Recognizing plasma leakage in dengue fever

Wednesday 29th July 2009 HCFI New Delhi: Dengue shock syndrome is the main lethal threat to dengue and is often predictable and treatable in time said Dr KK Aggarwal President Heart Care Foundation of India and Director IMAAKN Sinha Institute.

The period of maximum risk for shock is between the third and seventh day of illness. This tends to coincide with resolution of fever. Plasma leakage generally first becomes evident between 24 hours before and 24 hours after fever is over.  Often people insist on a discharge form the hospital when the fever is over or do not want to get admitted once the fever is over.

Plasma leakage is the most specific and life-threatening feature of dengue hemorrhagic fever. This increase in vascular permeability develops rapidly, over a period of hours and thus a person cam become worse over hours and die as in patients with marked plasma leakage, shock may develop, especially if supportive treatment is delayed.

Once a person develops clinical shock or low blood pressure (dengue shock syndrome) the case-fatality rate is 12 percent even with aggressive therapy.

Plasma leakage also coincides with severe low platelet counts and elevation of SGOT liver enzyme test. Abdominal pain also precedes the onset of plasma leakage in approximately 60 percent of patients.
The presence of intense abdominal pain, persistent vomiting, sudden change from fever to hypothermia, and marked restlessness or lethargy should alert the clinician to possible impending dengue shock syndrome.
A doctors can diagnose increased vascular permeability (plasma leakage syndrome) by demonstrating hemoconcentration (20 percent or greater rise in hematocrit above baseline value) or by presence of fluid in the lungs cavity (pleural effusion,) or in the abdominal cavity (ascites).

All such case will have a pallet count of lower than one lac, fever lasting 2-7 days and a hemorrhagic tendency (as demonstrated by a positive tourniquet test by the doctor) or spontaneous bleeding.
Another bed side easily done test is to demonstrate a lower pulse pressure or the difference between upper and lower blood pressure of less than 20 mm Hg.