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

Erythromelalgia is the main, pathognomonic and presenting symptom in patients with essential thrombocythemia and thrombocythemia associated with polycythemia vera. Complete relief from erythromelalgic and acrocyanotic pain is obtained with the cyclooxygenase inhibitors aspirin and indomethacin, but not with sodiumsalicylate, dipyridamol, sulfinpyrozone and ticlopedine. Thus, cyclooxygenase metabolites are necessary for erythromelalgia to develop. Local platelet consumption in erythromelalgic areas became evident by the demonstration of arteriolar fibromuscular intimal proliferation and occlusions by platelet-rich thrombi in skin biopsies, by the findings of shortened platelet survival times, significant higher levels of platelet activation markers beta-thromboglobulin, thrombomoduline and increased urinary thromboxane B2 excretion in thrombocythemia patients suffering from erythromelalgia. Aspirin treatment of erythromelalgia in thrombocythemia patients resulted in the disappearance of the erythromelalgic, thrombotic signs and symptoms, correction of the shortened platelet survival times, and a significant reduction of the increased levels of beta-TG, PF4, TM and urinary TxB2 excretion to normal. Erythromelalgia is frequently preceded or followed by atypical transient neurologic, ocular or coronary ischemic symptoms, which specifically respond to low-dose aspirin or reduction of platelet counts to normal. The broad spectrum of acropareshesias, erythromelalgia and acrocyanotic ischemia together with the episodic and transient atypical TIAs and ocular or coronary ischemic symptoms are caused by spontaneous activation and aggregation of hypersensitive platelets in the end-arterial microvasculature involving the peripheral, cerebral and coronary circulation of thrombocythemia patients. These microvascular circulation ischemic disturbances in thrombocythemia vera already occur at platelet counts in excess of 400 x 10(9) l(-1). Low-dose aspirin is highly effective and safe in the cure and prevention of thrombotic and ischemic events and does not elicit bleedings at platelet counts below 1000 x 10(9) l(-1). Spontaneous hemorrhages usually occur at very high platelet counts far in excess of 1000 x 10(9) l(-1) (HT) due to an acquired von Willebrand factor deficiency at increasing platelet counts. At platelet counts between 1000 and 2000 x 10(9) l(-1), thrombosis and bleeding (ETT and HT) frequently occur in sequence or paradoxically and low-dose aspirin does prevent thrombotic complications but aggravates or may elicit bleeding symptoms. Reduction of the platelet count to below 1000 x 10(9) l(-1) by platelet lowering agents usually results in the disappearance of the bleeding tendency and improvement of the von Willebrand syndrome, but the thrombotic tendency persists as long as platelet counts are above the upper limit of normal.
 ...
PMID:Platelet-mediated microvascular inflammation and thrombosis in thrombocythemia vera: a distinct aspirin-responsive arterial thrombophilia, which transforms into a bleeding diathesis at increasing platelet counts. 1278 99

In hematological disorders, thrombocytopenia is frequently observed, and it is sometimes difficult to diagnose the underlying disease. In this symposium, laboratory tests for platelet abnormality were reviewed. Tests for platelet aggregation were reported to be important for the diagnosis of platelet dysfunction. Thrombocytopenia is caused by disseminated intravascular coagulation (DIC), thrombotic microangiopathy (TMA), heparin-induced thrombocytopenia (HIT), antiphospholipid syndrome (APS), idiopathic thrombocytopenic purpura (ITP), etc. As DIC is classified according to the degree of fibrinolysis, it was stated that the measurement of hemostatic molecular markers was further required. TMA is caused by abnormality of ADAMTS13, verotoxin, DIC, etc. HIT is diagnosed by anti-PF4 antibody, but its specificity is not high. Further investigation of TMA and HIT is required. APS is one of the most important diseases which cause thrombosis or abortion, suggesting that a differential diagnosis of APS is important. It was reported that diagnostic criteria of ITP have been established using a new antibody assay for platelets, immature platelet fractions, thrombopoietin, etc. In myeloproliferative disorders such as polycythemia vera and essential thrombocythemia, the mutation of JAK2 V617F was reported to be an important risk factor for thrombosis.
 ...
PMID:[Summary of pathophysiology and diagnosis of patients with platelet abnormality]. 1952 56