Rheumatic Fever
Background
Acute rheumatic fever (ARF) is an autoimmune inflammatory process that develops as a sequela of streptococcal infection. ARF has extremely variable manifestations and remains a clinical syndrome for which no specific diagnostic test exists. Persons who have experienced an episode of ARF are predisposed to recurrence following subsequent (rheumatogenic) group A streptococcal infections. The most significant complication of ARF is rheumatic heart disease, which usually occurs after repeated bouts of acute illness.
Pathophysiology
ARF is characterized by nonsuppurative inflammatory lesions of the joints, heart, subcutaneous tissue, and central nervous system. An extensive literature search has shown that, at least in developed countries, rheumatic fever follows pharyngeal infection with rheumatogenic group A streptococci. The risk of developing rheumatic fever after an episode of streptococcal pharyngitis has been estimated at 0.3-3%. More recent investigations of rheumatic fever occurring in the aboriginal populations of Australia suggest that streptococcal skin infections might also be associated with the development of rheumatic fever. In Oceania and Hawaii, streptococcal strains that are not typically associated with rheumatic fever have been found to cause the disease.
Molecular mimicry accounts for the tissue injury that occurs in rheumatic fever. Both the humoral and cellular host defenses of a genetically vulnerable host are involved. In this process, the patient’s immune responses (both B- and T-cell mediated) are unable to distinguish between the invading microbe and certain host tissues.The resultant inflammation may persist well beyond the acute infection and produces the protean manifestations of rheumatic fever.
Frequency
United States
The incidence of ARF has declined markedly in the past 50 years in both the United States and Western Europe. Most Western physicians see only the late sequelae of rheumatic heart disease; the diagnosis of an acute case is usually reason enough for a ground rounds presentation. This remarkable decline of rheumatic fever likely reflects improved socioeconomic conditions, as well the decline in prevalence of the classically described rheumatogenic strains of group A streptococci.
Following two decades of almost total absence, a resurgence of ARF occurred in the 1980s among middle-class white children in Salt Lake City, Utah. Clusters were also reported in US Army and Navy training camps during the same period. These limited outbreaks were associated with mucoid rheumatogenic strains that were rarely seen in the preceding 20 years. Today, ARF remains a rarity in most of the United States, although Hawaii and American Samoa continue to see a significant number of cases, many of which are caused by streptococcal strains not usually associated with rheumatic fever in persons of Polynesian descent. Read more »
Tags: abdominal, aboriginal populations, acute case, acute illness, acute infection, acute rheumatic fever, adolescence, age, and, appearance, area, ARF, arthralgia, arthritis, attention, auscultation, bout, brain, breath, Carditis, Carey, central nervous system, Characteristic, chest, CHF, chorea, Clinical, cohort, Coombs, cough, damage, death, decrescendo, development, diagnosis, disability, disease, due, dyspnea, echocardiography, effusion, endocardium, enlargement, eruption, Erythema, Europe, evidence, evolution, exertion, failure, fair, family, featu, fever, flow, form, friction, ganglioside, gonococcal, group a streptococci, Hand, heart, history, host defenses, host tissues, incidence, infection, inflammation, inflammatory lesions, inflammatory process, involvement, Isolated, Jaccoud, Joint, laboratory, likelihood, literature search, locale, malaise, manifestation, marginatum, migratory, mimicry, mitral, murmur, Murmurs, myocardium, New Zealand, nocturnal, orthopnea, pain, patient, pattern, periarticular, pericardial, pericardium, pharyngitis, Physical, Polyarthritis, poststreptococcal, potential, predilection, predisposition, prevention, problem, process, puberty, rate, recall, Recurrent, regurgitation, Rheumatic, rheumatic heart disease, risk, rub, sequela, Severe, Sex, Sore, spine, streptococcal, streptococcal infections, streptococcal skin infections, streptococcal strains, Subcutaneous, subside, Sydenham, syndrome, tenderness, Tenosynovitis, throat, trunk, United States, valvular, variable manifestations, warmth, week, western physicians
Posted in medicalmatrix | February 13, 2010 | 
Comments (0)