Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0032463 (polycythemia vera)
 3,374 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In addition to the criteria of the Polycythemia Vera Study Group, positive markers for essential thrombocythemia (ET) include spontaneous BFU-E, splenomegaly, and megakaryocyte morphology in bone marrow smears and biopsy material. The hematologic features of 11 reported cases of ET in childhood showed platelet counts in excess of 1000 x 10(9)/L in all, slight leukocytosis in 8, and splenomegaly in 9. The presenting thrombohemorrhagic manifestations in 8 symptomatic cases were microcirculatory disturbances and transient neurologic ischemic attacks in 2, recurrent mucocutaneous bleedings in 6, and priapism in 1. There are no reports of ET in childhood complicated by microcirculatory disturbances at platelet counts below 1000 x 10(9)/L. Anagrelide and alpha-interferon, which are non-leukemogenic agents for the reduction of platelet counts, may become the treatment of choice in childhood ET. Anagrelide is tolerated better than alpha-interferon. The potential leukemogenic drugs hydroxyurea and busulfan should be used cautiously and withheld as long as possible.
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PMID:Essential thrombocythemia in childhood. 925 10

Therapeutic erythrocytapheresis (TEA) has been used in different diseases such as polycythemia vera (PV), secondary erythrocytosis or hemochromatosis as a process of the less cumbersome but more expensive phlebotomy. TEA is preferred in emergency conditions such as thrombocytosis or in conditions such as porphyria cutanea tarda (PCT) or erythropoietic porphyria when plasma exchange (PEX) is often combined with TEA to reduce extracellular levels of uroporphyrin which contribute to plasma hyperviscosity. TEA is often combined with drug therapy that varies from etoposide in PV to EPO and desferoxamine which are used to mobilize and reduce iron stores in hemochromatosis. Benefits from this combination may be more long lasting than expected. Nonetheless for TEA, there is no standard protocol and, clinical experience with this therapy remains highly anecdotal. Therapeutic red cell-exchange (TREX) has been used with much interest over the years, starting with the management of hemolytic disease of the newborn and later used to correct severe anemia in thalassemia patients thereby preventing iron overload. It has also been used for the management of complications of sickle cell disease such as priapism, chest syndrome, stroke, retinal, bone, splenic and hepatic infarction or in preparation for surgery by reducing HbS to less than 30%. Automated apheresis has also favored the use of TREX in conditions such as paroxysmal nocturnal hemoglobinuria and aniline poisoning, arsenic poisoning, Na chlorate intoxications and CO intoxications, hemoglobinopathies, autoimmune hemolytic anemia, reactions due to ABO incompatibility, in preparation for ABO incompatible bone marrow transplantation or for preventing anti-D immunization after the transfusion of D(+) cells to D(-) recipients. Another field of application has been in the emergency management of intraerythrocytic parasite infections such as malaria and babesiosis. Application of TREX may be wide but its real use remains limited. In our personal experience, in 16 years, only 167 TREX procedures have been carried out in a total of 13,747 therapeutic procedures. This represents only 1.21% of the total.
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PMID:Clinical application of therapeutic erythrocytapheresis (TEA). 1083 21

Essential thrombocythemia (ET) is one of the quite rare myeloproliferative disorders in children. The natural course and outcome of this disease have been reported to vary. We report three children (two boys and one girl, mean age at diagnosis 12 yr) with ET who showed different clinical courses. The girl was asymptomatic, but the boys had ankle pain and priapism, respectively. The platelet count ranged between 2300 and 2900 x 10(9)/L, and the diagnoses were made according to the criteria of the Polycythemia Vera Study Group. The serum thrombopoietin level reached 0.33 and 0.47 fmol/ml in two patients. All three children were administered aspirin or dipyridamole orally. Normalization of the platelet count was observed in two patients, and stable disease persisted in one. The 12 pediatric patients with ET reported previously in Japan demonstrated a low incidence of serious thrombohemorrhagic complications and a favorable outcome, none developing acute leukemia. Careful continuous observation and conservative treatment may be preferable in pediatric patients who do not have cardiovascular symptoms, avoiding the use of potential leukemogens such as alkylating agents and hydroxyurea.
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PMID:[Clinical features of essential thrombocythemia in three children]. 1119 34