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Flashcards in Disorders of hemoglobin Deck (22)
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1

Hb H:
- What is it?
- How to visualize Hb H inclusions?

- B4
- Supravital stain (Brilliant Cresyl blue): golf balls

2

Thalassemia major: surveillance recommended

- CBC at least yearly, before each transfusion
- Bone scan yearly (starting 10 y.o.)
- Monitoring of liver iron with T2* MRI yearly
- LFT and albumin yearly
- Ferritin yearly
- Monitoring of cardiac iron with T2* MRI yearly (starting 10 y.o.)
- HIV and hepatitis serologies for transfused pts
- Fasting glucose yearly (starting 10 y.o.)
- Endocrine panel 1 yearly (starting at 6 y.o.): TSH/T4, PTH, 25-OH-vit D, 1,25-OH2-vit D
- Endocrine panel 2 yearly (starting at 10 y.o.): FSH/LH, testosterone, estradiol

3

Indications for iron chelation (3)

1. Transfusion of >100-200 ml/kg RBC
2. Liver iron concentration > 5-7 mg/g dry weight
3. Ferritin > 1500-2000 ng/mL

4

Sickle solubility test:
False (-)ve
Falve (+)ve

False negative: severe anemia, elevated Hb F, HPFH, Hb S < 10%, co-inheritance of alpha-thal trait

False positive: some Hb variants (Hb Barts, Hb Jamaica I, ...), increased blood viscosity (e.g. polycythemia, hyperlipidemia, elevated serum proteins)

5

Iron chelation: which agents can be given PO?
Which agent requires parenteral administration?

Deferasirox (Exjade), desferiprone
Desferoxamine (IV or SC)

6

What are the most common side effects of deferasirox (Exjade)?
What side effect is specific to desferiprone?

GI upset, transaminitis, elevation in creatinine (reversible), ocular and auditory toxicity
Agranulocytosis

7

Thalassemia:
Indications for HSCT

Should be offered to all patients with severe phenotype, especially in the presence of a matched sibling donor

8

Thalassemia: how is prenatal diagnosis possible?
(3 methods)

- Chorionic villus sampling (10th week)
- Amniocentesis (18th week)
- Fetal DNA in maternal blood (not widely available)

9

HSCT for thalassemia: name 3 risk factors associated with poor outcome

1. Hepatomegaly
2. Inadequate therapy for iron overload
3. Portal fibrosis

10

Name 7 manifestations of iron overload

- Skin hyperpigmentation
- Fatigue
- Arthropathy
- Arrythmias, heart failure
- Liver disease
- Diabetes mellitus
- Hypogonadism
- Growth delay
* Iron deposits usually in skin, joints, liver, heart and endocrine organs predominantly.

11

Mechanisms of action of hydroxyurea (4)

1) Increase in Hgb F
2) Increase in RBC deformability (higher RBC volume, increased hydration)
3) Decrease in retics and neutrophils adhesiveness
4) Decrease in neutrophil count (inhibition of ribunucleotide reductase)

12

Treatment Diamond-Blackfan anemia

- Steroids (prednisone), started at 2 mg/kg/day (usually after 6 months) and tapered to lowest required dose; to be given with PCP prophylaxis
- RBC transfusion if steroid-resistant of younger than 6-12 months
- HSCT for selected cases

13

Indications of HSCT in patient with Blackfan-Diamong anemia

- Steroid-resistant patients, especially if MSD
- Progression to SAA
- Progression to MDS/AML

14

What did show the study BABY-HUG?

Hydroxyurea in infants with SCD led to:
- Reduction of pain episodes
- Reduction of dactylitis
- Reduction of acute chest syndrome
- Reduction of transfusion

15

What did show the study MSH?

Hydroxyurea in adults with SCD (replicated after with teenagers and older children) led to:
- Reduction of pain episodes
- Reduction in acute chest syndrome
- Reduction in admissions to hospital
- Reduction in transfusions

16

Indications of HSCT in sickle cell disease

- Stroke or central nervous system event lasting longer than 24 h
- Impaired neuropsychological function with abnormal brain MRI and angiography
- Recurrent acute chest syndrome
- Stage I or II sickle lung disease
- Recurrent vaso-occlusive painful episodes or recurrent priapism
- Sickle nephropathy (GFR 30%–50% of predicted normal)

17

Indications of HSCT in thalassemia

Severe phenotype, transfusion dependent
(Individualized, taking int account availability of a MSD and family and physician's preferences)

18

Thalassemia: main predictor or survival in TDT?

Compliance with iron chelation

19

What is the Pesaro classification?

Risk stratification of thalassemia patient undergoing transplant, based on 3 RF
- Hepatic fibrosis
- Inadequate iron chelation pre-transplant
- Degree of hepatomegaly
Class I: no RF, TFS: 94%
Class II: 1-2 RF, TFS: 77%
Class III: 3 RF, TFS 53%

20

What is the mutation in sickle cell disease?

Point mutation A>T at chr 11p15.5 leading to glutamic acid being substituted by valine

21

What bacterial pathogen is encountered with thalassemia?

Yersinia

22

What possible diagnoses can give a "FS" pattern on newborn screening for sickle cell disease?

- Hgb SS
- Hgb S-B0thal
- Compound heterozygosity for Hgb S and HFPH
- Hgb S-B+thal (produce low levels of A but sometimes below level of detection at birth)