dengue=total

1
DENGUE FEVER
2
Dengue Fever
3
(No Transcript)
4
Outline

• Introduction
• Epidemiology
• Vector
• Viral Morphology
• Mode of Transmission
• Pathogenesis
• Immune Response
• Clinical Manifestations
• Complications
• Lab Diagnosis
• Control and Prevention

5
Dengue Virus Dengue Disease
Dengue
Infected Aedes mosquito
Dengue
6
WHAT IS DENgUE ?introduction

• Dengue is a viral disease
• It is transmitted by the infective bite of female
  Aedes Aegypti mosquito
• Man develops disease after 5-6 days of being
  bitten by an infective mosquito
• It occurs in two forms Dengue Fever and Dengue
  Haemorrhagic Fever(DHF)
• Dengue Haemorrhagic Fever (DHF) is a more severe
  form of disease, which may cause death
• Person suspected of having dengue fever or DHF
  must see a doctor at once

7
Hemorrhagic Fever Viruses Taxonomy
Flaviviridae
Arenaviridae
Filoviridae
Bunyaviridae
8

• 1. Dr Benjamin Rush a professor of chemistry and
  medical theory at the UPEN, during the
  Philadelphia epidemic 1779 -1780 , first
  described the dramatic symptoms of dengue as
  break bone fever.
• 2.A small percentage of persons who have
  previously been infected by one dengue serotype
  develop bleeding and endothelial leak up on
  infection with another dengue serotype. This
  syndrome is termed dengue hemorrhagic fever
  (DHF). Also been termed dengue vasculopathy.
• 3. Vascular leakage in these patients results in
  hemoconcentration and serious effusions and can
  lead to circulatory collapse.
• 4.This, in conjunction with severe hemorrhagic
  complications, can lead to dengue shock
  syndrome(DSS), which poses a greater fatality
  risk than bleeding .

9
(No Transcript)
10
WHERE IS DENGUE FOUND
Present in most tropical and sub-tropical (less
humid) climates Africa Southeast Asia and China
India Middle East Caribbean and Central and
South America Australia and the South and
Central Pacific Some parts of the U.S., namely
Texas and Hawaii
11

• An estimated 5,00,000 cases of DHF require
  hospitalization each year, of which a very large
  proportion are children. At least 2.5 of cases
  die without proper treatment.
• A rapid rise in urban populations is bringing
  greater numbers of people into contact with this
  vector, especially in areas that are favorable
  for mosquito breeding, e.g. where household water
  storage is common and where solid waste disposal
  services are inadequate.
• Increased worldwide distribution of disease seen
  after World War II

12
(No Transcript)
13
(No Transcript)
14
Dengue virus

• Dengue fever is an acute infectious viral
  disease, also known as breakbone fever.
• It is a arthropod-borne (arboviral) illness in
  human . It is caused by infection with 1 of the 4
  serotypes of dengue virus (DENV1,2,3,4), which is
  a Flavivirus(a genus of single-stranded
  nonsegmented RNA viruses).
• Infection with one dengue serotype confers
  lifelong homotypic immunity to that serotype and
  a very brief period of partial heterotypic
  immunity to other serotypes, but a person can
  eventually be infected by all 4 serotypes
• .
• Several serotypes can be in circulation during
  an epidemic.
• Any serotype can cause severe / fatal disease
• Some genetic variants within each serotype appear
  to be more virulent or have greater epidemic
  potential

15
Dengue Virus small (50nm)viruses
Electron Micrograms
16
(No Transcript)
17
.At present DEN1 and DEN2 serotypes are
widespread in India
18
(No Transcript)
19
(No Transcript)
20
(No Transcript)
21
VECTOR OF DENGUE

• Man and mosquito are reservoirs of infection.
  Dengue is transmitted by the bite of female Aedes
  mosquito

AEDES EGYPTI
AEDES ALBOPTICUS

• In India Ae. aegypti is the main vector in most
  urban areas however, Aedes albopictus is also
  found as vector in few areas of southern India.

22
(No Transcript)
23
TRUE OR FALSE

1. Is spread by the vector aedes aegypti
2. Has an incubation period of 2-3 week
3. Has an incubation period of 3 to 14 days ,
   normally 4 to 7 days
4. Is caused by a flavivirus
5. Is more likely to cause haemorrhage in patients
   previously infected by a dengue virus
6. Characterized by Fever , muscle and join pain

24
T , F , T, F , T , T
25

• Female Aedes mosquito deposits eggs singly on
  damp surfaces just above the water line
• The eggs can survive one year without water. At
  low temperature, however, it may take several
  weeks to emerge.
• It is a day time feeder and can fly up to a
  limited distance of 400 meters.
• To get one full blood meal the mosquito has to
  feed on several persons, infecting all of them.

26
(No Transcript)
27
. Ae. aegypti has an average adult survival of
fifteen days. During the rainy season, when
survival is longer(around 1month), the risk of
virus transmission is greater. Transovarian
transmission (infection carried over to next
progeny of mosquitoes through eggs) has made the
control more complicated.
28
(No Transcript)
29

• Under optimal conditions the life cycle of
  aquatic stage of Ae. Aegypti (the time taken from
  hatching to adult emergence) can be as short as
  seven days

30
(No Transcript)
31
Few common and favoured breeding places/sites of
Ae. aegypti
32
TRANSMISSION CYCLE OF DENGUE
There is evidence that vertical transmission of
dengue virus from infected female mosquitoes to
the next generation occurs through eggs, which is
known as transovarian transmission.
33
Transmission
34
LIFE CYCLE IN 1 PERSON
The transmission cycle of dengue virus by the
mosquito Aedes aegypti begins with a
dengue-infected person. This person will have
virus circulating in the blooda viremia that
lasts for about five days. During the viremic
period, an uninfected female Aedes aegypti
mosquito bites the person and ingests blood that
contains dengue virus. Although there is some
evidence of transovarial transmission of dengue
virus in Aedes aegypti, usually mosquitoes are
only infected by biting a viremic person.
35
(No Transcript)
36
1.The virus is inoculated into humans with the
mosquito saliva. Once dengue enters ones body,
it enters the dendritic cells (specialized cells
found in most tissues) 2.The virus localizes and
replicates in various target organs, . Dengue
targets areas with high WBC counts(liver, spleen,
lymph nodes, bone marrow, and glands) 3.The
virus is then released from these tissues and
spreads through the blood to infect white blood
cells and other lymphatic tissues. 4.The virus
is then released from these tissues and
circulates in the blood.
37
LIFE CYCLE IN MOSQUITO

1. Then, within the mosquito, the virus replicates
   during an extrinsic incubation period of eight to
   twelve days.
2. The mosquito then bites a susceptible person and
   transmits the virus to him or her, as well as to
   every other susceptible person the mosquito bites
   for the rest of its lifetime
3. The mosquito ingests blood containing the virus.
4. The virus replicates in the mosquito midgut, the
   ovaries, nerve tissue and fat body. It then
   escapes into the body cavity, and later infects
   the salivary glands.
5. 7.The virus replicates in the salivary glands and
   when the mosquito bites another human, the cycle
   continues.

