30/11/2019
Epidemiology In 2010 the World Health Organisation (WHO) labelled SCD as a global health problem, with a world wide neonatal incidence of 294,000-330,000. It was previously isolated to sub-Saharan Africa, India and parts of the Mediterranean and Middle-East.
Sickle Cell Disease (SCD) Sickle cell disease (SCD) is a genetic condition caused by a gene mutation that affects protein structure producing haemoglobins. (Burner & Suddarths 2012). SCD is the commonest haemoglobinopathy in man. It is an autosomal recessive condition that leads to abnormal structured and functioning red cells that have shortened life span, or poor capacity to carry oxygen and a tendency to occlude micro vascular spaces. Significant morbidity and mortality result from organ sequestration, occlusion and sepsis. (Gibbons et. al 2015)
Globalisation and immigration has caused a shift in the geographic location of these individuals with SCD.
Current surge in the population with SCD is shown in an epidemiology study in 2005 which identified 160 children with SCD in Ireland. In some European countries SCD has become the most common genetic condition overtaking cystic fibrosis. (Roberts & DeMontalemdert, 2007).
13
14
Who needs to be tested The 2003 National Institute for Health and Care Excellence (NICE) guidelines advice that it is relevant to test all North African, West African, South/sub-Saharan Africa and Afro Caribbean patients including other ethnic groups considered to be at risk.
Aetiology • It is genetic • Individual must inherit the recessive gene form both parents • The term Sickle cell anaemia is used to refer to HbSS disease • The term SCD is used to represent all the genotypes HbSS,HbSC,HbSβ-thalassemia PROGNOSIS: Diagnosed in childhood, some children die in the first years of life, however symptoms and complications are better managed to support an average life expectancy of 42-48yrs. In some patients symptoms diminish by 30yrs of age which allow them to reach the 6 th decade of life. (Rees et, al. 2010)
It is also prevalent in people among people from South and Central America, some Eastern Mediterranean, Middle-East and Asia
There is an increase in race mixing which can be deceptive with who gets tested .
15
16
Anatomy of sickle blood
Sickle Cell Anaemia vs Sickle Cell Trait
• This gene causes red blood cell molecule to be defective. • The sickle haemoglobin S (HbS) acquires a crystal-like formation when exposed to low oxygen tension, hence the erythrocyte containing HbS changes shape from round pliable biconcave disc shape it becomes • Rigid and sickle in shape. ( Schnall & Benz, 2002)
• As for sickle cell trait, they don’t have the condition but they have one of the genes that cause the condition i.e. If HbS is inherited from one parent and a normal Hb from the other parent. • An individual with sickle cell anaemia and sickle cell trait can pass the gene on when they have children.
• In sickle cell anaemia it is inherited, life long disease, symptoms are profound and frequent • Individual inherits two copies of the gene, one from each parent HbSS genotype.
(Schnall & Benz, 2002)
17
18
3
Powered by FlippingBook