Thalassemia

WELCOME TO SEMINAR

Dr. Aysha SabihaDr. Maimuna Sayeed

Dr. Sharmin Akter LunaResidents (Phase-A)

Halima, a 11 years old girl of consanguineous parents presented with complaints of not growing well, gradual pallor & abdominal distension for 7 years.

On examination she was severely pale, facial dysmorphism & hepatosplenomegaly were present. She had history of repeated blood transfusion.

Case Scinerio

Hereditary hemolytic anemia

Diagnosis

SEMINAR ON

THALASSEMIA

Introduction

The term “Thalassemia” refers to a genetic disorder of hemoglobin synthesis characterized by a lack or decreased synthesis of one or more of the four Globin chains causing excessive breakdown of RBC.

"Thalassemia" is a Greek term derived from “Thalassa”, which means "the sea" and “Emia” means "related to blood."

World:• Beta thalassemia trait -

8% of population• More than - 100 million

carrier• Hb E - 53 millions

Bangladesh:• Beta thalassemia trait-

4.1%• Hb E trait - 6.1%• Hb E Beta thalassemia-

10.2%(Source: DSH Thalassemia center)

Incidence

Site of synthesis of globin

Normal hemoglobin component

Hb type Name ComponentsAdult A α2β2

A2 α2δ2Fetal F α2γ2Embryonic Portland ξ2γ2

Gower 1 ξ2ε2Gower 2 α2ε2

HbA98%

HbA2 <3.5%

HbF ~1%

Hemoglobin in normal adult

• α Thalassemia

• β Thalassemia

Types of thalassemia

Autosomal recessive

Inheritance

α-THALASSEMIA

Chromosome 16 defect

2 1 2 12

2 12 1

2 12 1

2 12 1

Normal Hb

One α gene deletionsilent carrier

Two α gene deletions- α-Thal. Minor

Four α gene deletionsHydrops fetalis or also

called: Erythroblastosis Fetalis.

Three α gene deletionsHb-H disease

CLINICAL PRESENTATION

Variants of alpha thalassemia Signs &Symptoms

Silent carrier AsymptomaticTrait Asymptomatic

Hb H diseaseModerate to severe hemolytic anemiaModest degree of ineffective erythropoiesisSplenomegalyVariable bone changes

Hb Bart's Born with massive generalized edema, usually fatal

Diagnosis of α-Thalassemia

CBC:• Silent Carrier: no microcytosis , no anaemia.• α-Thalassemia trait: microcytosis,

hypochromia, mild anaemia.• Hb H disease: variable severity of anaemia &

hemolysis.PBF: Hb H inclusion body (brilliant cresyl blue) in Hb H disease.

Hb electrophoresis – Hb H:

• (2-40%) Hb H• others Hb A• Hb F & Hb A2

Hb Bart's:• (80-90%) Bart's,• no Hb A, Hb F, Hb

A2

Diagnosis of α-thalassemia

Treatment of α-thalassemia

• Silent carrier & trait: do not require treatment.• Hb H disease: usually does not require regular

transfusions. But, with intercurrent illnesses, patient may require transfusion .

β-Thalassemia

With a mutation on one of the 2 beta globin genes , a carrier is formed with lower protein production but enough hemoglobin

Without a mutation enough hemoglobin

No carrier

With one mutation less hemoglobin

Beta thalassemia carrier but

less hemoglobin

Slight anemia

With two mutation No beta globin

Beta thalassemia major pt with

severe anemia

Gene from fatherGene from

mother

Chromosome 11 gene defects

Clinical syndrome Genotype Sign & symptom

Minor/ +

or/ °

Asymptomatic

Intermedia +/+ Variable degree of severity

Major+/°

or°/°

- Present within 1 year of age- Severe anemia- Growth retardation - Organomegaly- Skeletal deformities-Transfusion require within 2 year

Variants of β-thalassemia

An absence or deficiency of β-chain synthesis of adult HbAg

Pathophysiology of β-thalassemia

β Chain synthesis Hb-A

α , γ and δ chain

Hb A = α2β2

Pathophysiology of β-thalassemia

Physical Findings

An approach to thalassemia

History

Lab Investigations

• Severe Anemia• Thalassemic facies• Hepatosplenomegaly• Growth retardation,

etc

• Symptoms of anemia• +ve family history• H/0 blood transfusion• FTT

Thalassemia Major

Child with no transfusion or

inadequate transfusion

Child with regular blood transfusion but no chelation

Child with regular blood transfusion &

chelation

Leads natural course of disease,

may die within 5 yrs of age

Manifestation of iron overload at the

end of 1st decade

May enter into normal puberty & have normal life

expectancy

Clinical features

Natural course

General features

WeaknessGradual PallorFatigueDyspnoea on exertionPoor appetitePalpitationPoor growth

Features of marrow

expansion

Features of extramedullary hematopoiesis

Features of hemolysis

JaundiceHyperurecemia-Gout

Gallstone

Scoliosis,Kyphosis,vertebral collapse with cord compression

Features of iron overload

CirrhosisDiabetes Infertility

Pituitary failureHypothyroidism

ArrythmiaHeart failureDark skin

Liver Heart Endocrine organs

Hb E β-Thalassemia

• Most prevalent thalassemia variant in Southeast Asia & Bangladesh.

