Sickle Cell Disease Flashcards
What is the lifespan of RBCs?
- 90-120 days
What is sickle cell disease?
- Group of inherited RBC disorders resulting from a genetic mutation in the genes that encode hemoglobin
What is hemoglobin S?
- RBCs that contain abnormal hemoglbin is called hemoglobin S or sicke hemoglobin
What does hemoglobin S causes and what happens after?
- It causes RBCs to be rigid with a concave “sickle” shape
- Sickled RBCs burst (hemolyze) after 10-20 days, which causes anemia
Which population is mostly affected by SCD?
- African American
When does symptoms of SCD develop? Why?
- 2-3 months after birth
- A fetus or young infants have RBCs with fetal hemoglobin (HgbF), which blocks the sickling of RBCs
What is vascular occlusion and its complications?
- Vascular occlusion prevents oxygen from reaching the tissues, causing them to become ischemic
- This can lead to different types of sickle cell crises. The mos common is vaso-occlusive crises (VOC), or acute pain crisis
If the pain is in the chest and there is evidence of a pulmonary infection, it is called ___.
Fill in the blank
- Acute chest syndrome
What are chronic complications of SCD?
- Pulmonary HTN
- Renal impairment
- Chronic pain
- Avascular necrosis (bone death)
- Leg ulcers
- Gallstones
- Pregnancy complications
- Retinopathy
- Recurrent priapism
What are acute complications of SCD?
- Vaso-occlusive crisis (acute pain crisis)
- Acute chest syndrome
- Anemia
- Cholecystitis
- Infection
- Multiorgan failure
- Priapism
- Spleen sequestration
- Stroke
Which encapsulated organisms is an healthy spleen particularly responsible to clear?
- Streptococcus pneumoniae
- Haemophilus influenzae
- Neisseria meningitidis
What happens to the spleen in SCD?
- It becomes fibrotic and shrinks in size due to repetitive sickling and infarctions
- This causes functional asplenia (decreased or absent spleen fx)
Patients with functional asplenia are at an increased risk of ___ ; they require ___ and ___.
Fill in the blanks
- Serious infections
- Immunizations
- Prophylactic antibiotics
What are the non-drug treatment for SCD?
- Blood transfusions
- Bone marrow transplantation (the only cure)
What is the goal Hgb level when administering chronic blood transfusions?
- Should be no higher than 10 g/dL post-infusion
T/F: One of the risks of blood transfusions is iron overload and chelation therapy can be administered to remove excess iron
TRUE
What are drug treatments for SCD?
- Immunizations
- Antibiotics
- Analgesics
- Hydroxyurea (prevent/reduce complications)
- Chelation therapy (manage iron overload)
__ and __ due to S.pneumoniae, H. influenzae, N. meningitidis can occur.
- Sepsis
- Meningitis
What reduces the risk of death from invasive pneumococcal infections in young children?
- Prophylactic penicillin
What is the treatment for infants who screen positive for SCD at birth?
- Twice daily penicillin and treated until age 5 years
What are routine childhood vaccine series for SCD?
- Haemophilus influenzae type B (Hib)
- Pneumococcal conjugate (PCV13, Prevnar)
List additional vaccines for functional asplenia
- Meningococcal conjugate series plus routine boosters
- Meningococcal serogroup B (Bexsero, Trumenba) (at age >=10 years)
- Pneumococcal polysaccharide (PPSV23, Pneumovax 23) (at age >=2 years, booster 5 years later and at age >=65 years)
- Pneumococcal conjugate (PCV13, Prevnar) x1 in any patient >=6 years of age, if never received as a part of routine childhood series
Patients with severe pain and VOC will require ___ administration of ___ or patient-controlled analgesia (PCA)
Fill in the blanks
- IV
- Opioids
What is hydroxurea? What is it used for?
- Hydroxyurea is a disease-modifying drug that stimulates production of HgbF
- Long term use reduces the frequency of acute pain crises, episodes of acute chest syndrome and the need for blood transfusions
- It is indicated for adults with >=3 moderate-to-severe pain crises in one year
Hydroxyurea - BWs, warnings, monitoring
Boxed Warnings
* Myelosuppression
Warnings
* Fetal toxicity
- Contraception required during treatment and after discontinuation
- Hazardous drug: wear gloves when dispensing and wash hands before and after after contact
- Folic acid supplementation is recommended to prevent macrocytosis
- Avoid live vaccinations
Monitoring
* CBC with differential
- Round doses up to the nearest capsule size
Hydroxyurea - DDIs
- Do not use hydroxyurea with pimecrolimus, tacrolimus and other drugs that cause myelosuppression (e.g., clozapine, deferiprone, leflunomide, natalizumab, tofacitinib)
Other drugs that are used for SCD
- L-Glutamine
- Voxelotor - inhibits HgbS polymerization
- Crizanluzumab
Iron chelation treatment drugs
- Deferoxamine - not in PO formulation
- Deferasirox
- Deferiprone
