Family Medicine Board Review ยท Case-Based ยท Difficult Level

Thalassemia โ€” Clinical Vignette MCQs

Board-style cases built from the thalassemia summary โ€” screening pitfalls, subtype recognition (alpha and beta), diagnostic pattern traps, treatment thresholds, and complication mechanisms. Tap "Reveal Answer" on each, then read the pearl.

15 Questions โ—โ—โ—โ— Difficult Single Best Answer
Q1Screening / Microcytosisโ—โ—โ—โ— Very Hard

A 24-year-old asymptomatic woman has a low MCV (68 fL) noted on routine CBC. Her hemoglobin is 12.8 g/dL, RBC count is elevated at 5.9 million/ยตL, and ferritin is normal. What is the most appropriate next step?

Reveal Answer

Correct answer: B

Microcytosis with a normal-to-elevated RBC count and normal ferritin is a classic pattern favoring thalassemia trait over iron deficiency (where RBC count is typically low and ferritin low). Patients with low MCV should be screened for thalassemia with hemoglobin electrophoresis.

Why the others are wrong A โ€” empiric iron is inappropriate with normal ferritin and this RBC pattern; unnecessary iron in a thalassemia trait patient risks iron overload. C โ€” microcytosis always warrants at least basic evaluation, not blanket reassurance. D โ€” bone marrow biopsy is invasive and unnecessary for this straightforward workup; electrophoresis/HPLC is the correct noninvasive next step. E โ€” deferring for a year skips a simple, high-yield diagnostic test.
Exam Pearl The RBC count is a key differentiator: iron deficiency โ†’ low RBC count; thalassemia trait โ†’ normal or elevated RBC count, despite both causing microcytosis. This is often called the Mentzer index concept.
Q2Prenatal Testing Timingโ—โ—โ—โ—‹ Hard

A couple, both known carriers of beta-thalassemia trait, is currently at 9 weeks' gestation and wants the earliest possible prenatal diagnosis for their fetus. What is the most appropriate testing approach and timing?

Reveal Answer

Correct answer: B

Chorionic villus sampling (CVS) is performed at 10โ€“12 weeks' gestation and is the earliest prenatal diagnostic option; amniocentesis is used later, after 15 weeks' gestation, if CVS wasn't performed or additional testing is needed.

Why the others are wrong A โ€” amniocentesis is not performed this early (9 weeks); it's not appropriate or accurate at this gestational age. C โ€” CVS is a valid and earlier alternative; amniocentesis is not the only option. D โ€” maternal serum screening is not diagnostic for thalassemia in the fetus; direct genetic testing via CVS or amniocentesis is required. E โ€” prenatal diagnosis is available and well-established for thalassemia.
Exam Pearl Prenatal thalassemia testing timeline: CVS at 10โ€“12 weeks; amniocentesis after 15 weeks. Know both options and their respective windows.
Q3Iron Overload Assessmentโ—โ—โ—โ—โ— Extreme

A 19-year-old man with transfusion-dependent beta-thalassemia major has a serum ferritin of 1,450 ng/mL. His physician wants to more precisely quantify his organ-specific iron burden before adjusting chelation therapy. What is the most appropriate next test?

Reveal Answer

Correct answer: B

Once thalassemia (and iron overload risk) is established, organ-specific iron burden is best assessed with T2*-weighted cardiac MRI or R2*-weighted liver MRI โ€” noninvasive, quantitative, and specifically able to localize iron deposition in the heart and liver, which ferritin alone cannot do.

Why the others are wrong A โ€” ferritin is a useful trend marker but doesn't precisely quantify organ-specific iron burden the way MRI does. C โ€” liver biopsy is used rarely, reserved for cases where MRI is unavailable or inconclusive, not as the first-line test. D โ€” ultrasound doesn't quantify iron deposition. E โ€” serum iron/TIBC studies don't provide the organ-specific quantification needed to guide chelation intensity.
Exam Pearl Iron overload quantification hierarchy: T2* cardiac MRI / R2* liver MRI (first-line, noninvasive) โ†’ liver biopsy (rarely needed fallback). Cardiac iron deposition is the leading driver of thalassemia-related mortality, making cardiac MRI especially important.
Q4Transfusion Goalโ—โ—โ—โ— Very Hard

A 12-year-old girl with transfusion-dependent beta-thalassemia major is on a regular transfusion schedule. Her pretransfusion hemoglobin has been trending around 8.2 g/dL. What is the most appropriate adjustment, and why?

