Sickle Cell Disease Flashcards
For SCD what is the genotype and associated electrophoresis results?
SS-due to glutamic acid to valine change
Electrohphoresis-HbS>90%, HbA-0
For SC disease what does electrophoresis show and what is the symptom severity?
They will have 50% of Sickle hemoglobin and 50% of C hemoglobin. Due to glutamic acid to lysine change. They have mild anemia compared to SS dx and predominantly vasocclusive symptoms.
What is the electrophoresis for S beta null disease and what is the symptom severity? What is the MCV?
There will be 90% of Hb S and 0 of HbA. They have severe anemia with a very LOW MCV. They have severe hemolytic anemia and vaso-occlusive dx.
What is the electrophoresis for SB+ dx? What is the symptom severity?
They have about 75% HbS and 25% HbA. They mild/moderate anemia. Mostly have vaso-occlusive symptoms.
For sickle cell trait what is the electrophoresis and what is the symptom severity? What complications can they experience?
They should have more HbA (60%) compared to HbS (40%). They should have normal hemoglobin and MCV. They can have renal/thrombotic complications.
For patients with sickle cell disease with alpha thalssemia what effect does this have on their symptoms and why?
Because this causes less hemoglobin, there is less polymerization which in turn lessens the hemolysis.
In those SCD patients with persistence of fetal hemoglobin what effect does this have?
If they have a HbF greater than 20% they have less vaso-occlusive crises. HbF>10% also decreases CVA and AVN.
What are the clinical signs of aplastic crisis in sickle cell disease? What should you suspect and what is the tx?
They have a very low reticulocyte count. This is concerning for parvovirus. You treat with IVIG and simple transfusion. Send for IgM and PCR.
What are the clinical features to suggest hyperhemolytic syndrome if they received a prior transfusion? What is the time line of symptoms?
Here you will see the typical hemolysis labs, however the reticulocyte will be significantly low. The DAT will be positive. Typically they received a transfusion 2-14 days prior.
What is the tx of hyperhemolytic syndrome from transfusion?
IVIG, steroids, Ritxuimab. For severe episodes you can consider giving extended match red cell txn in addition or red cell exchange.
What are the clinical features seen with hyperhemolytic syndrome that is non immune mediated (not related to a transfusion)?
All of the hemolysis markers will be positive, in this case the reticulocyte count will be elevated. It is a TMA like process-you can get severe organ dysfunction. The DAT most of the time is negative.
What is the treatment of non immune mediated hyperhemolytic syndrome?
You do a red cell exchange. I’m GW lecture he says you can also consider Plasma Exchange if red cell exchange not working.
What are the clinical features of hepatic sequestration?
RUQ pain, sudden increase in hepatomegaly w/concomitant drop (2g or more) in Hgb, transaminitis (particularly ALT), liver failure, elevated conjugated bilirubin. Look for low platelets.
What is the treatment of hepatic sequestration?
Exchange or simple transfusion
What are the clinical features of splenic sequestration? In adults what type of sickle cell does this occur in?
LUQ pain with splenomegaly and thrombocytopenia. It occurs in SC and SB+ disease.
How do you treat splenic sequestration?
Really with red cell exchange. You can give a simple transfusion to start. Also have the option of splenectomy
What are the clinical features of intra-hepatic cholestasis? What is the tx?
Very high direct bilirubin (greater than 50% of total bilirubin), elevated PT/PTT (bleeding), renal dysfunction, encephalopathy. You give a red cell exchange.
What is the treatment for mild-mod acute chest vs severe acute chest?
Mild-Mod: simple transfusion
Severe-exchange txn
In pediatric patients with SCD what is primary prevention for CVA.
They get screened with transcranial doppler yearly. If it is high they go on chronic transfusion programs. Reduces risk by over 90%
In adult patients with SCD when they are diagnosed with stroke, what is the best next step?
They should be implemented on a chronic transfusion program to keep Hb s<30% and maintain Hb of 10 or higher.
If CT head is negative for CVA in a patient presenting with neurological symptoms what study should be ordered next?
MRA/MRV, MRV to rule out cerebral sinus venous thrombosis.
What is the tx for CVA in SCD?
Exchange transfusion to maintain Hb>10, Hb S< 30%, and O2 sat>95%.
What is the recommendation regarding screening for PAH in SCD?
Only screen patients with TTE who are symptomatic: chest pain, dyspnea, hypoxia, sleep disordered breathing, syncope/presyncope, loud P2
For patients with SCD that are found to have albumuniria what is the recommendation per ASH guidelines? How often do you screen for this?
Start a low dose ACE/ARB. Yearly starting at age 10. If positive you check every 3 months.
How is priapism managed for events that are less than 3 hours (stuttering priapism)?
Any event lasting over 1 hour requires urological eval. First you want to start IV fluids. For events less than 3 hours you do pseudo-ephedrine.
What type of priapism should you consider if the event last for over 4 hours and what is the management?
Remember all patients should be started on IV fluids right away! For over 4 hours you think ischemic priapism and you have to treat with cavernous aspiration +/- irrigation.
When should you consider starting iron chelation therapy in SCD? What is the goal ferritin?
With a ferritin greater than 1000. Less than 500.
What adhesion molecule does Crizanlizumab target?
P-selectin.
So currently the three agents that help reduce VOC in SCD are?
Hydrea, L-glutamine, and Crizanlizumab.
How does Voexelotor work? What is the main clinical effect?
It binds to the alpha globin chain to stabilize the oxygenation state to prevent polymerization. It increase the hemoglobin usually by 1g/dl.
What is the mechanism of Hydrea?
It inhibits RNA reductase
What is the vaccine recommendation for Pneumococcal vaccination?
PPV-23: At least 2 doses 5 years apart, and then every 5 years thereafter. If only two doses were given, then third dose given @ age 65.
PCV 13-one lifetime dose age 18 or after
What is the recommendation for Meningiococcal vaccination?
Quadrivalent conjugate vaccine for at least 2 doses followed by booster ever 5 years. Patients will also need serogroup B vaccine.
What are the clinical features of acute hepatic sickle crisis? What is the tx?
There will be elevations in ALT/AST. The bilirubin is usually normal or mildly elevated. PT/PTT are normal. No coagulopathy or organ failure. Tx-hydration, pain management.
