What is Sickle Cell Anemia?
Sickle cell anemia is an inherited form of hemolytic anemia.
- Sickle cell anemia is a severe hemolytic anemia that results from inheritance of the sickle hemoglobin gene.
- The sickle hemoglobin (HbS) gene is inherited in people of African descent and to a lesser extent in people from the Middle East, the Mediterranean area, and the aboriginal tribes in India.
- Sickle cell anemia is the most severe form of sickle cell disease.
The HbS gene causes the hemoglobin molecule to be defective.
- Exposure. The sickle hemoglobin acquires a crystal-like formation when exposed to low oxygen tension.
- Change in the shape. The oxygen level in venous blood can be low enough to cause the erythrocyte to lose its round, pliable, biconcave disk shape.
- Adherence. These long, rigid erythrocytes can adhere to the endothelium of small vessels; when they adhere to each other, blood flow to a region or organ is reduced.
- Reversion. If the erythrocyte is again exposed to adequate amounts of oxygen before the membrane becomes too rigid, it can revert to normal shape.
The causes of sickle cell anemia include:
- Cold temperature. Cold can aggravate the sickling process, because vasoconstriction slows the blood flow.
- Tissue hypoxia. Tissue hypoxia and necrosis causes a type of sickle cell crisis called the sickle crisis.
- Human parvovirus. Aplastic crisis results from infection with the human parvovirus.
- Splenic infarction. Sequestration crisis results when other organs pool the sickled cells, just like the spleen.
Symptoms of sickle cell anemia vary and are only somewhat based on the amount of HbS.
- Anemia. Anemia is always present; usually, hemoglobin values are 7 to 10g/dl.
- Jaundice. Jaundice is characteristic and usually obvious in the sclerae.
- Dysrhythmias. Dysrhythmias and heart failure may occur in adults.
- Enlargement of the bones. The bone marrow expands in childhood in a compensatory effort to offset anemia, sometimes leading to enlargement of the bones of the face and skull.
Complications of sickle cell anemia include:
- Infection. Patients with sickle cell anemia are unusually susceptible to infection, particularly pneumonia and osteomyelitis.
- Stroke. Due to the decrease in oxygen supply because of the sickling, stroke may occur.
- Renal failure. Blood flow is reduced to other body tissues including the kidneys, which may lead to renal failure.
- Heart failure. The heart compensates for the decreased blood distribution by pumping more blood, and it may ultimately fail if it wears out.
Assessment and Diagnostic Findings
The patient with sickle cell anemia usually has the following laboratory results:
- CBC: Reticulocytosis (count may vary from 30%–50%); leukocytosis (especially in vaso-occlusive crisis), with counts over 20,000 indicate infection, decreased Hb (5–10 g/dL) and total RBCs, elevated platelets, and a normal to elevated MCV.
- Stained RBC examination: Demonstrates partially or completely sickled, crescent-shaped cells; anisocytosis; poikilocytosis; polychromasia; target cells; Howell-Jolly bodies; basophilic stippling; occasional nucleated RBCs (normoblasts).
- Sickle-turbidity tube test (Sickledex): Routine screening test that determines the presence of hemoglobin S (HbS) but does not differentiate between sickle cell anemia and trait.
- Hemoglobin electrophoresis: Identifies any abnormal hemoglobin types and differentiates between sickle cell trait and sickle cell anemia. Results may be inaccurate if patient has received a blood transfusion within 3–4 mo before testing.
- ESR: Elevated.
- Erythrocyte fragility: Decreased (osmotic fragility or RBC fragility); RBC survival time decreased (accelerated breakdown).
- ABGs: May reflect decreased Po2 (defects in gas exchange at the alveolar capillary level); acidosis (hypoxemia and acidic states in vaso-occlusive crisis).
- Serum bilirubin (total and indirect): Elevated (increased RBC hemolysis).
- Acid phosphatase (ACP): Elevated (release of erythrocytic ACP into the serum).
- Alkaline phosphatase: Elevated during vaso-occlusive crisis (bone and liver damage).
- LDH: Elevated (RBC hemolysis)
- Serum potassium and uric acid: Elevated during vaso-occlusive crisis (RBC hemolysis).
