RF Flashcards
A 12-year-old child presents with polyarthritis, carditis, and a characteristic erythematous rash with a serpiginous border. A recent sore throat was reported 3 weeks prior. Which of the following is the most likely diagnosis?
A) Systemic lupus erythematosus
B) Acute rheumatic fever (ARF)
C) Infectious mononucleosis
D) Viral exanthem
B) Acute rheumatic fever (ARF)
Rationale: Acute rheumatic fever (ARF) often follows a group A streptococcal (GAS) throat infection and presents with polyarthritis, carditis, and characteristic erythema marginatum, a rash with a serpiginous edge. Systemic lupus erythematosus (A) and infectious mononucleosis (C) can present with similar symptoms but do not typically have the hallmark of erythema marginatum. Viral exanthems (D) are less likely in this context.
A patient with suspected acute rheumatic fever has migratory arthritis involving the knees, ankles, and elbows. Which of the following is most characteristic of joint involvement in ARF?
A) Symmetrical joint involvement
B) Migratory polyarthritis affecting large joints
C) Persistent joint involvement despite treatment with NSAIDs
D) Involvement of distal joints, such as fingers and toes
B) Migratory polyarthritis affecting large joints
Rationale: In acute rheumatic fever, migratory polyarthritis primarily affects the large joints (knees, ankles, elbows, hips) and is often asymmetric. Symmetrical joint involvement (A) and distal joint involvement (D) are not characteristic of ARF. Persistent joint involvement (C) despite NSAIDs is unlikely in ARF.
A 15-year-old girl presents with rapid, involuntary movements of her hands, face, and tongue. She also has a history of carditis. What is the most likely diagnosis?
A) Systemic lupus erythematosus
B) Sydenham’s chorea
C) Parkinson’s disease
D) Huntington’s disease
B) Sydenham’s chorea
Rationale: Sydenham’s chorea, a movement disorder associated with acute rheumatic fever, is characterized by choreiform movements, particularly of the face, hands, and tongue. This condition often occurs in females and can be accompanied by carditis.
Which of the following is the first-line treatment for polyarthritis in acute rheumatic fever?
A) Corticosteroids
B) Aspirin or NSAIDs
C) Antibiotics (Penicillin)
D) Methotrexate
B) Aspirin or NSAIDs
Rationale: Aspirin or NSAIDs are the first-line treatment for polyarthritis in acute rheumatic fever, as they provide relief from pain and inflammation. Corticosteroids (A) are controversial for treating arthritis in ARF but may be used in certain cases, particularly for carditis. Penicillin (C) is used to treat the underlying group A streptococcal infection but does not treat the arthritis itself. Methotrexate (D) is not typically used for ARF.
Which of the following is the most important aspect of secondary prevention in a patient with a history of acute rheumatic fever?
A) Annual influenza vaccination
B) Chronic corticosteroid therapy
C) Regular echocardiograms
D) Prophylactic antibiotics (Benzathine penicillin)
D) Prophylactic antibiotics (Benzathine penicillin)
Rationale: Prophylactic antibiotics, particularly benzathine penicillin, are the cornerstone of secondary prevention to prevent further episodes of acute rheumatic fever and rheumatic heart disease (RHD).
A 16-year-old male with a history of group A streptococcal throat infection presents with erythema marginatum and migratory arthritis. A diagnosis of acute rheumatic fever is made. What is the most likely long-term complication of untreated or recurrent ARF?
A) Renal failure
B) Chronic arthritis
C) Rheumatic heart disease
D) Pulmonary hypertension
C) Rheumatic heart disease
Rationale: Rheumatic heart disease (RHD) is the most common long-term complication of acute rheumatic fever if left untreated or if recurrent episodes occur.
A 14-year-old girl with a history of acute rheumatic fever is being treated for secondary prevention. She has a known penicillin allergy. Which of the following is the most appropriate antibiotic choice for this patient?
A) Amoxicillin
B) Azithromycin
C) Erythromycin
D) Penicillin V
C) Erythromycin
Rationale: Erythromycin (250 mg twice daily) is the recommended alternative for penicillin-allergic patients for secondary prevention of ARF and RHD.
A 7-year-old child presents with migratory arthritis, erythema marginatum, and a history of a sore throat 4 weeks ago. What is the next best step in diagnosing acute rheumatic fever (ARF)?
A) Anti-streptolysin O (ASO) and anti-DNase B titers
B) Echocardiogram
C) Throat culture for group A streptococcus
D) Chest X-ray
A) Anti-streptolysin O (ASO) and anti-DNase B titers
Rationale:
The correct answer is A. To diagnose ARF, evidence of a preceding group A streptococcal infection is essential, typically confirmed by anti-streptolysin O (ASO) and anti-DNase B titers.
Which of the following is the most appropriate treatment for severe Sydenham’s chorea in a patient with acute rheumatic fever?
A) Penicillin
B) Carbamazepine or sodium valproate
C) Aspirin
D) Prednisone or prednisolone
B) Carbamazepine or sodium valproate
Rationale: Carbamazepine or sodium valproate are the preferred treatments for severe Sydenham’s chorea, which is often the most problematic manifestation of ARF.