• Double heterozygous state.• Lysine substitutes glutamic acid in 26th position. • Divided into mild, moderate & severe form with

clinical features varying from thalassemia intermedia to thalassemia major

Types Sign & symptomMild Hb E β Thalassemia

Asymptomatic , Hb :9 -12 gm/ dl , require no treatment .

Moderately severe Hb E β Thalassemia

Majority of patient are in this group, Hb : 6 -7 gm/dl , resemble Thalassemia intermedia.

Severe Hb E β - Thalassemia

Clinical manifestation resemble Thalassemia major (severe anaemia, growth retardation, hepatosplenomegaly, skeletal deformities). Hb: 4-5 gm/dl , treated as thalassemia major.

Variants of Hb E β-thalassemia

Complications of thalassemia

A. Excessive erythropoiesisB. Iron overloadC. Chronic hemolysisD. Hypercoagulable diseaseE. InfectionF. Treatment of related complications

Facial changes:• Maxillary over growth• Malocclusion of teeth• Frontal bossing• Chronic sinusitis• Impaired hearing

A. Excess erythropoiesis

• Medullary expansion – cortical thinning, risk of fracture, osteopenia, osteoporosis, back ache.

• Vertebral expansion lead to spinal cord compression – neurological manifestations.

Bone Changes

• Hepatosplenomegaly• Lymphadenopathy

Endocrine failure:• Short stature• Delayed puberty• Estrogen/ testosterone

deficiency• Diabetes mellitus• Hypoparathyroidism

B. Iron Overload

B. Iron overload

Cardiac involvement:• Cardiomyopathy• Pericarditis• Arrhythmia• CCF

Hepatic involvement:CirrhosisHepatic fibrosis

B. Iron overload

C. Chronic hemolysis

• Gallstone 50-70% by around 15 years.

D. Hypercoagulable disease

Impaired platelet function Deep venous thrombosis

Elevated endothelial adhesion protein level Pulmonary embolism

Activation of coagulation cascade by damage RBC Cerebral ischemia

E. Infection

• Anemia• Iron overload – Yersinia, Klebsiella• Hypersplenism• Splenectomy – Pneumococci, Meningococci,

Hemophilus influenzae• Transfusion related – HBV, HCV, HIV etc.

F. Complications due to blood transfusion

• Acute hemolytic reactions• Delayed transfusion reaction• Autoimmune hemolytic anemia• Febrile transfusion reaction• Allergic reaction• Transfusion related acute lung injury (TRALI)• Graft versus host disease (GVHD)• Volume overload• Transfusion of disease – HAV, HBV, HIV

Causes of death in thalassemia

• Congestive heart failure• Arrhythmia• Sepsis due to increase susceptibility to infection• Multiple organ failure due to hemochromatosis

INVESTIGATIONS

Investigations

CBC:• Hb level - Depends on severity

– β-thalassemia minor: 10-13 gm/dl– β-thalassemia intermedia: 7-10 gm/dl– β-thalassemia major: 3-6 gm/dl

• TC/DC– normal / increased / decreased• Platelet- normal / decreased• RBC Indices- MCV, MCH, MCHC are low• RDW- Normal or raised• Reticulocyte count- Increased(5-10%)

PBF: Microcytic hypochromic cells with marked anisocytosis, poikilocytosis and other abnormal cells.

Abnormal RBCs in PBF

1. Target cell2. Tear drop cell3. Elliptocyte4. Hypochromic5. Microcyte

PBF: Normal

PBF: β-thalassemia major

PBF: β-thalassemia minor

Investigations

• Osmotic fragility: Decrease • Iron Profile:

S. Iron & ferritin- Increased TIBC- Decreased High % saturation of transferrin

• S. bilirubin (indirect): Increased

Hb electrophoresis

Hb NORMAL MAJOR MINOR INTERMEDIATE

Hb F <1% 90-98% 1-5 % Variable

Hb A 97% Absent 90-95% Variable

Hb A2 1-3% Variable 3.5-7% >3.5%

Normal Hb electrophoresis

Hb electrophoresis of homozygous β° thalassemia

• Widened diploic spaces

• Hair-on-end appearance

• Thinning of cortex

X-ray Skull

• Rectangular appearance• Medullary portion of bone

is widened• Bony cortex thinned out• Coarse trabecular pattern

in medulla

X-ray of hand

Investigations

• DNA analysis:Determine specific defect at molecular DNA level.