Reveal Answer

Correct answer: B

The treatment goal in transfusion-dependent thalassemia is to maintain Hb 9โ€“10.5 g/dL specifically to suppress the erythropoietin-driven marrow expansion that leads to extramedullary hematopoiesis and its complications (bony deformities, hepatosplenomegaly). A pretransfusion Hb of 8.2 is below this target and should prompt adjustment.

Why the others are wrong A โ€” 8.2 g/dL falls below the recommended 9โ€“10.5 g/dL target range. C โ€” allowing Hb to drop further defeats the purpose of transfusion therapy in transfusion-dependent disease and worsens marrow expansion complications. D โ€” hydroxyurea is an adjunct that may reduce transfusion frequency in some patients, but it doesn't replace transfusion therapy in transfusion-dependent major disease. E โ€” discontinuing transfusions in a transfusion-dependent patient risks severe untreated anemia, a described cause of death in beta-thalassemia major.
Exam Pearl Memorize the target: Hb 9โ€“10.5 g/dL is the specific transfusion goal to prevent extramedullary hematopoiesis โ€” this exact range is a favorite isolated fact on boards.
Q5Chelation Threshold โ€” Integrativeโ—โ—โ—โ—โ— Extreme

Two patients are being evaluated for iron chelation therapy. Patient X has transfusion-dependent thalassemia (TDT) with a ferritin of 950 ng/mL. Patient Y has non-transfusion-dependent thalassemia (NTDT) with a ferritin of 950 ng/mL. Which patient meets criteria for starting iron chelation therapy based on ferritin threshold alone?

Reveal Answer

Correct answer: B

Chelation thresholds differ by transfusion status: TDT โ†’ ferritin >1,000 ng/mL; NTDT โ†’ ferritin >800 ng/mL. At a ferritin of 950 ng/mL, Patient X (TDT, threshold 1,000) does not yet meet criteria, while Patient Y (NTDT, threshold 800) does meet criteria, since 950 exceeds the lower NTDT threshold.

Why the others are wrong A โ€” reverses the correct answer; Patient X's ferritin is below the TDT threshold. C โ€” incorrect since Patient X doesn't yet meet the higher TDT threshold. D โ€” incorrect since Patient Y does meet the lower NTDT threshold. E โ€” ferritin threshold is specifically how chelation initiation is determined in this framework.
Exam Pearl NTDT has the LOWER ferritin threshold (800) despite receiving fewer transfusions โ€” this is a deliberately counterintuitive board trap testing whether you actually memorized the numbers rather than assuming "more transfusions = lower threshold."
Q6Hydroxyurea Mechanismโ—โ—โ—โ—‹ Hard

A 16-year-old with beta-thalassemia intermedia is started on hydroxyurea by her hematologist to help reduce her transfusion needs. What is the mechanism by which hydroxyurea achieves this effect?

Reveal Answer

Correct answer: B

Hydroxyurea works in thalassemia (as in sickle cell disease) by promoting HbF (fetal hemoglobin) production, which can improve overall hemoglobin levels and reduce the frequency of needed transfusions in appropriate patients.

Why the others are wrong A โ€” hydroxyurea is not an iron chelator; that role belongs to agents like deferoxamine, deferasirox, or deferiprone. C โ€” it doesn't work by suppressing erythropoietin; in fact it works by favorably shifting hemoglobin composition. D โ€” genetic counseling remains important regardless of pharmacologic therapy and isn't replaced by hydroxyurea. E โ€” hydroxyurea doesn't directly address existing cardiac iron deposition; that requires chelation therapy.
Exam Pearl Hydroxyurea's shared mechanism across both SCD and thalassemia: induces HbF. In thalassemia, this can reduce transfusion frequency; it is not a substitute for chelation or genetic counseling.
Q7Curative Therapy Candidacyโ—โ—โ—โ— Very Hard

A family is exploring curative options for their child with transfusion-dependent beta-thalassemia major. The child is 10 years old and has a fully HLA-matched sibling donor available. What is the most appropriate counseling regarding stem cell transplantation?

