Sickle cell Flashcards

1
Q

Etiology of sickle cell

A

Valine substituted for glutamic acid at 6th position of beta globin chain, leading to decreased solubility, overwhelming RBC skeleton, leading to sickling

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2
Q

hgb electrophoresis in sickle cell anemia

A

90% hgb SS
5% hgb A2
3-4% hgb F

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3
Q

hgb electrophoresis in sickle cell trait

A

60% hgb A
40% hgb S
A2 normal
F normal

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4
Q

Hgb SC electrophoresis

A

50% hgb S
0% hgb A
50% hgb C

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5
Q

hgb SC specific clinical features

A
  • ocular complications, *sickle cell retinopathy. They have a higher incidence of sickle cell retinopathy than HbSS
  • osteonecrosis
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6
Q

sickle b0 phenotype

A

very similar to hgb ss

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7
Q

sickle b0 hgb electrophoresis

A

hgb s at 80%
A2 at 3%
*Just remember very little to no hgb A
hgb F at 17%

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8
Q

sickle b+ hgb electrophoresis

A

hgb s at 80%
A 20%
A2 3%
hgb F at 17%

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9
Q

complications sickle cell trait patients are at risk of

A
  • hematuria
  • renal papillary necrosis
  • pyelo
  • VTE during pregnancy
  • hypothesthenuria (inability of the kidney to concentrate the urine normally)
  • increased UTI’s in pregnancy
  • renal medullary carcinoma
  • risk of severe splenic infarction at high altitude
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10
Q

Malignancy sickle cell patients are at higher risk of

A

Renal medullary carcinoma

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11
Q

Sickle cell additional clinical complications

A
  • developmental delay
  • retinal vessel occlusion
  • osteomyelitis
  • leg ulcers
  • biliary stones
  • hepatic sequestration crises
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12
Q

Encapsulated organisms sickle cell pts are at risk of

A

Please SHind ME Skis
Pseudomonas
Strep
H flu
Meningitis
E coli
Salmonella
Klebsiella
Group b strep

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13
Q

Vaccinations sickle cell patients need

A
  • Strep pneumonia
  • H flu
  • neisseria meningitis
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14
Q

GU complications of sickle cell

A
  • priapism
  • renal medullary necrosis
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15
Q

indications for exchange in sickle cell

A

*acute retinal artery occlusion
- CVA
- severe ACS

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16
Q

How to reduce risk of alloimmunization in sickle cell patients

A

Extended red cell phenotyping (looking at kell antigens etc)

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17
Q

presentation of splenic sequestration crises

A
  • sudden drop in hgb (RBCs pool in spleen) + left upper quadrant pain + massive splenomegaly
    *can be in hypovolemic shock
    *Typically occurs in children <2. HOWEVER, adults who have milder forms (HbSC or HbS/b+ can happen because spleen is not auto-infarcted
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18
Q

hyperhemolytic crisis presentation

A
  • hematuria
  • severe hemolysis in the setting of transfusion
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19
Q

management of hyperhemolysis in sickle cell

A

*Suppress the antibody
- steroids
- IVIG
+/- rituxan
**Transfuse compatible blood, not exchange transfusion

20
Q

L glutamine evidence in SCD

A
  • decreased frequency of pain crises
21
Q

crizanlizumab mechanism

A

antibody against P selectin, which prevents sickled RBC’s from adhering to vascular endothelium

22
Q

crizanlizumab clinical benefit

A

decreased frequency of pain crises

23
Q

voxelotor mechanism

A

oxygen-affinity modulator.[7] Voxelotor has been shown to have disease-modifying potential by increasing hemoglobin levels and decreasing hemolysis indicators
*So it’s a polymerization inhibitor

24
Q

voxelotor clinical benefit

A

Improved hgb, thus reducing transfusion requirements

25
Howell-Jolly Body clinical significance
asplenia or significantly reduced splenic function
26
How to differentiate hgb SS vs. Hgb Sbeta0
Hgb Sbeta0 will have low MCV (<70)
27
Clinical features of hemoglobin S with persistence of fetal hemoglobin
- asymptomatic
28
Management of SCD pt with recurrent ACS
Chronic transfusion
29
1) How to screen for risk of CVA in kids with SCD 2) next steps
transcranial doppler IF abnormal, need regular transfusions to keep hgb S <30% *After 12 months can switch to maximally tolerated hydrea
30
Goal hgb S with exchange in setting of CVA
<20%
31
Regular screening for SCD
- MRI for silent CVA - TTE for pHTN ONLY if signs/symptoms suggestive of pHTN - annual albumin/creatinine ratio monitoring *IF albuminuria, ACEi - annual retinal exam for sickle cell retinopathy (need to see retinal specialist) - ferritin every 3 months for transfusional iron overload
32
Management of splenic sequestration
- transfusion (unplugs the spleen) *1 unit at a time. By unplugging spleen, blood can gush out and lead to volume overload and hyperviscosity.
33
Sickle cell intrahepatic cholestasis clinical features
- sickle cell occlusion in hepatic sinusoids - RUQ pain + very high bili + ALT can be in 1000s
34
Sickle cell intrahepatic cholestasis management
Red cell exchange
35
Renal papillary necrosis management
- hydration, urinary alkalization, relieve obstruction
36
Presentation of orbital infarction in SCD
- protrusion of eye + eye pain + lid/orbital edema
37
Management of orbital infarction in SCD
IV fluids, pain control, steroids
38
acute aplastic crisis presentation
Rapid drop in hgb with reticulocytopenia
39
Goal ferritin for SCD pts with transfusional iron overload
Less than 1000
40
hydroxyurea counciling for patients
IF child-bearing age, pregnancy test before starting **contraception to avoid pregnancy Men → discuss low sperm count and mobility IF planning on conceiving, stop for 1-2 months IF pregnant, STOP
41
L-glutamine mechanism of action in SCD
anti-oxidant which may increase availability of reduced glutathione, reducing susceptibility to oxidative stress
42
Management of elective surgery in SCD
High risk surgery (prolonged surgery or prolonged impaired blood supply, hypothermia, pulmonary or cardiac disease): exchange transfusion Intermediate risk surgery: simple transfusion to target hgb 10 Low risk surgery no transfusions
43
approved gene therapy products for SCD
- Lovotibeglogene autotemcel (lovo-cel) (gene addition using viral vector) - Exagamglogene autotemcel (exa-cel) (CRISPR gene edited)
44
SE's/sequelae of gene therapy for SCD
Primarily related to busulfan conditioning - secondary malignancies from busulfan conditioning - loss of fertility from busulfan conditioning
45
Management of priapism in SCD
- Emergent urology consult (exchange transfusion does not help in data, and urologists can do faster bedside interventions)
46
Hgb S/alpha thal trait vs. hgb s trait
Hbs 25% with alpha thal trait vs 35% w/ hgb s disease (less alpha to pair with hgb s so reduces severity/phenotype of disease)
47