---

Transfusion-Dependent Thalassemia (TDT) - Comprehensive PG Exam Case Presentation

---

SAMPLE CASE VIGNETTE (How to Present)

"I am presenting the case of Master/Miss _____, aged ___ years, resident of _____, belonging to a [Mediterranean / South Asian / Middle Eastern / South East Asian] family, who was brought by parents with complaints of: 1. Pallor since ____ 2. Abdominal distension since ____ 3. Repeated blood transfusions since ____ months of age"

---

SECTION 1: HISTORY OF PRESENTING ILLNESS (HOPI)

Chief Complaints (in order of duration)

1. Pallor - onset, progressive, when noted (most often 3-6 months of age as gamma-chain synthesis declines and beta deficiency becomes apparent)
2. Abdominal distension - when noticed, progressive
3. Poor feeding / failure to thrive / growth retardation
4. Repeated blood transfusion dependence - age at first transfusion, frequency, pretransfusion Hb, how many units per sitting, interval between transfusions (typically every 2-5 weeks)
5. Jaundice - episodic or chronic, scleral icterus
6. Bony deformities - frontal bossing, maxillary hyperplasia, dental crowding

Onset and Chronology

• Beta-thalassemia major typically presents 6-24 months of age (as HbF switches to HbA). This is a high-yield PG point - the child is normal at birth.
• HbE-beta thalassemia (most prevalent in South/Southeast Asia) may present slightly later.

HOPI Details to Elicit

---

SECTION 2: PAST HISTORY

• Transfusion history in detail:
  • Age at first transfusion
  • Number of transfusions per year
  • Any transfusion reactions (hemolytic / non-hemolytic / febrile)
  • Type of blood received (leukodepleted packed red cells - preferred)
  • Whether iron chelation has been started and which agent (deferoxamine, deferasirox, deferiprone)
• History of splenectomy (if yes: age, indication - hypersplenism, symptomatic splenomegaly; vaccinations given post-splenectomy)
• History of bone marrow transplantation or gene therapy
• History of jaundice / cholelithiasis / cholecystectomy
• History of cardiac disease / echocardiogram done
• Any endocrine workup (thyroid, glucose, bone density)
• Any hospitalizations for infections, especially encapsulated organisms post-splenectomy

---

SECTION 3: NEGATIVE HISTORY (Very Important for PG Exams)

Negative History to Specifically Mention

---

SECTION 4: FAMILY HISTORY

• Parents: Both parents should be carriers (thalassemia minor/trait) - both will have microcytic, hypochromic anemia with elevated HbA2 but be clinically well
• Siblings: Any sibling with similar illness, blood transfusion dependence, or unexplained childhood death
• Consanguinity: Autosomal recessive inheritance - inquire specifically
• Family origin: Mediterranean (Italy, Greece), South Asia (India, Pakistan, Bangladesh), Southeast Asia, Middle East, North/Central Africa - all high-prevalence regions
• Any sibling who died early of unexplained anemia

---

SECTION 5: BIRTH AND DEVELOPMENTAL HISTORY

• Full-term or preterm delivery
• Birth weight
• Was neonatal screening done? (Cord blood hemoglobin analysis)
• Development milestones - was the child normal until 3-6 months?
• Jaundice at birth (neonatal jaundice - present in hemolytic disease but not typical at birth for beta thal)
• Key point: Unaffected at birth, as HbF (gamma chains, not requiring beta chains) is predominant; disease manifests only as gamma-to-beta switch occurs after 3-6 months

---

SECTION 6: PERSONAL & SOCIAL HISTORY

• Dietary history (folic acid intake)
• Travel history / ethnic background
• Vaccination history (especially if splenectomy done - pneumococcal, meningococcal, H. influenzae b vaccines)
• School performance (due to chronic anemia affecting cognition)
• Psychological impact on child and family

---

SECTION 7: CLINICAL SIGNS TO LOOK FOR (Examination)

General Examination

Vitals

• Tachycardia (compensatory for anemia)
• May be normotensive or hypotensive if severely anemic

Cardiovascular Examination

• Cardiomegaly - displaced apex beat, loud heart sounds
• Signs of congestive cardiac failure - raised JVP, pedal edema, basal crepitations (iron overload cardiomyopathy - leading cause of death in TDT)
• Pericarditis signs (friction rub) - iron-related pericarditis

Abdominal Examination

Skeletal/Musculoskeletal Examination

• Hair-on-end appearance (on X-ray, but describe radiological correlate)
• Pathological fractures / kyphosis - osteoporosis from iron overload + marrow expansion
• Bony tenderness over sternum and other flat bones - marrow expansion
• Vertebral collapse signs - height loss, kyphosis
• Genu valgum - bone deformity in advanced untreated disease

Endocrine Signs

Neurological Examination

• Generally normal unless cerebrovascular complications
• Look for signs of hepatic encephalopathy in late disease (liver cirrhosis)
• Proximal myopathy (rare, from deferoxamine toxicity - high-dose)

Ophthalmological (Important for management)

