Disorders of hemoglobin Flashcards
Hb H:
- What is it?
- How to visualize Hb H inclusions?
- B4
- Supravital stain (Brilliant Cresyl blue): golf balls
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
Indications for iron chelation (3)
- Transfusion of >100-200 ml/kg RBC
- Liver iron concentration > 5-7 mg/g dry weight
- Ferritin > 1500-2000 ng/mL
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)
Iron chelation: which agents can be given PO?
Which agent requires parenteral administration?
Deferasirox (Exjade), desferiprone
Desferoxamine (IV or SC)
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
Thalassemia:
Indications for HSCT
Should be offered to all patients with severe phenotype, especially in the presence of a matched sibling donor
Thalassemia: how is prenatal diagnosis possible?
3 methods
- Chorionic villus sampling (10th week)
- Amniocentesis (18th week)
- Fetal DNA in maternal blood (not widely available)
HSCT for thalassemia: name 3 risk factors associated with poor outcome
- Hepatomegaly
- Inadequate therapy for iron overload
- Portal fibrosis
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.
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)
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
Indications of HSCT in patient with Blackfan-Diamong anemia
- Steroid-resistant patients, especially if MSD
- Progression to SAA
- Progression to MDS/AML
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
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
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)
Indications of HSCT in thalassemia
Severe phenotype, transfusion dependent
Individualized, taking int account availability of a MSD and family and physician’s preferences
Thalassemia: main predictor or survival in TDT?
Compliance with iron chelation
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%
What is the mutation in sickle cell disease?
Point mutation A>T at chr 11p15.5 leading to glutamic acid being substituted by valine
What bacterial pathogen is encountered with thalassemia?
Yersinia
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)
