Dengue Fever

Mahadevappa Hunasikatti MD DPM DCR, FCCP

President, Global Health Care Consultants MD PC2826 Old Lee highway # 250, Fairfax, VA 22031

Tel: 703-573-9212: Fax: 703-573-9219drhunasikatti@yahoo.com

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

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).

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.

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.

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

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

Clinical Features:

• Aches all over the body ( Breakbone syndrome)-Arthralgia, Myalgia

• Headache• Nausea , vomiting• Rash-maculo papular• Weakness• Sore throat• Anorexia

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.

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.

Signs to watch for Dengue Hemorrhagic Fever:--

• Abdominal pain• Hypothermia• Thrombocytopenia• Altered mental state• Restlessness

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

Diagnosis:

• 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

Diagnosis Dengue Fever:--

• Characteristics:• -Thrombocytopenia• -Leukopenia• -Moderate AST and ALT elevation

Dengue Hemorrhagic Fever:-

• Increased HCT• Hypoprototeinenia• Increased PT• Increased PTT• Decreased Fibrinogen• Increased Fibrin Split Products• Stool: OB• UA

Dengue Fever—Work Up:--

• Chest X Ray• ABG-in sever cases• CT Scan of Brain-if any altered mental state• Biopsy of skin lesion• EKG-Non-specific

Reportable illness in United States:

• Remember to report to authorities in USA:

• -Demographics • -Travel hisotry• -Date of onset of illness• -Hospitalized or not• -Outcome

Work up…

• Most common electrolyte abnormality: Hyponatremia

• Correct metabolic acidosis• Low Albumin• Increased Transaminases• DIC

Case definition Dengue fever:--

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

Case definition; Dengue Shock Fever:--

• Narrow Pulse Pressure: < 20 mm Hg-Elevated Diastolic pressure

• Cool, Clammy skin• Hypotension• Altered Mental state

Treatment of Dengue Fever:---

• Self limited disease –usually• Analgesia: Acetaminophen• Avoid:• -NSAID• -ASPIRIN• Corticosteroids

Treatment of Dengue fever:---

• IV Fluids: NS preferred: Isotonic fluids• Treat any hemorrhage• -PRBC• -Platelet• Bed rest• Treat Shock –asap with adequate fluids

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

Vaccination:

• No vaccine is currently available

• CDC:• Tel: 1-800-232-4636

Thank You

• If you have any questions feel free to e-mail me:

• drhunasikatti@yahoo.com