Family Medicine Board Review · Case-Based · Difficult Level

Hemolytic Anemia — Clinical Vignette MCQs

Board-style cases built from the hemolytic anemia summary — Coombs testing, ITP/TTP/DIC discrimination, extravascular vs. intravascular hemolysis, AIHA subtype treatment, TTP/HUS emergencies, and G6PD testing pitfalls. Tap "Reveal Answer" on each, then read the pearl.

15 Questions ●●●● Difficult Single Best Answer

Q1Acute vs. Chronic Presentation●●●○ Hard

A 45-year-old man presents with acute jaundice and dark urine over 2 days. A different 50-year-old woman presents with longstanding lymphadenopathy, hepatosplenomegaly, and recurrent gallstones. Which presentation pattern matches each patient?

A. Both presentations describe acute hemolysis
B. The man's presentation (jaundice, hematuria/dark urine) is classic for acute hemolysis; the woman's (lymphadenopathy, hepatosplenomegaly, cholestasis/gallstones) is classic for chronic hemolysis
C. The woman's presentation describes acute hemolysis, and the man's describes chronic hemolysis
D. Neither presentation is consistent with hemolytic anemia
E. Both presentations describe chronic hemolysis

Reveal Answer

Correct answer: B

Acute hemolysis classically presents with jaundice or hematuria in the presence of anemia — matching the man's rapid-onset jaundice/dark urine. Chronic hemolysis presents with lymphadenopathy, hepatosplenomegaly, cholestasis, and choledocholithiasis (gallstones from chronic bilirubin overproduction) — matching the woman's longstanding findings.

Why the others are wrong A/E — the two presentations describe distinctly different patterns (acute vs. chronic), not the same pattern for both. C — this reverses the correct pairing. D — both presentations are classic, recognized hemolysis patterns.

Exam Pearl Acute hemolysis → jaundice/hematuria; chronic hemolysis → lymphadenopathy, hepatosplenomegaly, cholestasis, gallstones. Chronic bilirubin overproduction from ongoing hemolysis is a classic driver of pigment gallstones.

Q2Direct vs. Indirect Coombs●●●●● Extreme

A 38-year-old woman with suspected autoimmune hemolytic anemia needs confirmatory testing. Separately, a pregnant woman needs screening to assess for antibodies that could affect her fetus. Which test is appropriate for each scenario?

A. Indirect Coombs for the AIHA patient; direct Coombs for the pregnancy screening
B. Direct Coombs (detects antibodies already on the patient's own RBCs) for the AIHA patient; indirect Coombs (detects antibodies in serum) is used in the context of hemolytic disease of the newborn/pregnancy screening
C. Both scenarios use the exact same test with no distinction
D. Neither test is relevant to either scenario
E. Direct Coombs is used exclusively for newborn screening, never for AIHA

Reveal Answer

Correct answer: B

Direct Coombs (DAT) detects antibodies already bound to the surface of the patient's own RBCs and is mainly done in AIHA. Indirect Coombs detects antibodies in the serum that recognize RBC antigens and is used in the context of hemolytic disease of the newborn (maternal antibody screening).

Why the others are wrong A — this reverses the correct test-to-scenario pairing. C — the two tests detect different things (antibodies on RBCs vs. antibodies in serum) and serve different clinical purposes. D — both tests are specifically relevant and appropriately matched to these scenarios. E — direct Coombs is specifically the test used for AIHA, not exclusively for newborn screening.

Exam Pearl Direct Coombs = antibodies ON the RBCs (diagnoses AIHA). Indirect Coombs = antibodies IN the serum (used for newborn/pregnancy antibody screening). A frequently confused pair — anchor it to "direct = on the cell, done in AIHA."

Q3ITP vs. TTP vs. DIC — Clinical Appearance●●●●● Extreme

A 25-year-old woman with new-onset petechiae and a platelet count of 15 × 10⁹/L appears well, is afebrile, and has entirely normal PT, PTT, and fibrinogen. Which diagnosis is most consistent with this clinical picture?