38
(No Transcript)
39
(No Transcript)
40

• The mosquito becomes infective approximately 7
  days after it has bitten a person carrying the
  virus.
• The mosquito remains infected for the remainder
  of its life. The life span of A aegypti is
  usually 21 days but ranges from 15 to 65 days.
• 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.

41
LIFE CYCLE IN 2 PERSON

• The mosquito then bites a susceptible person and
  transmits the virus .
• The virus then replicates in the second person
  and produces symptoms.
• The symptoms begin to appear an average of four
  to seven days after the mosquito bitethis is the
  intrinsic incubation period, within humans.
• It can range from 3 to 14 days (average 4-7 days)
• The viremia begins slightly before the onset of
  symptoms.
• Symptoms caused by dengue infection may last
  three to 10 days, with an average of five days,
• after the onset of symptomsso the illness
  persists several days after the viremia has ended.

42
TRANSMISSION

• Mosquito feeds viremic human ---- 8 to 14 days
  --- its becomes infective
• Virus multiplies in the system of vector
• Virus is injected into human by mosquito
• After 3-14 days (Incubation period) host develops
  fever , and other symptoms

43
While viral replication takes place in target
dendritic cells. Infection of target cells,
primarily those of the reticuloendothelial
system, such as dendritic cells, hepatocytes, and
endothelial cells
44
(No Transcript)
45
PathophysiologyImmune Response

• Primary Infection - host develops a Life-long
  protective immunity to the homologous (same)
  serotype
• Secondary Infection (caused by other 3 serotype)
  - host shows only partial and transient
  protection
• risk of Dengue Hemorragic Fever
  

46
Pathogenesis 0F Primary Infection

• Incubation period 4-7 days (range 3-14)
• Primary Dengue Infection Self Limited
• May also progress to severe dengue (DHF/DSS)
  (normally children, elderly immunocompromised)

Pathogenesis Of Secondary Infection
Antibody dependent enhancement mechanism
47
TRUE OR FALSE

1. After the Primary Infection , the host develops a
   Life-long protective immunity to the homologous
   serotype
2. Secondary Infection has less chances of Dengue
   Hemorrhagic Fever
3. Primary Dengue Infection is usually not self
   limited
4. Production of neutralizing antibodies is the key
   concept in Secondary Infection
5. Non Neutralizing antibodies Facilitate the entry
   of virus into monocytes through Fc Receptor and
   enables the virus to grow in the host cell
   (monocyte)
6. In secondary infection the immune response is
   destructive rather then protective Its due to
   Antibody dependent enhancement mechanism

48
T , F , F , F ,T , T
49
http//www.cdc.gov/dengue/
50

• This result in the production of immune mediators
  that serve to shape the quantity, type, and
  duration of cellular and humoral immune response
  to both the initial and subsequent virus
  infections.
• Fever typically begins on the third day of
  illness and persists 5-7 days, abating with the
  cessation of viremia. Fever may reach 41C.
• Occasionally, and more frequently in children,
  the fever abates for a day and recurs, a pattern
  that is termed a saddleback fever however, this
  pattern is more commonly seen in dengue
  hemorrhagic fever.

51
(No Transcript)
52
(No Transcript)
53
(No Transcript)
54
(No Transcript)
55
ANTIBODY DEPENDANT ENHANCEMENT
56
(No Transcript)
57
(No Transcript)
58
(No Transcript)
59
(No Transcript)
60
(No Transcript)
61
(No Transcript)
62
(No Transcript)
63
COMPLIMENT ACTIVATION MECHANISM
64
Clinical Manifestations of Dengue and Dengue
Hemorrhagic Fever
65
TRUE OR FALSE Regarding the WHO criteria for D
H F

• Fever
• Hemorrhagic manifestations
• Muscle and Join Pain
• Low platelet count (100,000/mm 3 or less
• Elevated hematocrit ( gt20 then normal)
• Elevated Hematocrit ( gt 50 then baseline)

66
Hematocrit (Hct) Percentage of the volume of
whole blood that is made up of red blood
cells Hct MORE THEN 50 PERCENT THEN baseline
means first day of admittance OR MORE THEN 20
percent then normal value for men or women
Normal Male Hct 40.7 to 50.3 Normal Female Hct
36.1 to 44.3
67
Dengue Clinical Syndromes

• Undifferentiated fever
• Classic dengue fever
• Dengue hemorrhagic fever
• Dengue shock syndrome( is actually a severe form
  of DHF.)

68
(No Transcript)
69
(No Transcript)
70
Undifferentiated Fever

• May be the most common manifestation of dengue
• Prospective study found that 87 of students
  infected were either asymptomatic or only mildly
  symptomatic
• Other prospective studies including all age-
  groups also demonstrate silent transmission

71
Clinical Characteristicsof Dengue Fever

• Fever
• Headache
• Muscle and joint pain
• Nausea/vomiting
• Rash
• Hemorrhagic manifestations

72
CLASSIc DENGUE

• Acute febrile illness with headache,
  retro-orbital pain, myalgia, arthralgia
• Break-bone fever
• High fever 5-7 days
• Second fever for 1-2 days in 5 patients
• Followed by marked fatigue days to weeks
• Classic dengue 15-60 of infections
• Nausea, vomiting, diarrhea (30)
• Macular or maculopapular rash (50)
• Respiratory symptoms cough, sore throat (30)

73
(No Transcript)
74
(No Transcript)
75
DF (Febrile Phase II)

• Anorexia, nausea, vomiting
• Sore throat, injected pharynx, conjunctiva
• Respiratory symptoms
• Epistaxis, gum bleeding, petechiae
• Classic DF with some hemorrhage is NOT DHF
• Massive (GU, GI) rare.
• PE
• Fever
• Generalized rash (may be replaced by
  macular/morbilliform later on). Petechial late
• Relative bradycardia
• Generalized lymphadenopathy
• Hepatomegaly
• Positive tourniquet test
• Lab
• Progressive decrease in WBC

76
Symptoms Dengue Fever Positive tourniquet test

• Goal of the test -
•  
• To asses fragility of capillary walls
• To identify thrombocytopenia
• In DHF grade 1, a positive tourniquet test serves
  as the only indicator of haemorrhagic tendency

• 20 or more petechiae per 1 square inch. (MOH
  MALAYSIA 2014)

77
How to do ?

• Take the patient's blood pressure and record it,
  for example, 100/70.
•  Inflate the cuff to a point midway between SBP
  and DBP and maintain for 5 minutes. (100 70)
  2 85 mm Hg
• Reduce the pressure and wait 2 minutes.
• Count petechiae below antecubital fossa. See
  image at right.
• A positive test is 20 or more petechiae per 1
  square inch.

