ACUTE RHEUMATIC FEVER

[Virtual Presenter] Acute Rheumatic Fever is a serious medical condition characterized by inflammation of the joints, heart, and other parts of the body. It is caused by an abnormal immune response to a streptococcal infection, often triggered by untreated or inadequately treated strep throat..

[Audio] An acute systemic immune-mediated disease that may develop after an infection with a Group A beta-hemolytic Streptococcal infection of the pharynx..

[Audio] The heart is one of the organs that can be affected by acute rheumatic fever. Inflammation of the heart muscle, known as myocarditis, can lead to damage and scarring. This can result in abnormal heart rhythms, heart failure, and even death if left untreated..

[Audio] Acute rheumatic fever typically affects children and young adults between the ages of five and fifteen years, with the peak age of occurrence being eight years old. Interestingly, this condition is more prevalent in low socioeconomic classes. In contrast, it is relatively rare in high-income countries in Western Europe and North America, where the incidence rate is approximately 0.5 cases per 100000 people. On the other hand, acute rheumatic fever is endemic in certain regions such as South Asia, Africa, and South America. Both males and females are affected equally, although women are slightly more prone to developing the condition. Furthermore, the disease is more common in temperate zones, particularly during the months of January, February, October, and November..

[Audio] The two stages of the rheumatic process involve distinct pathological changes. The first stage is characterized by exudative and non-specific features, exemplified by the Arthus phenomenon. This stage presents with oedema, hyperaemia, capillary haemorrhage, leukocytic inflammation, and collagen fragmentation..

[Audio] The condition is caused by an immune-mediated reaction to certain strains of group A streptococcus. These bacteria have antigens that can bind to cardiac myosin and sarcolemmal membrane proteins, triggering an inflammatory response in the endocardium, myocardium, and pericardium, as well as in the joints and skin. This inflammation leads to histological changes such as fibrinoid degeneration in the collagen of connective tissues. Aschoff nodules are a hallmark feature of this disease, occurring exclusively in the heart and consisting of multinucleated giant cells surrounded by macrophages and T-lymphocytes. These nodules appear during the subacute or chronic stages of rheumatic carditis..

[Audio] The clinical features of acute rheumatic fever usually appear with a combination of symptoms, including fever, anorexia, lethargy, and joint pain. This onset typically occurs two to three weeks after an episode of streptococcal pharyngitis, even if there is no prior history of sore throat. Additionally, patients may also experience arthritis, rashes, subcutaneous nodules, carditis, and neurological changes..

[Audio] The diagnostic criteria for rheumatic fever can be remembered using the mnemonic device: "Major Jones". Each letter represents a key feature to look for in patients presenting with suspected rheumatic fever. M stands for migration of joints, or polyarthritis. O indicates onset of symptoms within 19 days of streptococcal infection. N denotes nodules, or subcutaneous lesions. J signifies joint swelling and redness. O also represents oral lesions, such as rashes. N again stands for neurological signs, like chorea or seizures. E represents erythema marginatum, another type of rash. Finally, S stands for subcutaneous nodules..

[Audio] The laboratory tests confirm the presence of Streptococcus pyogenes in the throat swab culture. The raised ASO titre indicates that the patient has developed antibodies against streptococcal M protein. The elevated levels of anti-DNase B and other streptococcal antibodies suggest that the immune system is responding to the infection. Furthermore, the presence of streptococcal antigens and a history of recent scarlet fever provide additional evidence of Streptococcal infection. These findings collectively support the diagnosis of Acute Rheumatic Fever..

[Audio] The diagnosis of acute rheumatic fever is based on the presence of either two or more major manifestations or one major and two or more minor manifestations, accompanied by evidence of a previous streptococcal infection..

[Audio] The most common major manifestation of Acute Rheumatic Fever is polyarthritis, which occurs early on when streptococcal antibody titres are high. This condition is characterized by an acute, painful, and asymmetric inflammation of the large joints, typically affecting the knees, ankles, elbows, and wrists. The joints become inflamed in rapid succession, often appearing red, swollen, and tender for a period ranging from one day to four weeks..

[Audio] Rheumatic fever can cause a range of symptoms, including breathlessness, palpitations, and chest pain. The symptoms can be caused by inflammation affecting different parts of the heart, such as the endocardium, myocardium, and pericardium. This inflammation can also affect the valves of the heart, leading to murmurs and potentially causing heart failure. Some people may experience tachycardia, cardiac enlargement, or changes in their heartbeat. Furthermore, some individuals may develop conduction defects, including AV block, which can lead to syncope..

[Audio] Sydenham's chorea, also known as St. Vitus dance, is a late neurological manifestation that appears at least three months after the episode of acute rheumatic fever, when all other signs may have disappeared. It occurs in up to one-third of cases and is more common in females. Emotional lability may be the first feature, typically followed by purposeless, involuntary, choreiform movements of the hands, feet, or face. Speech may be explosive and halting. Spontaneous recovery usually occurs within a few months. Approximately one-quarter of affected patients will go on to develop chronic rheumatic valve disease..

[Audio] Erythema marginatum is a rare manifestation of acute rheumatic fever, occurring in less than 5% of patients. Characterized by red macular lesions that fade in the center but remain red at the edges, these lesions typically appear on the trunk and proximal extremities, excluding the face. As the lesions progress, they can coalesce or overlap, forming red rings or margins. In addition, subcutaneous nodules may also develop in approximately 5-7% of patients. These nodules are small, painless, and most easily palpated over the extensor surfaces of bones or tendons. Notably, they often appear more than three weeks after the onset of other symptoms, serving as a valuable diagnostic tool to confirm the presence of acute rheumatic fever..

[image]. Erythema marginatum. [image].

[Audio] Subcutaneous nodules are small, firm, and non-tender lesions that can appear anywhere on the body, typically attached to fascia or tendon sheaths over bony prominences. They are uncommon except in children, where they can be more frequent. These nodules persist for days or weeks and are often recurrent. In terms of appearance, they are indistinguishable from rheumatoid nodules..

Subcutaneous nodules.