Dengue Hemorrhagic Fever

A presentation on Dengue hemorrhagic fever, with proven insights from CDC, Medscape & Mayoclinic.

1. DENGUE HEMORRHAGIC FEVER BY ABDULLAHI S. SHEMA

2. OVERVIEW Dengue (DENG-gey) fever is a mosquito-borne illness that occurs in tropical and subtropical areas of the world. Mild dengue fever causes a high fever and flu-like symptoms. The severe form of dengue fever, also called dengue haemorrhagic fever, can cause serious bleeding, a sudden drop in blood pressure (shock) and death.

3. EPIDEMIOLOGY  Millions of cases of dengue infection occur worldwide each year. Dengue fever is most common in Southeast Asia, the western Pacific islands, Latin America and Africa. But the disease has been spreading to new areas, including local outbreaks in Europe and southern parts of the United States. Researchers are working on dengue fever vaccines. For now, in areas where dengue fever is common, the best ways to prevent infection are to avoid being bitten by mosquitoes and to take steps to reduce the mosquito population.

4. PATHOLOGY Plasma leakage is specific to the pleural and peritoneal surfaces: plasma leakage results from cytokine mediated increase in vascular permeability. The immune system is implicated in the pathogenesis of DHF owing to the increased propensity to develop DHF with secondary dengue infection. The pathogenesis of bleeding in DHF is unclear even though well-recognised coagulation disturbances do exist. 

5. MODE OF TRANSMISSION Dengue viruses are spread to people through the bites of infected Aedes species mosquitoes (Ae. aegypti or Ae. albopictus).  These are the same types of mosquitoes that spread Zika and chikungunya viruses. A pregnant woman already infected with dengue can pass the virus to her foetus during pregnancy or around the time of birth. Rarely, dengue can be spread through blood transfusion, organ transplant, or through a needle stick injury.

6. SYMPTOMS/CF Patients with Dengue fever usually present with a high fever — 104 F (40 C) — and any of the following signs and symptoms: Headache Skin erythema Myalgia Bleeding (any haemorrhagic manifestations) Muscle, bone or joint pain Nausea Vomiting Pain behind the eyes Swollen glands Rash

7. Most people recover within a week or so. In some cases, symptoms worsen and can become life-threatening. This is called severe dengue, dengue haemorrhagic fever or dengue shock syndrome. Severe dengue: happens when the blood vessels become damaged and leaky. And the number of clot-forming cells (platelets) in the bloodstream drops. This can lead to shock, internal bleeding, organ failure and even death.

8. WARNING SIGNS OF SEVERE DENGUE FEVER The warning signs usually begin the first day or two after the fever goes away, and may include: Severe stomach pain Persistent vomiting Bleeding from gums or nose Blood in urine, stools or vomit Bleeding under the skin, which might look like bruising Difficult or rapid breathing Fatigue Irritability or restlessness

9. DIAGNOSIS Dengue fever is diagnosed thorough careful clinical (History & Examination) and laboratory procedures which includes: Nucleic acid amplification tests (NAATs) Serologic tests Cross-reactive flaviviruses And IgG antibody testing amongst others.

10. MANAGEMENT APPROACH: Dengue fever is usually a self-limited illness. There is no specific antiviral treatment currently available for dengue fever. Supportive care with analgesics, fluid replacement, and bed rest is usually sufficient. Acetaminophen may be used to treat fever and relieve other symptoms.  Patients with dengue haemorrhagic fever or dengue shock syndrome may require intravenous volume replacement. Plasma volume expanders can be used in patients who do not respond to isotonic fluids. Aspirin, nonsteroidal anti-inflammatory drugs (NSAIDs), and corticosteroids should be avoided. Management of severe dengue requires careful attention to fluid management and proactive treatment of haemorrhage.

11. PREVENTION: The only way to truly prevent dengue virus acquisition is to avoid being bitten by a vector mosquito. VACCINATION: One vaccine is currently approved for the prevention of dengue infection. Sanofi Pasteur registered Dengvaxia (CYD-TDV), a live recombinant tetravalent vaccine, in several countries in late 2015-2016, with Mexico being the initial country to register the vaccine in December 2015.

12. CONCLUSION Dengue fever is a mosquito-borne illness that occurs in tropical and subtropical areas of the world which can be transmitted transplacental or rearely through blood transfusion and organ transplant. It is characterized by high fever and flu-like symptoms amongst others. The only way to prevent Dengue fever is to avoid mosquito bites and prevent mosquito population. It is a self-limited illness. There is no specific antiviral treatment currently available for dengue fever Supportive care with analgesics, fluid replacement, and bed rest is usually sufficient in management of dengue fever.

13. Reference: https://emedicine.medscape.com/article/215840-overview https://www.mayoclinic.org/diseases-conditions/dengue-fever/symptoms-causes/syc-20353078 https://www.cdc.gov /dengue/resources/dengue&DHF%20information%20for%20Health%20Care%20Practitioners_2009.pdf