SHORT DESCRIPTION ABOUT DENGUE BY DR. ANAND SINGH BHADORIYA (MBBS)

1. Dengue and
viral Haemorrhagic fevers

2. Viral hemorrhagic fevers
Dengue HF/shock syndrome
Lassa fever
Marburg / Ebola viral HF
Crimean-Congo HF
Bolivian and Argentinian HF
Hanta virus pulmonary syndrome
HF with renal failure
Rift valley fever
Kyasanur forest disease
Yellow fever

3. Clinical features
Virus causes endothelial dysfunction with development
of leaky capillaty syndrome
All HF start with high fever and severe body pains
Often assoc with sore throat
Hypovolaemic shock ARDS can develop
Leucopenia, thrombocytopenia and protinuria common
Lassa fever - reterosternal pain, pharyngitis, protinuria,
joint and abdominal pain, encephalopathy & ARDS
In Lassa fever Ribavirin ivi is effective

4. Invest and management
Invest :
 Clinical setting
 TLC, Platelet count, LFT, PBS
 Specific serology
Management :
 Analgesics, antipyretics
 Fluids
 Platelet concentrate, blood, FFP

5. Dengue fever

6. Dengue fever
It is most common arthropod borne viral
disease
Endemic in India, Bangladesh, Myanmar,
Thailand and Sri Lanka
Sporadic and epidemics reported from
America, Africa

7. Dengue fever
Agent: flavivirus group (group B arborvirus)
 Four serotypes
 All cause a similar clinical syndrome
 Homolytic immunity life long
 Heterotypic immunity between serotypes
is for few months only
Incubation period: 5-6 days

8. Dengue fever
Vector: Aedes aegypti
 Breeding in stationary water
 Inhabits dwellings
 Bites during day
Transmission:
 More during rainy season and in tropics
 Cycle is man - mosquito - man

9. Clinical Spectrum
1. Dengue fever
2. Dengue hemorrhagic fever (DHF )
3. Dengue shock syndrome

10. Dengue fever
1. Prodrome : 02 days - malaise , headache
2. Acute onset : fever, backache, arthralgia, headache,
generalised bodyache (bone breaking fever), A, N, V,
retro-orbital pain, lacrimation, scleral congestion. May
have relative bradycardia and LNopathy
3. Fever : continous or ‘saddle back type’ usually lasts
7-8 days
4. Rash : transient maular rash on first 1-2 days, scarlet
morbilliform rash on days 3-5 on trunk spreading
centrifugally, spares palms and soles
5. Convalescence : slow

11. Dengue hemorrhagic fever
More common in south east Asia
There is fever along with presence of
 Petechiae
 Ecchymoses
 epistaxis
 GI bleed
 Bleeding diathesis

12. Dengue Shock syndrome
Occur commonly in children
Occurs after three days of fever
There is fever +
 Features of DHF +
 Severe hypotension and circulatory failure with
features of capillary leak syndrome
Adults do not have classical DSS but have
 GI hemorrhage
 Haemostatic abnormalities
 Increased liver enzymes

13. Pathogenesis of DHF and DSS
Exact pathogenesis is unclear
Presence of pre-existing immunity to a dengue
virus serotype, heterotypic to one causing
current infection predisposis to development of
syndrome
Presence of these heterotypic antibodies
facilitates increased viral entry and replication
in the monocytes
Triggers an immunological response

14. Pathogenesis of DHF and DSS...
Viral infection in presence of preexisting antibodies triggers
an immunopathological reaction
release of vasoactive peptides activation of compliment system
vascular damage DIC
at post cap endoth. junctions
Hemorrhage & rash bleeding diathesis
Shock

15. Diagnosis & Investigations
Clinical features in an endemic area
Positive tourniquet test (>20 petechiae per sq inch)
Thrombocytopenia <1 lac / cu mm
Leucopenia
Hemoconcentration (Hct > 20% of base line)
Serological tests : detection of IgM antibodies
Appear at end of one week of symptoms
Remain positive for 1-3 months
Rising titers are confirmatory
Detection of virus / viral antigen from blood

16. Management
Symptomatic and supportive
Antipyretics, analgesics and tepid sponging
 Paracetamol preferred
 Avoid aspirin
Management of shock
 Volume replacement with NS / RL / DNS
 Blood transfusion and FFP splly if shock and DIC present
Steroids No
Antivirals use

17. Prevention
clearing of breeding sites
insecticides for adult mosquitoes
Vaccine under development