group C Require urgent ICU admission Complicated cases

DSS DHF Multi organ failure

Management of patient with no shock Hematocrit before fluid therapy Give only isotonic solutions- 0.9% NS, RL

Start with 5–7 ml/ kg/hour for 1–2 hours

3–5 ml/kg/hr for 2–4 hours

2–3 ml/kg/hr or less

Management of patient with compensated shock Hematocrit before fluid therapy

i.v bolus infusion @ 10 ml/kg

Assess after 1 hr

Maintenance fluid 2nd i.v. bolus for 24-48 hrs

Improvement No improvement

reassess

Management of patient with hypotensive shock Hematocrit before fluid therapy

i.v bolus infusion @ 10 ml/kg

Assess after 1 hr

Improvement 2nd i.v. bolus

Maintenance fluid Colloid for 24-48 hrs 10-20 ml/kg for ½-1 hr

Treatment

Complications Hemorrhagic complication Hyperglycaemia /hypoglycaemia Electrolyte and acid-base imbalances

Hyponatraemia, hypokalaemia, hyperkalaemia,

Co-infections and nosocomial infections

Patients at risk of major bleeding Prolonged/refractory shock Hypotensive shock and renal or liver failure

and/or severe and persistent metabolic acidosis Use NSAIDS/anti coagulants Pre-existing peptic ulcer disease Trauma / IM inj Patients with haemolytic conditions are at

risk of acute haemolysis with haemoglobinuria and will require blood transfusion

Treatment of haemorrhagic complications

Minimal mucosal – wait and watch Profound thrombocytopaenia- ensure

strict bed rest and protect from trauma to reduce the risk of bleeding

No intramuscular injections- haematoma Prophylactic platelet transfusions for

severe thrombocytopaenia in otherwise haemodynamically stable patients - NO ROLE

Treatment Blood transfusion is life-saving - the risk

of fluid overload Do not wait for the haematocrit to drop

too low Indication for platelet transfusion

Active bleeding Platelet <10,000/ml

Discharge criteria All to be present

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

Vaccine… National Institutes of Health - human

clinical testing. National Institute of Allergy and

Infectious Diseases (NIAID) and is undergoing clinical study at the Johns Hopkins Bloomberg School of Public Health in Baltimore

Thank You