Rheumatic fever is a systemic immune process that occur post beta hemolytic streptococcal infection. It is still common within developing country, approximately 100 cases in 100,000 populations. In the West, the incidence is decreasing and becoming rare, approximately 2 cases in 100,000 populations. Peak incidence is between 5-15 years old and tends to recur unless preventive measures are taken. Rheumatic fever is rare before age 4 years or after age 40 years.
Pharyngeal infection with Lancefield Group A beta haemolytic streptococci triggers rheumatic fever 2-4 weeks later in the susceptible 2% of the population. However, in rare case, it can appear as early as 1 week or as late as 5 weeks post infection. An antibody to the carbohydrate cell wall of the staphylococcus will cross reacts with the valve tissue. It may cause permanent damage to the heart muscle.
Investigations:
- Full blood count
- ASOT (Antistreptolysin O Antibody)
- Throat swab
- ESR
- CRP (C Reactive Protein)
Diagnosis done based on revised Jones criteria.
Management:
- Bed rest until CRP normal. It sometimes take up to 3 weeks
- IM benzylpenicillin 0.6-1.2g stat then oral penicillin V 250mg 6 hourly
- Pain relief for carditis or arthritis – Aspirin can be given orally 100mg/kg/day in divided dose (maximum is 8g/day) for 2 days, then 70mg/kg/day for 6 weeks. Alternative to aspirin is NSAIDs. It is important to monitor salicylate level because it may cause toxicity. Some symptoms of toxicity include tinnitus, hyperventilation and metabolic acidosis.
- Steroids may help to improve the symptoms
- In severe arthritis, immobilize the joints may help
- Tablet haloperidol 0.5mg 8 hourly or tablet diazepam may be prescribed if the patient has symptom of chorea
- Secondary prophylaxis will be given to all patients. Oral penicillin V 250mg twice daily will be given till patient is no longer at risk (> 30 years). If the patient is allergic to penicillin, tablet sulfadiazine 1g daily (0.5g if patient’s weight less than 30kg). It is important to give antibiotic prophylaxis to patient with CRHD in every surgery or prior to dental procedure.
Rheumatic fever and cardiac sequelae:
Rheumatic carditis and valvulitis may be self limited. However, it may also lead to slowly progressive to valvular deformity. The characteristic lesion is a perivascular granulomatous reaction with vasculitis. 60% of all carditis case will develop chronic rheumatic heart disease (CRHD). Cardiac sequelae will affect mitral valve (in 75-80% of cases), aortic valves (in 30% of cases, but rarely as the sole valve), tricuspid valve and pulmonary valves in less than 5% of cases.
Prevention of recurrent rheumatic fever:
Primary prevention of rheumatic fever is by early and efficient treatment of streptococcal pharyngitis. Secondary prevention is to prevent the recurrent episodes of rheumatic fever. The recurrence rate of rheumatic fever is high in those who have had carditis during their initial episode. In children, about 20% of cases have a second episode of rheumatic fever within 5 years.
The preferred antibiotic prophylaxis is intramuscular benzathine penicillin G, 1.2 million units every 4 weeks. Oral penicillin is found to be less reliable. If the patient is allergic to penicillin and sulfadizine, erythromycin and azythromycin may be substitute. If the patients do not have hypersensitivity against penicillin, antibiotics from cephalopsporine group may be considered.
Recurrence is rare after 5 years of initial infection or after 25 years of age (of the patient). At this time, the prophylaxis can be discontinued except for those with high risk of streptococcal infection. If there is no evidence of carditis during initial episode, prophylaxis can be stopped at 21 years old. For more detail about secondary prophylaxis, please read article on CRHD.
Prognosis:
In children, the initial episodes of rheumatic fever may last for few months but only few weeks in adults. Acute attacks may last up to 3 months. The recurrence may be precipitated by further streptococcal infections, pregnancy or the use of oral contraceptive pills. The immediate mortality rate consists of 1-2% of all cases.
Persistent rheumatic carditis with cardiomegally, heart failure and pericarditis will carry a poor prognosis to the patient. About 10% of children with this complication die within 10 years after the initial attack. Incompetent lesions will develop during the acute attacks. The valves become stenoses a few years later. 10 years after the initial infection, about 2/3 of the cases will have detectable valvular abnormalities. Usually, the valve will thicken and have limited mobility. Significant symptomatic valvular heart disease or persistent cardiomegally only occur in less than 10% of the cases with one episode of rheumatic fever.
Other relevant topic:
Reference:
- Murray Longmore et al. Oxford Handbook of Clinical Medicine. 7th edition. 2008. Oxford.
- Stephen J Mc Phee et al. Current Medical Diagnosis and Treatment 2009. Mc Graw Hill.