78
Main Problems

• Dehydration
• Febrile seizures
• Neurological disturbances

79
Rash
http//www.itg.be/itg/DistanceLearning/LectureNote
sVandenEndenE/imagehtml/ppages/CD_1038_061c.htm.
Used with permission
80
(No Transcript)
81
Subcutaneous hemorrhage in DHF
http//www.orble.com/aia/
82
Critical Phase I

• Occurs at time of defervescence
• Around days 3-7 of illness
• Temperature drops to 37.5-38.0C or below
• Lasts 24-48 hours
• Systemic vascular leak syndrome
• Increasing hematocrit
• Hypoproteinemia
• Pleural effusions
• Ascites

83
HCTIMPORTANCE
The haematocrit(hct)  also known as packed cell
volume (PCV) is the volume percentage () of red
blood cells in blood. When the plasma level
becoming lower , the blood is saturated with RBC
, thus haematocrit value increases So Measuring
the HCT is the most suitable way to detect
haemorrhage. Platelet level will be low in even
non severe dengue cases. The rapid drop in
platelet with raised Hct suggest us the patient
is in stage ( DHF)
84
Critical Phase II

• Progressive leukopenia
• Rapid thrombocytopenia
• Degree of plasma leakage varies
• Increase in Hct a good barometer
• Shock
• If is to occur, preceded by warning signs
• Follow fluid management closely
• CXR, US

85
Main Problems

• Shock from plasma leakage
• Can have fluid overload secondary to
  overhydration
• Organ Impairment
• Severe hemorrhage

86
(No Transcript)
87
Recovery Phase

• After critical phase, 48-72 hours of reabsorption
  of extravascular fluid
• Well-being, appetite improves
• Bradycardia common
• Hemodynamic status improves
• GI symptoms abate
• Blood counts normalize (RBCgtWBCgtPlt)
• Diuresis occurs
• Prolonged convalescence

88
Main Problems

• Hypervolemia
• Due to overly aggressive fluid resuscitation

89
(No Transcript)
90
WHO Guidelines for diagnosis, treatment,
prevention and control Geneva 2009
91
(No Transcript)
92
Severe Dengue I

• Severe plasma leakage
• Shock (DSS)
• Serosal fluid accumulation with respiratory
  distress
• Severe bleeding
• Clinically evident
• Multi-organ involvement
• Liver AST/ALT gt1000
• CNS Impaired consciousness, seizures,
  encephalopathy
• CV and other

93
Severe Dengue II

• Clinical signs
• Tachycardia, peripheral vasoconstriction
• DBP rises towards SBP (narrowed pulse pressure,
  20 mmHg)
• Patient may be conscious and lucid
• Poor perfusion
• Cold, clammy extremities
• Rapid, weak pulse
• Mental status changes
• Serosal fluid accumulation with respiratory
  distress

94
Severe Dengue III

• Severe bleeding
• Clinically evident
• Multi-organ involvement
• Liver AST/ALT gt1000
• CNS Impaired consciousness, seizures,
  encephalopathy
• CV (cardiomyopathy) and other
• Coagulopathy

95
Consider Severe Dengue

• Patient is coming from an area of high dengue
  risk, has had 2-7 days of fever, plus any of the
  following
• There is evidence of plasma leakage, such as
• high or progressively rising hematocrit
• pleural effusions or ascites
• circulatory compromise or shock (tachycardia,
  cold and clammy extremities,
• capillary refill time greater than three seconds,
  weak or undetectable pulse,
• narrow pulse pressure or, in late shock,
  unrecordable blood pressure).
• There is significant bleeding.
• There is an altered level of consciousness
  (lethargy or restlessness, coma, convulsions).
• There is severe gastrointestinal involvement
  (persistent vomiting, increasing or intense
  abdominal pain, jaundice).
• There is severe organ impairment (acute liver
  failure, acute renal failure, encephalopathy or
  encephalitis, or other unusual manifestations,
  cardiomyopathy) or other unusual manifestations.

96
Signs and Symptoms ofEncephalitis/Encephalopathy
Associated with Acute Dengue Infection

• Decreased level of consciousness lethargy,
  confusion, coma
• Seizures
• Nuchal rigidity
• Paresis

97
Hemorrhagic Manifestationsof Dengue

• Skin petechiae, purpura, ecchymoses
• Gingival bleeding
• Nasal bleeding
• Gastro-intestinal bleeding
  hematemesis, melena
• Hematuria
• Increased menstrual flow

98
(No Transcript)
99
Clinical Case Definition forDengue Hemorrhagic
Fever
WHO4 Necessary Criteria

• Fever, or recent history of acute fever
• Hemorrhagic manifestations(with a positive TT)
• Low platelet count (100,000/mm3 or less)
• Objective evidence of leaky capillaries
• elevated hematocrit (20 or more over baseline)
• low albumin
• pleural or other serosal cavity effusions

100
(No Transcript)
101
(No Transcript)
102
Four Grades of DHF

• Grade 1
• Fever and nonspecific constitutional symptoms
• Positive tourniquet test is only hemorrhagic
  manifestation
• Grade 2
• Grade 1 manifestations spontaneous bleeding
• Grade 3
• Signs of circulatory failure (rapid/weak pulse,
  narrow pulse pressure, hypotension, cold/clammy
  skin)
• Grade 4
• Profound shock (undetectable pulse and BP)

103
(No Transcript)
104
Danger Signs inDengue Hemorrhagic Fever

• Abdominal pain - intense and sustained
• Persistent vomiting
• Abrupt change from fever to hypothermia, with
  sweating and prostration
• Restlessness or somnolence

105
Warning Sings of Dengue

• Raised HCT, with rapid fall in platelet
• Fever to hypothermia
• Mucosal Bleed
• Liver Enlargement
• Normal Male Hct 40.7 to 50.3
• Normal Female Hct 36.1 to 44.3
• The normal number of platelets in the blood is
  150,000 to 400,000 platelets per microliter
  (mcL).

