<unk>  is defined as bluish discoloration of the skin and or mucous membrane resulting from insufficient oxygenation of the blood and the presence of at least 5g/dl unsaturated hemoglobin in tissue. Anemia may lead to hypoxia but is not the cause of<unk> . Right to left shunt in congenital heart disease causes central<unk> . Secondary erythrocytosis (increased red blood cell mass  due to hypoxia) and polycythemia (neoplastic proliferation of reb blood cell) are different conditions  and need different evaluation.<unk>   may be  classified into central<unk>  and peripheral<unk> .
Cyanosis classification
Uveitis classification
Retinitis classification
Polycythemia classification
Atherosclerosis classification
Hemosiderosis classification
Diabetic foot classification
Gangrene classification