9 - Sickle Cell Disease Flashcards
which form of Hb is more likely to sickle - oxy or deoxy?
deoxy
two main causes of complications of sickle cell disease
hemolysis
viscosity
hemolysis related complications of SCD
stroke, pulm HTN, priapism, leg ulcers
viscosity related complications of SCD
avascular necrosis, proliferative retinopathy, pain crisis, acute chest syndrome
best predictor of clinical severity in SCD
HbF levels
how do higher HbF levels improve outcomes in SCD?
first off, less cells that CAN sickle
also, HbF inhibits sickling of HbS
how does co-inheritance of alpha thalassemia affect the clinical course of SCD?
less Hb in cell > lower Hb conc > less sickling
fewer hemolytic complications, but higher viscosity related complications
PBS findings in SC anemia
sickling (duh)
Howell Jolly bodies (result of functional asplenia)
lots of retics
early clinical problems in SC anemia
splenic infarction > functional asplenia by 3-6 yrs
dactylitis
pain episodes
stroke
what type of strokes do SC anemia pts tend to have?
children - ischemic
adults - hemorrhagic
main strategy for stroke prevent in SCD
chronic transfusions
way to determine stroke risk in SCD patients
transcranial doppler ultrasound
high risk when velocity > 200 cm/s
acute chest syndrome
may develop day 3-4 of pain crisis
pain, dyspnea, fever, pulm infiltrates, leukocytosis
tx of acute chest syndrome
abx, incentive spirometry, O2, transfusion/exchange
high tricuspid regurgitant velocity in a sickle cell patient suggests
pulmonary hypertension, associated with early mortality
causes of death in SCD pts
organ failure - renal, hepatic, pulm htn
acute events - acute chest, stroke, sepsis (2/2 asplenia)
preventative care for SCD
vaccines for encapsulated orgs
prophylactic PCN until 5 yo
check UA for protein, ophtho for prolif retinopathy, echocardiogram?
hydroxyurea - what does it do
inc HbF production > less sickling
may also dec endothelial adhesion and WBC
side effects / warnings for hydroxyurea
birth defects (not observed, just evidence in animals) risk for hematologic malignancy? no evidence
GI sx
skin hyperpigmentation
excessive myelosuppression
clinical manifestations of sickle trait
splenic infarction at high altitude asymptomatic bacteriuria in women low urine specific grav hematuria pulm embolism glaucoma 2/2 hyphema sudden death during exercise renal medullary CA
bottom line: urine/kidney stuff and sudden death
Hemoglobin SC dz
C dehydrates cell - get “fat sickles”, lots of targeting, and spherocytes
get viscosity related complications, but overall milder course
spleen function lasts longer - early adulthood
how does the course of HbSbeta-thalassemia compare to other SCD types?
similar to HbSS
