Dengue Fever Review

1. Dengue Fever
Mahadevappa Hunasikatti
MD DPM DCR, FCCP
President, Global Health Care Consultants MD PC
2826 Old Lee highway # 250, Fairfax, VA 22031
Tel: 703-573-9212: Fax: 703-573-9219
drhunasikatti@yahoo.com

2. Definition:
• Most common arhtropod viral –Arboviral
illness in humans.
• 50-100 Millions are affected
• 4 types of Flavirus
• Its is transmitted by mosqitoes of the genus
Aedes-aegypti

3. Epidemiology:
• Most are asymptomatic 50-90%
• Some result in non-specific febrile illness
• Rarely –may result in complex of classic
dengue fever ( DF)
• Some-may result in bleeding-Dengue
Hemorrhagic Fever ( DHF).

4. Spread:
• Epidemic Spread: Isolated event-single viral
strain. Infection incidence of 25-50%.
Transmission begins in urban centers and then
spreads to rest of the country
• Hyper endemic Spread: Continuous circulation
of multiple viral serotypes –predominant
pattern of global transmission. Antibody
prevalence increases with age. Most adults
are immune.

5. Pathophysiology:
• Mosquito borne illness
• Serotypes DENV 1-4
• Aedes aegypti- is the predominant vector
globally
• Others: Aedes albopictus ( tiger mosquito)
• Hosts:
• Humans are primary reservoir for dengue.

6. Pathophysiology..
• Patients can remain infectious for 6-7 days
• The viruses replicate in the salivary gland
of mosquitos
• Once infected- the dengue has an
incubation period of 3-14 days
• Replicate in dendritic cells, hepatocytes
and endothelial cells

7. Clinical Features:
• Recent travel to endemic region
• Symptoms that begin more than 2 week
after travel from endemic region-is unlikely
to be Dengue fever
• Prodrome: Chills
• Classic: Fever, chills and severe aching ot
head, back and limbs
• Fever last 2-7 days –may be as high as 41
degree celsius

8. Clinical Features:
• Aches all over the body ( Breakbone
syndrome)-Arthralgia, Myalgia
• Headache
• Nausea , vomiting
• Rash-maculo papular
• Weakness
• Sore throat
• Anorexia

9. Clinical Features:-• Bleeding: Petechae, Bleeding
gums, epistaxis, and hematuria
• Lymphadenopathy
• Saddleback fever: Fever abates for a day only
to return next day
• Second rash: later: lasting 1-5 days:
morbilliform, maculopapular , and spares
palms and soles.

10. Clinical Features:--• Recovery is generally slow –but usually
complete recovery takes place.
• At the time of defervescence: Danger!
• --This is the time development of dengue
shock or dengue hemorrhagic fever can take
place.

11. Signs to watch for Dengue
Hemorrhagic Fever:-•
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Abdominal pain
Hypothermia
Thrombocytopenia
Altered mental state
Restlessness

12. Differential Diagnosis:
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Malaria
Ebola virus
Chikungunya fever
West Nile Encephalitis
ITP
Influenza
Hepatitis
Meningitis
Yellow fever
Rocky Mountain Spotted fever
Leptospirosis
Rickettsial infection

13. Diagnosis:
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Blood-Isolation of virus
Ig G and Ig M titers to dengue virus antigens
PCR in CSF or Serum
CBC
CMP
Serum patient and albumin
Liver Panel
DIC Panel

14. Diagnosis Dengue Fever:-•
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Characteristics:
-Thrombocytopenia
-Leukopenia
-Moderate AST and ALT elevation

15. Dengue Hemorrhagic Fever:•
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Increased HCT
Hypoprototeinenia
Increased PT
Increased PTT
Decreased Fibrinogen
Increased Fibrin Split Products
Stool: OB
UA

16. Dengue Fever—Work Up:-•
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Chest X Ray
ABG-in sever cases
CT Scan of Brain-if any altered mental state
Biopsy of skin lesion
EKG-Non-specific

17. Reportable illness in United States:
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Remember to report to authorities in USA:
-Demographics
-Travel hisotry
-Date of onset of illness
-Hospitalized or not
-Outcome

18. Work up…
• Most common electrolyte abnormality:
Hyponatremia
• Correct metabolic acidosis
• Low Albumin
• Increased Transaminases
• DIC

19. Case definition Dengue fever:-•
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Serology: IgG or IgM titres
-NS1
Tournquet test: postive
Petechae, echymosis
Purpura
Bleeding from any site
Thrombocytopenia
Plasma leakage-Increased HCT

20. Case definition; Dengue Shock
Fever:-• Narrow Pulse Pressure: < 20 mm HgElevated Diastolic pressure
• Cool, Clammy skin
• Hypotension
• Altered Mental state

21. Treatment of Dengue Fever:--•
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Self limited disease –usually
Analgesia: Acetaminophen
Avoid:
-NSAID
-ASPIRIN
Corticosteroids

22. Treatment of Dengue fever:--•
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IV Fluids: NS preferred: Isotonic fluids
Treat any hemorrhage
-PRBC
-Platelet
Bed rest
Treat Shock –asap with adequate fluids

23. Prevention:
• Mosquito Repellent: DEET: N, N
Methylbenzamide
• Protective clothing: Permethrine
insecticide impregntion is preferable.
• Mosquito netting: limited value. Aedes are
active in day time
• Indoor spray-eliminate mosquito vector

24. Vaccination:
• No vaccine is currently available
• CDC:
• Tel: 1-800-232-4636

25. Thank You
• If you have any questions feel free to email me:
• drhunasikatti@yahoo.com