This presentation is for medical students and general practitioner It contains detailed account of epidemiology, causation, clinical features, investigations,diagnosis, treatment of dengue fever. contains pictures. useful latest and comprehensive information about Dengue. It also contains dengue case definitions of WHO.It also lists the complications of dengue. It enumerates the warning signs for more severe form of dengue fever. Includes risk factors for dengue shock syndrome and dengue hemorrhagic fever.It includes a list if clinical markers of dengue. Also details about the habits of the dengue vector , aedes aegypti mosquito
Artifacts in Nuclear Medicine with Identifying and resolving artifacts.
Dengue fever- clinical features,investigations, diagnosis, treatment and prevention
1. DENGUE FEVER
Dr Deepak G Bhosle
Professor
Department of Medicine
Bharati Vidyapeeth Medical College
& Bharati Hospital,Pune
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2. DENGUE IS ALSO KNOWN AS
Philippine hemorrhagic fever
Thai hemorrhagic fever
Singapore hemorrhagic fever
Onyong- Nyang Fever
West Nile Fever
Dandy fever
Break Bone Fever
Dengue like Disease
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3. CAUSATIVE AGENT
Dengue virus is a Arbovirus from the genus
Flavivirus
Single stranded RNA virus
Four species – Den 1,2,3,4
Infection with one serotype provides lifelong
immunity for that species.
Transmitted by mosquito ,Aedes aegypti
closely associated with human habitation.
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4. ADES AEGYPTI MOSQUITO
Lays its eggs in clean, stagnant water.
One distinct physical feature – black and white
stripes on its body and legs – Tiger mosquito
Bites during the day.
On average, a female Aedes mosquito can lay
about 300 eggs during her life span of 14 to 21
days.
Only the female Aedes mosquito feeds on blood.
This is because they need the protein found in
blood to produce eggs. Male mosquitoes feed only
on plant nectar
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7. EPEDIOMOLOGY
Rapid expansion of urbanization
Inadequate closed drainage
↑ movement of human population within and
between countries
Insecticide resistance in mosquito vector population
are few of the reasons for ↑ dengue transmission in
recent years
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8. CLINICAL FEATURES
a) Classic Dengue – Break Bone fever
Incubation period is 4 – 6 days ( range 3 -14)
Abrupt onset of fever, chills, headache, retro orbital
pain and backache
Fever is 39 – 40◦ C; remission of 2days followed by
second febrile phase for 1 -2 d.
Biphasic curve or saddle back fever.
Fever lasts for 5- 7 days
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9. Transient generalized erythematous rash – first 24 – 48
hrs. This morbilliform rash appears on trunk, spreads to
face and limbs sparing palms and soles. It lasts for 1- 5
days.
Generalised myalgias, arthralgia and constitutional
symptoms like anorexia, nausea, vomiting and dysgeusia
may be +nt.
Relative bradycardia and generalised lymphadenopathy
may be +nt.
Marked leucopenia and thrombocytopenia.
↓ Platelets is due to impaired megakaryocyte production
& ↑ platelet destruction.
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15. b) Dengue Hemorrhagic fever
Is defined as acute febrile illness with minor or major
bleeding, thrombocytopenia (platelet ≤ 1.0 lakh/mm) &
evidence of plasma leakage ->hemoconcentration (↑
hematocrit ) & pleural or other effusions ( serositis).
Primarily in children and young adults.
Susceptibility ↓ after 12 yrs of age.
DHF, DSS develops arround 3rd to 7th day
+ve Tournquet test – inflate the BP cuff
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16. on upper arm to midway between systolic and diastoic BP
for 5 min. +ve test > 20 petechiae/ 2.5 cm square.
Also known as Hess Test.
Petechiae, bruised skin ,S/c bleeding at venepuncture
site seen in most cases.
Transudate due to excessive capillary leakage leads to
pleural effusion & ascites.
Progressively ↓platelet count, ↑ hematocrit indicate
probability of impending shock.
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18. c) Dengue shock syndrome
DSS is DHF with signs of circulatory failure
Warning signs are intense, sustained abdominal pain,
persistent vomiting, restlessness or lethargy & sudden
change from fever to hypothermia with sweating and
prostration.
Pt. may recover with i/v fluids, but shock may recur.
Once shock sets in ,mortality is high, 12 -44%
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19. WHO case definitions
Probable case – An acute febrile illness with 2 or more
of following – Headache, retro-orbital pain, myalgia &
arthralgia, nausea & vomiting, skin rash, hemorrhagic
manifestations ;
AND
supportive serology
OR
occurrence at the same location & time as other
confirmed cases of Dengue.
