dengue

2. PGR MRDICAL C MTI , LRH
PESHAWAR
DR SAQIB
PERVEZ
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3. CASE HISTORY #1
A 21 year old male presented with 3 days
history of continuous high grade fever ,
with generalized body-aches , headache
and retro-orbital pain.
O/E temp. 101F , BP 110/70, PR 90bpm
Generalized erythematous rash that
blanches on pressure
CBC (WBC 3100 , Hb 14 PLT 140,000)

4. CASE HISTORY#1
1.What is the most likely diagnosis?
2.What clinical test shall be done
to support the diagnosis?

5. CASE HISTORY#1
1. Dengue fever
2. Tourniquet test

6. CASE HISTORY#2
A 30 year old male with 2 days hx of
fever, sore throat and generalized body-
aches. Seen by doctor diagnosed as RTI
and sent home on oral medication.

7. CASE HISTORY#2
3 days later again presented with fever,
joint pain, epistaxis and gum bleeding and
malena.
O/E BP 100/80 PR 90bpm, Temp 100F,
RR 18/min
CBC (WBC 3500 , HB 13, PLT 40OOO)
LFTs shows elevated serum transaminases
and low serum albumin
Chest xray : b/l pleural effusion more on
right side.

8. CASE HISTORY #2
1.What is the likely diagnosis?
2. What would be the complication
, if the same patient has BP 100/90
with weak pulse & cold peripheries?

9. CASE HISTORY #2
1. Dengue hemorrhagic fever
(DHF)
2. Dengue shock syndrome
(DSS)

10. DENGUE
Dengue is most rapidly spreading
mosquito borne viral infection in the world.
The infection usually causes flu-like
illness, but occasionally develops into a
potentially lethal complication called severe
dengue.
DHF is more common in children under 5
years of age as compared to adults.

11. EPIDEMIOLOGY
WORLDWIDE
The global incidence of dengue has
grown dramatically in recent decades.
About half of the world population is now
at risk.
The virus is endemic in 128 countries
including countries in Southeast Asia.
International travel and transportation of
goods has helped the spread of both the
vector and the virus , making dengue a
global infection.

14. DENGUE
THE VIRUS
Dengue virus from the family flaviviridae.
4 serotypes : DEN1, DEN2 , DEN3 , DEN4
Infection with dengue serotype confers
lifelong immunity to that specific serotype ,
cross-protection for other serotype is only
short term.
Subsequent infections by other serotypes
increase the risk of developing severe
dengue.

16. THE VECTOR
Transmitted by the
Aedes genus of
mosquito (primarily
Aedes aegypti, but
also A albopictus)

17. FACTS ABOUT AEDES
MOSQUITO
Peak biting is at dawn and dusk.
The average lifespan of an Aedes
mosquito in nature is 2 to 4 weeks.
The mosquito can lay eggs about 3 times
in its lifetime, and about 100 eggs are
produced each time.
The eggs can lie dormant in dry
conditions for up to about 9 months, after
which they can hatch if exposed to
favourable conditions, i.e. water and food.

18. AEDES MOSQUITO
Only the female Aedes mosquito bites
as it needs the protein in blood to
develop its eggs.
The mosquito becomes infective
approximately 8 to 12 days after it has
bitten a person carrying the virus.
This is the extrinsic incubation period,
during which time the virus replicates in
the mosquito and reaches the salivary
glands.

21. VIRAL TRANSMISSION
Through the bite of infected Aedes mosquitoes.
Because of approx. 7-day viremia in humans,
blood-borne transmission is possible through
exposure to infected blood, organs, or other tissues
(such as bone marrow).
Peri-natal dengue transmission can occur.
Breastfeeding has been shown to transmit dengue
in a case study, however there are no clear
guidelines on the same.

22. DENGUE
RISK FACTORS
Residence in/travel from dengue-endemic
region within past 2 weeks
Children age 1 to 5 years
Older people
Pregnancy
Exposure to infected blood products
Others
(female gender , obesity , presence of co-
morbidities)

25. PATHOPHYSIOLOGY (PRIMARY
INFECTION)
 Mosquito bite inoculates the
virions in to the skin, infect the
dendritic cells.
 The virions are transported
through the lymphatic system
into the draining lymph nodes
and then into the blood
stream.
 The resulting viremia initates a
host immune response which
ultimately results in clearance
of the virus from the
bloodstream.

26. PATHOPHYSIOLOGY (SECONDARY
INFECTION)
 Antibody dependent enhancement
(ADE) of infection has been
hypothesized as a mechanism to
explain severe dengue in the course
of a secondary infection and in
infants with primary infections
(borne to dengue immune mothers).
 Enhances viral infectivity
 Also a diminished antiviral immune
response, an increased production of
cytokines and compliment activation
ultimately results in an enhanced
pro inflammatory response, higher
viral titers, increased vascular
permeability, and coagulopathy.