• HPLC (High Performance Liquid Chromatography):

Identify & quantify large number of abnormal Hb.

Normal10% (33)

β thalassemia trait44% (145)

homozygous β tha-lassemia5% (18)

Hb E β Thalassemia16% (52)

Hb E talassemia trait

21% (71)

Hb E disease2% (5)

β-Thalassemia major2% (7)

Unknown0% (1)

Patient diagnose as different variety of thalassemia by DNA analysis in BSMMU during the period of Sept 2007 to Aug 2016 (Total=332)

Diagnosing ThalassemiaFull medical and family history, CBC and RBC indices and PBF

Low MCV (< 80fl)± Low MCH (< 27pg)

Other cause of anemia?

Serum ferritin

≤12 ng/mlConsider iron

deficiency anemia

Adequate iron supplement for 3 months

Hb electrophoresis and HPLC

Improved

Not improved

Hb A2 variableHb F > 90-98%

Hb A2 ≥ 4%Hb F ≤ 0.1-5%

Hb A2 > 4%Hb F variable

Hb A2 < 4%Hb F < 1%

+ Other normal Hb variant

ß-Thalassemia major

ß-Thalassemiaminor

ß-Thalassemia intermedia 𝛼-Thalassemia Hb S, Hb E,

Hb C and others

DNA analysis for -globin ß-globin chain mutation

Serum ferritin>12 ng/ml

Microcytosis, Hypochromia, Target cells± inclusion bodies (Hb H)

To see complications

• Liver function test• Thyroid function test• FSH, LH, Testosterone, Estradiol• Blood Sugar• Bone profile• Ca, Phosphate, PTH• Liver Iron Concentration (LIC): T2 MRI, Liver

Biopsy• Cardiac Iron Measurement by: T2 MRI

• Bright areas represent high iron concentration.• Dark areas represent low iron concentration.

Monitoring iron overload by MRI

MANAGEMENT OF THALASSEMIA

Treatment modalities

A. SupportiveB. CurativeC. Preventive

A. Supportive management

• Multi-disciplinary approach• Focus on each patient’s clinical course

Transfusion

Iron Chelation

Fetal Hb Induction

Splenectomy

Objectives of supportive management

• Maintenance of growth and development• Correction of anemia• Prevention of iron overload• Treatment of complications• Counseling and Prevention

Blood Transfusion

Whom to transfuse?

Confirmed diagnosis of thalassemia major• Laboratory criteria:

• Hb < 7gm/dl on 2 occasions > 2 weeks apartor

• Hb > 7gm/dl with:• Facial changes• Poor growth• Fractures • Extramedullary hematopoiesis

Important issues before starting transfusion

• Blood grouping:– ABO and Rh(D) compatibility checked– Extended red cell antigen typing at least C, c,

E, e and Kell.• Screening of donor blood for HBV, HCV, HIV,

Syphilis, Malaria.• Avoidance of transfusion first-degree relative

donors.• Quality, adequacy and safety of blood

Transfusion protocol

To maintain pre transfusion Hb >9–9.5 gm/dl.• Typical programs:

• Transfusion of 10–15 cc/kg of packed Leuko-depleted red cells

• Lifelong regular blood transfusions, every 2–5 weeks

A higher pre-transfusion hemoglobin level of 11-12 gm/dl for patients with:

• Heart disease or other medical conditions • Patients who do not achieve adequate

suppression of bone marrow activity at lower Hb level.

Blood products for transfusion

• Packed red cell• Leukocyte reduced red cell• Washed red cell• Neocyte

Target in Hb Haematocrit of Donor Red Cells

50% 60% 75% 80%

1 gm/dl 4.2 ml/kg 3.5 ml/kg 2.8 ml/kg 2.6 ml/kg

2 gm/dl 8.4 ml/kg 7.0 ml/kg 5.6 ml/kg 5.2 ml/kg

3 gm/dl 12.6 ml/kg

10.5 ml/kg 8.4 ml/kg 7.8 ml/kg

4 gm/dl 16.8 ml/kg

14.0 ml/kg

11.2 ml/kg

10.4 ml/kg

Regularly Transfused

Irregularly Transfused

• Normal growth • Normal physical activities• Adequately suppresses

bone marrow activity• Minimizes iron

accumulation

Regular transfusion allows

Diet and supplementation

• High iron contained food should be avoided.• Diet which decreases iron absorption such as

milk & milk products should be taken adequately

• Folic acid• Zinc• Vit. D, Vit. E

Thalassemic diet

CHELATION THERAPY

Chelator MetalChelator

Toxic

Excretion

Metal

What is chelation therapy?

