Etiology, Biology

Assignment Help:

M protein of rheumatogenic GAS has distinct structural characteristics that are akin to human heart tissue, particularly sarcolemmal membrane proteins and cardiac myosin. The major factors that lead to risk of ARF are the severity of the immune response to GAS pharyngitis and persistence of GAS organisms during convalescence. A very small proportion (0.3-3 per cent) of patients suffering from GAS throat infection ultimately develop ARF and this along with a familial predisposition of ARF points to a genetic susceptibility. However, in our Indian patients a genetic linkage to HLA DR3 in patients, with ARF has been demonstrated. For confirmation of the initial diagnosis of acute rheumatic fever, evidence of prior GAS infection is required. Several rapid GAS antigen tests are available. Majority of these tests has a high degree of specificity but low level of sensitivity in clinical practice.

However, it must be stressed that a negative test does not rule out the GAS infection in the throat. At the same time in presence of a positive antigen test and positive throat culture, it is difficult to distinguish between a recent infection which can be associated with ARF and chronic carrier of GAS infection with ARF. Elevated or rising ASO titres (> 250Todd units in adults and >333 Todd units in children) are more reliable evidence of recent GAS infection than a positive culture or positive rapid antigen test and such titres are also significant for diagnosis.


Related Discussions:- Etiology

Do all mammals have a placenta, Do all mammals have a placenta? Mammals...

Do all mammals have a placenta? Mammals of the monotreme group (echidnas, platypus,) are oviparous, egg-laying, and they do not have a placenta. Mammals of the marsupial group

Explain about the management of food allergies, Normal 0 false ...

Normal 0 false false false EN-IN X-NONE X-NONE

Explain starch, Starch It is a plant polysaccharide synthesized by  the...

Starch It is a plant polysaccharide synthesized by  the plant by photosynthesis and stored mainly  in  grains,  legumes,  roots  and  tubers.  Its molecular formula is (C 6 H 1

Ecg, Sinus tachycardia is common. ECG abnormalities may reflect the underly...

Sinus tachycardia is common. ECG abnormalities may reflect the underlying coronary artery disease by way of pathological Q-waves, ST-T wave abnormalities. Left ventricular hypertro

What is a membrane, What is a membrane? Membrane is any delicate sheet ...

What is a membrane? Membrane is any delicate sheet that divides one region from another blocking or permitting (selectively or completely) the passage of substances. The skin,

Pathophysiology and medical mangement of acute renal failure, Pathophysiolo...

Pathophysiology of Acute Renal Failure It is usually reversible but the deviation of physiologic function can be extreme and mortality in pediatric age group remains high. Th

Describe the planes of muscles, Describe the Planes of Muscles The plan...

Describe the Planes of Muscles The planes of superior and inferior recti in primary position form an angle of about 23 0 with the Y-axis. Therefore, the axis of rotation of th

Physiological characteristics of molds, Q. Physiological Characteristics of...

Q. Physiological Characteristics of molds? The physiological characteristics of molds will be reviewed only briefly here and will be discussed in more detail subsequently. Mois

Name the three main arthropod classes, How are the three main arthropod cla...

How are the three main arthropod classes characterized according to the body division? In crustaceans and arachnids the head is fused with the thorax forming the cephalothorax.

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd