In sickle cell anaemia true is -

Ans. is 'a' i.e., Autosplenectomy due to thrombosis and infarction Clinical manifestations of sickle cell anemia o The clinical manifestations of sickle cell anemia are. Chronic hemolysis o Irreversible sickle cells have rigid, nondeformable cell membranes that lead to difficulty in negotiating the splenic sinusoids, sequestation, and rapid phagocytosis. This results in extravascular hemolysis. o Some intravascular hemolysis may also occur because of increased machanical fragility of severely damaged cells. Vasoocclusive symptoms o Reversible sickle cells express higher than normal levels of adhesion molecules and are abnormally sticky that is responsible for occlusion of microcirculation especially of bones, lungs, liver, brain, spleen and penis. o Vasoocclusive symptoms are the most common manifestation of sickle cell anemia. o They commonly manifest as - (i) Painful bone crises In children, painful bone crises are extremely common and often difficult to distinguish from acute osteomyelitis. They frequently manifest as a dactylitis of bones of the hands or feet are both --> Hand-foot syndrome. (ii) Autosplenectomy Because of its narrow vessels and function in clearing defective red blood cell, the spleen is frequently affected. It is usually infarcted before the end of childhood. This autosplenctomy increases the risk of infection from encapsulated organisms. (iii) Acute chest syndrome A condition characterized by fever, chest pain, difficult breathing due to sickling and vaso-occlusion within pulmonary vascular beds. (iv) Sequestration crises Massive sequestration of sickled red cells leads to acute painful enlargement of spleen. (v) Aplastic crises Infection by parvovirus B19 can cause cessation of bone marrow erythropoiesis ---> aplastic crises. (vi) CNS symptoms Seizure and stroke (vii) Priapism and infarction of penis (viii) Leg ulcers Remember o Sickle cell trait (hetrozygous state) is almost always asylnptomatic and the only significant manifestation is the renal concentration defect presenting with isothenuria.