Rheumatic Fever

Question 1

explain the Pathophysiology of Rheumatic Fever

Answer 1

• Acute rheumatic fever is a sequel of a previous group A streptococcal infection, usually
  of the upper respiratory tract. One beta-streptococcal serotype is linked directly to acute rheumatic fever. Rheumatogenicity of GAS is important factor as not all GAS pharyngitis is associated with development of rheumatic fever.
• Rheumatic fever follows Lancefield β hemolytic streptococcus pharyngitis within the interval of 2-3 weeks.

Question 2

explain the The mechanism of Rheumatic Fever

Answer 2

1- Dysfunction of the immune Response
2- Antigenic Mimicry , Similarity between the carbohydrate moiety if GAS and glycoprotein of heart valve
3- Molecular similarity between some Streptococcal antigens and sarcolemma or other moiety of human myocardial cells.
4- Several host related factors have been identified to have operated in relation to specific genetic function and difference in the immune response of individuals.
5- The disease involves the heart, joints, central nervous system (CNS), skin, and subcutaneous tissues. It is characterized by an exudative and proliferative inflammatory lesion of the connective tissue, especially that of the heart, joints, blood vessels, and subcutaneous tissue.

Question 3

Clinical Manifestation OF Rheumatic Fever

Answer 3

• Acute rheumatic fever is associated with 2 distinct patterns of presentation.
  1-The first pattern of presentation is sudden onset. It typically begins as polyarthritis 2-6 weeks after streptococcal pharyngitis, and it is usually characterized by fever and toxicity.
  2- The second pattern is insidious or subclinical and the initial abnormality is mild carditis.
• Age at onset influences the order of complications. Younger children tend to develop carditis first, while older patients tend to develop arthritis first

Question 4

Diagnosis of Rheumatic Fever

Answer 4

-Diagnosis of acute rheumatic fever requires a high index of suspicion, Jones criteria developed by the American Heart Association is used to make the diagnosis :
-Major Criteria :
1.Carditis
2.Migratory ply arthritis
3.Sydenham’s Chorea
4.Subcutaneous nodules
5.Erythema marginatum
-Minor Criteria:
1.Clinical : Fever ,Arthralgia
2.Laboratory :Elevated acute phase reactants : ESR,
3.CRP:Prolonged PR interval
-Plus: Supportive evidence of recent Group A streptococcal infection ( e.g. positive throat culture or rapid antigen detection test ; and/or elevated or increasing streptococcal antibody test : ASO titer , Anti DNAase , Anti NADase etc )
-NB! In addition to evidence of a previous streptococcal infection, the diagnosis of acute rheumatic fever requires 2 major Jones criteria or 1 major plus 2 minor Jones criteria.

Question 5

explain the major criteria

Answer 5

1) Carditis, (pancarditis here), occurs in as many as 40- 60% of patients and may manifest as:
a) New murmur
b) Cardiomegaly
c) Congestive heart failure
d) Pericarditis with or without a pericardial rub and resolve without squeal of constriction.
e) Valvular disease: mitral and aortic valves are commonly affected. Healing of rheumatic
valvulitis will lead into fibrous thickening and adhesion, resulting in progressive valvular
damage. But, about 80% of mild valvulitis would resolve. There is a risk of developing
endocarditis on a damaged valve.

2) Migratory polyarthritis occurs in 75% of cases and involves many joints at a time. The
larger joints are mainly affected.

3) Subcutaneous nodules: occur in 10% of patients and are edematous fragmented collagen
fibers. They are firm painless nodules on the extensor surfaces of wrists, elbows, and knees.

4) Erythema marginatum occurs in about 5% of cases. The rash is serpiginous and long
lasting.

5) Sydenham’s chorea (i.e., St Vitus’ dance) is a characteristic movement disorder that
occurs in 5-10% of cases. Sydenham’s chorea consists of rapid purposeless movements of
the face and upper extremities. Onset may be delayed for several months to years and may
cease when the patient is asleep

Question 6

Laboratory Studies of Rheumatic Fever

Answer 6

-No specific confirmatory laboratory tests exist. However, several laboratory findings indicate continuing rheumatic inflammation. Some are part of the Jones minor criteria.
–Supportive evidences
1. Streptococcal antibody tests disclose preceding streptococcal infection
1.1 ASO titer: positive in 80% of cases
1.2 Anti DNAase β & Anti hyaluronidase is positive in 95 % of cases
2.Isolate group A streptococci via throat culture which has 20-40% yield.
–Laboratory minor criteria
1-Acute phase reactants (e.g. raised ESR and C-reactive protein [CRP])
2-Leukocytosis may be seen.
3-Anemia usually is caused by suppression of erythropoiesis.
4-ECG: PR interval prolongation is seen in 25% of all cases but is neither specific to nor diagnostic.

Question 7

Treatment

Answer 7

-Medical therapy involves the following 5 areas:
1. Treat group A streptococcal infection regardless of organism detection, All patients with acute rheumatic fever should be given appropriate antibiotic.:
- Ampicillin 500 mg PO QID or Amoxicillin 500 mg PO TID for 10 days or
- Benzathin penicillin 1.2 million IU IM single dose or
- Erythromycin 500 mg PO QID for 10 days ( for penicillin allergic patient)
2. Therapy for manifestation of acute rheumatic fever
–Arthritis: ASA( aspirin ) is given at dose 2 gm four times per day for 4-6 weeks, no indication for steroids.
–Carditis :Severe Carditis with congestive heart failure should be treated with :
-Prednisolone 60 to 80 mg /day, to be tapered as patient improves
-Start ASA during tapering phase to be given for 4-6weeks
-But both have no influence on the future development of valvular heart disease (VHD).
–Congestive heart failure: Treats by conventional therapy such as digoxin and diuretics.
–Sydenham’s chorea: In majority of the cases it is self-limiting. But in symptomatic patients benzodiazepines (diazepam) or phenothiazines (haloperidol) may be helpful in controlling
symptoms.

Question 8

secondary prophylaxis

Answer 8

-Administer secondary prophylaxis: is indicated for all patients with rheumatic fever, Taking benzathin penicillin is the first choice for better compliance and longer prevention :
1-Benzathin penicillin 1.2 million IU IM every 4 weeks , but if the there is high risk of recurrence, it can be given every 3 weeks
2-Alternative antibiotics
2.1 Oral penicillin V (250mg twice/day)
2.2 Oral sulfadiazine (1g/day)
—N.B. In a patient with an established RHD, it is advisable to get the prophylaxis lifelong.