106
Warning Signs for Dengue Shock

• Alarm Signals
• Severe abdominal pain
• Prolonged vomiting
• Abrupt change from fever
  
  
  
  
  to hypothermia
• Change in level of
• consciousness (irritability
  
  
  
  
  or somnolence)

• Four Criteria for DHF
• Fever
• Hemorrhagic manifestations
• Excessive capillary permeability
• ? 100,000/mm3 platelets

• Initial Warning Signals
• Disappearance of fever
• Drop in platelets
• Increase in hematocrit

• When Patients Develop DSS
• 3 to 6 days after onset of
  
  
  
  
  symptoms

107
Unusual Presentationsof Severe Dengue Fever

• Encephalopathy
• Hepatic damage
• Cardiomyopathy
• Severe gastrointestinal hemorrhage

108
(No Transcript)
109
(No Transcript)
110
(No Transcript)
111
Risk Factors for DHF/DSS

• Pre-existing immunity from previous infection
  (heterogenous subtype)
• Diabetics, asthmatics, other chronic diseases
• DENV type
• DENV-1,3 gt 2,4
• Increased time between infections
• Under age 15
• Increased capillary fragility
• HLA type and race
• CaucasiangtAA
• HLA Class-1 alleles
• Female sex
• AB blood group
• Promotor variant of DC-SIGN receptor
• Single-nucleotide polymorphism in TNF gene

De la C Sierra B, Kouri G, Guzman MG. Arch.
Virol., 2007, 152(3) 533-42. Epub 2006 Nov. 16.
112

• If left untreated, dengue hemorrhagic fever most
  likely progresses to dengue shock syndrome.
  Common symptoms in impending shock include
  abdominal pain, vomiting, and restlessness.
  Patients also may have symptoms related to
  circulatory failure.

https//en.wikipedia.org/wiki/Dengue_fever
113
TRUE OR FALSE Regarding the WHO criteria for D
H F

• Fever
• Hemorrhagic manifestations
• Muscle and Join Pain
• Low platelet count (100,000/mm 3 or less
• Elevated hematocrit ( gt20 then normal)
• Elevated Hematocrit ( gt 50 then baseline)

114
Diagnosis
History tells us the endemic area, previous
dengue infection and etc Clinical diagnosis are
all the symptoms. We can make only provisional
diagnosis Lab Diagnosis is the confirmatory
115
Laboratory Tests in Dengue Fever

• Routine Clinical laboratory tests
• CBCWBCLeukopenia,Lymphocytosis,
• plateletsThrombocytopenia
• HematocritHaemoconcentration(Hct. inc. gt20)
• (Plasma leakge)
• AlbuminHypoalbumenia(Plasma leakge)
• Liver function testsElevated SGOT SGPT
• Urine--check for microscopic hematuria
• Peak proteinuria
• 0.56 v. 0.08 g/d (Plt0.001), onset 1 day after
  defervescence (-2 to 3 days)

116
(No Transcript)
117
Dengue-specific tests
118
Dengue-specific tests

• Direct detection of viral components
• Virus isolation Culture
• RT- PCR(reverse transcriptase-pcr)
• NS-1 AG det by (ELISA / lateral flow rapid)
• Indirect by serology
• Plaque reduction neutralisation test(PRNT)
• Haemagglutination inhibition test
• Antibody detectionIgM elisa IgG elisa
• Dengue Rapid Tests
• Complement Fixation Tests
• Dot Blot Immuno Assay

119
(No Transcript)
120
(No Transcript)
121
Viral cell culture

• Its confirmatory , identifies serotype .
• Needs acute serum sample(first 5 days)
• Does not differentiate between primary and
  secondary
• Can be done only at research lab

122
Virus isolation

• Detection of virus by culture is obviously the
  definitive diagnostic test.
• By the time a person infected with Dengue
  develops fever, the infection is widely
  disseminated.
• The virus is found in serum or plasma, in
  circulating blood cells and in selected tissues,
  especially those of the immune system, for
  approx. 2-7 days, roughly corresponding to the
  period of fever.
• Detection of dengue RNA using specific
  oligonucleotide primers, reverse transcriptase
  and thermostable polymerase are Faster and are
  applied in many Laboratories.

123
Laboratory Diagnosis of Dengue Fever Virus
detection

• Drawbacks and limitations of Viral isolation
• The period of illness when the dengue virus can
  be successfully detected is brief
• Within a day or 2 after subsidence of fever, the
  rising level of antibody interfere with virus
  culture
• Dengue virus is heat-labile and special
  precautions must be taken against the thermal
  inactivation of specimens.
• Laboratories equipped and staffed to culture
  viruses are expensive to develop and maintain.

124
Laboratory Diagnosis of Dengue Fever Virus
detection
125
Laboratory Diagnosis of Dengue Fever Virus
detection

• Inoculation into mosquitos
• Most sensitive dengue viral culture technique
• Serum, Plasma, CSF, Pleural fluid, Peripheral
  blood leucocytes tissue homogenates can be used
• Toxorhynchites mosquitos generally used
• They are not hematophagus and their large size
  facilitates inoculation
• Infection is detected by Immunofluorescence of a
  tissue smear prepared from the crushed head of
  the mosquito (Head Squash)
• High sensitive culture requires 5-20 mosquitos
  per specimen
• adult male Aedes aegypti Ae. Albopictus can
  also be used.

