Chapter 36: Sickle Cell Disease Flashcards
RBCs have a lifespan of about __-__ days
90-120
SCD is a group of inherited RBC disorders resulting from a genetic mutation in the genes that encode _____
hemoglobin
Patients with homozygous inheritance of the sickle cell gene have RBCs that contain abnormal Hgb, called ___
HgbS or sickle hemoglobin
Sickled RBCs burst (hemolyze) after __-__ days, which causes anemia and fatigue
10-20
SCD most commonly affects which population
African Americans
Symptoms of SCD develop ~__-__ months after birth
2-3
What is unique about fetus and young infants hgb?
a fetus and young infants have RBCs with fetal hemoglobin (HgbF), which blocks the sickling of RBCs.
____ prevents O2 from reaching the tissues, causing them to become ischemic
Vascular occlusion
If the pain from vaso-occlusive crisis is in the chest and there is evidence of a pulmonary infection, it is called ____
acute chest syndrome
Most common chronic complications of SCD are chronic pain, avascular necrosis (bone death), ____, and renal impairment
pulmonary HTN
healthy spleen aids in immune function and clears bacteria such as _____, ____ & ____
Streptococcus pneumoniae, Haemophilus influenzae and Neisseria meningitidis
All encapsulated organisms
In SCD, the spleen becomes fibrotic and shrinks, causing ______ & these patients are at increased risk for ____
functional asplenia (decreased or absent spleen function) serious infections
____ provide RBCs with HgbA
Blood-transfusions
When administering chronic (monthly) blood transfusions, the goal Hgb level should be no higher than __ g/dL post-infusion
10
One of the risks of blood transfusions is
iron overload
can lead to hemosiderosis (excessive iron that impairs organ fxn)
What can be done to remove excess iron
Chelation therapy
The only cure for SCD is
bone marrow transplantation
Primary drug classes used in SCD
- Immunizations & Antibiotics to reduce infection risk
- Analgesics to control pain
- Hydroxyurea to prevent or reduce the frequency of acute and chronic complications
- Chelation therapy to manage iron overload from blood transfusions
- L-glutamine, voxelotor and crizanlizumab
Which complications can occur from Streptococcus pneumoniae, Haemophilus influenzae and Neisseria meningitidis in SCD
Sepsis and meningitis
Prophylactic ___, given PO, reduces the risk of death from invasive pneumococcal infections in young children with SCD
penicillin
Infants who screen positive for SCD at birth should be initiated on ___ daily ___ and treated until age __ years
twice
penicillin
5
Key vaccines in SCD
Routine Childhood Series
* Haemophilus influenzae type B (Hib)
* PCV13
Additional Vaccines for Functional Asplenia
* Meningococcal conjugate series plus boosters
* Meningitis serogroup B (Bexsero, Trumenba) – age ≥ 10 yrs
* pneumococcal vaccines ≥ 19 years
1. PCV20
2. PCV15
Patients with severe pain and vaso-occlusive crisis will require __ administration of ___ or ____
IV administration of opioids or PCA
Hydroxyurea MOA
stimulates production of HgbF (blocks sickling of Hgb)
Hydroxyurea is indicated in which pts
For adults with ≥ 3 moderate – severe pain crises in one year, or patients w/ severe or recurrent acute chest syndrome, chronic symptomatic anemia or disability.
consider in all children ≥ 9 months
T/F: Hydroxyurea doses should be rounded to the nearest capsule size
True
Hydroxyurea boxed warning
Myelosuppression (↓ WBCs and plts)
what should be avoided with Hydroxyurea
live vaccines
Hydroxyurea requires ___ during treatment and after discontinuation due to a risk of ____
contraception
fetal toxicity
What must be worn when dispensing hydroxyurea
gloves & wash hands before and after handling (hazardous drug)
____ supplementation is recommended to prevent macrocytosis with hydroxyurea
Folic acid
Voxelotor MOA
inhibits HgbS polymerization, which is the cause of SCD
Iron chelation treatment: ____ was previously used, but it has significant toxicities, is not available PO, and requires slow, prolonged infusions
deferoxamine
Which oral chelating drugs are now used for chelation treatment with chronic blood transfusions
deferasirox and deferiprone
