Sickle Cell Disease Flashcards
Anemia
a deficiency in the #of RBCs, quantity or quality of hemoglobin and volume of packed RBCs (hematocrit)
main causes are due to (1) blood loss, (2) hypo proliferative and (3) hemolytic
Erythrocytes
RBC, lifespan is 120 days
contains hemoglobin
Erythropoiesis
production of RBCs
erythropoietin is a glycoprotein primary produced in the kidneys (therefore renal failure can cause hypo proliferative anemia)
Alterations in erythropoiesis
Three alterations may decrease RBC production.
(1) decreased hemoglobin synthesis
(2) defective DNA synthesis in RBCs
(3) diminished availability of erythrocyte precursors
Hypo proliferative anemia
impaired production of erythrocytes
caused by vitamin b12, iron or folate deficiency and cancer, renal failure
Hemolytic anemia
increased destruction of erythrocytes
caused by drug induced or autoimmune processes (e.g. sickle cell disease)
RBC function
transport O2 from lungs to systematic tissues and CO2 from the tissues back to the lungs.
because RBCs transport O2, erythrocyte disorders can lead to tissue hypoxia. therefore hypoxia is a sign of anemia (can cause confusion, bluish skin, rapid HR)
Sickle Cell anemia
hemolytic anemia, results from inheritance of sickle hemoglobin gene.
abnormal hgb causes RBCs to be rigid and therefore can get stuck in small capillaries.
current life expectancy - 42-48 years
Sickle cell anemia - populations at risk
inherited in people of African descent
autosomal recessive disease - one parent must have the disease and one must be a carrier.
Sickle cell anemia clinical manifestations
typical pt is asymptomatic except during sickling episodes.
sickled cells are rapidly hemolyzed - lifespan of 10-12 days.
Sickling Episodes
back, chest, extremities and abdomen most commonly effected.
blood vessels to part of the body become blocked.
infection is the most common precipitating factor.
pain episodes will have fever, swelling, tenderness, tachypnea, hypertension, N/V
Sickle cell crisis
severe painful, acute exacerbation of sickling causes a vaso-occlusive crisis.
results from tissue hypoxia and necrosis due to inadequate blood supply - very painful.
shock is a potential life threatening consequence
vaso-occlusive crisis protocol
1 - start IV fluids at maintenance rate
2 - administer a loading dose of pain med (e.g. morphine sulfate)
3 - assess 02 saturation
Complications of sickle cell disease
pneumonia - most common infection due to failure of spleen to phagocytize foreign substances
acute chest syndrome - fever, chest pain, cough, dyspnea (may require antibiotics, fluid therapy, o2 therapy)
pulmonary infarction - can cause pulmonary hypertension (which can cause death)
DX of sickle cell disease
peripheral blood smear
electrophoresis of hemoglobin - measure hgb levels and looks for abnormal hgb. ussually diagnoses at birth this way.
MRI, chest radiography, doppler studies
Nursing management of sickle cell anemia
pain management - pca continuous opioid analgesics often used for acute crisis
preventing/treating infections - immunizations, antibiotics
rest - reduces metabolic requirements
O2 for hypoxia and to control sickling
blood transfusions in crisis
should only fly on airplanes with pressurized cabins
Hydroxyurea
chemotherapy agent that decrease the formation of sickled cells.
side effect - chronic suppression of leukocyte formation.
Folic acid supplementation
people with sickle cell disease have increased RBC production to make up for anemia and therefore need more folate.
Blood transfusions
highly effective for acute exacerbation of anemia
risks include iron overload, infections (hepatitis, HIV), increased blood viscosity without reduction in concentration of sickle cell hemoglobin
