Dengue: A Global Hazard.

1. DENGUE : A GLOBAL HAZARD
Presented by,
Dr Abhinaba Saha,
Intern,
ESI-PGIMSR, ESIC MEDICAL COLLEGE AND
HOSPITAL, JOKA, KOLKATA - 700104

2. INTRODUCTION
• Dengue is a febrile illness caused by a flavivirus transmitted by
mosquitoes.
• Also known as BREAKBONE FEVER.
• More prevalent in tropical and subtropical regions.

3. CAUSATIVE AGENT
• Dengue virus.
• Vector: Aedes aegypti mosquito, which breeds in standing water in
containers, water-based air coolers and tyre dumps are a good
environment for the vector in large cities. Aedes albopictus is a vector in
some Southeast Asian countries.
• Reservoir of infection: Man and mosquito.
• There are 4 serotypes of the dengue virus, all producing a similar clinical
syndrome; type-specific immunity is lifelong but immunity against the
other serotypes lasts only a few months.
• Incubation period: 7-10 days.

4. DISEASE TRANSMISSION

5. CLINICAL FEATURES OF DENGUE
FEVER
1. Febrile phase: Acute febrile illness
Can be one or more than one of the followings:
 Body ache: maybe severe(“breakbone fever”): Arthralgia + Myalgia + Headache + Retro-orbital pain.
 Chills
 Cutaneous: initially flushed but on day 2-3 of fever maculopapular rash may appear which usually spares
palm/sole
 Complications: Usually appear (if at all) between day 3 to day 7 of illness however may appear earlier.
 Early warning signs are
Abdominal pain/tenderness
Bleeding manifestations
Blood parameters: ↑↑Hct/ Falling Platelet
Clinical evidence of fluid accumulation
Drowsiness
Dehydration
Enlarged liver: more than 2 cm
 Decreased energy level
 Eye: conjunctival congestion
 Enlarged organ: Hepatomegaly and/or Splenomegaly (clinical or radiological)

6. 2. Critical phase: Between Day 3 to Day 7 of illness – complications if at all occur during this phase
A. Hypovolemia: DSS (plasma volume depletion)
Increased capillary permeability leads to Plasma leakage:
• loss of plasma volume: Volume depletion
• Accumulation of fluid in serous cavities
1. Loss may be mild/moderate /severe: Depends on the degree of volume loss. The patient may develop
manifestations of different degrees of dehydration
 Asymptomatic
 BP: normal or low or Pulse pressure < 20 mm of Hg
 CRT: Normal or prolonged (more than 2 seconds)
 Decreased urine output & Dark urine
 Dry skin & mucous membrane
 Dry throat
 Drowsiness/Delirium
 Excessive thirst
 Extremity: cold/clammy
 Pulse: rapid +/- weak volume
2. Accumulation of Fluid in serous cavities: Fluid: Ascites/Pleural effusion
(maybe clinically obvious or radiologically seen)

7. B. Haemorrhage: DHF: Due to Thrombocytopenia
 Asymptomatic
 Bleeding manifestations: Spontaneous bleeding:
• Superficial: Purpura/Ecchymosis/Epistaxis/gum bleeding
• Deep-seated bleeding: GI bleed/GU bleed /ICH/Intra-abdominal bleeding
 Circulatory: Shock due to severe blood loss
C. Refractory shock and/or Cytokine release may lead to the following consequences in some patients with DHF/DSS:
 ARDS
 Acidosis
 Bleeding (severe)
 Circulatory failure
 DIC
 Dysfunction of Organs (Multiorgan dysfunction/failure)
 Acute Kidney Injury
 Acute Liver Injury

8. COMPLICATIONS OF DENGUE
• Dengue Haemorrhagic Fever and Disseminated Intravascular Coagulation.
• Dengue Shock Syndrome.
• Severe Organ Involvement.
• Vertical transmission, if infection within 5 weeks of delivery.

11. Risk factors for DHF
Virus factors: Host factors:
Virulence of strain Pre-existing anti-dengue antibody due to previous infection or
DHF risk is greatest when DEN-2 follows DEN-1 maternal antibodies in the infants
Hyperendemic transmission: locations with ≥ 2 serotypes circulating simultaneously
Under NVBDCP the case definitions recommended by WHO are as follows:
Dengue Fever: Clinical description
An acute febrile illness of 2-7 days duration with two or more of the following manifestations:
Headache
Retro-orbital pain
Myalgia
Arthralgia
Rash
Haemorrhagic manifestations

12. Criteria for Dengue Haemorrhagic Fever and Dengue Shock Syndrome
Dengue Haemorrhagic Fever:
a)A probable or confirmed case of dengue,
Plus
b) Haemorrhagic tendencies evidenced by ≥1 of the following
1. Positive tourniquet test
2. Superficial bleed: Petechiae, ecchymoses or purpura
3. Mucosal bleed: GI bleed/GU bleed
Plus
c). Thrombocytopenia
Plus
Evidence of plasma leakage due to increased vascular permeability, manifested by one or more of the following:
1. A > 20% rise in average haematocrit for age and sex
2. A > 20% drop in haematocrit following volume replacement treatment compared to baseline
3. Signs of plasma leakage: pleural effusion, ascites

