About Sickle cell disease

Three-quarters of sickle cell cases occur in Africa. A recent WHO (world health Organization) report estimated that around 2 percent of newborns in Nigeria were affected by sickle cell anemia, giving a total of 150,000 affected children born every year in Nigeria alone. The carrier frequency ranges between 10 percent and 40 percent across equatorial Africa, decreasing to 1 - 2 percent on the north African coast and less than 1 percent in South Africa. There have been studies in Africa that show a significant increase in infant mortality rate, ages 2-16 months, because of the sickle cell trait.

Sickle cell disease (SCD) is a group of blood disorders typically inherited from an individual's parents. The most common type is known as sickle cell anemia. It results in an abnormality in the oxygen-carrying protein hemoglobin found in the red blood cells. This leads to a rigid, sickle-like shape under certain circumstances. Problems in sickle cell disease in most cases 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 the hands and feet, bacterial infections and stroke. Long-term pain may develop as people get older (Wikipedia). The average life expectancy in the developed world is 40 to 60 years.

Sickle cell disease
Other names	Sickle cell disorder
Figure (A) shows normal red blood cells flowing freely through veins. The inset shows a cross section of a normal red blood cell with normal haemoglobin. Figure (B) shows abnormal, sickled red blood cells sticking at the branching point in a vein. The inset image shows a cross-section of a sickle cell with long polymerized sickle haemoglobin (HbS) strands stretching and distorting the cell shape to look like a crescent.
Specialty	Hematology
Symptoms	Attacks of pain, anemia, swelling in the hands and feet, bacterial infections, stroke
Complications	Chronic pain
Usual onset	5 - 6 months of age
Diagnostic method	Blood test
Treatment	Vaccination, antibiotics, high fluid intake, folic acid supplementation. pain medication, blood transfusions
Prognosis	Life expectancy 40 - 60 years (developed world)
Frequency	4.4 million (2015)
Deaths	114,800 (2015)

Sickle cell disease typically occurs when a person inherits two abnormal copies of the haemoglobin gene, one from each parent. This gene occurs in chromosome 11. Several subtypes abound, depending on the exact mutation in each haemoglobin gene. An attack can be set off by temperature changes, stress, dehydration and high altitude, and infections. 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 and management of patients 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 percentage of people can be cured by a transplant of bone marrow cells.

As of 2015, about 4.4 million people have sickle cell disease, while an additional 43 million have 65percent of whom are in Africa, with half of these cases occurring in Nigeria.

Management

Sickle Cell anamia or sickle cell crises takes on various shades and manifest in different forms such as, acute chest pain, and general bone marrow pains, spleen rupturing as a result of inflammation, leg ulcers,and in extreme cases heart failure and strokes.Treatment involves a number of measures. L-glutamine use was supported by the FDA starting at the age of 5 as it decreases complications.

Folic acid and penicillin

From child birth to the age of five years , administering penicillin on a daily basis is , due to the immature immune system that makes them more prone to early childhood illnesses is highly recommended. Dietary supplementation of folic acid had been previously recommended by the WHO (world health Organization). A 2016 Cochrane review of its use showed that "the effect of supplementation on anaemia and any symptoms of anaemia remains unclear" due to a lack of medical evidence.

Vaso-occlusive crisis

Majority of people with sickle cell disease have intensely painful episodes called vaso-occlusive crises. However, the frequency, severity, and duration of these crises vary tremendously. Painful crises are treated symptomatically with pain medications; pain management requires opioid administration at regular intervals until the crisis has subsided and is completely abated. For milder crises, a subgroup of patients manages on NSAIDs (such as diclofenac or naproxen.) For more severe crises, most patients require inpatient management for intravenous opioids; patient-controlled analgesia (PCA) devices are commonly used in this setting. Diphenhydramine is also an effective agent that doctors frequently prescribe to help control itching associated with the use of opioids [Wikipedia].

Acute chest crisis

Management is similar to vaso-occlusive crisis, with the addition of antibiotics (usually a quinolone or macrolide, since cell wall-deficient ["atypical"] bacteria are thought to contribute to the syndrome), oxygen supplementation for hypoxia, and close observation. Should the pulmonary infiltrate worsen or the oxygen requirements increase, simple blood transfusion or exchange transfusion is indicated. The latter involves the exchange of a significant portion of the person's red cell mass for normal red cells, which decreases the percent of haemoglobin S in the patient's blood. For patients with suspected acute chest syndrome it is recommended that they be admitted to the hospital with worsening A-a gradient an indication for ICU(intensive care unit) admission, because this crises could culminate in the shortness of breath due to reduced red blood cells and less oxidation during respiration. This condition when not properly handled results mostly in deaths of patients.

Hydroxyurea

The first approved drug for the causative treatment of sickle cell anaemia, hydroxyurea, was shown to decrease the number and severity of attacks in a study in 1995 and shown to possibly increase survival time in a study in 2003.This is achieved, in part, by reactivating fetal haemoglobin production in place of the haemoglobin S that causes sickle cell anaemia. Hydroxyurea had previously been used as a chemotherapy agent, and there is some concern that long-term use may be harmful, but this risk has been shown to be either absent or very small and it is likely that the benefits outweigh the risks. It is painful to note that 95percent of Sickle cell disease patients in Africa do not have access to this drug as a result of poverty and illiteracy, as well as systemic failure of governments as well as Primary Health Care (PHC) agencies.

Blood transfusion

Blood transfusions are often used in the management of sickle cell disease in acute cases and to prevent complications by decreasing the number of red blood cells (RBC) that can sickle by adding normal red blood cells. In children preventative red blood cell (RBC) transfusion therapy has been shown to reduce the risk of first stroke or silent stroke when transcranial Doppler(TCD) ultrasonography shows abnormal cerebral blood flow. In those who have sustained a prior stroke event it also reduces the risk of recurrent stroke and additional silent strokes. The Poor supply of electricity in most rural communities in Africa makes it quite challenging to maintain a decent blood bank in most government healthcare facilities which provide healthcare service for the larger majority of the populace, making it quite difficult for most SC patients in Africa in general and Nigeria in particular to access blood transfusion as a means of treatment in order to reduce death from crises.

Bone marrow transplant

Bone marrow transplants have proven effective in children. Bone marrow transplants are the only known cure for SCD. However, bone marrow transplants are difficult to obtain because of the specific HLA typing necessary. Ideally, a close relative (allogeneic) would donate the bone marrow necessary for transplantation. Bone marrow transplant as an option for treatment of SCD in sub-Saharan Africa is non-existent as not even a single center carries out the procedure today in the region.

Avascular necrosis

When treating avascular necrosis of the bone in people with sickle cell disease, the aim of treatment is to reduce or stop the pain and maintain joint mobility. Current treatment options are to rest the joint, physical therapy, pain relief medicine, joint replacement surgery, or bone grafting. High quality randomized controlled trials are needed to assess the most effective treatment option and determine if a combination of physical therapy and surgery are more effective than physical therapy alone.

Psychological therapies

Psychological therapies such as patient education, cognitive therapy, behavioral therapy and psychodynamic psychotherapy, that aim to complement current medical treatments, require further research to determine their effectiveness.

Gene-editing

In July 2019 the gene-editing tool CRISPR was used on a patient with sickle cell disease for the first time.

[Citation: Wikipedia, the free encyclopedia]