126
Laboratory Diagnosis of Dengue Fever Virus
detection

• Inoculation into mosquitos

Toxorhynchites Ae. aegypti Ae. Albopictus
Large, easy to inoculate Small, difficult to inoculate
Raising is labour intensive, as the larvae are carnivorous needs a second mosquito species larvae as food source Easier to maintain
Non Hematophagus, hence safe to handle Female spp cant be used due to ability to act as vector
127
Laboratory Diagnosis of Dengue Fever Virus
detection

• Inoculation into mosquito cell lines
• C6/36 and AP-61 cell lines can be used
• Less sensitive than direct inoculation into live
  mosquitoes
• Cell cultures to be screened for specific
  evidence of infection by an immunoassay as the
  cytopathic effects might be absent in many dengue
  virus isolates
• As mosquito cell lines are propagable in ambient
  tropical temperatures (25-34 C), it is easier to
  maintain and practice

128
Laboratory Diagnosis of Dengue Fever Virus
detection

• Inoculation into vertebratecell lines
• VERO and LLC-MK2 cell lines can be used
• Least sensitive than other direct inoculation
  methods
• All cultures are examined using serotype-specific
  anti-Dengue monoclonal Abs tagged to a second
  labelled Ab.
• Positive control Dengue-complex-reactibe MAb
• Intracerebral inoculation into newborn mice is
  also tried in certain laboratories but have
  proven to be very less sensitive

129
Laboratory Diagnosis of Dengue Fever Antigen
detection in fixed tissue

• Sample
• Peripheral Blood Leukocyte
• Autopsy Lung, Liver specimen
• Less commonly Autopsy Thymus, Spleen, Lymph
  node, Bone marrow
• Mainly for epidemiological purpose and
  confirmation of epidemic / outbreak.
• Immunohistochemistry examined using
  serotype-specific anti-Dengue monoclonal Abs
  tagged to a second labelled Ab.

130
(No Transcript)
131
RT-PCR
132
(No Transcript)
133
Real-time PCR

• Useful for first five days of symptoms
• 80-90 sens, gt90 specificity
• Better sensitivity when combined with serology
  follow
• FDA approved

134
Nucleic Acid Amplification (NAAT)

• RT-PCR, Real Time RT-PCR, NASBA
• Better sensitivity (80-100) than isolation
• Standardization? False positive results?
  Expensive (expertise and equipment)
• Cant differentiate between 1º and 2º infections
• Do not differentiate between the different
  serotypes
• Not as sensitive as isolation or RNA detection

135
(No Transcript)
136
Most widely used Diagnostic Test

• Non Structural Protein (NS1 antigen) Test- to
  detect NS1 antigen
• Serological Test using ELISA To Detect
  Antibody( Ig M and Ig G )
• Antigen Detection
• NS1, E/M antigens
• Antigen capture ELISA,
• lateral flow antigen detection,
• NS1 IgM, IgG responses

137
(No Transcript)
138
1. NS1 antigen (Non Structural Protein) Test

• Latest diagnostic tool for diagnosing dengue
• Useful in the diagnosing in the early phase
• Sensitivity in first 5 days febrile phase(3 to
  4 of illness) Some times even from second day of
  illness
• But It is not useful after 5 days of illness .
• Criteria for primary infection
• Postive NS1 antigen( gt90 for primary
  infection)
• Criteria for secondary infection(60-80 for
  secondary infection.)
• Usually Negative NS1 antigen rarely
• Can be Positive as well.

139
NS- 1 Ag

• Structural protein secreted by all flaviviridae
• Detectable upto 10 days after onset of illness
• Disappear once seroconversion has occurred
• ELISA/rapid test lat flow serology NS-1 specific
  IgM, IgG
• Many commercial rapid test 15mn
• Not FDA approved
• Cross reactivity due to other flaviviridae.
• Lateral flow test IgG, IgM, NS-1 Ag

140
Current Rapid Diagnostic Technologies
Agglutination
Flow through
Lateral Flow
Isothermal Nucleic Acid Tests
Solid Phase
141
Immune Response to Dengue Antibody Specificity
Increases over time
NS-1 Effective days 1-5 post onset of
symptoms IgM/IgG Effective after day 5 A
diagnostic capable of detecting both is desirable
Acute
Acute
Convalescent
Convalescent
Day 0 7
142
(No Transcript)
143
2. Serological Test by ELISA To Detect
Antibody (IGm and IgG)

• Criteria for primary infection
• Positive IgM after 5 to 7 days of illness
• Ig G present after 7 days
• Criteria for secondary infection
• Positive Ig G after 5 to 7 days onwards
• Usually Absence or slight increase in IgM after
  5 to 7 days onwards

144

• Most of the studies have shown that a
  combination rapid test comprising
  immunochromatographic assay for detection of both
  the NS1 Antigen and the anti-dengue Igm together
  yields satisfactory clinical results, instead of
  sole NS1 antigen detection.

145
(No Transcript)
146
(No Transcript)
147
(No Transcript)
148
Serology IgM capture ELISA

• The IgM Capture or the MAC-ELISA is the most
  widely used serological test
• Sensitivity 61.5-99
• FDA approved MAC -ELISA in april 2011
• Serum, Saliva, dried blood sample collected in
  Filter paper and CSF can be used as sample
• Can even detect a rise in dengue-specific IgM in
  acute phase at 1-day to 2-day interval
• Specimens collected at an interval of 2-3 days
  spanning the day of defervescence are usually
  diagnostic

149
Lab (elisa method)

• ELISA (serology)
• MAC(IgM-Antibody-Capture)-ELISA, IgG ELISA
• Cross reactive with malaria, lepto, old dengue
  infections
• IgM/IgG (Primary infection gt1.2 (1/100 dilution),
  gt1.4 (1/20 dilution secondary infection if ratio
  is less) not standardized
• IgA (peaks at Day 8 after fever undetectable by
  Day 40 cant distinguish primary vs. secondary
  infections)

150
(No Transcript)
151
Serology Haemagglutination-Inhibition test (HAI)

• Simple, sensitive and reproducible
• Reagents may be prepared locally
• Disadvantages
• Pretreatment of serum samples reqd with acetone/
  kaolin and then adsorbed with type O human RBCs
  to remove non-specific inhibitors of agglutinin
  and non-specific agglutinins.
• Paired sera are required with a gap of at least
  7 days.
• Cant reliably distinguish between closely
  related Flaviviruses Between Dengue and Jap
  Encephalitis or West Nile viruses

152
Haemagglutination inhibition test
Requires paired (acute, convalescent) sera Does
not discriminate between infections by different
flaviviruses
153
(No Transcript)
154
Laboratory Diagnosis of Dengue Fever Serology
Haemagglutination-Inhibition test (HAI)
The Interpretation of HAI results
Ref Dengue haemorrhagic fever diagnosis,
treatment, prevention and control. 2nd edition.
Geneva World Health Organization
155
(No Transcript)
156
NEUTRALISATION TESTS

• Plaque reduction and neutralisation assay, its a
  most specific serology tool .
• Measures titer and neutralising antibodies
• Labor intensive, requires maintenance of very
  specific cell lines
• Limited to research lab.

