Post-transfusion purpura

Post-transfusion purpura (PTP) is a rare but serious condition that can occur after a person receives a blood transfusion. PTP is characterized by a severe drop in the number of platelets in the blood, a condition known as thrombocytopenia, which occurs 5 to 12 days after the transfusion. This condition leads to an increased risk of bleeding and is more commonly observed in women, especially those who have been previously sensitized through pregnancy or prior transfusions.

Causes

PTP is caused by an immune response to platelet antigens, specifically the human platelet antigen-1a (HPA-1a). When an individual who lacks this antigen receives blood that contains it, their immune system may produce antibodies against the HPA-1a antigen. These antibodies can destroy the recipient's own platelets, leading to thrombocytopenia.

Symptoms

The primary symptom of PTP is the sudden onset of bleeding or purpura (purple bruises or spots on the skin) due to the severe decrease in platelet count. Other symptoms may include petechiae (small red or purple spots on the body), nosebleeds, bleeding gums, and in severe cases, internal bleeding.

Diagnosis

Diagnosis of PTP involves a combination of clinical assessment and laboratory tests. A history of recent blood transfusion, along with the symptoms of thrombocytopenia, can indicate PTP. Laboratory tests include complete blood count (CBC) to measure the platelet count and tests for antibodies against platelet antigens.

Treatment

Treatment of PTP focuses on increasing the platelet count and managing symptoms of bleeding. Intravenous immunoglobulin (IVIG) is the primary treatment and has been shown to be effective in increasing platelet counts. In some cases, steroids may also be used to suppress the immune response. Platelet transfusions are generally avoided as they can exacerbate the condition.

Prevention

Preventing PTP involves identifying at-risk individuals, such as those with known antibodies against platelet antigens, and using blood products that are matched or negative for the specific antigens. For individuals with a history of PTP, careful consideration and preparation are required before future transfusions.

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