Medicine -other -acute inflammatory pericarditis Acute Pericarditis Acute pericarditis, by far the most common pathologic process involving the pericardium, may be classified both clinically and etiologically. Pain, a pericardial friction rub, electrocardiographic changes, and pericardial effusion with cardiac tamponade and paradoxical pulse are cardinal manifestations of many forms of acute pericarditis. Table 1 Classification of Pericarditis CLINICAL CLASSIFICATION I. Acute pericarditis (6 months) A. Constrictive B. Effusive C. Adhesive (nonconstrictive) ETIOLOGIC CLASSIFICATION I. Infectious pericarditis A. Viral (coxsackievirus A and B, echovirus, mumps, adenovirus, hepatitis, HIV) B. Pyogenic (pneumococcus, streptococcus, staphylococcus, _Neisseria,__ Legionella_) C. Tuberculous D. Fungal (histoplasmosis, coccidioidomycosis, _Candida,_ blastomycosis) E. Other infections (syphilitic, protozoal, parasitic) II. Noninfectious pericarditis A. Acute myocardial infarction B. Uremia C. Neoplasia 1. Primary tumors (benign or malignant, mesothelioma) 2. Tumors metastatic to pericardium (lung and breast cancer, lymphoma, leukemia) D. Myxedema E. Cholesterol F. Chylopericardium G. Trauma 1. Penetrating chest wall 2. Nonpenetrating H. Aortic dissection (with leakage into pericardial sac) I. Postirradiation J. Familial Mediterranean fever K. Familial pericarditis 1. Mulibrey nanism_a_ L. Acute idiopathic M. Whipples disease N. Sarcoidosis III. Pericarditis presumably related to hypersensitivity or autoimmunity A. Rheumatic fever B. Collagen vascular disease (SLE, rheumatoid arthritis, ankylosing spondylitis, scleroderma, acute rheumatic fever, Wegeners granulomatosis) C. Drug-induced (e.g., procainamide, hydralazine, phenytoin, isoniazide, minoxidil, anticoagulants, methysergide) D. Postcardiac injury 1. Postmyocardial infarction (Dresslers syndrome) 2. Postpericardiotomy 3. Posttraumatic An autosomal recessive syndrome, characterized by growth failure, muscle hypotonia, hepatomegaly, ocular changes, enlarged cerebral ventricles, mental retardation, ventricular hypertrophy, and chronic constrictive pericarditis. _Chest pain_ is an important but not invariable symptom in various forms of acute pericarditis ; it is usually present in the acute infectious types and in many of the forms presumed to be related to hypersensitivity or autoimmunity. Pain is often absent in slowly developing tuberculous, postirradiation, neoplastic, or uremic pericarditis. The pain of acute pericarditis is often severe, retrosternal and left precordial, and referred to the neck, arms, or the left shoulder. Often the pain is pleuritic, consequent to accompanying pleural inflammation, i.e., sharp and aggravated by inspiration, coughing, and changes in body position, but sometimes it is a steady, constricting pain that radiates into either arm or both arms and resembles that of myocardial ischemia; therefore, confusion with acute myocardial infarction (AMI) is common. Characteristically, however, pericardial pain may be relieved by sitting up and leaning forward and is intensified by lying supine. The differentiation of AMI from acute pericarditis becomes perplexing when, with acute pericarditis, serum biomarkers of myocardial damage such as creatine kinase and troponin rise, presumably because of concomitant involvement of the epicardium in the inflammatory process (an epi-myocarditis) with resulting myocyte necrosis. However, these elevations, if they occur, are quite modest, given the extensive electrocardiographic ST-segment elevation in pericarditis. This dissociation is useful in the differentiation between these conditions. The _pericardial friction rub,_ audible in about 85% of patients, may have up to three components per cardiac cycle, is high-pitched, and is described as rasping, scratching, or grating; it can be elicited sometimes only when the diaphragm of the stethoscope is applied firmly to the chest wall at the left lower sternal border. It is heard most frequently at end-expiration with the patient upright and leaning forward. The rub is often inconstant, and the loud to-and-fro leathery sound may disappear within a few hours, possibly to reappear on the following day. A pericardial rub is heard throughout the respiratory cycle, while a pleural rub disappears when respiration is suspended. The _electrocardiogram_ (ECG) in acute pericarditis without massive effusion usually displays changes secondary to acute subepicardial inflammation. It typically evolves through four stages. In stage 1, there is widespread elevation of the ST segments, often with upward concavity, involving two or three standard limb leads and V2 to V6, with reciprocal depressions only in aVR and sometimes V1, as well as PR-segment depression. Usually there are no significant changes in QRS complexes. In stage 2, after several days, the ST segments return to normal, and only then, or even later, do the T waves become inverted (stage 3). Ultimately, weeks or months after the onset of acute pericarditis, the ECG returns to normal in stage 4. In contrast, in AMI, ST elevations are convex, and reciprocal depression is usually more prominent; QRS changes occur, particularly the development of Q waves, as well as notching and loss of R-wave amplitude; and T-wave inversions are usually seen within hours _before_ the ST segments have become isoelectric. Sequential ECGs are useful in distinguishing acute pericarditis from AMI. In the latter, elevated ST segments return to normal within hours. Figure 2 ACUTE PERICARDITIS OFTEN PRODUCES DIFFUSE ST-SEGMENT ELEVATIONS (in this case in leads I, II, aVF, and V2 to V6) due to a ventricular current of injury. Note also the characteristic PR-segment deviation (opposite in polarity to the ST segment) due to a concomitant atrial injury current. Early repolarization is a normal variant and may also be associated with widespread ST-segment elevation, most prominent in left precordial leads. However, in this condition the T waves are usually tall and the ST/T ratio is To see complete article click this link- mbbsdost/fbapp/index.php?mno=1148
Posted on: Sat, 19 Oct 2013 14:30:03 +0000
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