Mycobacterium Avium-Intracellulare (MAI) will be seen with PCR counts less than 50. There will be weight loss, fatigue, anemia, and fever. The bone marrow will be involved with an increased alkaline phosphatase. The best tests include the liver biopsy or bone marrow biopsy. A blood culture is not very sensitive. It is treated with azithromycin, rifampin, and ethambutol. Prevention is with azithromycin or clarithromycin.
Infective Endocarditis The diagnosis is made by satisfying the Duke criteria (two major and minor criteria). The major criteria include a positive blood culture for Strep viridans, Staph aureus, Strep epidermidis, Enterococci, gramnegative rods, or candida, and having an abnormal echocardiogram suggestive of endocarditis. Minor criteria include fever, risk factors, new murmur, vascular abnormalities (e.g., Janeway lesions), and immunological findings (e.g., Osler nodes and Roth spots). In a patient with fever and new or changing murmur, the next step is to perform two blood cultures. If these are positive, do an echocardiogram. The minor criteria are helpful if the blood cultures are negative. A transthoracic echo is only 60 percent sensitive, yet a TEE (transesophageal echo) is 90-95 percent sensitive and specific for bacterial endocarditis. The most common organisms for culturenegative endocarditis include Bartonella and Coxiella. The best empiric therapy is vancomycin and either gentamicin or ceftriaxone. This will cover for all major organisms, including MRSA. Treat for 4-6 weeks. If anatomic valvular abnormalities, consider valve surgery as antibiotics alone will not treat the infection. Preventive measures/prophylaxis is necessary under only these conditions: • • • • • • •
Unrepaired cyanotic heart disease Prosthetic valves Prior endocarditis Transplant patients with valvular disease Dental work likely to cause bleeding (amoxicillin or clindamycin) Respiratory tract surgery Infected skin surgery
It is not recommended for these conditions: • • • • • • • • •
Dental fillings OB/GYN procedures Urinary tract procedures Flexible endoscopy of any kind Aortic stenosis or regurgitation Pacemaker patients Mitral valve prolapse Mitral stenosis or regurgitation IHSS
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