Infectious diseases of the cardiovascular system

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Infective endocarditis can be fatal if not treated. Acute or chronic, mostly bacterial in origin, though fungal infections are becoming more common. Comes about due to bacteraemia- septicaemia is bactaeremia with system-wide inflammatory response. Usually an abnormal endothelial surface allows the bacteria to attach and grow, such as a prosthetic valve or abnormalities in native valves. Organisms can enter from oral cavity, especially if there is poor dental hygeine or when dental work has taken place. Can also enter from skin. Often occurs without any significant consequences and resolves naturally.
Heart or valve defects predispose to IE. Abnormalities lead to turbulent flow, deposition of platelets and fibrin to form large, macroscopic vegetations. Deposition provides a site for bacteria to adhere, somewhere to hide from the immune system, and for nutrients to grow. Systemic unwellness, fever, murmur, skin lesions such as Janeway lesions and Osler's nodes and haematuria are all signs of IE. There may be a large spleen or symptoms of acute cardiac failure. IE lesions need to be cultured, valvular lesions should also be seen in ECG. High doses of bactericidal antibiotics are usually given for up to six weeks, guided by blood culture results. Surgery may be required if the valve is badly damaged, vegetation is large or the patient is resistant to therapy. Dental prophylaxis may be reccommended for high risk groups or cases of IE.
Myocarditis and pericarditis are inflammation of specific layers of the heart, Coxsackie can cause. Myocarditis can lead to HF or arrythmia, and myocytes or the conductive system can be affected. Pericarditis often presents with pain, fever and friction rub, sometimes with malaise or weight loss. Can be caused by viral Coxsackie, TB or acute bacterial infection, most cases have no attributed cause. Many non-infective causes.
Fever of unknown origin is where the temperature is above 38.3 on several occasions for above 3 weeks and the cause remains unknown despite diagnosis. Infections and malignancies are common causes. Age and immunosuppressed status are important for cause, antibiotics are not commonly used.
Native valve commonly infected with oral strep and enterococci, staph aureus, coagulase-negative staph. IV drug user most likely to have staph aureus, oral strep and enterococci, gram -ve rods
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