TreatmentUpdate 67, Volume 8, No 3; April 1996
Sean Hosein

Platelets are small pieces of red blood cells that the body uses to help stop bleeding. When the number of platelets falls below the normal range (350-150) uncontrolled bleeding can occur. In some cases people can live with 50 to 150 platelets. Indeed, in some studies, doctors aim for increasing the platelet count to at least 50 platelets.

The spleen

The spleen is an organ located in the lower left side of the chest under the ribs. Blood flows through the spleen which filters the blood. The spleen contains cells of the immune system and in some cases of HIV infection these cells attack and `eat' the platelets causing the platelet count to fall, a condition called ITP (idiopathic thrombocytic purpura).

Therapies

A number of drugs may be used to increase the platelet count including;

* AZT

* danazol

* dapsone

* prednisone and related drugs

In some people with ITP unrelated to HIV infection, doctors found that taking one gram/day of vitamin C was able to raise the platelet count. In cases where the platelet count remains dangerously low some doctors may decide to remove the spleen (splenectomy). Reports on ITP have appeared in TreatmentUpdate 30, 41, 51 and 54.

Study details

In this experiment researchers used six subjects with AIDS who had symptoms of ITP (no further information was provided). The average CD4+ cell count was 13. Subjects in this study had been treated with infusions of antibodies or AZT, dapsone and prednisone but this did not increase the platelet count. So the researchers then gave them Decadron(R) (dexamethasone) 10 mg four times per day for between 2 and 4 days.

Results

On average it took 17 days for the platelet count to increase to at least 50 platelets. The increased counts ranged between 63 and 248. In four subjects the platelet count fell below 50 but this decrease took up to 6 months to happen in one subject.

Survival

Three subjects died of "AIDS-related [life-threatening] infection [6,7 and 8] months after [receiving] dexamethasone." One subject died from a bacterial infection "2 weeks after [he received Decadron]." The researchers admitted that the Decadron may have played a role in this subject's death. The remaining two subjects have more than 50 platelets and were alive at the time the doctors wrote their report. The researchers note that Decadron should by considered when "standard therapies [don't work]." They also suggested that short courses of Decadron between 2 and 4 days should be tested for the treatment of ITP.

REFERENCES:

1. Ramratnam B, Parameswaran J, Elliot B, et al. Short course of dexamethasone for thrombocytopenia in AIDS. American Journal of Medicine 1996;100:117-118.

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