Medical Microbiology and Infection

at a Glance

Fourth EditionStephen Gillespie and Kathleen Bamford

Case Studies

Case 15

A 26-year-old man presented to the A&E department of a large city hospital. He complained that he felt weak and unwell, 'as if I have "flu", and had been getting worse over the last few days. The patient admitted taking illicit drugs intravenously, and this was confirmed on examination with evidence of multiple puncture marks. He was hot to the touch and his skin appeared clammy. His temperature was 38.5 °C and his pulse was 108, with a blood pressure of 90/50 mmHg. His jugular venous pressure (JVP) was elevated and pulsatile. Careful examination of the skin revealed bluish-purple patches.

  • 1. What do you think is the likely diagnosis?

    This is a typical story of a patient with infective endocarditis. The severity and speed of presentation is acute, so care must be taken with management.

  • 2. Why is the JVP pulsatile?

    This is because the tricuspid valve is diseased and is incompetent.

  • 3. Where is the infection likely to be located?

    See answer 2. You should confirm this clinical diagnosis with an echocardiogram.

  • 4. What is the most likely organism that could be present?

    His clinical history indicates that he injects himself and is therefore at risk of infection of his heart valves if his sterile technique fails. With the acute presentation and the history of intravenous substance misuse, one naturally thinks of organisms found on the skin and injected. Staphylococcus aureus would cause this sort of picture and would be the number one diagnosis.

  • 5. List the investigations that are necessary.

    At least two sets of blood cultures, urea and electrolytes (to monitor renal function), full blood count and C-reactive protein (this may help monitor progression). Echocardiogram including views of the aortic root where abscesses may form. Other investigations may be carried out to detect other infectious risks associated with intravenous drug use, e.g. hepatitis B, hepatitis C and HIV.

  • 6. What should your initial treatment be?

    Flucloxacillin and gentamicin.

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