Evaluation of iron overload

Serum ferritin concentration

Liver iron concentration (LIC) Liver biopsy

– n=1.8 -7 mg/dry wt , >15-20 mg SQUID MRIOthers: NTBI and T2*MRI

Guideline- Thalassemia International Federation-2008

Guidelines for starting treatment of iron overload in patients with β-thalassemia major

Thalassemia International Federation guidelines for the clinical management of thalassemia (2008)1 recommend that chelation therapy is considered when patients:

Have received 10–20 transfusion episodesORHave a serum ferritin level of >1000 ng/mL

1Thalassemia International Federation. Guidelines for the clinical management of thalassemia, 2nd Edition revised 2008; 2Angelucci E et al. Haematologica 2008;93:741–752

Primary goals of chelation therapy

Completechelation

The primary goals of iron chelation therapy are to remove excess iron and provideprotection from the effects of toxic iron

Iron balance

Removal of ironat a rate equal to transfused

iron inputPrevents end-organ damage

due to iron

Normalization of stored tissue

iron

May take years in established iron overloadSafe levels of

tissue iron differs between

organs

Control of toxic iron over 24-hr

period

24-hr control of NTBI/LPI and

intracellular labile iron

Prevents end-organ damage

due to iron

Goals of chelation Therapy is achieved by:• Keeping serum ferritin <1000-2,000 ng/mL or• LIC <15 mg/g dry weight

Iron chelating agents

• Desferrioxamine (DFO)• Deferiprone• Deferasirox

Management: iron chelatorsAgent Route T1/2

hoursSchedule Clearance Toxicity

Deferoxamine IV/SQSlow

infusion

0.5 8-24 hours

5-7 days per week

Renal andhepatic

Infusion site reactions,allergic reactions,ocular and auditory

Deferiprone Oral 2-3 3 daily Renal Nausea/ vomiting, arthropathy,neutropenia, agranulocytosis

Desferrioxamine

Oral 12-16 1 daily Hepatic Bad taste, nausea,epigastric pain, rash

Desferrioxamine

Regular rotation of the site of infusion allows proper absorption of the medication and decreases the risk of skin breakdown and scar tissue formation.The most common sites are abdomen, thighs and upper arms.

Deferioxamine……contdIntensive chelation with Desferrioxamine – continuous 24-hourly infusions IV or SC.Indications:

a) Persistently high serum ferritin;b) LIC > 15 mg/g dry weight;c) Significant heart disease, and;d) Prior to pregnancy or bone marrow transplantation

Dose: 50 mg/kg/day (up to 60 mg/kg/day)In-dwelling catheters: danger of infection and thrombosis

Fetal Hb Induction

Induction of fetal hemoglobin

Hb F enhancement• Hydroxyurea• Myelaran• Butyrate derivatives• Erythropoietin • 5-Azacytadine

• Increasing the synthesis of fetal hemoglobin can help to alleviate anaemia and thereby improve the clinical status of patients with thalassemia intermedia.

• Agents including cytosine arabinoside and hydroxyurea may alter the pattern of erythropoiesis and increase the expression of alpha-chain genes.

• Erythropoietin has been shown to be effective, with a possible additive effect in combination with hydroxyurea.

• Butyrate are a further experimental category, still unlicensed and with difficult intake.

SPLENECTOMY

Deferred as long as possible. At least till 5-6 yrs age.

Indications:• Massive splenomegaly causing mechanical

discomfort• Blood requirements >200-220 ml/kg/year• Hypersplenism

The risk of splenectomy

Overwhelming infection

Age—(<2 years of age)

Time since splenectomy (1-4 years after surgery)Immune status of patient

Commonly associated pathogen

Streptococcus pneumoniae

Haemophilus influenzae

Neisseria meningitidis

Preventative measures

Immunoprophylaxis– At least 2 weeks before splenectomy Pneumococcus/meningococcus/Hemophilus

Chemoprophylaxis- Chemoprophylaxis with life-long oral

penicillin. Education

Only curative option available.Overall outcome depends on-

• Inadequate chelation therapy,

• hepatomegaly,• presence of portal

fibrosis.Treatment-related mortality is approximately 10%.

