MI3.1-9 | Bloodstream & Cardiovascular Infections — Practice Quiz

A 14-year-old boy presents with fever, migratory polyarthritis, and a new pansystolic murmur 3 weeks after a sore throat. His antistreptolysin O (ASO) titre is 400 IU/mL (normal <200). Anti-DNase B titre is also elevated. Which mechanism best explains his cardiac injury?

A patient with rheumatic fever is evaluated using the Jones Criteria. Which of the following combinations satisfies the diagnostic requirement for a first episode?

In a patient with suspected rheumatic fever presenting 4 weeks after a sore throat, the ASO titre is 180 IU/mL (borderline). What is the most appropriate next step to strengthen evidence of prior GABHS infection?

A 45-year-old with a prosthetic aortic valve develops fever and rigors. Three blood cultures drawn from separate venepuncture sites over 24 hours all grow Staphylococcus aureus. Echocardiography shows a perivalvular abscess. According to Duke's criteria, what is the diagnosis?

During blood culture collection for suspected infective endocarditis, the nurse draws all three sets from a single arm vein over 10 minutes, with the patient afebrile at the time. Which statement best evaluates the adequacy of this collection?

A 28-year-old traveller returns from Bihar with 10 days of fever. He has a temperature of 39.5°C, pulse 72 bpm, and rose spots on his trunk. Which laboratory test has the highest sensitivity at this stage of enteric fever?

A Widal test performed on a patient from Chennai with 5 days of fever shows O agglutinin titre 1:80 and H agglutinin titre 1:160. The patient denies prior typhoid vaccination. How should these results be interpreted?

A 32-year-old woman from Kerala presents with 3 weeks of fever, mild jaundice, and mild anaemia (Hb 9.5 g/dL). Peripheral blood smear shows ring-form trophozoites in erythrocytes, some with multiple rings per cell. Urinalysis reveals haemoglobinuria. Which mechanism of anaemia is operating here?

A 25-year-old patient with sickle cell disease develops an acute aplastic crisis with sudden drop in haemoglobin from 8 to 3 g/dL and reticulocyte count near zero. No new Plasmodium infection is found. Which pathogen is most likely responsible?

A 50-year-old man with cryptogenic cirrhosis presents with fever 38.3°C for 3 weeks. Multiple investigations including routine blood cultures, chest X-ray, urine culture, abdominal ultrasound, and anti-malarial smear are all negative after 7 days of thorough inpatient workup. Which category of PUO does this represent?