Reveal Answer

Correct answer: B

Stem cell transplantation is a potentially curative option in thalassemia, with the ideal candidate profile being younger than 12 years old with a matching donor โ€” this child, at age 10 with a matched sibling donor, fits that ideal profile closely.

Why the others are wrong A โ€” stem cell transplant is specifically described as potentially curative, contradicting this statement. C โ€” delaying until 18 moves the patient outside the ideal <12-year-old window, working against the best chance of successful outcome. D โ€” a matching donor is a key part of the "ideal candidate" description; donor matching matters significantly for transplant success and complication risk. E โ€” stem cell transplant is discussed in the context of thalassemia broadly (including beta-thalassemia major), not restricted to alpha-thalassemia.
Exam Pearl Ideal stem cell transplant candidate in thalassemia: age <12 years + matched donor. This is the only potentially curative option listed among thalassemia therapies.
Q8Luspaterceptโ—โ—โ—โ—‹ Hard

An adult with transfusion-dependent beta-thalassemia is started on a new injectable medication aimed at reducing his overall transfusion burden, distinct from iron chelators and hydroxyurea. What medication is this most likely to be?

Reveal Answer

Correct answer: B

Luspatercept is specifically indicated to decrease overall transfusion burden in beta-thalassemia, representing a distinct therapeutic class from iron chelators and hydroxyurea.

Why the others are wrong A โ€” deferasirox is an oral iron chelator, not a transfusion-burden-reducing agent in this sense. C โ€” allopurinol isn't part of standard thalassemia management. D โ€” erythropoietin alone isn't the described therapy for reducing transfusion burden in this population. E โ€” folic acid is a standard supportive supplement (especially in beta-thalassemia major), not a transfusion-burden-reducing targeted therapy.
Exam Pearl Luspatercept = beta-thalassemia-specific therapy that reduces transfusion burden โ€” a distinct, newer agent class worth knowing by name alone as an isolated board fact.
Q9Beta-Thalassemia Minorโ—โ—โ—โ— Very Hard

A 30-year-old asymptomatic woman undergoes hemoglobin electrophoresis after incidental microcytosis is found. Results show HbA2 of 4.2% (normal 1.5โ€“3.5%), MCV of 66 fL, and Hb of 118 g/L. What is the most appropriate management?

Reveal Answer

Correct answer: B

This lab pattern โ€” elevated HbA2 (3.5โ€“5%), MCV <70, and Hb in the 100โ€“140 g/L range โ€” is classic for beta-thalassemia minor (trait). This condition requires no treatment; the appropriate management is genetic counseling for the patient and family given reproductive implications.

Why the others are wrong A โ€” regular transfusion is reserved for transfusion-dependent disease (major), not trait/minor, which is typically asymptomatic. C โ€” chelation therapy is tied to iron overload from repeated transfusions, not to HbA2 elevation itself; trait patients aren't transfusion-dependent and don't develop this iron burden from the disease itself. D โ€” splenectomy is a major-disease consideration (after age 6, less frequently performed now), not indicated in trait. E โ€” folic acid 5 mg/day is part of major disease management, not indicated as primary therapy in asymptomatic trait.
Exam Pearl Beta-thalassemia minor signature: HbA2 3.5โ€“5% (vs. normal 1.5โ€“3.5%), MCV <70, Hb 100โ€“140 g/L, asymptomatic, no treatment โ€” just genetic counseling.
Q10Intermedia vs. Major Paradoxโ—โ—โ—โ—โ— Extreme

A hematology fellow states that thalassemia major patients should have a higher rate of leg ulcers, gallstones, thrombosis, and extramedullary hematopoiesis than thalassemia intermedia patients, since major disease is more severe. Is this statement accurate?

Reveal Answer

Correct answer: B

This is a specifically flagged paradox: extramedullary hematopoiesis, leg ulcers, gallstones, and thrombosis are more common in thalassemia intermedia than major. The proposed explanation is that major-disease patients are transfused early and regularly, suppressing the erythropoietin-driven marrow expansion and extramedullary hematopoiesis that drives these complications โ€” while intermedia patients, who are not regularly transfused, experience more unchecked marrow drive.

