[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [General pathology](https://durgical.com/en/general-pathology/) › Red cells and bleeding disorders # Red cells and bleeding disorders Anaemias, polycythaemia, platelet and clotting disorders, and transfusion. 25 pages ## Mechanism - [**Acquired coagulation factor disorders** Most clotting factor problems are acquired: too little vitamin K, a failing liver, antibodies…](https://durgical.com/en/general-pathology/acquired-coagulation-factor-disorders/) - [**Anaemia of chronic inflammation: IL-6, hepcidin and locked-away iron** In long infections, autoimmune disease or cancer, the body hides iron from microbes](https://durgical.com/en/general-pathology/anaemia-of-chronic-inflammation-il-6-hepcidin-and-locked-away-iron/) - [**Haemolysis: extravascular vs intravascular** Red cells that die early are eaten by macrophages or burst inside vessels](https://durgical.com/en/general-pathology/haemolysis-extravascular-vs-intravascular/) - [**Thrombocytopenia: mechanisms** A low platelet count comes from poor production, quick destruction, trapping in a big spleen or…](https://durgical.com/en/general-pathology/thrombocytopenia-mechanisms/) ## Topic - [**Anaemia: classification** Anaemia is too little red cell mass](https://durgical.com/en/general-pathology/anaemia-classification/) - [**Bleeding disorders: overview** Bleeding comes from weak vessels, too few or faulty platelets, or missing clotting factors](https://durgical.com/en/general-pathology/bleeding-disorders-overview/) - [**Complications of transfusion** Transfusion is safe but not risk-free: fever, allergy, destroyed donor cells, lung injury, fluid…](https://durgical.com/en/general-pathology/complications-of-transfusion/) - [**Red cell morphology on the smear** Red cell shapes and inclusions are clues: each abnormal form points to a small set of diseases](https://durgical.com/en/general-pathology/red-cell-morphology-on-the-smear/) ## Lesion - [**Aplastic anaemia** The marrow empties of blood-forming cells and fills with fat](https://durgical.com/en/general-pathology/aplastic-anaemia/) - [**G6PD deficiency: oxidant haemolysis, Heinz bodies and bite cells** Red cells cannot defend against oxidants](https://durgical.com/en/general-pathology/g6pd-deficiency-oxidant-haemolysis-heinz-bodies-and-bite-cells/) - [**Haemophilia A and B** Boys born without enough factor VIII or IX bleed deep into joints and muscles](https://durgical.com/en/general-pathology/haemophilia-a-and-b/) - [**Hereditary spherocytosis** An inherited weakness of the red cell skeleton makes cells lose membrane and become spheres that…](https://durgical.com/en/general-pathology/hereditary-spherocytosis/) - [**Immune thrombocytopenias: ITP and HIT** Antibodies coat platelets so the spleen removes them](https://durgical.com/en/general-pathology/immune-thrombocytopenias-itp-and-hit/) - [**Immunohaemolytic anaemia** Antibodies stick to red cells and mark them for destruction](https://durgical.com/en/general-pathology/immunohaemolytic-anaemia/) - [**Iron deficiency anaemia** The commonest anaemia in the world: iron stores empty first, then cells become small and pale](https://durgical.com/en/general-pathology/iron-deficiency-anaemia/) - [**Megaloblastic anaemias: B12 and folate** Without vitamin B12 or folate, cells cannot copy DNA](https://durgical.com/en/general-pathology/megaloblastic-anaemias-b12-and-folate/) - [**Other marrow failure: PRCA and myelophthisis** Sometimes only red cells stop being made, sometimes tumour fills the marrow, and sometimes…](https://durgical.com/en/general-pathology/other-marrow-failure-prca-and-myelophthisis/) - [**Paroxysmal nocturnal haemoglobinuria** An acquired stem cell mutation removes the shields that protect blood cells from complement](https://durgical.com/en/general-pathology/paroxysmal-nocturnal-haemoglobinuria/) - [**Platelet function disorders** Platelets can be present in normal numbers but fail to stick, clump or release their signals](https://durgical.com/en/general-pathology/platelet-function-disorders/) - [**Sickle cell disease** One amino acid change makes haemoglobin stack into rods when oxygen is low](https://durgical.com/en/general-pathology/sickle-cell-disease/) - [**Thalassaemias: β and α** Too few globin chains of one kind: cells are small and pale, the unpaired chains clump and kill…](https://durgical.com/en/general-pathology/thalassaemias-and/) - [**Thrombotic microangiopathies: TTP vs HUS** Platelet clots plug small vessels, cut red cells and starve organs](https://durgical.com/en/general-pathology/thrombotic-microangiopathies-ttp-vs-hus/) - [**Traumatic haemolysis** Red cells can be cut by abnormal valves, fibrin strands in small vessels or repeated blows to…](https://durgical.com/en/general-pathology/traumatic-haemolysis/) - [**Vascular bleeding disorders** When the small vessels themselves are weak, the skin and mucosa bleed even though platelets and…](https://durgical.com/en/general-pathology/vascular-bleeding-disorders/) - [**Von Willebrand disease** The commonest inherited bleeding disorder: too little or faulty von Willebrand factor, so…](https://durgical.com/en/general-pathology/von-willebrand-disease/) ## A to Z - [A](https://durgical.com/en/general-pathology/a-z/a/) - [B](https://durgical.com/en/general-pathology/a-z/b/) - [C](https://durgical.com/en/general-pathology/a-z/c/) - [D](https://durgical.com/en/general-pathology/a-z/d/) - [E](https://durgical.com/en/general-pathology/a-z/e/) - [F](https://durgical.com/en/general-pathology/a-z/f/) - [G](https://durgical.com/en/general-pathology/a-z/g/) - [H](https://durgical.com/en/general-pathology/a-z/h/) - [I](https://durgical.com/en/general-pathology/a-z/i/) - [J](https://durgical.com/en/general-pathology/a-z/j/) - [K](https://durgical.com/en/general-pathology/a-z/k/) - [L](https://durgical.com/en/general-pathology/a-z/l/) - [M](https://durgical.com/en/general-pathology/a-z/m/) - [N](https://durgical.com/en/general-pathology/a-z/n/) - [O](https://durgical.com/en/general-pathology/a-z/o/) - [P](https://durgical.com/en/general-pathology/a-z/p/) - [R](https://durgical.com/en/general-pathology/a-z/r/) - [S](https://durgical.com/en/general-pathology/a-z/s/) - [T](https://durgical.com/en/general-pathology/a-z/t/) - [U](https://durgical.com/en/general-pathology/a-z/u/) - [V](https://durgical.com/en/general-pathology/a-z/v/) - [W](https://durgical.com/en/general-pathology/a-z/w/) [← General pathology](https://durgical.com/en/general-pathology/) Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. 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