A. DIC, given the low platelet count
B. ITP — classically a well-appearing patient with isolated thrombocytopenia and normal coagulation studies
C. TTP, given the presence of thrombocytopenia
D. HUS, based on the platelet count alone
E. All three conditions are equally likely given this information

Reveal Answer

Correct answer: B

ITP is characterized by antiplatelet antibodies causing isolated thrombocytopenia in a patient who is classically "not ill"-appearing, with normal PT, PTT, and fibrinogen — matching this well-appearing patient exactly.

Why the others are wrong A — DIC patients are ill-appearing with deranged PT/PTT/fibrinogen (increased PT/PTT, decreased fibrinogen); her normal coagulation studies and well appearance argue strongly against DIC. C — TTP patients are ill-appearing and typically show additional features (fever, renal injury, neurologic dysfunction, schistocytes on smear), none of which are described here. D — HUS is defined by MAHA and acute kidney injury with thrombocytopenia, not simply an isolated platelet count. E — her specific well-appearing status with normal coagulation studies specifically favors ITP over the other two.

Exam Pearl ITP = well-appearing + normal coagulation studies + isolated thrombocytopenia. This "looks fine, labs (besides platelets) are clean" pattern is the key to distinguishing ITP from the more dangerous TTP/DIC on boards.

Q4TTP vs. DIC — Coagulation Discriminator●●●●● Extreme

Two critically ill patients both present with thrombocytopenia and schistocytes on peripheral smear. Patient A has a normal PT, PTT, and fibrinogen. Patient B has an elevated PT, elevated PTT, and markedly decreased fibrinogen. Which diagnosis is more consistent with each patient?

A. Both patients have TTP, since both show schistocytes
B. Patient A is more consistent with TTP (coagulation studies remain essentially normal); Patient B is more consistent with DIC (deranged PT/PTT/fibrinogen from thrombin excess)
C. Patient A has DIC and Patient B has TTP
D. Both patients have identical underlying pathophysiology
E. Schistocytes rule out both TTP and DIC

Reveal Answer

Correct answer: B

Both TTP and DIC can present with thrombocytopenia and schistocytes, both are ill-appearing conditions — but the coagulation panel is the key discriminator: TTP keeps PT/PTT/fibrinogen essentially normal (the pathology is an endothelial/ADAMTS13 defect, not a global consumptive coagulopathy), while DIC shows increased PT/PTT and decreased fibrinogen due to thrombin excess consuming clotting factors.

Why the others are wrong A — the presence of schistocytes alone doesn't distinguish TTP from DIC; the coagulation studies do. C — this reverses the correct pairing. D — TTP and DIC have distinct underlying pathophysiology (endothelial/ADAMTS13 defect vs. thrombin excess/consumptive coagulopathy) despite some overlapping features. E — schistocytes are compatible with both TTP and DIC; they don't rule out either.

Exam Pearl When schistocytes + thrombocytopenia + ill-appearing patient could be either TTP or DIC, check the coagulation panel: normal PT/PTT/fibrinogen → TTP; deranged (↑PT, ↑PTT, ↓fibrinogen) → DIC.

Q5Extravascular Hemolysis Recognition●●●●● Extreme

A 34-year-old woman with suspected hemolysis has a peripheral smear showing numerous spherocytes. Direct Coombs is positive. Which additional finding would be most consistent with an extravascular (rather than intravascular) mechanism of hemolysis?

A. Positive urine hemosiderin
B. Negative urine hemosiderin, with RBC destruction occurring via splenic macrophages
C. Markedly, severely decreased haptoglobin (more severe than typically seen in extravascular hemolysis)
D. Schistocytes on smear instead of spherocytes
E. Site of destruction within the blood vessels themselves

Reveal Answer

Correct answer: B

Extravascular hemolysis occurs via macrophages in the spleen, is associated with spherocytes on smear (matching this patient), a low (but not "very low") haptoglobin, high (but not "very high") LDH, and negative urine hemosiderin.

Why the others are wrong A — positive urine hemosiderin is the intravascular pattern, not extravascular. C — markedly/severely decreased haptoglobin is more characteristic of intravascular hemolysis ("very low"); extravascular hemolysis shows a milder ("low") reduction. D — schistocytes are the intravascular hemolysis smear finding; this patient already has spherocytes, consistent with extravascular hemolysis. E — destruction within blood vessels describes intravascular, not extravascular, hemolysis (which occurs via splenic macrophages).

