Final answer:
The Duke's Major Criteria for the diagnosis of infective endocarditis involves positive blood cultures, echocardiogram evidence, and clinical symptoms like fever. Acute endocarditis requires prompt treatment with antibiotics, whereas subacute endocarditis progresses slowly and can lead to significant valve damage.
Step-by-step explanation:
The Duke's Major Criteria for diagnosing infective endocarditis includes positive blood cultures for infective endocarditis, evidence of endocardial involvement from an echocardiogram, and symptoms such as fever, which may be indicative of the condition. The diagnosis is made by combining these findings with the clinical picture. In the case of acute endocarditis, which can rapidly destroy heart valves leading to death within days, aggressive treatment with high doses of intravenous antibiotics is necessary. Subacute endocarditis, on the other hand, progresses more slowly over months, leading to vegetations on the valves and possibly necessitating valve replacement surgery due to the damage caused. Blood cultures, echocardiograms, and clinical symptoms are fundamental in confirming the diagnosis and differentiating between acute and subacute forms.
For instance, cases of acute endocarditis may present with rapid health deterioration, as seen in the Clinical Focus scenario where a patient shows signs of shock and multiple organ failure despite antibiotic treatment. In subacute cases, symptoms like fever develop more gradually and may include the formation of vegetations, as illustrated in Figure 25.6.