Sickle cell disease is an umbrella term used to describe a group of inherited disorders of the haemoglobin known as haemoglobinopathies and includes Sickle Cell Anaemia, which generally is the most severe form. It is found in people of African and Caribbean origin and to a lesser extent in people of Mediterranean, Asian and Middle Eastern origin. People of these origins live all over the world, therefore the Sickle Cell disorder is of international significance, (Pembrey, 1994). Sickle Cell Disorder is the most common and fastest growing genetic disorder in England and now affects 15,000 people in the UK, and one in 2,400 babies, with prevalence growing (NHS, 2006). The most common forms of sickle cell disease (SCD) are sickle Haemoglobin C (Hb SC), Sickle Beta Thalassaemia (Hb S BThal), and Sickle Cell Anaemia (Hb SS).The most common and most severe form is Sickle Cell Anaemia (Hb SS). There is no cure. This assignment will briefly describe a case study with discussion of a patient admitted to hospital with one of the complications of Sickle Cell Anaemia, namely Acute Chest Syndrome. This assignment will further discuss the pathophysiology and management of Acute Chest syndrome (ACS). Case Study
A 19 year old African Caribbean male presented to the Emergency Admissions Unit (EAU) with severe pleuritic chest pain. The pain had begun three hours previously with coughing, fever and chills for the previous 24 hours. This was his first hospital admission this year with a sickle cell crisis, although he stated that he was was unwell two weeks previously. On examination, the patient was found to be dyspnoeic and pyrexial (39º C), tachycardic (Pulse 110), hypertensive (BP 145/90), with oxygen saturation at 90%. Bronchial breath sounds with inspiratory crackles were heard on inspiration. Assessment of the patient suggested chest infection leading to Acute Chest Syndrome (ACS). The plan for the patient was to give pain relief using patient controlled analgesia morphine infusion and oxygen therapy, along with bronchial dilators. Full blood count and blood cultures, arterial blood gases, also cross matched blood for possible blood transfusion. A chest x-ray and intravenous fluids to rehydrate the patient were initiated, along with oxygen therapy. Broad spectrum antibiotics were to be given. The patient was to be admitted to the haematology ward for monitoring.
The sickle cell gene is transmitted by recessive inheritance and can manifest as trait (Heterozygote Hb AS) or sickle cell anaemia (Homozygote Hb SS). According to Porth (2005), individuals who are heterozygous only have approximately 40% of sickle haemoglobin (HbS) and generally have no symptoms other than very mild anaemia, whereas the homozygous individual has 80-90% of sickle haemoglobin. Porth further asserts that variations in proportions exist and the concentration of HbS correlates with risk for ‘sickling’. This would account for the variations in the severity of the condition noted in individuals.
It is recognised that half of individuals with Sickle cell Anaemia will develop Acute chest Syndrome (ACS) at least once in their lifetime (Mak, Davies 2003), (Gladwin, Rodgers, 2000). Furthermore, it is the second most common reason for admission to hospital for people with sickle cell anaemia after the vaso-occlusive crisis. It also accounts for approximately 25% of premature deaths amongst sufferers (Gladwin, Rodgers, 2000).
ACS is a form of lung injury that can develop into acute respiratory distress syndrome rapidly. It is an amalgamation of signs and symptoms that include pain, fever, tachypnoea, leukocytosis and pulmonary infiltrates. Recurrent exacerbations of ACS may result in pulmonary fibrosis, pulmonary hypertension and cor pulmonale (Hajeri et al, 2008). It is a medical emergency and as such should be treated immediately. Treatment with transfusions and bronchodilators improves oxygenation. The causes, clinical presentation and possible outcomes of ACS has been well evidenced (Mak, Davies, 2003). However, management of this complication of sickle cell anaemia is less well known (Schnog et al, 2004) and therefore has implications for the management and outcomes for ACS, bearing in mind that it is the leading cause of death in patients with sickle cell anaemia.
Sickle cell disorder is caused by autosomal recessive defects of the red blood cells and can manifest as trait (heterozygous)with one HbS gene, or as sickle cell anaemia, with two HbS genes. There are over 600 varieties of haemoglobinopathies and they can affect either the structure of the beta-globin chain (Sickle cell disorders), or reduce the quantity of either alpha or beta haemoglobin chains (Thalassaemias). The normal adult haemoglobin (HbA) is the most predominant haemoglobin type (97%), and consists of two alpha and two beta globin chains. These chains are wrapped around a haem (iron containing) molecule. Other haemoglobins are HbA2 (2-3%) and foetal haemoglobin (HbF