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Molecules and Cells (Unit 1) > Sickle Cell Disease > Flashcards

Sickle Cell Disease Flashcards

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Organic Chemistry 101 flashcards
1
Q

Hemoglobin SC Disease

•“ Less Severe than SS”

Survival same as general population.

  • Longer ________ survival (Hgb ~10)
  • ↑ __________

_______ toxic to RBC membrane

_________loss from RBC’s (explains MCH)

↑ Hb concentration __________ cells and produces ______

•Common with SC: ________, __________ + ___________ and ________

Annual eye exams

A

RBC

MCH

HbC

K+

Dehydrate; target cells

retinopathy, splenomegaly; infarcts; bone

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2
Q

Diagnostic testing

Isoelectric focusing (IEF):

  • Separates variants by __________
  • Complementary with _______

High performance liquid chromatography (HPLC):

  • High resolution________
  • Quantify relative fractions of HbF, HbA2, HbS, HbC, Hb Barts and other variants.

Hemoglobin electrophoresis at _______ pH. pH range? (6.0 to 6.2).

  • Identify Hb variants with or without quantification?
  • Separation of C from ___ and ________; S from ______and _____

Citrate agar ________

Hemoglobin electrophoresis at ________ pH. pH range?

  • _____ / _______- co-migration.
  • ____ / _____ / _______/ _____ co-migration

Cellulose _______electrophoresis.

Sickle Dex (turbidity test) to confirm the presence of ________

A

Isoelectric points

HPLC

Separation

Acidic; 6.0 to 6.2

E and OArab; D and G

Electrophoresis

Alkaline; 8.2 to 8.6

S;D

C; E; A2; OArab

Acetate

HbS

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3
Q

•Adult HbA P50 = ______ mmHg

•

• HbF P50 = ____ mmHg

•

• HbS P50 in SS = ______mmHg

A

26.5

20

34

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4
Q

Are oxygen affinity and P50 directly or inversely related?

A

Inversely

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5
Q

•Which high HbF mutation combined with sickle is milder?

A

Sickle HPFH

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6
Q

THALASSEMIA caused by ineffective _______

A

erythropoiesis

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7
Q

SICKLE GENOTYPES

SS (sickle cell anemia). Mutation?

SC (hb SC disease). Mutation?

SOArab. Mutation?

SD. Mutation?

A

Glu6Val (GAG→GTG)

Glu6Lys (GAG→AAG)

Glu121Lys (GAA→AAA)

Glu121Gln (GAA→CAA)

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8
Q

Left shift (Dissociation Curve)

↑ ______ (Bohr effect)

↓ __________

↓ _______

A

pH

2,3-DPG

Temperature

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9
Q

Normal life span of a RBC

A

120 days

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10
Q

Acute Chest Syndrome (ACS) Treatment

A
  • Oxygen
  • Broad spectrum antibiotics
  • Transfusion
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11
Q

First Vaso-Occlusive Manifestation

  • Dactylitis
  • Occlude ___________; hypoxia; ___________ injury in fingers
  • Onset _________
  • Co-incides with post-natal fall in _________
  • Prior to screening, often led to diagnosis
  • Supportive care
A

Post-capillary venules; ischemia reperfusion

6 mo. – 2 yrs.

HbF

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12
Q

S trait eliminates risk of death from ____________malaria in kids

A

cerebral falciparum

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13
Q

What factors enhance sickle hemoglobin polymerization?

A
  • High [deoxy HbS]
  • Dehydration
  • Acidosis
  • ↑ 2,3-DPG reduces O2 affinity of HbS
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14
Q

•All newborns with SS start ________

A

Penicillin Prophylaxis

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15
Q

HEMOGLOBINOPATHY

  • Classification:
  • Low solubility / stability: ___________
  • Low O2 affinity: __________
  • High O2 affinity: _________
  • Oxidation of heme iron: ___________ and ________
A

Hemolytic anemic

Anemic

Erythrocytosis

Cyanosis; erythocytosis

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16
Q
  • ___________= asymptomatic due to pancellular distribution of HbF
  • Inhibits ___________ polymerization in all rbcs

•

  • _____________ = symptomatic despite high HbF
  • HbF restricted to sub-set of rbcs (________ cells)
A

Sickle HPRH

HbS

Sickle δβ0 Thalassemia

F

17
Q

b Globin gene cluster: Chromosome ________

A

11

18
Q

a Globin gene cluster: Chromosome ________

A

16

19
Q

Sickle cell anemia. Severity?

SC. Severity?

Sβ+ thalassemia. Severity?

Sβ0 thalassemia. Severity?

SHPFH. Severity?

A

Severe

Mild to Mod

Mild to Mod

Mod to Severe

Asymptomatic

20
Q

•Note that sickle can combine with traits for other variants to result in other forms of sickle cell disease

____________

___________

____________

A
  • Hemoglobin C-trait
  • β0 thalassemia trait
  • β+ thalassemia trait
21
Q

•Acute Chess Syndrome defined by 5 clinical features:

A

pulmonary infiltrates (see images below)

fever

pleuritic chest pain

hypoxemia (SaO2 < 92% on RA)

cough

22
Q

b-THAL MUTATIONS AFFECTING HB F IN SICKLE

•Deletional mutations significantly _________ Hb F production classically grouped into 2 broad categories:

___________

__________

A

Increasing

  • Hereditary Persistence of Fetal Hemoglobin (HPFH)
  • δβ0 Thalassemia
23
Q

•Red cells release oxygen in__________

•

•___________forms sickle polymers.

•

•_________deform cells into rigid sickled shape.

•

•Sickled RBCs obstruct ___________-

A

Capillaries

Deoxy hemoglobin S

Polymers

Post- capillary venules

24
Q

What factors inhibit polymerization?

A
  • Fetal hemoglobin inhibits HbS polymer formation
  • ↑ HbF = longer survival
  • Low [HbS] (as in sickle cell trait)
25
Q

Right shift

↓ __________(Bohr effect)

↑ _________

↑ _________

A

pH

2,3-DPG

Temperature

26
Q

New Born Screening, Functional Asplenia, Sepsis

•High incidence of infection with encapsulated organisms:

__________

__________

___________

  • ________ + _________ vaccines
  • ___________ = empiric antibiotics
A

Streptococcus pneumoniae

Haemophilus influenzae type B

Salmonella sp.

Prevnar; Hib

Fevers

27
Q

Acute complications of Sickle Cell Disease

A
28
Q

Therapy for SCD

A
  • Prophylactic PCN (<5 years of age)
  • Hydroxyurea
  • Transfusion Therapy (q month)
  • Marrow Transplant / Gene Therapy
29
Q

Chronic Complications of Sickle Cell Disease

A
30
Q
  • Thrombo-embolic:
  • ________ fat embolism from marrow________associated with _______
A

Pulmonary; necrosis; vaso-occlusive crises

31
Q

Hemoglobin Variant: S

Globulin chain______

Amino acid substitution: _______

Comments:______

Hemoglobin Variant: C

Globulin chain:________

Amino acid substitution:______

Comment:_____

Hemoglobin Variant: D Los Angeles

Globulin chain:________

Amino acid substitution:______

Comment:_____

Hemoglobin Variant: O Arab

Globulin chain:________

Amino acid substitution:______

Comment:_____

A

B

Glu6Val

Polymerizes

B

Glu6Lys

Crystallizes

B

Glu121Gln

SCD variant

B

Glu121Lys

SCD variant

Molecules and Cells (Unit 1) (48 decks)

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