• Cataract / Night blindness / Retinal deposits - deferoxamine toxicity (especially high-dose)
• Bronze corneal deposits - deferasirox side effect
• Fundal iron deposits

Skin

• Bronze discoloration (hemochromatosis/iron overload)
• Injection site reactions - from subcutaneous deferoxamine
• Pallor of creases of palms

---

SECTION 8: INVESTIGATIONS TO ORDER AND INTERPRET

Hematological

Hemoglobin Analysis (Diagnostic)

Iron Studies

Organ Assessment for Iron Overload

• MRI T2 (liver and cardiac)* - gold standard noninvasive measurement of hepatic and myocardial iron concentration
• Liver biopsy - LIC (Liver Iron Concentration) >7 mg/g dry weight = significant; done if MRI unavailable
• Echocardiography + ECG - cardiomyopathy, arrhythmias
• LFTs - AST, ALT, GGT, bilirubin (indirect hyperbilirubinemia), albumin
• Blood glucose / HbA1c - diabetes from pancreatic iron
• Thyroid function tests (TSH, T4)
• PTH, calcium - hypoparathyroidism
• LH, FSH, testosterone/estradiol - hypogonadism
• Cortisol / ACTH stimulation test - adrenal function

Radiology

Genetic Studies

• DNA analysis / Mutation testing - PCR-based to identify specific beta-globin gene mutations (definitive diagnosis; also needed for prenatal counseling)
• Multiplex ligation-dependent probe amplification (MLPA) - for alpha thalassemia deletions

---

SECTION 9: DIFFERENTIAL DIAGNOSIS

1. Iron Deficiency Anemia (IDA)

• Serum ferritin grossly elevated in TDT (low in IDA)
• RBC count relatively high in thalassemia despite low Hb (Mentzer index < 13 suggests thalassemia; > 13 suggests IDA)
• HPLC pattern diagnostic
• Target cells, nucleated RBCs absent in IDA
• No response to iron supplementation in TDT
• Thalassemia trait: disproportionate microcytosis relative to degree of anemia

2. Sickle Cell Disease (SCD) / HbSS

• No vaso-occlusive painful crises in TDT
• No dactylitis, no ACS, no stroke
• No sickling on sickling test / no HbS on HPLC
• Blood film: no sickle-shaped cells
• Spleen involutes in SCD over time (autosplenectomy); TDT has massive splenomegaly
• HbF is high in TDT; HbS predominates in SCD

3. HbE-Beta Thalassemia

• HPLC: HbE: 50-70%, HbF: 30-50%, no HbA
• Clinical phenotype overlaps with beta thal major
• Most prevalent severe thalassemia in Bangladesh, Thailand, India

4. Hereditary Spherocytosis (HS)

• Blood smear: spherocytes (not target cells/nucleated RBCs) in HS
• Osmotic fragility test: increased fragility in HS
• MCV is not low in HS (normocytic or mildly elevated due to spherocyte-related changes)
• HPLC normal in HS
• No ethnic/geographic predisposition pattern
• No bony deformities / thalassemia facies

5. G6PD Deficiency

• Episodes typically triggered by drugs/infections/fava beans
• X-linked inheritance (predominantly affects males)
• No chronic transfusion dependence between episodes
• Blood smear: bite cells, Heinz bodies
• G6PD enzyme assay diagnostic

6. Leukemia (ALL / AML) - especially in children

• Anemia in leukemia is normocytic/normochromic
• Bleeding tendency (thrombocytopenia), bone pain (infiltration)
• Fever, lymphadenopathy prominent
• Peripheral smear: blasts present
• Bone marrow: hypercellular with blasts
• No elevated HbF / elevated HbA2 on HPLC
• No family history pattern (AR)

7. Aplastic Anemia

• Pancytopenia with hypocellular marrow (vs. hypercellular in thalassemia)
• No splenomegaly
• No microcytosis / not hemolytic
• Drug/toxin/autoimmune cause often identified
• Normocytic anemia

8. Nutritional Megaloblastic Anemia

• Macrocytic / normocytic (not microcytic)
• Dietary history relevant
• Responds to B12/folate supplementation
• Hypersegmented neutrophils on smear
• No thalassemia facies / splenomegaly

9. Autoimmune Hemolytic Anemia (AIHA)

• Positive Direct Coombs Test (DCT)
• Spherocytes on smear
• Often acute onset, precipitated by infections / drugs / autoimmune disease
• HPLC normal

---

SECTION 10: PATHOPHYSIOLOGY (For Viva Questions)

1. Beta-globin gene mutation -> reduced/absent beta chain synthesis
2. Excess unpaired alpha chains precipitate within developing erythroblasts
3. Alpha chain precipitates -> membrane damage -> intramedullary destruction (ineffective erythropoiesis) - PRIMARY mechanism of anemia
4. Reduced deformability of surviving RBCs -> extravascular hemolysis in spleen/liver
5. Severe anemia -> bone marrow expansion -> bony changes
6. Marrow expansion -> increased iron absorption via hepcidin suppression
7. Chronic transfusions -> transfusional iron overload -> deposits in heart, liver, endocrine glands
8. Iron toxicity (free radical generation via Fenton reaction) -> cardiomyopathy, liver cirrhosis, endocrinopathy