157
(No Transcript)
158
Tests Used for the Lab Diagnosis of Primary
Dengue Infection (2)
Test Diagnostic Window Sample Required Sample Storage Turnaround Time Facilities/Cost
Antigen Detection 1-6 days Serum, tissues Refrigerate or frozen 1 day or more (histological) ELISA facilities (), Histology facilities ()
IgM ELISA Day 5 to Day 90 post infection Serum, plasma, blood Frozen or refrigerated 1-2 days ELISA facilities,
IgM Rapid Test Day 5 to Day 90 post infection Serum, plasma, blood Frozen or refrigerated 30 mins No additional supplies,
IgG (paired sera) by ELISA, HI or neutralization Acute sera 1-5 days Convalescent after 15 days Serum, plasma, blood Frozen or refrigerated 7 days or more ELISA facilities, BSL-2 for neutralization,
159
Rapid Diagnostic Tests (RDTs)

• Important for
• Quick diagnosis (lab results take time and
  require labs)
• In resource-limited settings
• Alerts a unit to ID threats
• Helpful for triage during outbreaks
• Curtail geographic spread of infectious diseases
• Stability operations and infrastructure building
• Worldwide demand for better diagnostics to manage
  treatment and prevention

Current RDTs
160
Product INFORMATION

• IgG/IgM Dengue Duo kit (PANBIO)
• 10µL of serum, plasma, or whole blood
• 15 minute (time to result)

NS-1/IgG/IgM Dengue Duo (SD) 120µL of serum or
plasma 15 minute (time to result)
161
Standard Diagnostics Dengue Duo (NS-1) RDT
NS1 Ag
IgG/IgM Ab
3 drops (110 µl) of plasma or serum for early
acute phase samples (day 1 5)
10 µl of plasma or serum for early convalescence
phase samples (after day 5 14)
1 2 3 5 7 10 12
1 2 3 5 7 10 12
Slide courtesy of Dr. Subhamoy Pal
162
Interpretation
163
Advantages and limitations of different dengue
diagnostic tests
Diagnostic tests Advantages limitations
Viral isolation and identification Confirmed infection Specific Identifies serotypes Requires acute sample (05 days post onset) Requires expertise and appropriate facilities Takes more than 1 week Does not differentiate between primary and secondary infection Expensive
RNA detection Confirmed infection Sensitive and specific Identifies serotype and genotype Results in 2448 hours Potential false-positives owing to contamination Requires acute sample (05 days post onset) Requires expertise and expensive laboratory equipment Does not differentiate between primary and secondary infection
164
Advantages and limitations of different dengue
diagnostic tests Serology
Diagnostic Tests Advantages Limitations
IgM or IgG seroconversion Confirmed infection Least expensive Easy to perform IgM levels can be low in secondary infections Confirmation requires two or more serum samples Can differentiate between primary and secondary infection
IgM detection (single sample) Identifies probable dengue cases Useful for surveillance, tracking outbreaks and monitoring effectiveness of interventions IgM levels can be low in secondary infections
Primary infection IgM-positive and IgG-negative
(if samples are taken before day 810) secondary
infection IgG should be higher than 1,280
haemagglutination inhibition in convalescent
serum.
165
Advantages and limitations of different dengue
diagnostic tests Antigen Detection
Diagnostic Test Advantages Limitations
Clinical specimens (for example, using blood in an NS1 assay) Confirmed infection Easy to perform Less expensive than virus isolation or RNA detection Not as sensitive as virus isolation or RNA detection
Tissues from fatal cases (for immunohistochemistry, for example) Confirmed infection Not as sensitive as virus isolation or RNA detection Requires expertise in pathology
166
(No Transcript)
167
WHO Guidelines for diagnosis, treatment,
prevention and control Geneva 2009
168
Can we rule out dengue fever if NS1 Antigen is
negative?

• Answer WE CAN NOT Rule out dengue fever if NS1
  antigen is negative

State your reasons 1. Its only useful in the
diagnosing in the early phase as it is
detectable in the blood from 3 to 4 of illness .
Some times even from second day of illness. But
It is not detectable after 5 days of illness as
its level will decline 2. Usually Negative NS1
antigen in secondary dengue infection
169
Scenario 1
Day of illness 4 Ig M - Positive Ig G -
Negative NS1 - Antigen Positive Diagnosis ?
170
Dengue FeverPrimary infection
171
Scenario 2
Day of illness 4 Ig M Negative Ig G Positive
NS1 Negative Diagnosis - ?
172
Dengue FeverSecondary infection
173
Scenario 3
Day of illness 3 Ig M Negative Ig G
Negative NS1 Positive Diagnosis - ?
174
Dengue FeverPrimary infection
175
(No Transcript)
176
DIFFERENTIAL DIAGNOSIS

• The DDS of DF includes viral respiratory and
  influenza like diseases. Early stages of Malaria
  , mild yellow fever, scrub typhus, viral
  hepatitis and leptospirosis.
• Four arboviral diseases have dengue like courses
  but without rash Colorado Tick fever, sand fly
  fever, Rift valley fever and Ross river
• Meningo Cocccemia , Yellow Fever other viral
  hemorrhagic fevers, many in rickettsial diseases
  and other severe illneses caused by a variety of
  agents may produce clinical picture similar to DHF

177
(No Transcript)
178
TRUE OR FALSE

1. Dengue Fever has no specific treatment , only
   supportive care is provided
2. The Supportive care in dengue includes fluid
   replacement and close monitoring of platelet and
   Hct
3. Dengue fever can be cured by antiviral
4. Platelet transfusion is given in Dengue Fever
5. Dengue vaccine is used in all the endemic
   countries currently
6. Dengue vaccine is given to new born babies as
   preventive method
7. We can advice the people above 45 years old to
   take dengue vaccine

179
T , T , F , F , F , F , F
180
(No Transcript)
181
Monitoring

• Patients should be monitored constantly until
  there is a reasonable certainly that the danger
  as passed in practice.
• Pulse, BP, RR Temp. be taken every 15 to 30
  minutes are more often until the shock resolves.
• Hematocrit or Hb studies should be performed
  every two hours for the first six hours then
  every four hours thereafter until the patient is
  stable.
• Accurate record of intake and output including
  the type of fluid given should be made.

