SICKLE CELL DISEASE: Factors, Types, Crisis, Signs and Management

Sickle Cell Disease is an inherited condition characterized by a sickle (crescent) shaped red blood cells and chronic anaemia due to excessive destruction of red blood cells.
Sickle cell disease is a genetic condition that is present at birth. It is inherited when a child receives two sickle cell genes; one from each parent. Sickle cell disease is caused by a mutation in the gene that tells your body to make the iron-rich compound that makes blood red and enables red blood cells to carry oxygen from your lungs throughout your body (hemoglobin).

Pathophysiology Of Sickle Cell Disease

Sickle cell disease is a genetic disease which occurs by the inheritance of two abnormal genes from both parents. The Red blood cells of a sickle cell patient contain two abnormal haemoglobin (HbS). Sickle cell disease occurs when amino acid (valine) substitute glutamic acid on the 6th chain of haemoglobin, making oxygenated Hb S much less soluble than oxygenated Hb A. When an erythrocyte gives up it oxygen to the interstitial fluid or is exposed to low oxygen tension, the abnormal haemoglobin (HbS) changes in shape and flexibility. This cause the erythrocytes containing Hb S to lose it round, pliable, biconcave disk shape and becomes deformed, rigid and sickle shaped. It life span reduce from 120 days to 10 to 20 days. Even though erythropoietin is stimulated by loss of the sickled shaped cells, it cannot keep pace with haemolysis. This cause the individual to suffer hemolytic anaemia resulting in reduced amount of oxygen in the system. When the long, rigid erythrocytes adhere to the endothelium of the small blood vessels, they adhere to each other causing blood flow to a region or an organ to be reduced causing Ischemia or infarctions. This exposes the individual to pain, swelling and fever.

Precipitating Factors for Sickle Cell Disease

1. Infection and illness such as malaria
2. Exposure to extreme cold temperature
3. Flying at a higher altitude
4. Dehydration
5. Severe blood loss
6. Vigorous exercise
7. Emotional stress

Classification Of Sickle Cell Disease

1. Haemoglobin AS (Hb AS): This is a heterozygous genetic inheritance of normal haemoglobin A from one parent and an abnormal haemoglobin S from another parent.
2. Haemoglobin SC (Hb SC): There is inheritance of an abnormal hemoglobin S from one parent and abnormal hemoglobin C from the other parent. It symptoms are similar to sickle cell anaemia but milder.
3. Haemoglobin SS (Hb SS): This is also known as sickle cell anaemia. It is by inheritance of two abnormal haemoglobin SS, one from each parent. It is the severest form of sickle cell disease.
4. Thalassaemia: This is a hereditary disease. This occurs when haemoglobin A is produced in smaller amounts without any abnormality in the haemoglobin, this can be classified into two types:

• Thalassaemia major: It is also called Cooley anaemia, and it is very severe hemolytic disease, often fatal at childhood and rare in adult.
• Thalassaemia minor: With this the individual only has the trait and shows fewer symptoms.

Clinical Manifestation Of Sickle Cell Disease

1. Joint and bone pain – due to occlusion of the capillaries at the joint by the sickle shaped cells.
2. Abdominal pains (common in the spleenic region) – this is due to the enlargement of the spleen.
3. Anorexia– due to bitterness of the mouth.
4. Dehydration – as a result of less intake of water and during excessive loss of blood.
5. Growth retardation – due to less blood supply to the tissues of the body for growth
6. Pallor -due to the excessive destruction of red blood cell.
7. Short trunk, long and thin legs due to hyperactivity of the bone marrow in the long bones.
8. Low hemoglobin level (between 6g/dl- 8g/dl-) -due to excess red blood cell destruction.
9. Delay sexual maturity especially in males.
10. Hepatomegaly due to retention of huge number of the sickle cells in the liver.
11. Splenomegaly due to accumulation of the sickle cells in the spleen with the attempt to destroy them.
12. Fever due to infection by the malaria parasite.
13. Weakness due to decrease in blood volume.
14. Dizziness due to low level of blood.

Sickle Cell Crisis

Is a severe pain which occurs in sickle cell patient as a result of hemolysis due to tissue hypoxia and dehydration.

Types of Sickle Cell Crisis

1. Haemolytic Crisis
2. Aplastic Crisis
3. Splenic Sequestration Crisis
4. Vaso Occlusive Crisis

Haemolytic Crisis
These are acute accelerated drops in hemoglobin level. The red blood cells break down at a faster rate. It is common in patients with co-existing G6PD deficiency. Management is by blood transfusion.

Aplastic Crisis
If a person with sickle cell disease is infected with parvovirus, it causes the bone marrow to suddenly stop producing red blood cells to replace the lost ones, resulting in sudden and severe anemia.This result in the patient presenting with signs and symptoms like pallor, shortness of breath and fatigue. About 5 to 10 days after a crisis starts, the bone marrow usually recover on its own. This causes the red blood cell production to return to its usual rate.

Splenic Sequestration Crisis
Splenic sequestration crisis occurs as a result of narrowed blood vessels and clearance of defective red blood cells, which normally affect the spleen. This is an acute painful enlargement of the spleen. The sinusoids and gates would open at the same time resulting in sudden pooling of blood into the spleen and circulatory defect leading to sudden hypovolaemias. The abdomen becomes bloated and very hard. Splenic sequestration crisis is considered an emergency. If not treated, patients may die within 1-2hours due to circulatory failure. Management is supportive, sometimes with blood transfusion.

