Causes and Symptoms of Rheumatic Fever and Heart Disease, Study notes of Cardiology

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Rheumatic Heart Disease Objectives: • To understand the basis of rheumatic fever as an immunologically mediated late complication of Streptococcal infection • To know that autoimmunity results from production of cross reacting antibodies against Streptococcal antigens • To describe Rheumatic heart disease as one of the several manifestations of rheumatic fever • To know the signs, symptoms, pathogenesis, treatment and prophylaxis of rheumatic heart disease Red: important Grey: Extra explanation  An inflammatory disease that can involve the heart, joints, skin, and brain.  All cases associated with recent infection by Group A β-haemolytic streptococcus. e.g. Strep. throat infection (Pharyngitis) or scarlet fever.  Commonly appears in children ages 5-15, However it can arise in adulthood  The onset of the clinical features is delayed about 3-4 weeks after the infection (Latent period)  3% of persons with untreated group A streptococcal pharyngitis develop rheumatic fever  15-20 million new cases a year in developing countries Risk factors: 1)Crowding in developing countries 2)Low standard of living due to immunodeficiency 3)Individual (HLA) susceptibility MHC class II allele DR7 is associated with RHD, and its combination with certain DQ alleles is seemingly associated with the development of valvular lesions (genetic factors). So APC’s bearing the DR7 molecule recognize heart tissue protein! The associated alleles probably encode molecules that facilitate the presentation of some streptococcal peptides to T cells that later trigger autoimmune reactions mediated by molecular mimicry. Pathogenesis : 1. Group A streptococcus cell wall composed of M proteins that are highly antigenic 2. Activated antigen presenting cells present the bacterial antigen to helper T cells 3. Helper T cells activate self reactive B cells and produce antibodies against the cell wall of streptococcus (anti-group A carbohydrate antibody ) IgE antibodies , Also it activates cross-reactive T- cells which release TNF , IFN-y , IL-2 and other cytokines 4. Antibodies may cross react with Myocardium , valvular tissue and joints producing the symptoms of Rheumtic fever. This inflammation occurs through direct attachment of complement and Fc receptor-mediated recruitment of neutrophils and macrophages. 5. Up-regulates the vascular cell adhesion molecule-1 (VCAM-1) on the valve and T-cells adhere to the VCAM-1 on the valve endothelium and extravasate into the valve 6. Tissue destruction (endothelium) making the inner structure exposed "laminar basment membrane" The inflammatory hypersensitivity reaction type II response causes : 1. Breakdown of valve proteins 2. Epitope spreading (T-cells respond to other valve proteins such as Vimentin and collagen) 3. Avascular valve become neovascularized "the healthy valves which don't have blood supply are now having blood going through them" 7. Granuloma formation, gamma interferon production and scarring in the valve Anti-streptococcal antibodies cause : 1- Antigen-antibody complex (Type III hypersensitivity reaction) 2- Antibody attached to tissues (Type II hypersensitivity reaction) VCAM-1 on the valve endothelium and not found on the myocardium Clinical presentation 1. Joints (Arthritis) - Usually polyarthritis - Sometimes flitting from joint to joint (migratory) - Affecting the larger joints more than the smaller ones. Findings: - Swelling, Redness & Tenderness (common) - Joint effusions (occasionally) 4. Skin (Erythema Marginatum) Skin lesions: The classical erythema marginatum Lesions with prominent margins slightly raised 5. Central nervous system (Sydenham's chorea) - The choreiform movements affect particularly the head and the upper limbs. - They may be generalized or restricted to one side of the body (hemi-chorea) - Chorea eventually resolves completely, usually within 6 weeks 3. Subcutaneous Nodules - These are painless, round, firm lumps overlaid by normal looking skin. - They range from a few millimeters to 1.5 cm in diameter, and are localized over bony prominences like the elbow, shin and spine. - They sometimes last longer than a month. JONES criteria 2. Heart -Up to 60% of patients with RF progress to Rheumatic Heart Disease - The endocardium (including valves and chordae tendineae) , pericardium (fibrinous or serofibrinous deposition between visceral and parietal pericardium) and myocrdium (can cause sudden death) may be affected (pandcarditis) -Valvular damage is the hallmark of rheumatic carditis (mitral valve is almost affected) MCQ's Q1: What is the Antigen-presenting molecule from RHD patients that recognizes heart-tissue proteins ? A- CYT p450. B- HLA-DR7. C- CD40L . D- CD28. Q2: Rheumatic fever is an inflammatory disease which may develop after a ………….. infection? A- Staphylococcus Aureus . B- Group A Streptococcal C- Group B Streptococcal. D- Yeast. Q3:Which of the following is not effected by Rheumatic fever ? A- heart. B-Skin. C- Brain. D- Liver. Q4: Rheumatic fever commonly appears in children that are 5 to 15 years old ? A- True. B- False. Q5: All cases are associated with recent infection like Laryngitis ? A- True. B- False. Q6: Which proteins help in the Adherence of Streptococcus pyogenes to host cells and inhibit the host’s immune response ? A- M proteins. B- IgE. C- IgM. D- Monoclonal antibodies. Q7: The function of Streptokinases is to ? A- Degrades proteins. B- Camouflage the bacterium. C- Dissolve blood clots. Q8: The cross-reactivity is a Type ……….. hypersensitivity reaction. A- Molecular Mimicry. B- Type I hypersensitivity. C- type III hypersensitivity . Q9: During a Strep. infection activated antigen presenting cells such as macrophages present the bacterial antigen to helper T cells ? A- True. B- False. Q10: Up to 20% of patients with ARF progress to Rheumatic Heart Disease ? A- True. B- False. 1 - B 2 - B 3 - D 4 - A 5 - B 6 - A 7 - C 8 - A 9 - A 1 0 - B Thank you for checking our work, Good luck! If you have any suggestions or alterations contact us! Email Immunology435@gmail.com جواهر الحربي أثير النشوان لمياء القهان إبراهيم البيشي