182
Monitoring parameters

• Body temperature
• Respiratory rate
• Heart rate
• Blood pressure
• Pulse pressure/ volume
• Capillary refill time
• Abdominal pain
• Bleeding
• Vomiting

183
Managementintoto

• There is no specific anti viral treatment .
• The management is essentially supportive and
  symptomatic (Bedrest)
• The key to success is frequent monitoring and
  changing strategies depending on clinical and
  laboratory evaluations.
• Antipyretics or cold sponging should be used to
  keep the body temperature lt 40C.
• Analgesics and mild sedation may be required to
  control pain

184
Management(1)

• 1st step Is this dengue?
• Live in/travel to dengue endemic area
• Fever and 2 of the following
• Anorexia/nausea
• Rash
• Aches/pains
• Warning signs
• Leukopenia
• TT positive
• Laboratory confirmed dengue

185
Management (2)

• 2nd step Warning Signs present?
• Abdominal pain/tenderness
• Persistent vomiting
• Clinical fluid accumulation
• Mucosal bleed
• Lethargy, restlessness
• Liver enlargement gt2cm
• Lab Increased Hct with rapid decrease in Plt

Requires strict observation and medical
intervention
186
Management (3)

• Classifications
• Dengue without warning signs
• May be sent home
• Dengue with warning signs
• IF Dengue is suspected, and has warning signs,
• Dengue with no warning signs, BUT has co-existing
  conditions or social circumstances
• Referred for in-hospital care
• Severe Dengue
• Severe plasma leakage with shock and/or fluid
  accumulation with respiratory distress
• Severe bleeding
• Severe organ impairment
• Require emergency treatment

187
(No Transcript)
188
Management (4)

• Dengue without warning signs
• Patients who do not have warning signs AND
• Able to tolerate PO fluids
• Pass urine q6H
• Lab CBC if stable Hct, can be sent home
• Treatment Bed rest, PO intake, paracetamol 4GM
  max/day
• Monitoring daily review for disease progression
  
• Decreasing WBC
• Defervescence
• Warning signs (until out of critical period)
• If any of these occur, return to hospital
  immediately

189
Management of those who do not need Admissionop
treatment

• Following treatment measures are recommended
• Ensure adequate oral fluid intake of around 2500
  ml for 24 hours (if the body weight is less than
  50kg give fluids as 50ml/kg for 24 hours).
• This should consist of oral rehydration fluid,
  coconut water, other fruit juices, kanji or soup
  rather than plain water.
• Exclude red and brown drinks which could cause
  confusion withhaematemesis or coffee ground
  vomitus.commercial carbonated drinks that exceed
  the isotonic level should be avoided.

190

• ? Adequate physical rest
• ? Tepid sponging for fever
• ? Paracetamol not exceeding 2 tablets six hourly
  (reduce dose for patients with lower body
  weights). Warn the patient that the fever may
  not fully settle with paracetamol and advice not
  to take excess.
• ? Anti-emetics and H2 receptor blockers if
  necessary
• ? Avoid all NSAIDS and steroids
• ? Withhold Aspirin, Clopidogrel Dipyridamole in
  patients who take these on long term basis

191

• Advise immediate return for review if any of the
  following occur
• ? Clinical deterioration with settling of fever
• ? Inability to tolerate oral fluids
• ? Severe abdominal pain
• ? Cold and clammy extremities
• ? Lethargy or irritability/restlessness
• ? Bleeding tendency including inter-menstrual
  bleeding or menorrhagia
• ? Not passing urine for more than 6 hours

192
Management (5)

• Dengue without warning signs BUT has co-existing
  conditions or social circumstances
• Co-existing conditions pregnancy, infancy, old
  age, DM, renal failure
• Social circumstances living alone, distance
  challenge
• Lab CBC
• Rx PO fluids, if not tolerated, start IV (0.9 NS
  or RL at maintenance)
• Monitoring
• Temperature pattern
• I/O (Uop)
• Warning signs
• CBC (Hct, WBC, Plt)

193
Management (6) Dengue with warning signs

• Lab CBCRx
• Obtain reference Hct before fluid treatment
• Isotonic solutions (NS, RL) 5-7 mL/kg/hr for 1-2
  hr, then 3-5 mL/kg/hr for 2-4 hr, then 2-3
  mL/kg/hr or less per clinical response
• Reassess clinical status, Hct, fluid infusion
  rates
• If Hct same or min rise, 2-3 mL/kg/hr for 2-4 hr
• Crashing increase rate to 5-10 mL/kg/hr for 1-2
  hr
• Reduce IVF gradually when rate of plasma leakage
  decreases towards the end of the critical phase
  adequate Uop/fluid intake, Hct decreases below
  baseline value in a stable patient
• Monitoring
• VS, peripheral perfusion (q15min-1hr) until pt is
  out of critical phase
• Uop (4-6 hourly)
• Hct (pre- post IVF, then 6-12 hourly)
• Glucose
• Renal, hepatic, coags, CNSprn

194
Indications of hospitalizations

• Restlessness or lethargy frequent vomiting one or
  two days of febrile illness.
• Cold extremities or circumoral cyanosis.
• Bleeding in any form.
• Rapid and weak pulse.
• Capillary refill time gt 3 seconds.
• Narrowing of pulse pressure (lt20 mm Hg) or Hypo
  tension.
• Hematocrit of 40 or rising hematocrit.
• Platelet count of lt 1,00000/ mm3
• Acute abdominal pain
• Evidence of Plasma leakage. Eg. Pleural effusion
  /Ascities

195
Management (7)Severe Dengue

• Lab CBC, other organ function tests
• Compensated Shock
• IVF (isotonic crystalloid, 5-10 mL/kg/hr over 1
  hr).
• Reassess
• If improved decrease IVF gradually to 5-7
  mL/kg/hr for 1-2 hr, then to 3-5 mL/kg/hr for 2-4
  hr, then to 2-3 mL/kg/hr for 2-4 hr, then further
  per hemodynamic status
• If unstable Check Hct after first bolus
• Hct increased/high (gt50) repeat second bolus of
  crystalloid at 10-20 mL/kg/hr improvement? Then
  decrease to 7-10 mL/kg/hr for 1-2 hrs, continue
  to wean
• Hct decreases Cross match and transfuse blood
  ASAP

196
(No Transcript)
197
Management (8) Hypotensive shock

• IVF resuscitation with crystalloids or colloids
  at 20 mL/kg as a bolus for 15 min
• Improved?
• Crystalloid/colloid solution (10 mL/kg/hr) for 1
  hr, taper gradually
• Unstable?
• Review Hct taken prior to first bolus
• HCT low (lt40 in children/adult females, lt45
  adult males) cross match and transfuse!
• HCT high (WRT baseline) change to IV colloids at
  10-20 mL/kg as a second bolus over 30 min to 1
  hr, reassess
• Improving decrease rate to 7-10 mL/kg/hr (1-2
  hrs), then back to IV crystalloids and reduce
  rates as above
• Unstable repeat Hct
• Decreased bleedingT/C, transfuse
• Increased/remains high (gt50) continue colloid
  (10-20 mL/kg) as a 3rd bolus (1 hr), reduce to
  7-10 mL/kg/hr (1-2 hr), change to crystalloid and
  reduce rate as above
• Hemorrhage PRBC (5-10 mL/kg) or whole blood
  (10-20 mL/kg)

198
The replacement of plasma loss

• Immediate replacement of plasma loss with
  isotonic salt solution (5 dextrose in ringer
  acetate solution or 5 dextrose in NS) at the
  rate of 10-20ml / kg body weight are in case of
  profound shock (grade-4) as a bolus of 10ml/kg
  body weight (1-2 times) should take place.

