Sickle Cell Anemia Flashcards
What is sickle cell anemia ?
an inherited genetic disorder which is characterized by a abnormal shape of hemoglobin in RBC
How do sickle cell anemia RBCs respond to treatment ?
they “bounce back” to their normal shape
- over time they will use the ability to bounce back
- can cause irreversible damage to the lungs, kidneys, brain, retina, or bones
What are some characteristics of sickled cells ?
- stiff and angular in response to low O2 levels
- inflexible
- crescent shaped
- get stuck easily in the capillaries
What hemoglobin indicates sickle cell and normal hemoglobin ?
- SCA: Hgb S
- normal: Hgb A
What are characteristics of Hgb SS ?
most severe sickle cell anemia
- is inherited from both parents (homozygous)
What are characteristics of Hgb SA ?
sickle cell trait
- mild to asymptomatic condition
- Hgb S is inherited from 1 parent and the other has a normal hemoglobin
What are characteristics of sickle cell thalassemia and sickle cell Hgb C disease ?
- less common and less severe
- a person inherits Hgb S from 1 parent and another type of abnormal Hgb from the other parent (either thalassemia or Hgb C)
What is thalassemia ?
blood disorder that prevents the body from producing enough hemoglobin
What is Hgb C disease ?
a genetic condition that causes a mild anemia, or low blood count, in people who inherit the gene from both parents
- mutation in beta-globin chain of Hgb which makes hemoglobin variant unstable
- causes RBCs to break down faster than normal
What is the main trigger that causes sickling episodes ?
low oxygen (hypoxia)
What are other causes of sickling episodes ?
- infection (bacterial or viral)
- dehydration
- high altitude
- emotional stress
- physical stress (strenuous exercise)
- surgery
- blood loss
- acidosis
- low body temp
- there isn’t always a obvious cause
What is the spleen’s function in sickle cell anemia ?
the sickled cells are hemolyzed by the spleen because of the abnormal shape
- the cells get trapped into the spleen’s narrow blood vessels
- they get damaged and destroyed by the macrophages as it filters blood
- this leads to anemia
What is the main symptoms in sickling episodes ?
pain
- can range from mild to excruciating pain
- common sites are: back, chest, extremities and abdomen
- pain episodes often associated with: fever, swelling, tenderness, tachypnea, HTN, N/V
What are some symptoms of anemia ?
- dizziness or light-headedness,
- pale pallor in mucous membranes
- skin may be gray-ish
- jaundice and gallstones common due to hemolysis
Why does hemolysis lead to jaundice ?
when RBCs breakdown they release bilirubin (byproduct of Hgb)
- if the body can’t excrete it quick enough it can accumulate in the blood
- this can lead to an excess bile which leads to gallstones
- the buildup of bile causes the jaundice (NOT a liver issue but a buildup of byproducts)
What is a vaso-occlusive crisis ?
severe, painful, acute exacerbation of an RBC sickling episode
- as there is a block of blood flow then vasospasm (constriction of arteries) occurs which further constricts blood flow
What can eventually occur during vaso-occlusive crisis ?
tissue ischemia, infarction, and necrosis due to lack of O2
- shock is possible because of severe hypoxia to tissue and decreased circulating fluid volume (ICU care)
What is acute chest syndrome ?
an acute lung injury caused by sickled cells blocking small blood vessels in the lungs
- may be caused by infections and embolisms
- often results in lung injury or infarction
What are some symptoms of acute chest syndrome ?
- fever
- chest pain
- congested cough, may contain blood
- dyspnea and tachypnea
- wheezing
- retractions
- decreased O2 sats
- increased WBCs due to inflammatory process
What conditions can occur because of vaso-occlusive crisis ?
- lungs: acute chest syndrome
- brain: cerebrovascular accident (CVA)
- spleen: splenic sequestration
What is splenic sequestration ?
occurs when sickled cells clump together and block the exit of blood from the spleen
- lead to enlarged spleen (splenomegaly)
- results in drastic reduction of blood flow to the other organs in the body (hypovolemia)
- death can occur within 30 mins
What are some S&S of splenic sequestration ?
- low BP and tachycardia
- pale
- lethargic
- life threatening anemia (low Hgb levels)
- occurs primarily in kids < 2 yrs
- will require a splenectomy
What are some S&S of cerebrovascular accident (CVA) ?
- change in LOC
- seizures
- weak extremity one side
- slurred speech
- vision changes
- vomiting
- severe HA
What labs are monitored during sickling episodes ?
- CBC: monitor RBCs, Hgb levels
- liver labs: shows us hemolysis of sickled cells
- may also be imaging, head CT, MRI, chest x-ray,
What are diagnostics for sickle cell anemia ?
- often diagnosed at birth
- peripheral blood smear may reveal sickled cells
- high electrophoresis can determine amount of Hgb S
- for splenic sequestration there aren’t tests needed: only thru labs and physical exam
What are some maintenance meds for sickle cell ?
- hydroxyurea
- folic acid
- antibiotics
- immunizations
What are some characteristics of hydroxyurea ?
“anti-sickling” agent
- prevents RBCs from becoming sickled
- increases the production of fetal hemoglobin (Hgb f) and RBCs
- keeps RBCs round, flexible and slippery
- take daily or will not work
- pregnant women can’t take
How is folic acid used with sickle cell ?
increases Hgb F, Hgb, and RBC production
Why are antibiotics used with sickle cell ?
- prophylactic to prevent infections (could be decreased O2)
- especially in pt’s without a spleen (asplenic)
What are some fluids and meds taken for sickling episodes and vaso-occlusive crisis ?
- IV fluids
- pain meds: PCA, IVP, PO, nerve block
- electrolytes
- antibiotics
- hydroxyurea/folic acid
- tylenol: must treat fever
Why are fluids important for sickle cell ?
- IV fluids break up the sickled cells
- helps maintain renal function
- oral hydration just as important
Why do you give electrolyte replacement ?
if we are giving lots of fluids then you need to give electrolytes appropriately to keep up
What are exchange transfusions used for ?
separates the pt’s blood into its components, removes the sickle-shaped RBCs and replaces them with donor RBCs
- can take 1-2 hrs with 2 insertion sites and a blood warmer
- pt’s remaining blood like plasma, and WBCs returned to them
Which patients may get a exchange transfusion ?
for pt’s with frequent crisis or to prevent serious complications
- like acute chest syndrome, CVA and other forms of vaso-occlusive crisis
Why are standard blood transfusions not done commonly ?
- increases pt’s risk of developing antibodies to RBC
- iron overload
What is the only curable treatment for sickle cell anemia currently ?
hematopoietic stem cell transplants (HSCT)
What is a hematopoietic stem cell transplant ?
an immature cell that can develop into all types of blood cells, including WBCs, RBCs, and platelets
- taken from healthy pt’s to pt’s with SCD
- possibility for rejection of transplanted cells
- not widely done because of scarcity of donors, risks and cost
What are some RN interventions for sickling episodes/vaso-occlusive crisis ?
- hydration
- oxygen: prevents further sickling
- pain management: monitor for respiratory depression, distraction, warm packs (for dilation)
- rest: need rest because movement increases O2 demands, DVT prophylaxis and incentive spirometer
- assessments: respiratory, cardiac, neurologic
