UNCLASSIFIED
Flight Surgeon RSV Day
ANGRC
Joint Base Andrews
Integrity - Service - Excellence
UNCLASSIFIED
Tropical Medicine : Dengue Fever
Bryan S. Delage MD COL MC FS SAS
JFHQ North Dakota National Guard
26 July 2014
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Dengue Fever
• I have no pharmaceutical bias or relationship to
report
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Patient
• Jim was a 61 y.o. male, who had returned from
the Dominican Republic on vacation and
presented to his primary care physician after a
week of fever, and chills and not feeling well, with
some fatigue myalgias and headache.
• His primary care physician sent blood work to rule
out malaria, and then after the patient had left
came to my office to ask the question – What do
you think is going on with this guy ?
• Blood work returned normal, and the patient had
defervesced, and had no further sequelae
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What’s your Diagnosis
• So what would your answer be ?
• Obviously a definitive diagnosis cannot be had
with limited laboratory testing,
• But ……. A case can be made for Dengue Fever!
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Tropical Medicine- Dengue Fever
•
Dengue Fever –
• 1. Overview
• 2. Signs and Symptoms
• 3. Clinical Course
• 4. Diagnosis
• 5. Treatment and Management
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Dengue Fever
• Overview:
• Dengue virus is one of
the leading causes of
illness and death in
tropical and
subtropical areas
• 400 million people are
infected with the 4
strains of Dengue
virus yearly
• It is caused by 4 distinct
serotypes of the dengue
virus (DENV, called
DENV1, ..2, ..3, ..4)
• Single stranded RNA virus
• A Flavivirus in the family
Flaviviridae
• Other viruses in this group
that are important (Yellow
Fever Virus, West Nile
Virus, Japanese and St.
Louis Encephalitis
viruses)
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Dengue Fever
• Overview (cont.) :
• It is an arbovirus, which
means it is arthropodborne, and is transmitted
primarily through an
infected Aedes species of
mosquito; but can be
transmitted by blood
transfusion, organ
transplant, or by needle
stick (all of these from an
infected individual)
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Dengue Fever
Signs and Symptoms:
• Infection with Dengue
virus can manifest in a
spectrum of Dengue that
ranges from an acute mild
febrile illness to classic
dengue fever, to the
severe forms of the
disease DHF ( Dengue
Hemorrhagic Fever) and
DSS ( Dengue Shock
Syndrome)
• About 75% of Dengue
infections are
asymptomatic, and
25% symptomatic ,
most symptomatic
infections present as a
mild to moderate
acute febrile illness;
up to 5% can develop
severe life threatening
disease.
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Dengue Fever- Clinical Course
• The illness begins
abruptly after an
incubation of 4 – 7
days (range 3-14
days).
• It typically goes
through 3 phasesfebrile, critical and
convalescent
• The Fever lasts 2 to 7
days,
• Signs and Symptoms
include: severe
headache, retroorbital pain, muscle
and joint, as well as
bone pain. A macular
or maculo-papular
rash, and can include
petechiae,
ecchymosis, purpura,
epistaxis, bleeding
gums, hematuria
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Dengue Fever – Clinical Course
• The severe forms of
DHF and DSS tend to
occur at the time of
defervescence and on
or about day 7, a high
index of suspicion and
early supportive care
with fluid resuscitation
and colloid
replacement for the
critical 24 to 48 hours
can improve outcome.
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Dengue Fever- Clinical Course
• Markers for more serious
disease include severe
abdominal pain, persistent
nausea, and vomiting,
bleeding mucosa, difficulty
breathing (pulmonary
edema), hypovolemic
shock, abrupt
thrombocytopenia, and
increased hematocrit due
to hemo-concentration.
• Patients will typically
improve during this 24-48
hour critical phase, but
patients with severe
plasma leakage may have
a marked drop in BP, and
irreversible shock and
death may occur. Also
hemorrhagic
complications including
hematemesis, melena and
hematochezia, or
menorrhagia
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Dengue Fever – Clinical Course
• If patients can be
supported through this
critical phase with fluids,
colloid and transfusions,
as the plasma leakage
starts to subside, and fluid
is re-absorbed their
hemodynamics will
stabilize, and a natural
diuresis will typically start
to reverse the fluid
retention, and edema as
well as ascites.
• Hematocrit may drop
due to dilution effects
as fluid is reabsorbed,
and white count starts
to rise, and then a
slow recovery of
platelets. During the
convalescent phase
the rash may
desquamate and
become pruritic.
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Dengue Fever – Lab Findings
• There can be
leukopenia, as well as
thrombocytopenia,
hyponatremia, AST,
and ALT elevation,
and sed rates typically
remain stable.