Exam Pearl Extravascular hemolysis signature: spherocytes, splenic macrophage destruction, low (not very low) haptoglobin, high (not very high) LDH, negative urine hemosiderin. Warm AIHA is the classic extravascular example.

Q6Intravascular Hemolysis Recognition●●●●● Extreme

A 55-year-old man with a mechanical heart valve develops fatigue and dark urine. Labs show markedly decreased haptoglobin, very high LDH, and positive urine hemosiderin. Peripheral smear shows schistocytes. What mechanism and destruction site best explain this presentation?

A. Extravascular hemolysis via splenic macrophages
B. Intravascular hemolysis, with RBC destruction occurring directly within blood vessels — consistent with mechanical trauma from the prosthetic valve
C. This pattern is inconsistent with any recognized hemolysis mechanism
D. Extravascular hemolysis, since haptoglobin is decreased
E. This pattern specifically indicates G6PD deficiency exclusively

Reveal Answer

Correct answer: B

Schistocytes, markedly decreased haptoglobin, very high LDH, and positive urine hemosiderin together describe intravascular hemolysis, with destruction occurring directly within blood vessels — mechanical trauma from a prosthetic/endovascular device (his mechanical valve) is a classic cause of microangiopathic hemolytic anemia via this mechanism.

Why the others are wrong A — extravascular hemolysis shows spherocytes and negative urine hemosiderin, not this pattern. C — this is a well-recognized, classic intravascular hemolysis pattern. D — while haptoglobin is decreased in both types, the degree (markedly/very low) plus schistocytes and positive urine hemosiderin specifically point to intravascular, not extravascular, hemolysis. E — while G6PD deficiency is also a cause of intravascular hemolysis, his mechanical valve is the more specific and directly relevant trigger described here (trauma from an endovascular device), not a G6PD-specific presentation.

Exam Pearl Intravascular hemolysis signature: schistocytes, vessel-based destruction, very low haptoglobin, very high LDH, positive urine hemosiderin. Mechanical heart valves and other endovascular devices are classic mechanical triggers via trauma to RBCs.

Q7Warm AIHA Treatment●●●○ Hard

A 42-year-old woman is diagnosed with warm autoimmune hemolytic anemia (IgG-mediated) with a positive DAT and hemoglobin of 7.8 g/dL. What is the most appropriate first-line treatment?

A. Avoidance of cold exposure as the primary intervention
B. Glucocorticoids, along with management of any underlying condition and supportive care (± blood transfusion if necessary)
C. Plasma exchange as first-line therapy
D. Antibiotics targeting an underlying infection, regardless of clinical context
E. Observation only, with no treatment indicated

Reveal Answer

Correct answer: B

Warm AIHA (IgG-mediated, more common) is treated with glucocorticoids, management of the underlying condition, blood transfusion if necessary, and supportive care.

Why the others are wrong A — cold avoidance is the management approach for cold AIHA, not warm AIHA. C — plasma exchange is the treatment for TTP, not the first-line approach for warm AIHA. D — antibiotics aren't the described first-line treatment for warm AIHA itself, though an underlying infectious trigger (if present) would be separately addressed. E — with symptomatic anemia (Hgb 7.8) and a confirmed diagnosis, active treatment (not mere observation) is indicated.

Exam Pearl Warm AIHA → glucocorticoids (steroid-responsive). Contrast this directly with cold AIHA, which does NOT respond to steroids and is managed supportively instead.

Q8Cold AIHA Treatment●●●●● Extreme

A 60-year-old man is diagnosed with cold agglutinin disease (IgM-mediated AIHA) after presenting with hemolysis symptoms that worsen in cold weather. His physician starts high-dose glucocorticoids as first-line therapy. Is this the most appropriate approach?

