Infectious diseases (sepsis, endocarditis) — MCQs

A 42-year-old IV drug user with known HIV (CD4 count 85 cells/mm³, not on antiretroviral therapy) presents with fever and a new heart murmur. Blood cultures grow Candida albicans. Transesophageal echocardiogram shows a 20 mm vegetation on the tricuspid valve with moderate regurgitation but no heart failure. He is treated with micafungin and shows clinical improvement after 1 week. Evaluate the definitive management strategy for this patient.

A 72-year-old man with severe sepsis from pneumonia is started on norepinephrine and broad-spectrum antibiotics. After 12 hours, his blood pressure is 90/55 mmHg on norepinephrine 0.4 mcg/kg/min, heart rate 95/min, and lactate has decreased from 4.5 to 2.8 mmol/L. Random cortisol level is 18 mcg/dL. He has a history of COPD on chronic prednisone 10 mg daily. Evaluate the role of corticosteroid therapy in this patient.

A 35-year-old woman with a history of mitral valve prolapse presents with fever, Osler nodes, and Janeway lesions. Three sets of blood cultures grow Haemophilus parainfluenzae. Transesophageal echocardiogram shows a 15 mm vegetation on the mitral valve with severe regurgitation and mild left ventricular dysfunction. She develops sudden left-sided weakness and CT head shows an acute ischemic stroke in the right MCA territory. Evaluate the optimal timing and approach to management.

A 48-year-old man with prosthetic mitral valve develops fever and back pain 6 weeks after valve replacement. Blood cultures grow Enterococcus faecalis. MRI of the spine shows diskitis at L3-L4 with epidural abscess. Transesophageal echocardiogram reveals perivalvular abscess with moderate dehiscence of the prosthetic valve. He is neurologically intact but has progressive heart failure. Analyze the optimal management strategy.

A 55-year-old woman with diabetes mellitus presents to the ICU with septic shock secondary to pyelonephritis. Despite 4 liters of crystalloid resuscitation over 2 hours, her blood pressure remains 82/50 mmHg, heart rate 125/min, and lactate 5.1 mmol/L. Central venous pressure is 10 mmHg. Analyze the most appropriate next step in management.

A 70-year-old man with aortic stenosis undergoes dental extraction. He develops fever and malaise 2 weeks later. Blood cultures grow Streptococcus gallolyticus (S. bovis). Transesophageal echocardiogram confirms aortic valve endocarditis with a 10 mm vegetation. After initiating appropriate antibiotic therapy, what additional evaluation is most important?

A 38-year-old IV drug user presents with fever, cough, and pleuritic chest pain. Physical examination reveals a new systolic murmur at the left lower sternal border. Chest X-ray shows multiple peripheral nodular infiltrates. Blood cultures are pending. Based on the clinical presentation, apply the most likely diagnosis and empiric treatment.

A 58-year-old man with a prosthetic aortic valve develops fever 8 months after valve replacement. Blood cultures grow Staphylococcus epidermidis resistant to methicillin. Transesophageal echocardiogram shows a 6 mm vegetation on the prosthetic valve with no evidence of abscess or dehiscence. He is hemodynamically stable. Apply the appropriate treatment strategy for this patient.

A 62-year-old woman with a history of rheumatic heart disease presents with fever, night sweats, and fatigue for 3 weeks. Physical examination reveals a new heart murmur and splinter hemorrhages under her fingernails. Blood cultures grow viridans group streptococci. Transthoracic echocardiogram shows a 12 mm vegetation on the mitral valve with moderate regurgitation. What is the most appropriate antibiotic regimen?

A 45-year-old man presents to the emergency department with fever, chills, and confusion for 2 days. Vital signs show temperature 39.2°C (102.6°F), heart rate 118/min, blood pressure 88/54 mmHg, and respiratory rate 28/min. Laboratory studies show WBC 18,000/mm³, lactate 4.2 mmol/L, and creatinine 2.1 mg/dL (baseline 0.9 mg/dL). Blood cultures are drawn. What is the most appropriate initial management?