Final answer:
Recommended prophylaxis for a patient with signs of acute rheumatic fever includes long-term antibiotic therapy, typically with benzathine penicillin G intramuscularly every four weeks to prevent recurrent attacks and protect against rheumatic heart disease.
Step-by-step explanation:
The recommended prophylaxis for a patient presenting with fever, polyarthralgia, a new early diastolic murmur, and positive antistreptolysin O (indicative of a recent streptococcal infection) is long-term antibiotic prophylaxis to prevent recurrent attacks of acute rheumatic fever (ARF) and progression to rheumatic heart disease (RHD). As per guidelines, penicillin is often the antibiotic of choice due to its efficacy in preventing streptococcal infections.
Acute rheumatic fever is an immune-mediated inflammatory disease that can occur following an untreated or inadequately treated infection caused by Streptococcus pyogenes. Joint pain, fever, and heart valve damage characterized by murmurs are common features of ARF. In patients with a known history of ARF, prophylactic antibiotics are crucial to prevent recurrences, which could lead to worsening cardiac damage such as RHD.
For this patient, without known drug allergies, benzathine penicillin G intramuscularly every four weeks is typically recommended. If the patient is allergic to penicillin, alternatives like erythromycin or azithromycin may be considered. The key is immediate treatment and adherence to long-term prophylaxis to prevent further damage, particularly to the heart valves.