Vaso Occlusive Crisis
This normally occurs when the sickle cells become massed and clogged in the capillaries obstructing blood flow to more distal areas and organs. The joint and the extremities are the part mostly affected. This result in ischemia, pain and organ damage. With the individual showing abdominal pain, joint pains, distal ischemia and infarction, impaired liver function and priapism.

Diagnostic Investigations

1. Full Blood Count: this is to reveal the haemoglobin and reticulocyte level, with haemoglobin level reading between 6 and 8g/dl.
2. Haemoglobin electrophoresis: to detect abnormal haemoglobin and indicate whether a person has sickle cell trait or sickle cell disease.
3. Amnocentesis and gene mapping: taking blood sample from the uterus to diagnose the chromosomal defect of a fetus.
4. Sickle cell test: this is to detect the abnormal shape or sickle cell in one’s system.
5. X-ray of the bone which will reveal dead red blood cells that has accommodated in the joints.
6. Family history of both parents having the sickling gene.

Specific Medical Management

Sickle cell disease has no known therapy for it or a permanent cure, but there are primary preventive and supportive measures which are used as treatment to help reduce the crisis occurrence and it complications that arise when the individual is exposed to the predisposing factors. Emphasis was placed on the prevention, early detection and prompt treatment of infection.
Hydrate patient if dehydrated to help maintain blood volume to normal.
Pneumococcal vaccine (pneumovax) is also given as prophylactics to decrease the incidence of pneumococcal infection in children.
Prophylactic Antibiotic: Phenoxymethyl- Penicillin is given to patient with sickle cell anaemia. This reduces the morbidity and mortality associated with infection.
Folic acid supplement 5mg daily to replenish the foliate stores, depleted during haemolysis if normal dietary level are not sufficient for the manufacturing of red blood cells.
Blood transfusion is requested when sickle cell crisis occurs frequently and patient is anaemic in order to increase the red blood cell of the patient.
Analgesics and sedatives are given to decrease the severity and duration of pain during crisis.
Oxygen is administered, if patient is presenting with hypoxia.

Nursing Management

Rest and Sleep

1. Nurse patient in a quiet and well ventilated environment
2. Put patient in a preferred position where she will be comfortable
3. Restrict visitors when patient is asleep.
4. Avoid unnecessary interruption by performing all nursing activities together.
5. Administer prescribed analgesics for the pain and sedatives to relax the muscles for sleep.

Pain Relief

1. Assist patient to assume a comfortable position.
2. Nurse patient in a warmed bed
3. Apply warm compress on the affected joint to relieve pain.
4. Assist patient in using the affected site in passive exercise.
5. Provide a diversion therapy for patient, example; engaging patient in a conversation.
6. Massage joint with ointment to give patient relief.
7. Serve prescribed analgesics to relieve pain.

Nutrition

1. Serve copious fluid about 2 to 3 liters a day to prevent dehydration.
2. Serve highly nutritious diet, rich in protein, iron, vitamins and folic acid to enhance red blood cell production.
3. Serve fruits which are rich in vitamin C to boost the immune system.
4. Include patient in planning his/her diet.
5. Food should be served in an attractive manner.
6. Where patient cannot tolerate oral feed, serve prescribed intravenous fluids.

Observation

1. Assess patient’s level of pain using exhibiting characteristics such as rapid pulse
2. Monitor patient’s temperature, pulse, respiration and blood pressure four hourly and record.
3. Monitor intake and output regularly.
4. Monitor patient for signs of complications such as jaundice

Personal Hygiene

1. Give patient warm bath to reduce pain and prevent severity of condition.
2. Assist patient to perform oral hygiene twice daily.
3. Trim patients nail if grown and encourage her to keep them neat to prevent infection

Elimination

1. Encourage patient to empty bowel when there is the urge.
2. Encourage patient to take in more roughage to prevent constipation.
3. Encourage patient to take in more fluid to enhance free bowel movement.

Prevention and Health Education

1. Educate patient and family on sickle cell disease especially the precipitating factors and the prevention measures.
2. Educate patient on predisposing factors of sickle cell crisis
3. Educate patient and family on the need for genetic counselling before marriage in order to choose a partner with a favorable sickle status
4. Encourage patient to eat adequate diet
5. Educate patient and family on the need for regular medical check-ups.
6. Educate patient and family on home management of mild crisis.
7. Educate patient and family on importance of warmth, adequate hydration and prevention of infections in preventing crisis.
8. Educate the patient on the need to complete her medication as prescribed.
9. Educate patient on the need for daily intake of folic acid.

Complications Of Sickle Cell Disease

1. Pulmonary hypertension: This is due to the attempt of the pulmonary to send blood to the heart.
2. Priapism: This is due to accumulation of blood in the vessels of the penis
3. Heart failure: This is due to low blood volume to the heart for it normal function
4. Stroke/ Cerebrovascular Accident: This due to low supply of oxygenated blood to the brain
5. Renal failure: This is due to low blood supply to the kidney for it normal function
6. Anaemia: This is due to excessive break down of Red Blood Cells in circulation
7. Jaundice: This is due to excess bilirubin in circulation due to the excess RBC break down
8. Leg ulcer: This is due to poor blood supply to tissues of the affected leg.
9. Hepatomegaly: due to accumulation of excessive broken down sickle cells in the liver.
10. Splenomegaly: due to the over activity of the spleen in breaking down sickled RBC’s.
11. Osteomyelitis: this occurs when there is infection of the bone.
12. Ischemia: due to the reduction of blood supply to vital organs of the body.