Archive for the ‘Yellow Fever In Children’ Category

Clinical Course Of Dengue

Rationale:

Dengue is the most important mosquito borne viral disease that burdens tropical regions around the world. A recent estimate of 36 million cases of dengue fever occur annually, resulting in 2.1 million severe dengue cases with 21,000 deaths each year. Thailand has been a dengue endemic area since the 1950s. Knowledge and experience on dengue viral infection has been accumulated and applied for effective management and control of dengue infection. Through this particular training course, participants will gain knowledge and experience from real situation in this highly endemic area. Proper management of dengue viral infection requires an update comprehensive knowledge in all relevant aspects.

Objective:

To provide, review and update basic and most relevant advanced knowledge and experience with dengue disease, regarding its epidemiology, clinical management, integrated vector management and disease control.
Course venue:
The course will be held during 16-21 August 2010, at the Faculty of Tropical Medicine, Mahidol University, 420/6 Ratchawithi Road, Bangkok, 10400, Thailand

Participant:

Medical Doctors or Health Officers
Course Registration Fee:

• 6 days whole course: 1,200 USD
• 4 days theoretical aspects: 750 USD
• 2 days workshop (select only one workshop): 550 USD

The course registration fee includes lunches, welcome and farewell dinners, coffee breaks, field site traveling and accommodation during field visit. The fee should be paid in advance directly to the Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand. This course requires a minimum of participants at least 5 persons, and maximum is 20 persons for each workshop.
Course content:
1. Dengue epidemiology current situation
2. Dengue virology
3. Pathogenesis & Pathophysiology of dengue infection
4. Potential antiviral drugs
5. Clinical characteristics of dengue
6. Clinical approach to suspected dengue infection
7. Dengue infection in adolescent and adult
8. Dengue in special circumstances
9. Unusual manifestations in dengue infection
10. Management of dengue fever / dengue hemorrhagic fever
11. Laboratory dengue diagnosis
12. Future directions in dengue diagnosis/ management
13. Current topics in vector biology
14. Integrated vector management
15. Dengue vaccines currently in the pipeline

2-Day Workshop

1. Practice in dengue laboratory diagnosis
2. Clinical diagnosis & management
3. Vector control & community participation

Learning experience:

This course consists of lectures, case demonstrations and discussion at the Faculty of Tropical Medicine, Bangkok as well as case studies, ward rounds, laboratory practices in a hospital and visiting vector control unit in a dengue endemic area during workshop’s field visit. The course will be conducted entirely in English.

Facilitators:

Experts in various fields of dengue viral infection
Registration & Certificate:
Participants can register for the whole course or select only theoretical course or one workshop. A Certificate of Completion will be awarded to successful participants achieving the registered course accordingly.
Accommodation:
TROPMED International House: single occupancy air-conditioned deluxe class (900 Baht/room/day); does not include meals.

Dengue – clinical course:

Classical dengue fever begins fairly suddenly with fever, headache and sometimes lymphadenopathy. There is no splenomegaly. There is marked muscle pain (breakbone fever), especially in the back and in the extraocular eye muscles (pain behind the eyes when looking sideways). The course of the fever is typically in two episodes (biphasic fever). A rash may appear around the 3rd to 5th day in a minority of patients. After the fever has disappeared, recovery may be long and difficult.

Complicated dengue is rare. Sometimes dengue infection is accompanied by haemorrhaging (Dengue Haemorrhagic Fever) and/or very low blood pressure (Dengue Shock Syndrome). This may be dramatic and mortality is high (50% without treatment). This occurs mainly in children. The cause of this serious course is not an infection with a more virulent virus. Dengue infection leads to the development of circulating antibodies. These mainly protect against the serotype involved (“neutralising” antibodies). However, sometimes these antibodies enhance virus multiplication and cause an increase in the severity of disease following symptoms infection with a different serotype. After infection there is probably life-long immunity against the serotype which caused the infection. In DHF, one can expect :

• fever
• haemorrhagic complications or positive tourniquet test
• thrombocytopenia <>
• signs of plasma loss such as pleural fluid, ascites, hypoproteinaemia, an increase in the haematocrit to > 20% above normal or a drop in the haematocrit of > 20% after hydration.
• The severity of the condition (DHF/DSS) can be given by a clinical score:
• Grade 1: thrombocytopenia (<100,000/µl>20% of the starting value)
• Grade 2: idem as 1 + spontaneous haemorrhages or positive tourniquet test
• Grade 3: idem as 1 or 2 + hypotension
• Grade 4: idem as 3 but the blood pressure is not measurable

Clinical Guidance:

Dengue Virus:

Dengue infection is caused by any one of four distinct but closely related dengue virus (DENV) serotypes (called DENV-1, -2, -3, and -4). These dengue viruses are single-stranded RNA viruses that belong to the family Flaviviridae and the genus Flavivirus—a family which includes other medically important vector-borne viruses (e.g., West Nile virus, Yellow Fever virus, Japanese Encephalitis virus, St. Louis Encephalitis virus, etc.). Dengue viruses are arboviruses (arthropod-borne virus) that are transmitted primarily to humans through the bite of an infected Aedes species mosquito. Transmission may also occur through transfusion of infected blood or transplantation of infected organs or tissues. Human transmission of dengue is also known to occur after occupational exposure in healthcare settings (e.g., needle stick injuries) and cases of vertical transmission have been described in the literature (i.e., transmission from a dengue infected pregnant mother to her fetus in utero or to her infant during labor and delivery).

Clinical Dengue:

Infection with any of the four dengue serotypes can produce the full spectrum of illness and severity.  The spectrum of illness can range from a mild, non-specific febrile syndrome to classic dengue fever (DF), to the severe forms of the disease, dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). Severe forms typically manifest after a two to seven day febrile phase and are often heralded by clinical and laboratory warning signs.  Early clinical recognition of dengue infection and anticipatory treatment for those who develop DHF or DSS can save lives.  While no therapeutic agents exist for dengue infections, the key to the successful management is timely and judicious use of supportive care, including administration of isotonic intravenous fluids or colloids, and close monitoring of vital signs and hemodynamic status, fluid balance, and hematologic parameters. (Recommended therapies and treatment courses for DF, DHF and DSS can be found at the links provided below.)

As the early presentations of DF and DHF/DSS are similar and the course of infection is short, timely identification of persons that will develop severe manifestations can be challenging. There is a long-standing debate as to whether DHF/DSS represents a separate pathophysiological process or is merely the opposite end of a continuum of the same illness. DF follows an uncomfortable but relatively benign self-limited course. DHF may appear as a relatively benign infection at first but can quickly develop into life-threatening illness as fever abates. DHF can usually be distinguished from DF as it progresses through its three predictable pathophysiological phases:

Febrile phase:

Viremia-driven high fevers Critical/plasma leak phase: Sudden onset of varying degrees of plasma leak into the pleural and abdominal cavities
Convalescence or reabsorption phase: Sudden arrest of plasma leak with concomitant reabsorption of extravasated plasma and fluids

For optimal management of the patient with dengue infection, it is important to understand these phases and to be able to distinguish DHF from DF. Early recognition of a patient’s clinical phase is important in order to tailor clinical management, monitor effectiveness of the treatment, and to anticipate when changes in their management are needed.