199

• ABCS
• If the patient is not responding to two boluses
  of crystalloid, contributory causes for shock
  other than plasma leakage should be considered.
  These
• are,
• Acidosis check venous blood gas (if present,
  check liver and renal profiles)
• Bleeding check HCT
• Calcium and other electrolytes (sodium and
  potassium) - check serum
• Sugar check random capillary blood sugar

200
Fluid management Colloids

• Dextran 40 and plasma
• Management of Shock
• DSS is a medical emergency that requires prompt
  and vigorous volume replacement therapy.
• There are also electrolytes (sodium) and acid
  base disturbances it must be consider that there
  is a high potential for developing DIC. And
  stagnant acidemia.
• Blood will promote and or enhance DIC which may
  lead to sever hemorrhage and or irreversible
  shock.

201

• It is important to correct these conditions as
  quickly as possible.
• If the patient is clinically acidotic one dose
  of 50 ml of 8.4 sodium bicarbonate may be
  given empirically if blood gas cannot be
  assessed.
• Empirical treatment with 10 calcium gluconate 10
  ml over 10 minutes is justifiable if a patient
  is in shock and is not responding to adequate
  fluid replacement, this may be continued six
  hourly.
• IV calcium gluconate may be used in patients
  who show evidence of myocardial involvement as
  well, as hypocalcaemia is common in DHF patients
  and calcium may improve the myocardial
  contractility in such patients

202

• If the blood g l u c o s e l e v e l i s
  less than 7 0 mg/dl correct it by giving
• 15 20g glucose orally or intravenously. At the
  time of shock, use
• 3040 ml of 50 Dextrose (15-20g) intravenously.
  Re-check capillary
• blood sugar in 15 minutes and if it is less than
  7 0 mg/dl repeat 30-
• 40ml of 50 Dextrose intravenously.

203
D H F Discontinuation of IV fluids

• WHEN
• The hematocrit reading drops to around 40
• Vital signs are stable.
• A good urine out flow indicates sufficient
  circulate renal volume.
• A return of appetite and diuresis are signs of
  recovery

204
D H F Management (contd)

• Sedations are needed in some cases because of
  marked agitation.
• Hepatotoxic drugs should be avoided.
• Chloral hydrate orally or rectally recommended in
  a dose of 30 50 mg/kg as a single hypotonic
  dose (maximum dose 1gram).

205
D H F Management (contd)

• In cases without pulmonary complications
  paraldehyde 0.1ml/kg I.M. (maximum dose 10ml)
  also be use.
• Oxygen therapy should be given to all patients in
  shock. The oxygen mask or tent may increase
  apprehension.

206
Management of fluid overload

• Review the total intravenous fluid therapy and
  clinical course and check and correct for abcs.
• All hypotonic solution should be stopped .
• Switch from crystalloid to colloid solutions as
  bolus fluid .
• Dextran 40 is effective as 10 ml/kg bolus
  infusion , but the dose is restricted to
  30ml/kg/day because of its renal effects .

207
ManagementBlood transfusion

• Transfusion with fresh whole blood is preferable
  and the amount to given should be such that
  normal RBC concentration is not exceeded.
• Fresh Frozen Plasma (FFP) may be indicated in
  cases where consumptive coagulopathy causes
  massive bleeding. DIC is usual in sever shock and
  may play an important part in the development of
  massive bleeding or lethal shock.

208
ManagementPlatelet transfusion

• Platelet transfusion in cases of DHF / DSS is
  also surrounded with controversies. Mild
  reductions in platelet counts are usually not
  associated with significant bleeding.
• Secondly thrombocytopenia in DHF / DSS is a short
  lived phenomenon with platelets returning to
  normal by 7 to 9 days.
• Platelet transfusions are recommended only for
  children with platelet count of 50,000 / mm3 and
  having significant bleeding manifestations.
• Prophylactic platelet concentrate is indicated
  when platelet count is less than 10000-20000 /
  mm3 (10 to 20ml / kg of platelet).

209
Polyserosities

• Caution must be taken before drainage as the
  chances of sever hemorrhages are high.
• Patients should be haematologically stabilized
  first with use of fresh whole blood, FFP or
  platelet concentrates and drainage of these
  fluids should be done slowly to prevent sudden
  circulatory collapse.
• Large pleural effusions during the recovery phase
  after 48 hours may need small doses of frusemide
  (0.25 to 0.5 mg / kg B/w 6th hourly) with these
  method it may possible to avoid insertion of
  intercostal drains.
• Generally steroids do not shorten the duration of
  disease or improve the prognosis in children
  receiving careful supportive therapy.

210
Complications

• 1- Febrile phase - Dehydration
• 2- Critical phase - Shock from plasma
  leakage severe haemorrhage organ impairment
• Dengue Shock Syndrome
• 3- Recovery phase - Hypervolaemia

211
Management of Hepatic Encephalopathy in DHF

• ? Maintain adequate airway and oxygenation
• ? Infuse minimal intravenous fluids sufficient to
  maintain intravascular volume (80 of
  maintenance)
• ? Use hyper-oncotic colloid solution early if HCT
  is increased
• ? Infuse Mannitol to reduce intracranial pressure
  if renal functions are normal
• ? Take measures to maintain serum sodium
  in-between 145-155 meq/L. (3 hypertonic saline
  may be of use if Mannitol cannot be used, and if
  serum sodium is very low)

212

• Maintain blood sugar above 60 mg/dl
• ? Give a single dose of Vitamin K 10 mg IV
• ? Give Lactulose to maintain 3-4 bowel motions
  per day. However, lactulose commonly causes