Disorders of Hemoglobin Flashcards Preview

Heme/Lymph > Disorders of Hemoglobin > Flashcards

Flashcards in Disorders of Hemoglobin Deck (31):
1

2 main categories of hemoglobin disorders?

structure variants
thalassemias

2

Consequences of structural abnormalities?

sickling
instability
altered O2 affinity
increased susceptibility to oxidation to methemoglobin
underproduction

3

How to diagnose globin problem in lab?

Hb electrophoresis
HPLC (high performance liquid chromatography)

4

What to patients with sickle cell trait gain?

protection against malaria

5

What is the extent of HbS polymerization dependent on?

time & concentration

6

List some clinical settings that predispose to sickling

hypoxia
acidosis
dehydration
cold temp
infections

7

What is the lifespan of a sickled cell?

20 days

8

Major effects of RBC sickling

chronic hemolysis and microvascular occlusion with resultant tissue hypoxia and infarction

9

When do the effects of sickle cell first show up after birth?

10-12 weeks of age

10

Main clinical manifestations (14)

severe anemia
acute pain crisis
auto-splenectomy
acute chest syndrome
strokes
aplastic crisis
splenic sequestration crisis
megaloblastic anemia
growth retardation
bony abnormalities
renal dysfunction
leg ulcers
infections
cholelithiasis

11

What is most common cause of death in sickle cell?

acute chest syndrome

12

What is the main cause for aplastic crisis in sickle cell?

parvovirus B19 infection

13

What happens during a splenic sequestration crisis?

acute pooling of blood in spleen
drop in Hb
potential for hypovolemic shock

14

Why does megaloblastic anemia cocur in Sickle Cell?

increased folate consumption because of chronic erythroid hyperproliferation

15

Lab findings in sickle cell

sickeld cells, target cells, polychromasia
increased reticulocytes
chronic anemia
increased bilirubin
post splenectomy changes in adults

16

What can happen to the kidneys in pts w/sickle cell trait?

sub clinical damage

17

What is Hemoglobin SC disease?

sickling disorder
HbC form glu to lys substitution
milder than SS usually

18

What is HbS/Beta thalasemia?

hetero HbS with trans beta thalassemia allele
asymptomatic to SS like
HbS>HbA

19

What is a thalassemia?

inherited disorder characterized by decreased production of structurally normal globin chains

20

Distribution of beta thal?

mediterranean, middle east, some parts of india and pakistan, SE asia

21

distribution of alpha thal?

africa, mediterranean, middle east, SE asia

22

Features of thalassemai?

microcytic, hypochromic anemias of varying severity

23

Beta-Thal major features

absense in beta chain production on both beta alleles
severe anemia
bizarre red cell morphology
transfusion dependence
hybrid of hemolytic anemia and ineffective erythropoiesis

24

Problems in inadequately transfused beta thal major?

stunted growth
mongoloid facies/bony abnormalities/frontal bossing
wasting
hyperuricemia
HSM
infections
folate defic
death in childhood

25

Beta thal minor features

heterozygous
asymptomatic
common in mediterranean and asian populations
mild or no anemia
scattered target cells and basophilic stippling
elevated HbA2

26

Beta thal intermedia

intermediate severity

27

Alpha thalassemia features/types

gene deletion
silent carrier (1 del)
trait (2 del)mild
HbH disease (3 del) mild-mod chronic hemolytic anemia HbH is beta tetramers
Hydrops fetalis (4del) stillborn or die first few hours of life

28

Effects of HU (hydroxiuria) dose escalation in sickle cell

decreased sickling

29

Does cis or trans mutation in alpha thal matter for treatment?

no but it does for genetic counseling

30

Splenic sequestration TX short and long term

short term: fluids, O2, RBCs
long term: splenectomy

31

What cells does parvovirus B19 infect?

erythroblast