Thu18November0303AM 9

With respect to a patient with possible infective endocarditis:

True / False

A history of intravenous drug abuse is a risk factor Correct

MRI scanning is the best modality to confirm the diagnosis Correct

If the patient is afebrile the diagnosis is unlikely Incorrect answer selected

Two positive blood cultures 12 hours apart is a major criterion Correct

The most likely causative organism is streptococcus or staphylococcus Correct

Explanation

Infective endocarditis (IE) is a systemic life-threatening disease mainly affecting patients with heart valve disease, prosthetic valve, intracardiac devices and intravenous drug abusers.

The majority of cases of IE are caused by gram-positive bacteria. Staphylococcus aureus is now more common than oral Streptococci and it has become the most frequent microorganism causing IE (31-54%).

Stigmata of IE such as Osler's nodes (3%) or Janeway lesions (5%) are uncommon, and physical examination is often normal. A history of weight loss and chills is frequently described (up to 96% of cases); a new or a different heart murmur (48% and 20%, respectively) and elevated C-reactive protein are also common findings. Peripheral embolism is common. In up to 30% of patients, embolic events usually present before clinical recognition of the disease (renal, spleen, heart, brain and intestine).

Major criteria for the diagnosis of IE include positive blood cultures and a positive echocardiogram (oscillating intracardiac mass, intracardiac abscess or a new dehiscence of intracardiac prosthetic valve).

Transoesophageal echocardiography is the imaging modality of choice in all patients with suspected or confirmed IE.

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Average score: 78.32%

Times answered: 238