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20. Confirmed Case
Confirmation of the Dengue case is based on Lab
criteria. Virus isolation from serum or tissue samples.
OR
Demonstration of 4 fold rise in IgG or IgM antibody titers
in paired serum samples.
OR
Demonstration of Dengue antigen in tissue, CSF by
immunocytochemistry or detection of genomic sequence
by PCR.
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21. CRITERIA FOR DHF
(ALL 4 CRITERIA ARE REQUIRED)
Fever or h/o fever lasting 2-7 days
Hemorrhagic tendency
- a +ve tourniquet test
- Petechae, ecchymosis, purpura
- Bleeding per mucosa, GIT , etc.
- Hematemesis, Malena
Thrombocytopenia, Platelets < 1.0 lakh/mm3
Plasma leakage
- rise in hematocrit > 20%
- fall in hematocrit > 20% after i/v fluids
- Pleural effusion, ascites, hypoalbuminemia.
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22. CRITERIA FOR DSS
DSS requires all the DHF criteria in addition a
circulatory failure manifested by
- Rapid and weak pulse
- Narrow pulse pressure ( < 20 mm Hg)
- Hypotension, For age > 5yrs < 90 mm Hg
for age < 5 yrs < 80 mm Hg
- Cold dry skin, restlessness
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23. LAB DIAGNOSIS
1. Culture of the virus from serum obtained during
febrile phase. Remains detectable in blood during
febrile period.
2. Serologic diagnosis – by demonstrating a rise in
antibody titer in paired sera drawn 7 to 14 days
apart (This could be by any method like
haemagglutination inhibition, complement fixation
or, neutralizing anibodies)
Rise in IgM antibody is more specific for recent
infection; rising titer more specific.
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24. 3. Newer techniques like RT-PCR ( reverse transcriptase
polymerase chain reaction) are very sensitive & specific
for detecting viral RNA.
4. Thrombocytopenia & hemoconcentration
5. Drop in platelets to , 1.0lakh/mm3 is seen between 3rd
to 8th day of illness
6. Hemoconcentration, with ↑ in hematocrit by 20% is
definitive evidence of ↑ vascular permeability & plasma
leakage
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25. 7. Leucopenia (↓ TLC) & neutropenia; towards the end of
febrile phase
8. Relative lymphocytosis
9. Deranged RFT & LFT & prolonged PT is seen in severe
cases of DHF
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27. DENGUERAPIDCARDTEST-USEDINPRACTISE
In practice in
a patient
with acute
febrile illness
with
thrombocyto
penia and a
positive
rapid card
test for
Dengue IgM
antibody or
Dengue NS1
antigen is
taken as
evidence of
Dengue
fever
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34. TREATMENT
Symptomatic - Paracetamol for fever & myalgia.
Aspirin, NSAIDS avoided due to risk of erosive
gastritis and bleeding.
Rest
Oral rehydration
In DHF careful & repeated estimation of volume
status & fluid replacement is corner-stone of
management. Use isotonic i/v fluids.
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35. TREATMENT 2
Because patients have loss of plasma they must be
given isotonic solution or plasma expanders.
Platelets are replaced if the count is less than
10000 /mm3 or clinical bleeding is +nt. It is better to
give Single donor apheresis Platelets (SDAP) as
compared to RDP to lower the risk of
alloimmunization.
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36. TREATMENT 3
Besides bleeding other complications are ARDS,
renal failure, hepatic failure & encephalopathy.
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37. PREVENTION AND CONTROL
It is by control of mosquitoes which live & breed in
stagnant water in and around the house.
Lays eggs preferentially in jars, discarded containers,
coconut shells, old tires etc.
Year round breeding
Tropical regions like India are its favorite zones.
How to prevent mosquito spread?
Do not allow empty vessels, coconut shells, plastic
containers, flower pots, tires etc to collect rain water
in them
Frequently (once in 2-3 days) empty all water storage
containers
Cover your overhead tanks to prevent mosquitoes
breeding in fresh water
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38. PREVENTION AND CONTROL 2
Vector control can be done by simple measures like
using insect repellants, indoor space spray
insecticides .
How to prevent mosquito bites?
Screen your homes with mosquito screens like
Netlon .
Wear full clothing – long sleeves
Apply mosquito repellents like Odomos, Goodnignt
Keep Dengue fever patient under mosquito net
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39. If you think education is
expensive ,Try Ignorance.
- Dereck Bok
dgbhosle@
gmail.com
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