A. Yes, glucocorticoids are first-line for both warm and cold AIHA equally
B. No — cold AIHA is managed with supportive measures, avoidance of triggers (cold exposure), and treatment of any underlying disease; it is not glucocorticoid-responsive in the same way as warm AIHA
C. Yes, but only if the dose is doubled compared to warm AIHA dosing
D. No, because no treatment exists for cold AIHA under any circumstance
E. Yes, since IgM-mediated disease always responds better to steroids than IgG-mediated disease

Reveal Answer

Correct answer: B

Cold AIHA management centers on supportive measures, avoidance of triggers (particularly cold exposure), and management of any underlying disease — it does not share warm AIHA's strong glucocorticoid responsiveness, making high-dose steroids an inappropriate first-line choice here.

Why the others are wrong A — the two subtypes have different first-line management approaches; glucocorticoids are specifically warm AIHA's treatment. C — simply increasing the steroid dose doesn't address the underlying lack of steroid responsiveness in cold AIHA. D — supportive treatment options do exist for cold AIHA (trigger avoidance, underlying disease management); it's not untreatable. E — this is factually incorrect; IgM-mediated (cold) disease is specifically the one that does NOT respond well to steroids, opposite to this statement.

Exam Pearl Cold ≠ steroids. Cold agglutinin disease (IgM) management = supportive care + trigger/cold avoidance + underlying disease treatment. Warm AIHA (IgG) = the one that gets glucocorticoids.

Q9Drug-Induced Immune Hemolytic Anemia●●●● Very Hard

A 68-year-old man on a new medication for the past several weeks develops gradually progressive fatigue and is found to have hemolytic anemia with a positive DAT. What is the most appropriate management approach?

A. Continue the medication and add glucocorticoids as the primary intervention
B. Identify and remove the offending medication, consistent with the typically gradual progression and positive DAT seen in drug-induced immune hemolytic anemia
C. Immediate plasma exchange is the first-line treatment
D. No specific management is needed since drug-induced hemolysis always resolves on its own regardless of continued drug exposure
E. Splenectomy is the first-line treatment

Reveal Answer

Correct answer: B

Drug-induced immune hemolytic anemia typically shows a gradual progression and a positive DAT, matching this patient's presentation. The core treatment is removal of the offending agent.

Why the others are wrong A — continuing the offending medication works against resolution; removal is the key step, not simply adding steroids while continuing the drug. C — plasma exchange is the TTP treatment, not the first-line approach for drug-induced immune hemolytic anemia. D — continued exposure to the offending drug would be expected to perpetuate the hemolysis; removal is specifically required. E — splenectomy isn't the described first-line treatment for this condition.

Exam Pearl Drug-induced immune hemolytic anemia: gradual onset + positive DAT + treatment = remove the offending drug. A relatively simple, single-intervention answer once the diagnosis is recognized.

Q10MAHA — Mechanical Cause●●●○ Hard

A 70-year-old woman with a recently placed left ventricular assist device (LVAD) develops anemia with schistocytes on peripheral smear. What is the most likely underlying mechanism?

A. Autoimmune destruction via antiplatelet antibodies
B. Microangiopathic hemolytic anemia from mechanical trauma related to the endovascular device
C. G6PD deficiency triggered by the device itself
D. Cold agglutinin disease provoked by the device
E. This finding is unrelated to the LVAD and should be attributed to an unrelated cause

Reveal Answer

Correct answer: B

Microangiopathic hemolytic anemia (MAHA) can be caused by trauma from an endovascular device (such as an LVAD or mechanical heart valve) — the mechanical shear stress damages RBCs as they pass through the device, producing schistocytes.

Why the others are wrong A — antiplatelet antibodies describe ITP's pathogenesis, not this mechanical RBC destruction process. C — G6PD deficiency is an enzymatic/oxidative stress-related condition, not device-triggered. D — cold agglutinin disease is IgM-antibody-mediated and temperature-triggered, unrelated to device trauma. E — the temporal relationship (recent device placement) and classic mechanism (mechanical trauma) make the LVAD the most likely explanation, not an unrelated coincidence.

Exam Pearl Endovascular devices (mechanical valves, LVADs) → mechanical MAHA → schistocytes. Recognize device-related trauma as a specific, classic cause of intravascular hemolysis distinct from TMAs like TTP/HUS.

