Infective endocarditis

Published on 02/04/2015 by admin

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Last modified 02/04/2015

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17 Infective endocarditis

Instruction

This patient is suspected to have endocarditis; would you like to examine him?

Salient features

History

• Fever, malaise, anorexia, weight loss, rigors: non-specific symptoms of inflammation

• Progressive heart failure: caused by valve destruction (can be dramatic)

• Stroke, pulseless limb, renal infarct, pulmonary infarct: caused by embolization of vegetations

• Arthralgia, loin pain: caused by immune-complex deposition

• Obtain a history of recent dental procedures

• History of valvular heart disease, history of IV drug abuse

Examination

• Look for the following signs:

• Clubbing (seen in 20% of the cases)

• Splinter haemorrhages in the nails (vasculitic phenomenon; probably caused by embolic phenomena in the nail bed) (Fig. 17.1)

• Osler’s nodes (vasculitic phenomenon): tender, erythematous, pea-sized nodules seen in the pulp of the fingers caused by inflammation around the site of the infected emboli lodged in distal arterioles (Fig. 17.2)

• Janeway lesions (vasculitic phenomenon): flat, non-tender red spots found on the palms and soles; they blanch on pressure)

• Petechiae: conjunctiva, palate and skin

• Digital infarcts

• Maculopapular rash.

• Record the temperature.

• Listen to the heart for murmurs and look for signs of cardiac failure.

• Examine the fundus for Roth’s spots (vasculitic phenomena).

• Examine the abdomen for splenomegaly.

• Look for embolic phenomena: stroke, viscera or occlusion of peripheral arteries.

• Test urine for microscopic haematuria (vasculitic phenomena).

• Remember that ostium secundum atrial septal defects almost never have infective endocarditis.

Fig. 17.1 Splinter haemorrhages: parallel streaks in the distal third of the finger.

Fig. 17.2 Osler’s nodes.

(With permission from Goldman L, Ausiello DA 2007.)

Diagnosis

This patient has Janeway lesions and Roth’s spots (lesions), confirming infective endocarditis, and is in severe heart failure (functional status).

Questions

How would you investigate such a patient?

• Test the urine for microscopic haematuria.

• Take a FBC to show normocytic, normochromic anaemia and raised white cell count.

• Test for raised erythrocyte sedimentation rate (ESR).

• Blood culture: take three samples from different sites in 24 h. It is the most important test for diagnosing endocarditis and cultures are negative in >50% of cases of fungal aetiology.

• Transthoracic echocardiography may show vegetations. A negative study does not rule out endocarditis as vegetations <3–4 mm in size cannot be detected. Furthermore, all the leaflets of the aortic, tricuspid and pulmonary valves may not be visualized in every patient. Transoesophageal echocardiography is usually indicated in infective endocarditis.

What are the major categories of infective endocarditis?

Infective endocarditis can be classified as:

• native-valve infective endocarditis

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