---

SECTION 11: MANAGEMENT (Complete for PG Exam)

A. Transfusion Therapy (Definitive Supportive)

• Target pretransfusion Hb: 9-10.5 g/dL
• Frequency: every 2-5 weeks (Harrison's 22E)
• Use leukoreduced packed red cells (minimizes alloimmunization, febrile reactions, CMV transmission)
• Phenotype-matched blood (for C, E, Kell antigens) preferred if available
• Transfusion suppresses ineffective erythropoiesis and allows normal growth/development

B. Iron Chelation (Mandatory)

C. Splenectomy

• Indications: hypersplenism causing increased transfusion requirements, symptomatic massive splenomegaly
• Delay until >5 years of age
• Pre-splenectomy vaccinations: pneumococcal, meningococcal, H. influenzae type b
• Post-splenectomy: lifelong penicillin prophylaxis (due to ~50% mortality from overwhelming post-splenectomy infection [OPSI])

D. Folic Acid

• 1-5 mg/day supplementation (supports ongoing erythropoiesis)

E. New Agents (Very High Yield for PG 2025-26)

• Luspatercept (Reblozyl): Recombinant fusion protein - binds TGF-beta superfamily ligands, reduces Smad2/3 signaling - enhances late-stage erythropoiesis. Given SC 1 mg/kg every 3 weeks. Approved for adult TDT. Reduces transfusion burden by ≥33%. [PMID: 41353598 - 2026 SR confirms its role in supportive therapy]
• Sotatercept: Activin type IIA receptor fusion protein - similar mechanism

F. Curative Therapy

• Allogeneic Hematopoietic Stem Cell Transplantation (HSCT): Potentially curative. Best outcomes in young patients with matched sibling donor (Class I Pesaro). Outcomes depend on pre-transplant iron overload and hepatic status (Pesaro classification).
• Gene Therapy: Betibeglogene autotemcel (Zynteglo) - lentiviral vector delivering functional beta-globin gene. FDA-approved for TDT in patients ≥12 years. Potentially curative.

G. Endocrine and Organ Complications Management

• Cardiac: Annual echocardiography + MRI T2*. Cardiomyopathy - intensify chelation (combined DFP + DFO); calcium channel blockers have been studied [PMID: 40069102 - 2025 SR on CCBs for cardiomyopathy in TDT]
• Diabetes: Standard diabetic management; insulin in most (beta-cell destruction irreversible)
• Hypogonadism: Hormone replacement therapy (testosterone in males, estrogen/progesterone in females)
• Hypothyroidism: Levothyroxine replacement
• Osteoporosis: Calcium, Vitamin D, bisphosphonates; weight-bearing exercise
• Gallstones: Laparoscopic cholecystectomy when symptomatic

---

SECTION 12: COMPLICATIONS SUMMARY TABLE

---

SECTION 13: KEY EXAM VIVA POINTS

1. Why is the child normal at birth? - HbF (alpha2-gamma2) does not require beta chains; disease manifests as gamma-to-beta switch occurs after 3-6 months.
2. Mentzer Index: MCV / RBC count. < 13 = thalassemia; > 13 = iron deficiency anemia
3. Transfusion-dependent definition: Requires 8+ RBC transfusions/year to maintain acceptable quality of life (Goldman-Cecil)
4. Leading cause of death in TDT: Iron overload cardiomyopathy
5. Best non-invasive assessment of cardiac iron: MRI T2* (< 20 ms indicates significant cardiac iron loading)
6. Why not give iron to a thalassemia patient? Iron stores are already elevated; giving iron is harmful. The common clinical trap - a child labeled "iron deficiency anemia" given years of iron is actually TDT. Serum ferritin will confirm.
7. Pesaro Classification for HSCT: Class I (no hepatomegaly, no portal fibrosis, good chelation) has >90% thalassemia-free survival; Class III (all three risk factors present) has ~60% thalassemia-free survival.
8. Post-splenectomy - most feared infection: Streptococcus pneumoniae (OPSI - overwhelming post-splenectomy infection with ~50% mortality)
9. Yersinia enterocolitica infection in TDT: Classic association with deferoxamine use - iron is a growth factor for this organism; ask about abdominal pain/diarrhea in a patient on DFO
10. HbE-beta thalassemia: Most prevalent form of TDT in South/Southeast Asia; often missed because HbE itself is a mild condition but when combined with beta-thal mutation = TDT phenotype

---

SECTION 14: PROGNOSIS STATEMENT (For Case Closing)

"This child with transfusion-dependent thalassemia, if adequately transfused to maintain pretransfusion Hb above 9 g/dL and placed on effective iron chelation therapy (deferasirox/deferiprone), can be expected to survive into the 4th-5th decade with good quality of life. The leading cause of mortality remains iron overload cardiomyopathy. A matched sibling donor for HSCT or eligibility for gene therapy represents the only currently available curative options. Regular multidisciplinary monitoring of cardiac, hepatic, and endocrine function is mandatory throughout the patient's life."

---