PA H5 | Hemolytic Anemias — Practice Quiz

Which of the following best distinguishes intravascular haemolysis from extravascular haemolysis?

A 22-year-old man from sub-Saharan Africa presents with sudden pallor, jaundice and dark urine after taking primaquine for malaria prophylaxis. His CBC shows Hb 7.2 g/dL, reticulocytosis, and the peripheral smear reveals bite cells and blister cells. The most likely enzyme deficiency responsible is:

A 35-year-old pregnant woman has a reticulocyte count of 12%, LDH 980 U/L, indirect bilirubin 4.2 mg/dL, undetectable haptoglobin, and haemoglobin 8.1 g/dL. Which single additional test best quantifies the severity of ongoing haemolysis?

A 16-year-old boy with known sickle cell anaemia presents with severe chest pain, fever, tachypnoea and new infiltrates on chest X-ray after an upper respiratory infection. His oxygen saturation drops from 96% to 88% over 6 hours. This presentation is best described as:

A peripheral blood smear from a patient with suspected sickle cell disease shows elongated, crescent-shaped cells with pointed ends. Which confirmatory test is the gold standard for diagnosing HbS?

A 3-year-old child from a Mediterranean family presents with severe anaemia (Hb 5.8 g/dL), hepatosplenomegaly and frontal bossing. Peripheral smear shows target cells, nucleated RBCs, hypochromia and microcytosis. Haemoglobin electrophoresis reveals HbF 85%, HbA2 5%, HbA absent. The most likely diagnosis is:

A 28-year-old woman with a silent carrier state for α-thalassaemia has a partner who is also a silent carrier. On routine obstetric workup, the expected haemoglobin pattern of their child with HbH disease (--/-α) would include:

A 55-year-old woman presents with gradually worsening anaemia, fatigue and dark-coloured urine in cold weather. Her reticulocyte count is 9%, DAT (polyspecific) is positive, and her blood group is O+. Repeat DAT using monospecific antisera is positive for complement (C3d) only, negative for IgG. The blood film shows red cell agglutinates at room temperature that disperse at 37°C. The most likely diagnosis is:

A 30-year-old woman with systemic lupus erythematosus (SLE) develops haemolytic anaemia. Her DAT is positive for IgG. The peripheral smear shows spherocytes. The most appropriate initial treatment is:

A 42-year-old woman presents with acute-onset thrombocytopaenia, microangiopathic haemolytic anaemia (MAHA), fever, renal failure (creatinine 3.8 mg/dL) and neurological symptoms (confusion, transient aphasia). Her ADAMTS13 activity comes back at <10%. The most likely diagnosis and immediate treatment priority is:

A 6-year-old child presents with acute diarrhoea (bloody) caused by Shiga toxin-producing E. coli O157:H7, followed by oliguria, pallor and petechiae. Lab results show: Hb 7.1 g/dL, platelets 28 × 10⁹/L, creatinine 3.2 mg/dL, schistocytes on blood smear, ADAMTS13 activity 85%, and negative stool culture for Salmonella. The most specific finding that confirms MAHA in this case is:

A laboratory profile shows: Hb 9.2 g/dL, reticulocyte count 8%, unconjugated bilirubin 3.6 mg/dL, LDH 610 U/L, haptoglobin undetectable, MCV 102 fL (high), and negative DAT. Which ONE combination of findings is most consistent with a hereditary haemolytic anaemia that is extravascular in pattern and associated with a red cell membrane defect?