ABSTRACT
Sickle cell anaemia is an inherited blood disorder mostly affecting Afro-Caribbean people but can be found in Eastern Mediterranean and Middle Eastern people (WHO, 2006). This disease is one of the most common genetic blood disorders in the world (Westerdale, 2004). Sickle cell anaemia occurs when a person inherits two genes from Haemoglobin S (HbS; one gene from each parent). HbS forms long polymers upon deoxygenation. These rod-like polymers change the normally round and pliable red blood cells into rigid cells with a crescent or sickle shape that has a life span of only 10 days. Bundles of these deformed cells act as plugs within the capillaries. This results in a reduction of bloodflow, causing localised tissue hypoxia and promoting further sickling. If uncorrected, tissue necrosis and infarction follow, causing severe pain, multisystem organ damage and possibly early death (Gladwin et al., 2004; Taher, 2007). A sickle cell (vaso-occlusive) crisis occurs when the inflexible sickled cells become lodged in the arterial and micro-circulation causing stasis, obstruction of bloodflow and damage to surrounding tissues and organs, resulting in infarction. A crisis can last for a matter of minutes or several months (De, 2005). Triggers for sickling of the blood include infection (especially viral), stress (both emotional and physiological), dehydration or sources of external temperature, hypoxia, hypothermia, smoking and alcohol (Firth, 2005).