13. DHF GRADING:

14. DIAGNOSIS
Investigations:
1. To confirm the diagnosis:
Days Post onset of symptoms Tests recommended
Day1 to 5 Detection of Viral protein: NS1 antigen
Day 5 onwards NS1 antigen
Dengue IgM +/- IgG
2. To look for complications: these tests help to monitor the activity of the disease:
CBC:
Hb: if bleeding significant
TC: common in viral fever
Platelet: often monitoring is required on a regular basis- frequency depends on the trend of platelet count
Hct:↑ indicates haemoconcentration (due to dehydration from plasma leakage)
Can be due to
Correction of dehydration with fluid
Bleeding

15. Hct: often monitoring is required on a regular basis- frequency depends on the trend
Biochemistry: Required in selected patients if complications arise
Urea/Cr: Impaired due to dehydration
Na/K: dyselectrolytemia due to dehydration
LFT: abnormal in complicated cases(nonspecific hepatitis)
ABG: Metabolic acidosis in complicated cases
CxR: effusion
USG abdomen: Ascites

16. TREATMENT
A: Airway- Intubate if needs to be ventilated
B: Bed rest till symptomatic recovery occurs
B: Blood parameter monitoring: Hct, platelet- frequency depends on the trend
B: Breathing: Ventilate if ARDS
B: Bedsore prevention for comatose patients
C: Circulation: Adequate Fluid/Hydration is the cornerstone of management
Oral fluid only for patients without any symptoms/signs of fluid deficit
IV fluid: for Hypovolemic patients: Amount/rate of administration/duration depends on clinical status
C: Catheterise if urine output monitoring becomes essential
C: Complication: monitor closely and treat if develops
ARDS: Intubate & Ventilate
Acidosis: IV NaHCO3 in severe acidosis (pH < 7.1)
Bleeding: Blood transfusion +/- Platelet transfusion
Coagulopathy: Thrombocytopenia: Platelet transfusion only if bleeding or platelet count <10,000/cumm
DIC: FFP transfusion
Dysfunction of Organs: AKI: Dialysis(if required) ALI: supportive treatment
D: Diet: Nutritious diet
D: Drugs: ● Antipyretic: Paracetamol ● Analgesic: NSAIDS for severe pain ● Antiemetic:
Domperidone/Ondansetron
D: DVT prophylaxis for immobile/bedbound patients

17. E: Eligible for Discharge when:
Afebrile for at least 24 hours without antipyretic
Appetite returning
At least 2- 3 days after recovery from shock
Blood: Platelet count > 50,000/ cumm and trend is upwards
Clinical improvement obvious

19. Improvement = Haematocrit falls, pulse rate and blood pressure stable, urine output rises
No Improvement = Haematocrit or pulse rate rises, pulse pressure falls below 20 mmHg, Urine output falls
Unstable Vital signs = Urine output falls, signs of shock

20. Prevention is better than cure….
•Use insect repellents and mosquito nets to avoid being bitten. Bodies could be protected
from mosquito bites by applying insect repellent (containing DEET) on the clothes and
exposed part of the body especially when you travel to Dengue Fever endemic areas.
•Wear long-sleeved clothes and long trousers while going outdoors.
•The best preventive measure for residents living in areas infested with Aedes aegypti is to
clean the places where the mosquito lays its eggs, primarily artificial containers that store
water. Items that collect rainwater or are used to store water (for example, plastic
containers, drums, buckets, or used automobile tires) should be cleaned or discarded. Pet
watering containers and flower vases should be emptied and scrub dried at least once a
week. This will eliminate the mosquito eggs, and larvae and reduce the number of
mosquitoes present in these areas.
•The risk of being bitten by mosquitoes can also be reduced by screening the windows and
doors.
•Patient should stay under a bed net or in a place with intact window/door screens to
prevent Aedes mosquito bites during the first week of illness. This will prevent the further
spread of dengue to other persons.
• Cover water containers tightly so that mosquitoes can’t get in to lay eggs.
• In cultivation ponds, water tanks or large containers, biological controls such as
larvivorous fishes (gambusia/guppy) and biological larvicides (Bacillus thuringiensis)
would be a good option.
•Chemical larvicide such as Temephos can be safely used in potable water.
•Pesticide spraying or "fogging" can also be effective.

21. Did you know?
There are no effective antiviral treatments available against dengue, and up until recently, there was no available
prophylaxis. In May 2019, however, the FDA approved the first vaccine for dengue disease, Dengvaxia (Sanofi
Pasteur).3 The vaccine will be available in the United States this year (2022)

22. DENGUE: GLOBAL STATUS

23. THANK
YOU!!!!