- Serum iron: May be elevated or normal (increased iron absorption due to excessive RBC destruction).
- Total iron-binding capacity (TIBC): Normal or decreased.
- Urine/fecal urobilinogen: Increased (more sensitive indicators of RBC destruction than serum levels).
- Intravenous pyelogram (IVP): May be done to evaluate kidney damage.
- Bone radiographs: May demonstrate skeletal changes, e.g., osteoporosis, osteosclerosis, osteomyelitis, or avascular necrosis.
- X-rays: May indicate bone thinning, osteoporosis.
Treatment for sickle cell anemia is the focus of continued research.
- Peripheral blood stem cell transplant. This may cure sickle cell anemia, however, this is only available to a small subset of affected patients, because of either the lack of a compatible donor or because severe organ damage is a contraindication.
- Transfusion therapy. Chronic RBC transfusion therapy may be effective in preventing or managing complications from sickle cell anemia.
- Supportive therapy. Adequate hydration is important during a painful sickling episode; aspirin is very useful in diminishing mild to moderate pain; NSAIDs are useful for moderate pain or in combination with opioid analgesics.
- Monitoring pulmonary function. Pulmonary function is monitored and pulmonary hypertension is treated early if found. Infections and acute chest syndrome, which predispose to crisis, are treated promptly. Incentive spirometry is performed to prevent pulmonary complications; bronchoscopy is done to identify source of pulmonary disease.
- Hydroxyurea has shown to be effective in increasing fetal hemoglobin levels in patients.
- Arginine has antisickling properties and enhances the availability of nitric oxide, the most potent vasodilator, resulting in decreased pulmonary artery pressure.
Nursing management for a patient with sickle cell anemia focus on the following:
Assessment data for a sickle cell anemia patient should include:
- Factors causing previous crisis. The patient is asked to identify factors that precipitated previous crisis and measures the patient uses to prevent and manage the crisis
- Pain levels. Pain levels should always be monitored using a pain intensity scale.
- Characteristics of pain. The quality, frequency, and factors that aggravate or alleviate the pain are included in the assessment.
- Infection. Because patients with sickle cell anemia are susceptible to infections, they are assessed for the presence of any infectious process.
Based on the assessment data, major nursing diagnosis for the patient include:
- Acute pain related to tissue hypoxia due to agglutination of sickled cells within blood vessels.
- Risk for infection.
- Risk for powerlessness related to illness-induced helplessness.
- Deficient knowledge regarding sickle cell crisis prevention.
Nursing Care Planning and Goals
Main Article: 6 Sickle Cell Anemia Crisis Nursing Care Plans
The major goals for the patient are:
- Relief of pain.
- Decrease incidence of crisis.
- Enhance sense of self-esteem and power.
- Absence of complications.
Nursing interventions for sickle cell anemia include:
- Use patient’s subjective description of pain and pain rating on a pain scale to guide the use of analgesic agents.
- Support and elevate any joint that is acutely swollen until swelling diminishes.
- Teach patient relaxation techniques, breathing exercises, and distraction to ease pain.
- When acute painful episode has diminished, implement aggressive measures to preserve function (eg, physical therapy, whirlpool baths, and transcutaneous nerve stimulation).
Preventing and Managing Infection
- Monitor patient for signs and symptoms of infection.
- Initiate prescribed antibiotics promptly.
- Assess patient for signs of dehydration.
- Teach patient to take prescribed oral antibiotics at home, if indicated, emphasizing the need to complete the entire course of antibiotic therapy.
Promoting Coping Skills
- Enhance pain management to promote a therapeutic relationship based on mutual trust.
- Focus on patient’s strengths rather than deﬁcits to enhance effective coping skills.
- Provide opportunities for patient to make decisions about daily care to increase feelings of control.
- Teach patient about situations that can precipitate a sickle cell crisis and steps to take to prevent or diminish such crises (eg, keep warm, maintain adequate hydration, avoid stressful situations).
- If hydroxyurea is prescribed for a woman of childbearing age, inform her that the drug can cause congenital harm to unborn children and advice about pregnancy prevention.
Monitoring and Managing Potential Complications
- Management measures for many of the potential complications are delineated in the previous sections; additional measures should be taken to address the following issues.
- Protect the leg from trauma and contamination.
