VOL: 98, ISSUE: 25, PAGE NO: 56
Elizabeth N. Anionwu, RN, HV Tutor, PhD, CBE, is professor of nursing and head of the Mary Seacole Centre for Nursing Practice, Thames Valley University, LondonElizabeth N. Anionwu, RN, HV Tutor, PhD, CBE, is professor of nursing and head of the Mary Seacole Centre for Nursing Practice, Thames Valley University, London
Sickle cell disorders (SCDs) are a group of haemoglobinopathies that include sickle cell anaemia (Hb SS), haemoglobin SC disease (Hb SC), sickle beta thalassaemia (Hb SβThal) and SD disease (Hb SD).
They are inherited in an autosomal recessive manner (Serjeant and Serjeant, 2001; Anionwu and Atkin, 2001), which means that children inherit a SCD from both parents, who are usually healthy carriers. If both parents are carriers of the sickle cell trait, each pregnancy carries a 25% risk of sickle cell anaemia, 50% of sickle cell trait or 25% of normal haemoglobin type (Hb AA).
Screening and diagnosis
Sickle cell trait and SCDs can be detected in unborn babies from 11 weeks' gestation, using chorionic villus sampling or amniocentesis. Otherwise, it is detected from blood samples, using investigations such as haemoglobin electrophoresis (Bain, 2001).
Prevalence of sickle cell disorders
It is estimated that there are approximately 12,500 cases of SCDs in the UK (Streetly et al, 1997). They are varying and unpredictable illnesses with a range of consequences. These include mild to excruciatingly painful crises requiring opiates, anaemia, damage to various organs such as the spleen, lungs, hips, eyes and brain (stroke), leading to possible disability and early death, leg ulcers and vulnerability to serious and life-threatening infections.
Early diagnosis, before the age of four months, is vital to prevent life-threatening pneumococcal infections by the use of prophylactic penicillin. Factors that trigger 'sickling' of the red blood cells need to be avoided or reduced wherever possible - these include dehydration, low oxygen tension, fever, changes in temperature, infection and over-exertion.
Sickling occurs when sickle haemoglobin gives up its oxygen to the tissues. It sticks together to form long rods inside the red blood cells, making them rigid and sickle-shaped. These cells can block small blood vessels and thus prevent oxygenation of the tissues around the vessels. This in turn can lead to severe pain and organ damage.
Management of SCDs also includes timely and appropriate pain management, which may include the use of opiates, adequate hydration, treatment of infections, occasional use of exchange blood transfusion for certain complications such as strokes, sociopsychological support and education of practitioners (Koshy et al, 1989; Davies and Oni, 1997; Castro, 1999; Steinberg, 1999). Newer therapies include hydroxyurea and bone marrow transplantation, and there may be a future role for gene therapy. Life expectancy has increased in the past two decades, and most people with sickle cell anaemia can expect to reach their forties or beyond, although deaths can still occur at an early age.
Leg ulcers and sickle cell disorders
Cackovic et al (1998) noted a 25-75% incidence of leg ulcers in patients with SCD, and 25-63% of people with SCD will develop leg ulcers during their lifetime. They usually occur in younger people (10-35 years), and healing can take up to 16 times longer than in those with leg ulcers from other causes.
Leg ulcers are more common in people with sickle cell anaemia (Hb SS) than with other forms of SCD, and males appear to be more commonly affected than females. Ulceration may follow trauma, although they can occur spontaneously. Other possible factors include venous incompetence and vasoconstriction on dependency.
Management of leg ulcers in SCD
A vast array of treatments has reportedly been used in the management of leg ulcers for people with SCD, many of which are without merit. Examples cited in various publications (Cackovic et al, 1998; Docherty, 1999; Serjeant and Serjeant, 2001) include the following:
- Eusol (alone or in combination with metronidazole or honey);
- Bed rest, elevation of leg;
- Moist dressing;
- Debridement - for instance, with papaya;
- Sodium hypochlorite;
- Topical iodine;
- Hydrogen peroxide;
- Unna Boot, elastic bandages, tubular dressings;
- Blood transfusion*;
- Chemotherapeutic agents*;
- Skin grafting;
- Hydroxyurea (can itself cause leg ulcers);
- Preventing loss of fluid;
- Topical hydrocolloid;
- Recombinant human erythropoietin;
- Pain management.
(* without proven merit)
Cackovic et al (1998) stated that assessment of leg ulcers in people with SCD should ideally include ulcer site, depth and area, pain assessment, Doppler index, prior therapy, speed of onset and predisposing factors, especially trauma, complications of osteomyelitis, cellulitis and lymphadenitis. Tissue oxygenation may be a strong predictor of healing in some ulcers. They recommend the following management strategy:
- Maintain a moist wound environment to prevent contamination;
- Prevent pain, loss of fluid, cell dehydration and death;
- Maintain function of surface wound-healing factors (epidermal growth factor, platelet-derived growth factor, and transforming growth factor β).
It is clear from Alesha's account above that a considerable amount of education and service development is urgently required to enable a wider dissemination of more effective treatment of leg ulcers for people with SCD. It is extremely disconcerting to see the slow progress for affected individuals in this country. Many of the psychosocial problems Alesha describes are similar to those identified in a Jamaican study undertaken nearly three decades ago (Alleyne et al, 1977).
Those affected by this painful and devastating complication are predominantly young people, mainly from minority ethnic groups. Nurses involved in either the specialties of leg ulcers or sickle cell disorders must play a proactive and collaborative role in addressing this neglected aspect of the management of those affected by SCD. This area is crying out for further research and it is to be hoped that nurses will reflect on Alesha's experience and take an enthusiastic lead in addressing this challenge.