dengue
DENGUE

Dengue infection is caused by the dengue virus that belongs to the family Flaviviridae. It is generally self-limiting and rarely fatal.
There are 4 serotypes (DEN-1, DEN-2, DEN-3, DEN-4). Infection w/ dengue serotype confers lifetime protective immunity to that specific serotype; cross-protection for other serotypes is only short-term.
It is transmitted to humans through the bites of infected Aedes mosquitoes. It is primarily transmitted by female Aedes aegypti, a tropical and subtropical species.Humans & monkeys are the amplifying hosts after the mosquito bite.
After 4-10 days of incubation period, illness begins immediately.
The acute phase of illness lasts for 3-7 days, but the convalescent phase may be prolonged for a week and may be associated with weakness and depression especially in adults.

Supportive Therapy

The management of dengue fever (DF) & dengue hemorrhagic fever (DHF) is symptomatic & supportive

  • Rest
    • Bed rest is advisable during the acute febrile phase
  • Fluids
    • Drink plenty of oral fluids to prevent dehydration
    • Fruit juice or electrolyte replacement solution is preferable over plain water
  • Adequate diet
  • Sponging
    • Tepid sponging to keep the body temp below 40°C
  • Oxygen
  • Provide for all patients in shock

Fluid Replacement Therapy

Dengue Fever (DF)

The management of DF is symptomatic & supportive

  • Electrolytes & oral rehydration solution (ORS)
    • Recommended to prevent dehydration in patients with excessive sweating, nausea & vomiting (N/V) or diarrhea who can tolerate oral fluids
  • Intravenous (IV) fluids
    • Administer to patients who are unable to take fluids orally to prevent dehydration

Dengue Hemorrhagic Fever (DHF)

No specific antiviral therapy is recommended. Symptomatic & supportive treatment is effective & life-saving if given appropriately. Prognosis depends on early diagnosis of DHF.

  • Transfusion of platelets is not recommended for thrombocytopenia
    • May be considered in patients with hypertension & platelets <10,000/mm3

Intravenous (IV) Fluids

  • Judicious volume replacement therapy is mandatory
  • Isotonic crystalloid solutions should be given during the critical period
    • Hyperoncotic colloid solutions eg Dextran 40 or starch solution may be given in patients unresponsive to crystalloids or those with immense plasma leakage
  • Volume & rate of IV fluid therapy should be adjusted according to the volume & rate of plasma loss
  • For isotonic dehydration, 5% glucose diluted 1:1 or 1:2 in normal saline solution (NSS)
  • Adjust throughout the 24-48 hour period of leakage by serial hematocrit determinations & through frequent assessment of vital signs & urine output in order to ensure adequate volume replacement & to avoid overhydration
  • The volume of fluid replacement should be the minimum that is sufficient to maintain effective circulation during the period of plasma leakage that occurs in the convalescent stage
  • Excessive fluid replacement & continuation after leakage stops will cause massive pleural effusion, ascites & pulmonary congestion/edema with respiratory distress when reabsorption of the extravasated plasma occurs in the convalescent stage
    • IV therapy duration <60-72 hours for patients who do not have shock & <24-48 hours for those who have shock
  • The fluid administered to correct dehydration from high fever, anorexia & vomiting is calculated according to the degree of dehydration & electrolyte loss & should have the following composition: 5% glucose in 1/2 or 1/3 physiological saline solution
  • Can also be administered in outpatient rehydration units in mild or moderate cases when vomiting produces or threatens to produce dehydration or acidosis or when hemoconcentration is present

Oral Rehydration Solution (ORS)

  • Eg WHO ORS (90 mmol of Na/L): 1 L of solution contains 3.5 g NaCl, 2.9 g Trisodium citrate dihydrate, 1.5 g KCl, 20 g Glucose; administered 2:1 of WHO ORS to water or fruit juice
  • Generous amounts of fluids should be given orally since high fever, anorexia & vomiting lead to thirst & dehydration

Dengue Shock Syndrome (DSS)

  • Shock is a medical emergency. Patients in shock are in danger of dying unless appropriately managed
    • The duration of shock is usually short; the patient may die within 8-24 hours, but recovery is usually rapid following antishock therapy
  • Volume replacement is the most important treatment measure & immediate administration of IV fluid to expand plasma volume is essential
  • IV fluids
    • Start initial IV fluid therapy with Ringer’s acetate or 5% Glucose in NSS
    • Run fluids as rapidly as possible & positive pressure may be necessary in cases of profound shock
    • Continue even when there is a definite improvement in the vital signs & hematocrit is decreased
  • Plasma or plasma expander
    • Administer colloidal plasma soln or plasma expander if shock persists after initial fluid resuscitation

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