Why the others are wrong A โ€” this intuitive assumption is specifically incorrect for this complication list. C โ€” these complications are discussed specifically in the beta-thalassemia intermedia/major context, not exclusively in alpha-thalassemia. D โ€” the pattern applies to the whole complication cluster, not gallstones alone. E โ€” there is a described difference, with intermedia showing higher rates.
Exam Pearl Don't assume "more severe genotype = more of every complication." Regular transfusion in major disease actually protects against marrow-expansion-driven complications that are paradoxically more common in the less severe, non-regularly-transfused intermedia form.
Q11Beta-Thalassemia Major โ€” Infection Riskโ—โ—โ—โ—โ— Extreme

A 15-year-old with beta-thalassemia major and known iron overload (ferritin 2,800 ng/mL) presents with fever, abdominal pain, and bloody diarrhea. Blood cultures are pending. Which organism should be specifically considered given his iron overload status, beyond the general encapsulated organisms of concern in other hemolytic anemias?

Reveal Answer

Correct answer: A

In beta-thalassemia major, iron overload specifically increases susceptibility to Yersinia, Klebsiella, and fungal infections (iron is a growth factor for these organisms), in addition to the general increased bacterial infection risk from chronic anemia. His presentation (fever, abdominal pain, bloody diarrhea) with known significant iron overload should specifically raise concern for Yersinia enterocolitica enterocolitis/sepsis.

Why the others are wrong B โ€” S. pyogenes isn't the iron-overload-specific organism highlighted in this framework. C โ€” Mycoplasma isn't linked to iron overload in this context. D โ€” C. difficile isn't the iron-overload-specific pathogen being tested, though it remains a general consideration in diarrheal illness. E โ€” Lyme disease organism isn't relevant to this iron-overload infection risk pattern.
Exam Pearl Iron overload in thalassemia major specifically raises risk for Yersinia, Klebsiella, and fungal infections โ€” iron is a key growth nutrient for these organisms. This is distinct from (and additive to) the general anemia-related bacterial infection susceptibility.
Q12Beta-Thalassemia Major โ€” Skeletalโ—โ—โ—โ— Very Hard

A 4-year-old boy with untreated beta-thalassemia major (family declined regular transfusions) presents with frontal bossing, maxillary hypertrophy, and a pathologic fracture after minimal trauma. Skull x-ray is obtained. What finding is most likely to be seen?

Reveal Answer

Correct answer: B

Untreated/undertreated beta-thalassemia major leads to marked marrow expansion from chronic erythropoietin drive, producing the classic "hair-on-end" appearance on skull x-ray, along with a thin bony cortex and increased tendency toward pathologic fractures โ€” both described complications in this patient.

Why the others are wrong A โ€” "ground-glass" appearance is classically associated with fibrous dysplasia, not thalassemia. C โ€” "soap bubble" lesions are seen in other bone lesions (e.g., giant cell tumor, ABC), not the classic thalassemia finding. D โ€” skull involvement is specifically described in thalassemia major, and pathologic fractures are common overall, not limited to long bones alone. E โ€” "onion-skin" periosteal reaction is classically associated with Ewing sarcoma, not thalassemia.
Exam Pearl "Hair-on-end" skull x-ray = beta-thalassemia major (from marrow expansion) โ€” a classic radiographic pattern-recognition fact, paired clinically with frontal bossing, maxillary hypertrophy, and pathologic fractures from thinned cortical bone.
Q13Beta-Thalassemia Major โ€” Labsโ—โ—โ—โ—โ— Extreme

A 5-month-old infant presents with severe pallor, poor feeding, and hepatosplenomegaly. Hemoglobin is 54 g/L. Peripheral smear shows teardrop cells and target cells. Hemoglobin electrophoresis shows HbA 4%, HbA2 3%, and HbF 93%. What is the most likely diagnosis?

Reveal Answer

Correct answer: B

Severe microcytic anemia (Hb <60 g/L) presenting at age 3โ€“6 months, with hepatosplenomegaly, teardrop and target cells on smear, and hemoglobin electrophoresis showing HbA 0โ€“10%, HbA2 >2.5%, and HbF 90โ€“100% is the classic diagnostic picture of beta-thalassemia major.

