Sickle-cell disease (SCD) is a group of blood disorder . The most common type is known as sickle-cell anaemia (SCA). It results in an abnormality in the oxygen-carrying protein haemoglobin (hemoglobin S) found in red blood cells. This leads to a rigid, sickle shape under certain circumstances. sickle cell disease typically begin around 5 to 6 months of age. A number of health problems may develop, such as attacks of pain (“sickle-cell crisis”),anemia, swelling in hand and feet, bacterial infections and stroke .Long term pain may develop as patient get older.
Sickle-cell disease occurs when a person inherits two abnormal copies of the hemoglobin gene, one from each parent. This gene occurs in chromosome 1. Several subtypes exist, depending on the exact mutation in each haemoglobin gene. An attack can be set off by temperature changes, stress,dehydration, and high altitude.A person with a single abnormal copy does not usually have symptoms and is said to have sickle cell trait. Such people are also referred to as carriers. Diagnosis is by a blood test and some countries test all babies at birth for the disease. Diagnosis is also possible during pregnancy.The care of people with sickle-cell disease may include infection prevention with vaccination and antibiotics , high fluid intake , folic acid supplementation, and pain medication. Other measures may include blood transfusion, and the medication hydroxycarbamide (hydroxyurea)A small proportion of people can be cured by transplant of bone marrow.
Sickle Cell Disease is one of the most frequent genetic disease worldwide. It is present on four continents: in sub-Saharan Africa , in Asia (Middle-East, Arabic peninsula, India,Pakistan), in the Americas, on the North (USA), centre (Guatemala, Caribbean islands), and on the South (Brazil,Surinam, Guiana), in Southern Europe (Southern Italy and Sicily, Greece, Turkey). It is estimated that 500.000 are born every year with this severe and invalidating condition and that 50% of them will die before the age of 5 years..
Abnormal haemoglobin forms can be detected on haemoglobin electrophoresis. Sickle-cell haemoglobin (HgbS) and haemoglobin C with sickling (HgbSC) the two most common forms . The diagnosis can be confirmed with high performance liquid chromatography ,Genetic testing, are highly specific for HbS and HbC .An acute sickle-cell crisis is often precipitated by infection. Therefore, a urinalysis to detect an occult urinary tract infection, and chest X-ray to look for occult pneumonia should be routinely performed.People who are known carriers of the disease often undergo genetic counseling, before they have a child. A test to see if an unborn child has the disease takes either a blood sample from the fetus or a sample of amniotic fluid. Since taking a blood sample from a fetus has greater risks, the latter test is usually used. Neonatal screening provides a better method of early detection for individuals with sickle-cell disease
SIGN AND SYMPTOMS
The terms “sickle-cell crisis” or “sickling crisis” may be used to describe several independent acute conditions occurring in patients with SCD. SCD results in anemia and crises that could be of many types including the vaso occlusive crisis,aplastic crisis, sequestration crisis, haemolytic crisis, and others. “Although infection, dehydration, and acidosis (all of which favor sickling) can act as triggers, in most instances, no predisposing cause is identified
Painful crises are treated with hydration, analgesics , and blood transfusion, pain management requires opoids administration at regular intervals until the crisis has settled. For milder crises, a subgroup of patients manage on (NSAIDs) such as diclofenac and naproxen. For more severe crises, most patients require inpatient management for intravenous opioids devices are commonly used.
Splenic sequestration crisis
Because of its narrow vessels and function in clearing defective red blood cells, the spleen is frequently affected.It is usually Infarcted before the end of childhood in individuals suffering from sickle-cell anemia. This spleen damage increases the risk of infection from encapsulated organism. preventive antibiotics and vaccinations are recommended.Splenic sequestration crises are acute, painful enlargements of the spleen, caused by intrasplenic trapping of red cells and resulting in a precipitous fall in hemoglobin levels with the potential for hypovolemic shock. Sequestration crises are considered an emergency. If not treated, patients may die within 1–2 hours due to circulatory failure. Management is supportive, sometimes with blood transfusion. These crises are transient, they continue for 3–4 hours and may last for one day
Acute chest syndrome
(ACS) is defined by at least two of the following signs or symptoms: chest pain, fever, pulmonary infiltrate or focal abnormality, respiratory symptoms
Aplastic crises are acute worsenings of the patient’s baseline anaemia, producing palor ,increased heart rate and fatigue. This crisis is normally triggered by parvovirus B19, which directly affects production of red blood cells by invading the red cell precursors and multiplying in and destroying them. Parvovirus infection almost completely prevents red blood cell production for two to three days. In normal individuals, this is of little consequence, but the shortened red cell life of SCD patients results in an abrupt, life-threatening situation.Reticulocyte counts drop dramatically during the disease (reticulopenia), and the rapid turnover of red cells leads to the drop in haemoglobin. This crisis takes 4 days to one week to disappear. Most patients can be managed supportively; some need blood transfusion.
Hemolytic crises are acute accelerated drops in haemoglobin level. The red blood cells break down at a faster rate. This is particularly common in patients with coexistent G6DP deficiency. Management is supportive, sometimes with blood transfusion.
The World Health Organization (WHO) has started work to promote a world wide agenda to address hemoglobin dysfunctions.
WHO has made a commitment to:
· Recognize that sickle cell disease is a major health issue.
· Increase awareness of the world community regarding sickle cell disease.
· Eliminate harmful and wrong prejudices associated with sickle cell disease.
· Urges member countries where sickle cell disease is a public health problem to establish health programs at the national level and operate specialized centers for sickle cell disease and facilitate access to treatment.
· Promote satisfactory access to medical services to people affected with sickle cell disease.
· Provide technical support to all countries to prevent and manage sickle cell disease.
· Promote and help research to improve the lives of people affected with sickle cell