- Use scrupulous aseptic technique to prevent nosocomial infections.
- Refer to a wound–ostomy–continence nurse, which may facilitate healing and assist with prevention.
PRIAPISM LEADING TO IMPOTENCE
- Teach patient to empty the bladder at the onset of the attack, exercise, and take a warm bath.
- Inform patient to seek medical attention if an episode persists more than 3 hours.
- Emphasize the importance of complying with prescribed treatment plan.
- Promote trust with patient through adequate management of acute pain during episodes of crisis.
- Suggest to patient that receiving care from a single provider over time is much more beneﬁcial than receiving care from rotating physicians and staff in an emergency department.
- When a crisis arises, emergency department staff should contact patient’s primary health care provider for optimal management.
- Promote continuity of care and establish written contracts with patient.
Promoting Home and Community Based Care
- Involve the patient and his or her family in teaching about the disease, treatment, assessment, and monitoring needed to detect complications. Also teach about vascular access device management and chelation therapy.
- Advise health care providers, patients, and families to communicate regularly.
- Provide guidelines regarding when to seek urgent care.
- Provide follow up care for patients with vascular access devices, if necessary.
Expected patient outcomes are:
- Relief of pain.
- Decreased incidence of crisis.
- Enhanced sense of self-esteem and power.
- Absence of complications.
Discharge and Home Care Guidelines
Education is always the best way to impart what the patient and the family need to know for home care.
- Vascular access management. Nurses in outpatient facilities or home care nurses may need to provide follow-up care for patients with vascular access devices.
- Communication. All health care providers who provide services to patients with sickle cell disease and their families need to communicate regularly with each other
The focus of documentation in a patient with sickle cell anemia include:
- Client’s description of response to pain.
- Acceptable level of pain.
- Prior medication use.
- Signs and symptoms pf infectious process.
- Plan of care.
- Teaching plan.
- Responses to interventions, teaching, and actions performed.
- Attainment or progress toward desired outcome.
- Long term needs.
Practice Quiz: Sickle Cell Anemia
1. A nurse expects an adult patient with sickle cell anemia to have a hemoglobin value of:
A. Near 3 g/dl.
B. Near 5 g/dl.
C. Between 5 and 7 g/dl.
D. Between 7 and 10 g/dl.
2. Sickle-shaped erythrocytes cause:
A. Cellular blockage in small vessels.
B. Decreased organ perfusion.
C. Tissue ischemia and infarction.
D. All of the above.
3. A person with sickle cell trait would:
A. Be advised to avoid fluid loss and dehydration.
B. Be protected from crisis under ordinary circumstances.
C. Experience hemolytic jaundice.
D. Have chronic anemia.
4. On the basis of the knowledge of the inheritance of the sickle cell gene, the nurse expects the patient to be of what descent?
C. Middle Eastern.
5. On assessment, the nurse notes that the patient’s face and skull bones are enlarged. She knows this is a compensatory response to:
Answers and Rationale
1. Answer: D. Between 7 and 10 g/dl.
A patient with sickle cell anemia has a hemoglobin level of between 7 and 10 g/dl.
2. Answer: D. All of the above.
- D: All of the options are correct.
- A: Sickle-shaped erythrocytes cause cellular blockage in small vessels.
- B: Sickle-shaped erythrocytes cause decreased organ perfusion.
- C: Sickle-shaped erythrocytes cause tissue ischemia and infarction.
3. Answer: B. Be protected from crisis under ordinary circumstances.
- B: A person with sickle cell trait experiences a crisis called sickle crisis.
- A: A person with sickle cell trait would not be advised to avoid fluid loss and dehydration.
- C: A person with sickle cell trait would not experience hemolytic jaundice.
- D: A person with sickle cell trait would always have chronic anemia.
4. Answer: A. African.
- A: The sickle hemoglobin (HbS) gene is inherited in people of African descent.
- B: The sickle cell gene is inherited to a lesser extent from the Indian descent.
- C: The sickle cell gene is inherited to a lesser extent from the Middle Eastern descent.
- D: The sickle cell gene is inherited to a lesser extent from the Mediterranean descent.
5. Answer: B. Anemia.
The bones are enlarged as compensatory response to offset anemia.
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