Q11TTP — DAT-Negative Trap●●●●● Extreme

A 33-year-old woman presents with fever, confusion, thrombocytopenia, acute kidney injury, and schistocytes on peripheral smear. Direct Coombs testing returns negative. A colleague suggests this makes TTP unlikely, favoring an autoimmune process instead. Is this reasoning correct?

A. Yes, TTP always shows a positive DAT
B. No — TTP is classically DAT-negative (a nonimmune, mechanical process), so a negative DAT is actually consistent with, not against, this diagnosis
C. Yes, a negative DAT excludes all forms of hemolytic anemia
D. No, because DAT results are irrelevant to any hemolytic process
E. Yes, but only in patients under age 40

Reveal Answer

Correct answer: B

TTP's characteristic investigation findings include schistocytes, negative DAT, and normal coagulation studies. A negative DAT is expected and consistent with TTP (a nonimmune, mechanical microangiopathic process), not evidence against it. Her overall picture (fever, confusion, thrombocytopenia, AKI, schistocytes) fits the TTP pentad well.

Why the others are wrong A — this is the opposite of the correct fact; TTP is specifically DAT-negative. C — a negative DAT specifically excludes immune-mediated causes (like AIHA), not all hemolytic anemia broadly — nonimmune causes like TTP remain very much on the table. D — DAT results are highly relevant and specifically used to differentiate immune from nonimmune hemolysis. E — this DAT relationship isn't age-restricted.

Exam Pearl TTP = DAT-negative. Don't let a negative Coombs talk you out of TTP — it's expected. The DAT specifically helps separate immune (AIHA, DAT+) from nonimmune (TTP, HUS, MAHA — DAT−) hemolysis.

Q12TTP — Emergent Treatment●●●●● Extreme

A 29-year-old woman presents with the classic TTP pentad: fever, thrombocytopenia, MAHA, renal injury, and neurologic dysfunction. Labs confirm schistocytes and a negative DAT. What is the most appropriate immediate management?

A. Await hematology consultation over the next 24–48 hours before initiating any treatment
B. Begin plasma exchange and glucocorticoids immediately
C. Platelet transfusion as the primary and sole intervention
D. Broad-spectrum antibiotics as first-line therapy
E. Observation only, since TTP typically resolves spontaneously

Reveal Answer

Correct answer: B

TTP is a hematologic emergency: plasma exchange and glucocorticoids should begin immediately once suspected/confirmed, given the high mortality risk without prompt treatment.

Why the others are wrong A — delaying treatment for 24–48 hours risks significant morbidity/mortality in this emergency; treatment should not be delayed. C — platelet transfusion is generally avoided/used cautiously in TTP (can worsen microthrombosis) and is not the primary described intervention; plasma exchange is. D — antibiotics are not the first-line treatment for TTP itself. E — TTP does not reliably resolve spontaneously and requires urgent treatment; observation alone is dangerous.

Exam Pearl TTP = medical emergency → immediate plasma exchange + glucocorticoids. Don't delay for additional workup once the diagnosis is suspected with a compatible clinical picture.

Q13HUS — Prodrome Timing●●●● Very Hard

A 4-year-old boy had abdominal pain and bloody diarrhea 7 days ago after eating undercooked ground beef at a family barbecue. He now presents with pallor, decreased urine output, and petechiae. Labs show anemia with schistocytes, thrombocytopenia, and elevated creatinine. What is the most likely diagnosis and its underlying cause?

A. TTP unrelated to his recent gastrointestinal illness
B. Hemolytic uremic syndrome from Shiga toxin–producing E. coli (STEC), with the GI prodrome preceding the MAHA/AKI/thrombocytopenia by the classic 5–10 day interval
C. ITP, given the presence of thrombocytopenia
D. Cold agglutinin disease provoked by the barbecue
E. This presentation is inconsistent with any recognized foodborne-associated hematologic syndrome

Reveal Answer

Correct answer: B

This is the classic STEC-associated HUS presentation: inadequately cooked ground beef exposure, a prodrome of abdominal pain with diarrhea, followed by MAHA, acute kidney injury, and thrombocytopenia occurring 5–10 days later — his 7-day interval fits perfectly. HUS mainly affects children, also matching his age.

