<prompt> Which is the clinical type of acute pericarditis?SerousFibrinousCaseousPurulent  <response>: Ans. is b i.e., Fibrinous Classification of pericarditisClinical classificationI. Acute pericarditis 6 weeksa Fibrinousb Effusive serous or sanguineousII. Subacute pericarditis 6 weeks to 6 monthsa Effusinve-constrictiveb ConstrictiveIII Chronic pericarditis 6 monthsa Constrictiveb Effusivec Adhesive nonconstrictive Serous pericarditis is characteristically produced by non- infectious inflammatory diseases, including rheumatic fever, SLE, and scleroderma, as well as tumors and uremia. An infection in the tissues contiguous to the pericardium-- for example, a bacterial pleuritis--may incite sufficient irritation of the parietal pericardial serosa to cause a sterile serous effusion that can progress to serofibrinous pericarditis and ultimately to a frank suppurative reaction. Fibrinous and serofibrinous pericarditis are the most frequent types ofpericarditis; these are composed of serous fluid variably admixed with a fibrinous exudate. Common causes include acute MI, postinfarction Dressier syndrome an autoimmune response appearing days-weeks after an MI, uremia, chest radiation, rheumatic fever, SLE, and trauma. A fibrinous reaction also follows routine cardiac surgery. Purulent or suppurative pericarditis reflects an active infection caused by microbial invasion of the pericardial space. Hemorrhagic pericarditis has an exudate composed of blood mixed with a fibrinous or suppurative effusion; it is most commonly caused by the spread of a malignant neoplasm to the pericardial space. Caseous pericarditis is, until proved otherwise, tuber- culous in origin; infrequently, fungal infections evoke a similar reaction. 