•
•
Lab confirmation can be made
from a single acute phase
serum specimen that is drawn
early <= to 5 days from onset of
fever; with Reverse
Transcriptase – PCR for DENV
genomic sequences, or
immunoassay for DENV
nonstructural protein 1 (NS 1)
Later in the course ( 4 days or
more after onset of fever) the
PCR or NS1; and IgM antiDENV may be confirmatory
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Dengue Fever- Diagnosis
• The diagnosis of Dengue
should be considered in a
patient presenting with
fever who was in an
endemic area within 2
weeks of the onset of
illness, that persists, and
should be reported to the
local health department;
as it is nationally
reportable
• As listed on the last
slide confirmation by
RT- PCR or
Immunoassay for NS1
are confirmatory, and
IgM- anti-DENV
suggests a likely
recent DENV infection
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Dengue – Endemic Areas
• Dengue is a tropical
and sub-tropical
disease, and its
distribution is
throughout central and
South America, the
Caribbean, Southeast
Asia and Africa, who’s
range has increased
over time.
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Dengue Fever – Endemic Areas
• Africa
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Dengue Fever- Endemic Areas
• Pacific and Asia
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Treatment and Management
• There is no anti-viral
medication that is
effective for Dengue
• Treatment is aimed at
symptoms, and
• Treatment of severe
cases such as DHF or
DSS, includes fluid
replacement, treatment or
coagulation disorders, and
colloid, crystalloid and
isotonic fluids until the
symptoms start to abate.
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Treatment and Management
• Close monitoring for
development of more
serious dengue,
• Avoidance of ASA,
and other NSAID’s
with the increased
bleeding risk
• Confirmed or
suspected cases need
to be reported to the
State Health
Department and CDC.
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Another Possibility ?
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Chikungunya Virus
• Arbovirus
• Similar symptoms to
Dengue Fever
• http://www.cdc.gov/me
dia/DPK/2014/dpkchikungunya.html?s_c
id=cdc_homepage_wh
atsnew_001
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Chickungunya virus
• Transmitted by an
Aedes mosquito,
predominantly Aedes
aegypti, and Aedes
albopictus
• Humans are the
primary host
• Blood borne
transmission is
possible, as well as in
utero and is found in
breast milk
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Chikungunya
• Now there are cases
found in the US
• Incubation is 3-7 days,
• Usually marked by the
acute onset of fever and
polyarthralgia
• Usually symptoms are
bilateral, symmetric, and
severe and debilitating
• Other symptoms include
headache, myalgia,
arthritis, nausea and
vomiting, as well as a rash
that is maculo-papular
• http://www.cdc.gov/chi
kungunya/geo/unitedstates.html
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Chikungunya
• Preliminary diagnosis
is based on clinical
feature’s, places and
dates of travel; and
activities
• Lab diagnosis by
testing of serum or
plasma for virus, viral
nucleic acid or virus
specific IgM
• Chikungunya testing is
done at the CDC, a few
state health departments,
and one commercial
laboratory
• Viral culture in the first 3
days of illness may be
utilized
• Chikungunya virus
antibodies normally
develop toward the end of
the first week of illness
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Chikungunya
• Instructions for sending
samples can be found on
the CDC website
• There are no serious
forms like in Dengue, no
DHF or DSS variants
• There is some increased
morbidity and mortality at
the extremes of age
• Symptoms can persist,
especially the arthralgia
for prolonged periods of
time
• http://www.cdc.gov/chi
kungunya/geo/americ
as.html
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Summary
•
•
•
Dengue Fever is an acute
febrile illness seen throughout
the tropics and subtropics
Diagnosis can be done by RTPCR less than 5 days and
immunoassay for NS 1, as well
as IgM for DENV later
There are more serious
manifestations that can result in
increased morbidity and
mortality (DHF and DSS) that
typically occur about the 7th day
at about the time of
defervescence, and need
aggressive fluid management
and possible transfusion of
blood products, and
management of bleeding
• Service members
traveling to these areas
especially the carribbean
and other tropics need to
be informed about the
need to use protective
measures to avoid
infection,
• Also information on
chikungunya and need to
use measures to avoid
infection with clothing and
repellant in this case as
well
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Summary
• In both cases,
suspected cases need
to be reported to the
CDC through the
State Health
Department.
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Bibliography
• Dengue haemorrhagic
fever; Diagnosis,
treatment, prevention
and control; 2nd
edition, World Health
Organization ,
Geneva, 1997
• CDC.gov
• http://www.cdc.gov/me
dia/DPK/2014/dpkchikungunya.html?s_c
id=cdc_homepage_wh
atsnew_001
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