Dengue Fever

DENGUE FEVER

Epidemiology and Pathogenesis

• endemic in South East Asia, Africa, Caribbean.
• principle vector is Aedes aegypti
• 4 serotypes of dengue virus
• Homotypic immunity is life long but heterotypic immunity between serotypes lasts only a few months.
• Incubation period : 2-7 days

Clinical features

1. Prodrome

• 2 days of malaise and headache

2. Acute Onset

• Fever
• Backache
• Arthralgias
• Headache
• Generalised pains (breakbone fever)
• Pain on eye movement
• Lacrimation
• Anorexia
• Nausea
• Vomiting
• Relative bradycardia
• Prostration
• Depression
• Lymphadenopathy
• Scleral injection

3. Fever

• continuous or saddle back, with break on the 4th/5th day, usually lasts 7-8 days.

4. Rash

• Transient macular in first 1-2 days
• Maculo-papular, scarlet morbiliform on trunk from days 3-5
• Typically described as islets of white in a sea of red appearance
• Blanches under pressure

Dengue Haemorrhagic Fever

• Pre-existing immunity to a dengue virus serotype, heterotypic to the one causing current infection predisposes to the syndrome.
• Thrombocytopoenia, haemoconcentration, hypotension, circulatory failure
• Minor or major haemorrhagic signs
• Disseminated Intravascular Coagulation, complement activation and release of vasoactive mediators contribute to the pathogenesis.
• Mainly occurs in children
• In adults, may be characterized by elevated liver enzymes, haemostatic abnormalities and GI bleeding

Investigations

Confirmed by

1. Fourfold rise in IgG titres
2. Isolation of dengue virus from blood
3. Detection of genomic sequences by PCR

Management and Prevention

• No specific treatment
• Pains relieved by Paracetamol (avoid aspirin)
• Volume replacement, manangement of shock
• Abolish breeding places of vector

DENGUE MANAGEMENT SCHEME IN MELAKA GH

Definition Of Dengue Fever

Acute onset of high grade fever (2-5 days) associated with 2 of the following :

1. Frontal Headache
2. Retro-ocular pain
3. Myalgia and arthralgia
4. Rash and mild haemorrhagic manifestation

Clinical Case Definition Of Dengue Haemorrhagic Fever

1 or more of the following:

1. Thrombocytopoenia
2. Positive torniquet test (Hess test)
3. Petechiae, ecchymoses or purpura & bleeding from mucosa/injection site/others
4. Sign of plasma leakage, i.e. ascites, pleural effusion & hypoproteinemia

Clinical Case Definition Of Dengue Shock Syndrome

All above criteria and evidence of circulatory failure manifested by :

1. Rapid and weak pulse
2. Hypotension with cold and clammy hands
3. Altered mental status

Provisional/Suspected case

A case compatible with the clinical description.

Confirmed case

A case compatible with the clinical description and lab confirned (positive serological test)

All suspected/confirmed cases must be reported as a case of dengue to the local authorities.

ANILDEV SINGH MALHI
041303008