Thrombocytopenia (Purpura Hemorrhagic, Idiopathic Purpura). This disease is characterized by diminution of the platelets with prolonged bleeding time and a nonretractile blood clot. The coagulation time in glass is not markedly affected. Clinically, there are spontaneous hemorrhages, epistaxis, menorrhagia and petechiae in the skin or mucous membranes. Children and young adults are most frequently affected. Capillary resistance is diminished and the so called tourniquet test is positive. In order to make a diagnosis of primary purpura it is necessary to rule out acute leukemia or aplastic anemia. There is no enlarged spleen, such as occurs in Banti's disease, Gaucher's disease or hemolytic jaundice. The blood shows a reduction of platelets, fewer than 60,000 per cubic. millimiter. and the platelets vary in size and staining characteristics. There may be an anemia due to blood loss, and a posthemorrhagic leukocytosis with relative lymphocytosis. The marrow shows increased numbers of megakaryocytes but inhibited platelet production. Small, repeated transfusions of whole blood are temporarily beneficial. Splenectomy may be curative.
Anaphylactoid Purpura (Schonlein and Henoch's Purpura). this condition is due to increased permeability of the capillary endothelium which permits extravasation of blood into the tissue spaces. Henoch's variety is characterized by colic and other gastro-intestinal symptoms, which often precede the purpuric eruptions so that needless operations may be performed. Schonlein's purpura is characterized by effusion into the joints and periarticular structures, which may precede the purpuric manifestations so that an erroneous diagnosis of rheumatic fever may be made.
Myeloid Metaplasia (Megakaryocytic Myelosis). A number of cases have been reported which have in common megakaryocytic infiltrations of the bone marrow, liver and spleen. At times there is a marked leukocytosis with increased number of megakaryocytes in the peripheral blood, The constant features of the disease are the splenomegaly, the infiltration of the hematopoietic organs with megakaryocytes, the tendency for the bone marrow to undergo progressive fibrosis and frequent fatal termination. more recently, bacilli which take the acid-fast stain have been found in the lungs of these patients. Because of the involvement of the bone marrow by fibrosis, and the compensatory hematopoiesis in the spleen, splenectomy is contraindicated.