Why the others are wrong A — the temporal relationship and classic GI-prodrome-to-MAHA timeline strongly link this to his recent illness, not an unrelated TTP process (which also doesn't have this classic dietary/prodrome association). C — ITP doesn't explain his schistocytes, renal injury, or the antecedent diarrheal illness pattern. D — cold agglutinin disease isn't linked to ground beef exposure or this GI prodrome pattern. E — this is precisely the classic, well-recognized STEC-HUS pattern.

Exam Pearl STEC-HUS timeline: diarrheal prodrome (undercooked ground beef) → MAHA/AKI/thrombocytopenia 5–10 days later, mainly affecting children. This dietary/timing combination is a classic board setup.

Q14HUS — Antibiotic Contraindication●●●●● Extreme

The same 4-year-old boy with confirmed STEC-associated HUS is being managed in the hospital. A resident suggests starting antibiotics to treat the underlying E. coli infection. What is the most appropriate response?

A. Agree — antibiotics should be started immediately to eradicate the E. coli
B. Disagree — antibiotics are NOT recommended in STEC-associated HUS; management is supportive care with continued evaluation of renal function
C. Agree, but only if the antibiotic is a fluoroquinolone specifically
D. Disagree, because no infectious cause is actually present in HUS
E. Agree, since antibiotics are always indicated in any diarrheal illness

Reveal Answer

Correct answer: B

In STEC-associated HUS, antibiotics are specifically NOT recommended. Management is supportive care with continued evaluation of renal function. Treating the underlying E. coli with antibiotics is a recognized concern because it may increase Shiga toxin release, potentially worsening the clinical course.

Why the others are wrong A/C/E — all incorrectly advocate for antibiotic use, which is specifically avoided in this condition regardless of antibiotic class or the general instinct to treat diarrheal illness with antibiotics. D — an infectious trigger (STEC) is indeed present and identified; the reasoning for avoiding antibiotics isn't that infection is absent, but that treating it can worsen toxin-mediated disease.

Exam Pearl STEC-HUS: antibiotics NOT recommended. This is one of the classic "don't treat the obvious infection" exceptions in medicine — a favorite, easily-tested board fact.

Q15G6PD Deficiency — Testing Pitfall●●●●● Extreme

A 19-year-old man develops acute hemolysis after eating fava beans. G6PD enzyme activity is tested during the acute episode and returns normal. His physician concludes G6PD deficiency is excluded. Is this conclusion appropriate?

A. Yes, a normal G6PD level during acute hemolysis definitively excludes the diagnosis
B. No — false-negative results can occur during acute hemolysis because the most severely deficient (oldest) cells have already been destroyed; testing should be repeated 3 months after the episode resolves
C. Yes, because G6PD levels are unaffected by the timing of testing relative to hemolysis
D. No, because G6PD deficiency cannot be triggered by fava beans
E. Yes, and no further testing would ever be indicated regardless of clinical suspicion

Reveal Answer

Correct answer: B

G6PD enzyme activity testing can produce false-negative results when performed during acute hemolysis, because the most severely G6PD-deficient (typically older) RBCs have already been destroyed, leaving a population of younger cells with relatively preserved enzyme activity that masks the true deficiency. Testing should be repeated 3 months after the hemolytic episode has resolved to obtain an accurate result.

Why the others are wrong A — this is exactly the false-negative pitfall being tested; a normal level during acute hemolysis does not reliably exclude the diagnosis. C — timing relative to the hemolytic episode specifically and significantly affects test accuracy. D — fava beans (favism) are the classic specific dietary trigger for G6PD-deficient hemolysis; his clinical scenario is a textbook example of this trigger. E — given his classic presentation and the false-negative pitfall, repeat testing later is specifically indicated, not abandoned.

Exam Pearl G6PD testing during acute hemolysis can be falsely negative — repeat testing 3 months after resolution for an accurate result. Also remember: fava beans are the specific food to avoid in G6PD deficiency (favism).