Test: Rheumatic Heart Disease - NEET PG MCQ

Milder cases of Sydenham's chorea are managed by providing a calm environment.
In severe chorea carbamazepine or sodium valproate is preferred to haloperidol. Response takes 1-2 weeks to develop.
However for severe and refractory cases of chorea, corticosteroids are effective and lead to rapid symptom reduction. If all of these fail, IVIG is used.

The hallmark of the pathogenesis of rheumatic fever is Molecular mimicry where the streptococcal group A carbohydrate epitope, N acetyl glucosamine, and the α-helical coiled-coil streptococcal M protein structurally mimic cardiac myosin in the human disease.

A short, mid diastolic murmur is rarely heard during an episode of acute rheumatic fever (Carey-Coombs murmur) and probably is due to flow through an edematous mitral valve. An opening snap is not present in the acute phase, and the murmur dissipates with resolution of the acute attack.

• During acute RF, Aschoff bodies and are pathognomonic for RF
• Aschoff bodies consist of a central zone of degenerating, hyper-eosinophilic extracellular matrix infiltrated by lymphocytes (primarily T cells), occasional plasma cells, and plump activated macrophages called Anitschkow cells,
• The Anitschkow cells have abundant cytoplasm and central nuclei with chromatin arrayed in a slender, wavy ribbon (Caterpillar cells)
• Valve involvement results in fibrinoid necrosis along the lines of closure forming 1- to 2-mm vegetations (verrucae) that have little effect on cardiac function. These irregular, warty projections probably arise from the precipitation of fibrin at sites of erosion caused by underlying inflammation and collagen degeneration.

• In case a course of penicillin is commenced within 9 days of sore throat onset, it will prevent almost all cases of ARF.
• Primary prevention for ARF remains primary prophylaxis (i.e, the timely and complete treatment of group A streptococcal sore throat with antibiotics).

The functional consequence of RHD is valvular stenosis and regurgitation (stenosis tends to predominate). RHD is overwhelmingly the most frequent cause of mitral stenosis accounting for 99% of cases. The mitral valve alone is involved in 70% of cases of RHD, with combined mitral and aortic disease in another 25%; the tricuspid valve is usually less frequently and less severely involved, and the pulmonic valve almost always escapes injury.

Aortic stenosis presents with

• Insidious progression of fatigue and dyspnea associated with gradual curtailment of activities.
• Dyspnea results primarily from elevation of the pulmonary capillary pressure caused by elevations of LV diastolic pressures secondary to reduced left ventricular compliance and impaired relaxation.
• Angina pectoris usually develops somewhat later and reflects an imbalance between the augmented myocardial oxygen requirements and reduced oxygen availability.
• Exertional syncope may result from a decline in arterial pressure caused by vasodilation in the exercising muscles and inadequate vasoconstriction in non-exercising muscles in the face of a fixed CO, or from a sudden fall in CO produced by an arrhythmia.
• Because the CO at rest is usually well maintained until late in the course, marked fatigability, weakness, peripheral cyanosis, cachexia, and other clinical manifestations of a low CO are usually not prominent until this stage is reached. Orthopnea, paroxysmal nocturnal dyspnea, and pulmonary edema, i.e., symptoms of LV failure, also occur only in the advanced stages of the disease.
• Severe pulmonary hypertension leading to RV failure and systemic venous hypertension, hepatomegaly, AF, and TR are usually late findings in patients with isolated severe AS.

• In rheumatic heart disease, the damage to chordate tendinae by inflammatory Aschoff nodules results in development of mitral regurgitation in pediatric presentation.
• The most common valve involvement > 18 years of age is mitral stenosis
• Remember that pulmonic valve is not involved in rheumatic etiology.

Secondary Prophylaxis for Rheumatic Fever
Macrotide or azalide antibiotic (for patients allergic to penicillin and Sulfadiazine)

• In a patient allergic to penicillin, sulfadiazine is the next consideration for prophylaxis.
  • In a pt weighing 27 kg or less - 0.5 g PO/day
  • In a pt weighing 27 kg or less -1 g PO/day
• Macrolide (Erythromycin/clarithromycin) is considered in a patient allergic to both Penicillin and sulfadiazine.

Bacterial Endocarditis
The AHA no longer recommends prophylaxis for infective endocarditis in most patients with rheumatic heart disease. The exceptions are:

• Patients with prosthetic valves or valves repaired with prosthetic material,
• Patients with previous endocarditis or specific forms of congenital heart disease, and
• Cardiac transplant recipients who develop cardiac valvulopathy.