Why the others are wrong A โ€” thalassemia minor is asymptomatic with much milder lab derangement; this presentation is far too severe. C โ€” silent carrier alpha-thalassemia is clinically silent with normal Hb/MCV/HPLC โ€” not this severe anemia. D โ€” HbH disease typically presents in adults, not as severe anemia in infancy, and would show HbH on HPLC rather than this HbF pattern. E โ€” iron deficiency doesn't produce this hemoglobin electrophoresis pattern (markedly elevated HbF) or present with hepatosplenomegaly in this fashion.
Exam Pearl Beta-thalassemia major lab triad: severe anemia at 3โ€“6 months of age + teardrop/target cells + HbF 90โ€“100% on electrophoresis. The dramatic HbF elevation (compensating for absent/reduced HbA) is the signature finding.
Q14Alpha-Thalassemia โ€” HbH Diseaseโ—โ—โ—โ—โ— Extreme

A 34-year-old man of Southeast Asian descent presents with fatigue and is found to have splenomegaly, decreased MCV, and decreased hemoglobin. He reports chronic leg ulcers. HPLC shows an abnormal hemoglobin band consistent with a beta-globin tetramer. Genetic testing confirms 3 defective alpha-globin genes. What is the most appropriate management approach?

Reveal Answer

Correct answer: B

Three defective alpha-globin genes produces HbH (ฮฒ4) disease, which presents in adults with decreased MCV, decreased Hb, splenomegaly, variable growth retardation, leg ulcers, and infections โ€” HPLC shows HbH (a beta-globin tetramer forming when alpha chains are severely deficient). Management is similar to beta-thalassemia intermedia, generally without the need for regular transfusion.

Why the others are wrong A โ€” this describes the 1-gene-deletion silent carrier state, not the symptomatic 3-gene HbH disease seen here. C โ€” stem cell transplant isn't described as mandatory for HbH disease; management parallels intermedia (non-regular-transfusion) rather than requiring transplant. D โ€” incompatibility with life describes the 4-gene deletion (Hb Barts/hydrops fetalis), not the 3-gene HbH disease, which is compatible with adult life. E โ€” regular transfusion every 2โ€“3 weeks reflects transfusion-dependent disease (like beta-thalassemia major), not the typical HbH disease course.
Exam Pearl Alpha-thalassemia gene-deletion ladder: 1 gene = silent carrier (normal HPLC) โ†’ 2 genes = trait (normal HPLC, โ†“MCV) โ†’ 3 genes = HbH disease (abnormal HPLC, manage like beta-intermedia) โ†’ 4 genes = Hb Barts/hydrops fetalis (incompatible with life).
Q15Alpha-Thalassemia โ€” Hydrops Fetalisโ—โ—โ—โ—โ— Extreme

A pregnant woman at 24 weeks' gestation, whose partner and she are both known carriers of alpha-thalassemia (each with 2 defective genes in cis configuration), undergoes fetal ultrasound showing severe fetal edema, ascites, and cardiomegaly. What is the most likely underlying diagnosis, and what does this imply about prognosis?

Reveal Answer

Correct answer: B

Both parents carrying 2 defective alpha-globin genes in cis configuration (both deletions on the same chromosome) creates a risk of the fetus inheriting 4 defective alpha-globin genes total, resulting in Hb Barts (ฮณ4) disease, which presents as hydrops fetalis โ€” the described fetal findings (edema, ascites, cardiomegaly) are consistent with this. This condition is usually incompatible with life.

Why the others are wrong A โ€” HbH disease (3-gene deletion) is compatible with adult life and doesn't typically cause hydrops fetalis; this presentation is more severe. C โ€” the described fetal findings are far from clinically insignificant; they represent a severe, life-threatening condition. D โ€” beta-thalassemia major doesn't typically cause hydrops fetalis in this manner, and is not simply "treatable with routine postnatal transfusion alone" as a reassuring description of this fetal presentation. E โ€” the parental carrier status (both with cis-configuration deletions) directly explains the risk of this fetal finding; it is not unrelated.
Exam Pearl Cis-configuration alpha-thalassemia carriers (both deletions on the same chromosome) in both parents creates the specific reproductive risk of Hb Barts hydrops fetalis โ€” a critical genetic counseling point distinguishing cis vs. trans carrier configurations, since trans-configuration carriers do not carry this same severe combined risk in the same way.
Thalassemia Board Review ยท Case-Based MCQ Set ยท 15/15 Questions