Makindo Medical Notes.com

Related Subjects: |Congenital Acyanotic Heart Disease |Congenital Cyanotic Heart Disease |Cardiac Embryology |Cyanosis - Central and Peripheral |Down's syndrome (Trisomy 21) |Tetralogy of Fallot |Patent Foramen Ovale (PFO) |Ventricular Septal defect (VSD) |Mitral Regurgitation (Incompetence) |Mitral Stenosis |Mitral Stenosis vs Regurgitation |Mitral Valve prolapse |Atrial Fibrillation (AF) |Cardiac Valve replacement |Prosthetic Valves <

Introduction

• An autoimmune condition whereby an immune-mediated delayed response to specific strains of group A streptococci
• These cross react with cardiac myosin and sarcolemmal membrane protein.
• There is an inflammatory process in the endocardium, myocardium and pericardium, as well as the joints and skin.

Epidemiology

• Rheumatic fever is one of the common causes of acquired heart disease and has been a burden in countries with low income.
• The incidence of acute rheumatic fever (ARF) has declined in Europe and North America over the past 4-6 decades
• The global distribution of ARF and RHD is heterogeneous; certain geographic regions and specific ethnic and socioeconomic groups experience very high rates of ARF
• Low risk is defined as an ARF incidence <2 per 100,000 school-aged children (5-14 years old)

Aetiology

• The disease process starts when the S. pyogenes (Group A) bacterium affects an individual which causes an acute episode of pharyngitis
• Autoimmune reaction to Group A Streptococci then produces antibodies which cross-react with cardiac tissue and nephrons and Myosin and Sarcolemmal membrane protein with Localised areas of endocardial inflammation - Aschoff nodule with giant cells and Pancarditis affecting pericardium, epicardium, myocardium, and endocardium
• Progressive fibrosis and valve and supporting structures damaged resulting in
  • Valvular stenosis: Over time the lesion scars with involvement of the valve and the valve can become stenosed
  • Valves may also become incompetent
  • There is increased risk of Endocarditis

Clinical

• Onset 2-3 wks after episode of streptococcal throat.
• Fever, anorexia, lethargy, joint pains.
• Pancarditis: endocarditis, myocarditis, pericarditis to varying degrees
• Breathlessness, heart failure, palpitations. Pericarditis.
• Chest pain, Tachycardia, cardiomegaly, new murmurs, soft MDM mitral valvulitis (Carey Coombs)
• Acute, painful, asymmetric and migratory arthritis knees, ankles, elbows, wrists most common
• Erythema marginatum: red macules, pale centres, red edges. On trunk and proximal but not the face.
• Subcutaneous nodules: small, firm, painless. Extensor surfaces of bone or tendons. Seen at 3 wks

Later Complications

• Sydenham's chorea (St Vitus dance) is a late (> 3 mths) emotional lability, choreiform movements
• Chronic rheumatic heart disease with progressive scarring after 5-10 years:
• Mitral stenosis and regurgitation in > 90% of cases, with the aortic valve the next most frequently involved.
• Causes severe valvular heart disease in the young may need surgery and also a risk of endocarditis.

Investigations

• FBC: Raised WCC, ESR and CRP
• ECG: 1st degree AV block or worse, pericarditis changes, ST/T wave changes with myocarditis
• Echo: cardiac dilatation, valve changes.
• CXR: Cardiomegaly, Pulmonary oedema
• Throat swab: Group A ß-Haemolytic strep. The organism is grown on horse or sheep blood agar medium
• ASO titres: rising/levels Adult > 200 u Child > 300 u

Diagnosis: relies on the Jones criteria.

To diagnose rheumatic fever, the revised Jones criteria require the presence of either two major criteria or one major and two minor criteria, along with evidence of a preceding Group A streptococcal infection.

Management

• ABC. O₂ if hypoxic. Bed rest, diuretics and fluid restriction should be done as needed.
• High-dose Aspirin to treat arthritis. Response within 24 hrs helps to confirm the diagnosis.
• Bed rest lessens joint pain and reduces cardiac workload. Manage Cardiac failure and palpitations
• Prednisolone may be used for severe carditis or severe arthritis. ESR will settle.
• Chorea is debilitating then try valproate or carbamazepine

Group A Streptococci Eradication

• Acute Rheumatic fever eliminate GAS Either
  • Penicillin V (Oral): Children: 250 mg BD or TDS for 10 days
  • Penicillin V (Oral): Adults: 500 mg BD or TDS for 10 days
  • Treat for 10 days to eradicate the initial streptococcal infection.
  • Penicillin G Benzathine (IM): 0.6 MU as a single dose for children.
  • Penicillin G Benzathine (IM): 1.2 MU as a single dose for adults.
  • Erythromycin (Oral): children: 10 mg/kg per dose, four times daily for 10 days.
  • Erythromycin (Oral): adults: 250 mg four times daily for 10 days.
• Long term Prevention often until age 21 (Take advice) Either
  • Penicillin G Benzathine (IM): 1.2 MU units every 3-4 weeks for adults and older children.
  • Penicillin G Benzathine (IM): 0.6 MU units every 3-4 weeks for young children.
  • Oral Penicillin V: Dose for children: 250 mg twice daily.
  • Oral Penicillin V: Dose for adults: 250 mg twice daily.
  • Erythromycin (Oral): Dose for children: 250 mg twice daily.
  • Erythromycin (Oral): Dose for adults: 250 mg twice daily.
  • Without carditis: Prophylaxis 5 years or until the patient is 21 years old, whichever is longer.
  • With mild carditis but no residual heart disease: Prophylaxis for 10 years or until 21 years old, whichever is longer.
  • With severe carditis and residual heart disease: Prophylaxis for 10 years or more, sometimes lifelong, depending on the severity.

References

• Revised Jones Criteria for Acute Rheumatic Fever