Which of the following is the appropriate dosage for benzathine penicillin G for secondary prevention of rheumatic fever in an adult patient?
A) 500 mg every 4 weeks
B) 1.2 million units every 4 weeks
C) 600,000 units every 4 weeks
D) 1.2 million units every 6 weeks
B) 1.2 million units every 4 weeks
Rationale: For secondary prevention of rheumatic fever, the typical dose of benzathine penicillin G is 1.2 million units every 4 weeks.
Which of the following statements regarding the prevalence of rheumatic heart disease (RHD) is TRUE?
A) RHD is most commonly found in males aged 5-14 years
B) The prevalence of RHD peaks between 25 and 40 years of age
C) ARF is mainly seen in adults aged 25-40 years
D) RHD is more common in males, sometimes up to twice as frequently as females
B) The prevalence of RHD peaks between 25 and 40 years of age
Rationale: The prevalence of RHD peaks between 25 and 40 years of age and affects females more commonly than males (sometimes up to twice as frequently).
What is the most widely accepted theory for the pathogenesis of acute rheumatic fever (ARF)?
A) Antibody response to viral infections leading to immune complex formation
B) Molecular mimicry, where antibodies to group A Streptococcus also react with human tissues
C) An autoimmune response exclusively targeting the heart valves
D) Direct bacterial invasion of the heart valves
B) Molecular mimicry, where antibodies to group A Streptococcus also react with human tissues
Rationale: The most widely accepted theory of ARF pathogenesis is based on molecular mimicry, where antibodies directed at streptococcal antigens cross-react with human tissues, particularly endothelial cells on heart valves. This leads to inflammation and valvular damage.
Which of the following best describes the epidemiological profile of acute rheumatic fever (ARF)?
A) It is mainly a disease of adults aged 25-40 years
B) It is most commonly seen in children aged 5–14 years
C) Recurrent episodes of ARF are rare in adolescents and young adults
D) ARF affects males and females equally
B) It is most commonly seen in children aged 5–14 years
Rationale: ARF is most commonly a disease of children aged 5–14 years. Recurrent episodes are common in adolescents and young adults, and ARF does not affect males and females equally; females tend to be more affected by RHD (Rheumatic Heart Disease).
PROGNOSIS
* Untreated, ARF lasts on average 12 weeks
* Inflammatory markers should be monitored every 1–2 weeks until they have normalized (usually within 4–6 weeks)
* Echocardiogram should be performed after 1 month to determine if there has been progression of carditis
SECONDARY PREVENTION
* The mainstay of controlling ARF and RHD is secondary prevention.
* Benzathine penicillin G (1.2 million units, or 600,000 units if ≤27 kg) delivered every 4 weeks
* Oral penicillin V (250 mg) can be given twice daily instead but is less effective than benzathine penicillin G
* Penicillin-allergic patients can receive erythromycin (250 mg) twice daily.
CHOREA
* Milder cases can usually be managed by providing a calm environment.
* In patients with severe chorea, carbamazepine or sodium valproate is preferred to haloperidol.
* A response may not be seen for 1–2 weeks, and medication should be continued for 1–2 weeks after symptoms subside
* corticosteroids are effective and lead to more rapid symptom reduction in chorea
* Prednisone or prednisolone may be commenced at 0.5 mg/kg daily, with weaning as early as possible, preferably after 1 week if symptoms are reduced, although slower weaning or temporary dose escalation may be required if symptoms worsen
SALICYLATES AND NSAIDS
* used for the treatment of arthritis, arthralgia, and fever, once the diagnosis is confirmed
* Aspirin is a common first-line choice, delivered at a dose of 50–60 mg/kg per day, up to a maximum of 80–100 mg/kg per day (4–8 g/d in adults) in 4–5 divided doses.
* When the acute symptoms are substantially resolved, usually within the first 2 weeks, patients on higher doses can have the dose reduced to 50–60 mg/kg per day for a further 2–4 weeks.
* Fever, joint manifestations, and elevated acute-phase reactants sometimes recur up to 3 weeks after the medication is discontinued
* clinicians prefer to use naproxen at a dose of 10–20 mg/kg per day
JOINT INVOLVEMENT
* The most common form of joint involvement in ARF is arthritis
* Polyarthritis is typically migratory, moving from one joint to another over a period of hours.
* almost always affects the large joints—most commonly the knees, ankles, hips, and elbows—and is asymmetric.
* pain is severe and usually disabling until anti-inflammatory medication is commenced
* joint manifestations of ARF are highly responsive to salicylates and other nonsteroidal anti-inflammatory drugs (NSAIDs).
* joint involvement that persists for more than 1 or 2 days after starting salicylates is unlikely to be due to ARF
CLINICAL FEATURES
* There is a latent period of ~3 weeks (1–5 weeks) between the precipitating group A streptococcal infection and the appearance of the clinical features of ARF.
* exceptions are chorea and indolent carditis, which may follow prolonged latent periods lasting up to 6 months
* The most common clinical features are polyarthritis (present in 60–75% of cases) and carditis (50–75%).