28. CLINICAL FEATURES
After the incubation period (3 to 14 days)
, the illness occurs in 3 phases:
1. Febrile phase
2. Critical phase
3. Recovery phase

31. DENGUE
WHO CLASSIFICTION
Year classification
1997 1. Dengue fever (DF)
2. Dengue hemorrhagic
fever (DHF)
3. Dengue shock syndrome
(DSS)
1999 1. Dengue without warning
signs
2. Dengue with warning
signs
3. Severe dengue

32. WHO CASE DEFINITIONS
DENGUE FEVER
An acute febrile illness defined by the
presence of fever and 2 or more of the
following
Retro-orbital or ocular pain
Headache
Rash
Myalgia
Athralgia
Leukopenia
Hemorrhagic manifestations (but not
meeting the case definition of DHF)

33. CASE DEFINITION
DHF
Characterized by all of the following:
1. Fever lasting from 2-7 days
2. Evidence of hemorrhagic manifestation or a positive
tourniquet test
3. Thrombocytopenia
4. Evidence of plasma leakage
(↑Hct ≥20 % above the average for age or ↓in Hct
≥20% of baseline following fluid replacement) or
Pleural effusion, or ascites or hypoproteInemia

34. CASE DEFINITION
DSS
DSS (DHF plus circulatory failure) as
evidenced by:
Rapid and weak pulse and narrow pulse
pressure (<20 mmHg), or
Age specific hypotension and cold,
clammy skin and restlessness

36. PHYSICAL EXAMINATION
LOOK FOR
Rash
Hemorrhagic signs (petechiae , purpura
or positive tourniquet test)
Hepatomegaly
Evidence of plasma leak (edema , ascites,
pleural effusion)
Circulatory collapse (cold clammy skin,
rapid weak pulse with narrow pulse
pressure, capillary refill time >3 seconds,
reduced urine output)

39. DENGUE
ATYPICAL PRESENTATION
Encephalitis
Hepatic failure
Myocarditis
Severe gastrointestinal hemmorhage
Myositis
Rhabdomyolysis

40. DIFFERENTIAL DIAGNOSIS

43. INVESTIGATIONS
FIRST INVESTIGATIONS TO ORDER
CBC (WBC, platelet , Hct)
LFTs
Serum albumin level
RT-PCR
NS1 antigen
Serology

44. INVESTIGATIONS
INVESTIGATIONS TO CONSIDER
Coagulation studies
Chest xray
Abdominal ultrasound
Urinalysis

48. LABORATORY CRITERIA DHF/DSS
Rapidly developing , severe
thrombocytopenia
Decreased total WBC and neutrophils
and changing neutrophil-to-lymphocyte
ratio
Elevated hematocrit (i.e 20% increase
from baseline is objective evidence of
plasma leakage)
Hypoalbuminemia
Elevated LFTs (i.e AST:ALT >2).

49. MANAGEMENT

60. TREATMENT PLAN FOR
HEMORRHAGIC COMPLICATIONS
Give 5-10 ml/kg of fresh packed RBCs or
10-20ml/kg of fresh whole blood at an
appropriate rate and observe the clinical
response.
Prophylactic platelet transfusion is
unnecessary even when the counts are
very low if there is no evidence of
significant bleeding.

61. PLATELET TRANSFUSION
INDICATIONS
Rose W, Jacob J E Adhikari DD, Verghese VP. Dengue
illness in children. Curr Med Issues 2017;15;95-105
Platelet count /cmm with
<50,000 1. Severe bleeding
2. Invasive procedure is
planned
<20,000 1. Severe bleeding
2.Clinically unstable patient
(features of shock)
3. Associated risk factors
present
<5000 1. Minor bleeding

65. DENGUE IN PREGNANCY
 Physiological changes in
pregnancy (↓Hct , baseline BP
lower, pulse pressure wider, heart
rate may be higher)
 Detection of 3rd space fluid
difficult (gravid uterus)
 Sign and symptoms may be
confused with other
complications of pregnancy
HELLP syndrome

66. DENGUE IN PREGNANCY
Unless imperative, to avoid induction of labour
/Caesarean section during critical phase, as risk
of bleeding is at its peak during that period.
Baby should be evaluated and monitored post
delivery as vertical transmission of disease has
been observed.

67. DENGUE IN CAD PATIENT

68. PREVENTION
DENGUE VACCINE
 First dengue vaccine, more
effective in population with
high sero-positivity rate
 Live recombinant tetravalent
vaccine
 3 dose series on a 0/6/12
months schedule
 Age 9-45 yr in endemic areas
 Other vaccine are under
evaluation

71. REFRENCES
1. World Health Organization. Dengue Gui
delines for Diagnosis, Treatment, Preventio
nand Control-New Edition 2009. WHO;2009
2. Rose W, Jacob J E Adhikari DD, Verghese
VP. Dengue illness in children. Curr Med
Issues 2017;15;95-105