Diagnosis tip for dengue

Sanjay Mandal

The drop in platelet count is not the most crucial dengue indicator this season, doctors said on Tuesday. Hematocrit, the volume percentage of red blood cells in the blood, is what one should look out for.

"There has been a change in the dengue management strategy over the past two years," K.K. Aggarwal, the honorary secretary general of Indian Medical Association (IMA), said over the phone from Delhi.

"We don't rely on platelet count anymore but on hematocrit. If the hematocrit rises by more than 20 per cent and the platelet is not dropping, even then the patient needs to be given fluid immediately."

The IMA headquarters in Delhi have recently sent an advisory to its members about the revised strategy of dengue management.

According to Aggarwal, if the hematocrit level rises by more than 20 per cent, it means the difference between lower and upper blood pressure levels is less than 20, a condition that can lead to multi-organ failure.

Doctors in Calcutta, too, said hematocrit should be given priority while treating patients who are not bleeding.

They said many patients go into shock irrespective of the platelet count - a phenomenon explained by the fact that the main pathological problem in dengue is capillary leak, which causes plasma to leak out, leading to shock.

"The most important factor in dengue management is maintaining fluid balance, which prevents the patient from going into shock even if there is a capillary leak. Hematocrit is an indicator of the body's fluid status," said infectious disease specialist Chandramouli Bhattacharya.

Platelet count is essentially a marker of how active the dengue virus is within one's system. A low count suggests an active dengue virus, whereas a rising count indicates recovery.

The normal platelet count is between 1.5 lakh and 4 lakh per micro litre of blood.

"Dengue management should be guided by hematocrit," said paediatric critical care specialist Parthasarathi Bhattacharya. "If it rises, we know the fluid within the body is less than adequate."

Bhattacharya said platelet transfusion was advised unnecessarily in many cases. "Platelet transfusion should be advised if there are specific conditions like bleeding manifestations, particularly mucosal bleeding," he said.

Calcutta has been witnessing an early spurt in dengue - since July - because of intermittent rainfall and lack of proper preventive measures by the civic authorities.