Bone marrow/stem cell transplantation


Risk stratification for BMT

Hepatomegaly >3cms Liver fibrosis Inadequate chelation

Class I – no risk factors Class II- one to two risk factors Class III- all three risk factors

Outcome of BMT in thalassemia


Class probabilities of survival (%)

disease-free survival (%)

risk of rejection (%)

risk of mortality (%

I 93 91 2 8

II 87 83 3 15

III 79 58 28 19

B. Curative treatment in thalassemia

• Stem cell transplantation• Gene therapy

Stem cell transplantation?

Stem cell transplantation

Whom to offer?


Cost Vs Risk benefit of patient

andAvailability of

DONOR


Gene therapy

Gene therapy

• Insertion of normal globin genes into marrow stem cell may ultimately cure Thalassemia .

• Globin gene transfer in autologous CD34+cells is beginning to be evaluated

• As per FDA recommendation, the current study is restricted to adults. Paediatric patients will be included at a later date after reviewing safety and efficacy data obtained in adults.

Guidelines for the Management of transfusion dependent Thalassemia,3rd

Role of surgery in thalassemia

• Cholelithiasis – Cholecystectomy• Choledocholithiasis – Choledocholithotomy• Cirrhosis (due to iron overload) – Liver biopsy

and liver transplantation• Leg ulcer – Surgical dressing• Pathological fracture – Surgical correction• Spinal cord compression - Laminectomy

Follow up

Follow up

Monthly:• Complete blood count• Complete blood chemistry (including liver

function tests, BUN, creatinine) if taking deferasirox

• Record transfusion volume.

Follow up

Every 3 months:• Measurement of height and weight• Measurement of ferritin (trends in ferritin used

to adjust chelation); • Complete blood chemistry, including liver

function tests

Follow up

Every 6 months:• Complete physical examination including Tanner

staging, • Monitor growth and development• Dental examination

Follow upEvery year:• Cardiac function – echocardiograph, ECG, Holter

monitor (as indicated)• Endocrine function (TFTs, PTH, FSH/LH, fasting

glucose, testosterone/estradiol, FSH, LH, IGF-1, Vitamin D levels)

• Ophthalmological examination and auditory acuity

• Viral serologies (HAV, HBV panel, HCV (or if HCV1, quantitative HCV RNA PCR), HIV)

• Bone densitometry• Ongoing psychosocial support.

Follow up

Every 2 years:• Evaluation of tissue iron burden• Liver iron measurement – R2 MRI, SQUID, or

biopsy• T2* MRI measurement of cardiac iron (age .10

years).

C. Prevention and control

Career detection/Screening Genetic counseling Prenatal diagnosis Health education

Screening

• RBC indices (MCV, MCH, MCHC)• NESTROFT• HbA2

Career detection/screening

Mass screening: NESTROFT (Necked Eye Single Tube Red Cell Osmotic Fragility Test)

• Very cheap and easy to perform require small amount of blood

• Based on principle that Thalassemic red cell resists hypotonic solution more than that of normal person

• Give positive result on NESTROFT• Sensitivity 90-98% and specificity 85-90%

NESTROFT

Career detection/screening

Automated CBC:• Thalassemic red cells are microcytic and

hypochromic• WHO recommends MCV <77fl and MCH <27 pg

as screening tools to pick up cases for confirmation by electrophoresis

DCIP (Di Chloro phenol indol phenol): Screening for Hb E

Genetic counseling

• Index case parents and relatives.• Antenatal visits of pregnant mothers.

Genetic counseling

• β/α ratio: <0.025 in fetal blood

• Chorionic villous biopsy (10-12 weeks)

• Cordocentesis• Amniocentesis (15-18th

week) Analysis of fetal DNA

• PCR to detect β globin gene

Prenatal diagnosis

Chorionic Villus Biopsy

Health education/awareness

• Knowledge of genetic nature of thalassemia• Transmission of the disease• Ways to avoid to have further child with the

disease• Aware about economic burden to the family and

govt.

Prognosis

Thalassemia major-life expectancy:

• Without regular transfusion - Less than 10 years• With regular transfusion and no or poor iron

chelation - Less than 25 years• With regular transfusion and good iron chelation

- 40 years, or longer?

The commonest cause of death is iron overload

Conclusion

• Management needs extensive hands • Prevention program is rudimentary• Awareness about thalassemia is though

increasing still very much lacking• Manpower is developing-good news• Thalassemia center dedicated to children to be

established

Thalassemia day

8th May is the international Thalassemia Day. This day is dedicated to Thalassemia, to raise public awareness for prevention of Thalassemia and to highlight the importance of clinical care for Thalassemia patients in all countries.

Thank You

Health & Medicine

Thalassemia