Rheumatic fever (RF) is an inflammatory disease that can develop as a complication of untreated or inadequately treated group A streptococcal throat infection. It is an immune-mediated condition that primarily affects children aged 5 to 15 years but can occur in people of all ages. Rheumatic fever can cause serious complications, particularly involving the heart, joints, skin, and central nervous system. 

Etiology 

• Caused by an abnormal immune response to infection with Streptococcus pyogenes (group A streptococcus). 
• Molecular mimicry plays a central role, where the immune system mistakenly attacks host tissues due to structural similarities between bacterial antigens and human tissues. 

Pathophysiology 

• The immune response generates cross-reactive antibodies and T-cells, leading to inflammation in various tissues. 
• Common targets of inflammation include: 
•   Heart: Can result in rheumatic carditis and valvular damage (most commonly the mitral and aortic valves). 
•   Joints: Acute, migratory polyarthritis is characteristic. 
•   Skin and Subcutaneous Tissue: Erythema marginatum and subcutaneous nodules may appear. 
•   Central Nervous System: Sydenham's chorea (involuntary movements). 

Common Symptoms 

1. Fever 

• Often mild to moderate and persistent. 

2. Migratory Polyarthritis 

• Pain, redness, swelling, and tenderness in large joints (e.g., knees, ankles, elbows, wrists). 
• Affects one joint at a time before moving to another (migratory pattern). 

3. Carditis 

• Inflammation of the heart, which may involve: 
• Endocardium: Leading to valvular damage (mitral or aortic valve most commonly affected). 
• Myocardium: Causing heart muscle inflammation. 
• Pericardium: Leading to chest pain due to pericarditis. 
• Symptoms of carditis: 
• Chest pain or discomfort. 
• Shortness of breath. 
• Fatigue. 
• Palpitations (irregular heartbeats). 

Sydenham’s Chorea 

• Neurological symptoms include: 
• Involuntary, jerky, or dance-like movements of the face, hands, or feet. 
• Emotional instability, irritability, or mood swings. 
• Muscle weakness and difficulty with fine motor tasks. 

5. Skin Manifestations 

• Erythema Marginatum: 
• Non-itchy, pink or red circular rashes with a pale center. 
• Found on the trunk and limbs, sparing the face. 
• Subcutaneous Nodules: 
• Small, painless lumps under the skin. 
• Found over bony areas such as elbows, knees, or the back of the wrists. 

6. General Symptoms 

• Fatigue and malaise. 
• Loss of appetite or weight loss. 

Less Common Symptoms 

• Nosebleeds. 
• Abdominal pain. 

Chronic Symptoms 

• Long-term complications, such as rheumatic heart disease, may result in: 
• Persistent heart murmurs. 
• Progressive heart valve dysfunction leading to heart failure. 

Note: Not all symptoms occur in every patient. The severity and combination of symptoms depend on the individual case and whether the heart, joints, skin, or nervous system is primarily affected. 

How do doctors diagnose rheumatic fever? 

Doctors diagnose rheumatic fever based on a combination of clinical findings, laboratory tests, and a history of recent streptococcal infection. The revised Jones criteria is commonly used for diagnosis, which requires evidence of a prior group A streptococcal infection and a combination of major and minor clinical criteria. 

Steps in Diagnosis 

1. Medical History 

• A recent history of symptoms of strep throat (e.g., sore throat, fever, swollen lymph nodes). 
• Evidence of untreated or inadequately treated group A streptococcal pharyngitis. 

2. Physical Examination 

• Doctors look for signs of the major clinical manifestations, such as:  
• Migratory arthritis (pain and swelling in joints). 
• Carditis (heart murmur, chest pain, or signs of heart failure). 
• Sydenham’s chorea (involuntary movements). 
• Erythema marginatum (pink skin rashes). 
• Subcutaneous nodules (painless lumps under the skin). 

3. Jones Criteria 

To confirm the diagnosis, the doctor checks for: 

• Major criteria:  
• Carditis, polyarthritis, Sydenham's chorea, erythema marginatum, subcutaneous nodules. 
• Minor criteria:  
• Fever, arthralgia (joint pain without swelling), elevated inflammatory markers (ESR, CRP), prolonged PR interval on ECG. 

Diagnosis is confirmed if: 

• 2 major criteria are met, or 
• 1 major + 2 minor criteria are present, along with evidence of a preceding streptococcal infection. 

4. Evidence of Streptococcal Infection 

• Throat culture: To detect group A streptococcus. 
• Rapid antigen detection test (RADT): For faster results. 
• Blood tests:  
• Elevated or rising antistreptolysin O (ASO) titers or anti-DNase B antibodies. 

5. Laboratory Tests 

• Complete blood count (CBC): To check for signs of inflammation or infection. 
• C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR): Elevated levels indicate inflammation. 
• Electrocardiogram (ECG): To detect heart abnormalities, such as a prolonged PR interval. 
• Echocardiogram: To assess for carditis and valvular damage. 

Key Considerations 

• Accurate diagnosis requires ruling out other conditions with similar symptoms. 
• Early diagnosis is crucial to prevent complications like rheumatic heart disease. 

What types of complications can occur if someone has rheumatic fever? 

If rheumatic fever is not treated promptly or recurs, it can lead to various complications, some of which can be severe and long-lasting. The most serious complication is rheumatic heart disease (RHD). Below are the potential complications of rheumatic fever: 

1. Rheumatic Heart Disease (RHD) 

• Description: Chronic damage to the heart valves caused by repeated inflammation and scarring due to rheumatic fever. 
• Valves Most Affected:  
• Mitral valve (most common). 
• Aortic valve. 
• Consequences:  
• Heart murmurs. 
• Valvular stenosis (narrowing) or regurgitation (leakage). 
• Increased risk of heart failure, atrial fibrillation, and stroke. 

2. Heart Failure 

• Severe carditis (heart inflammation) can weaken the heart muscles, leading to decreased pumping efficiency and heart failure. 

3. Arrhythmias 

• Damage to the heart’s conduction system may cause irregular heart rhythms (e.g., atrial fibrillation). 

4. Infective Endocarditis 

• Damaged heart valves are more prone to infection by bacteria, leading to infective endocarditis, a life-threatening condition. 

5. Joint Damage 

• Although arthritis from rheumatic fever is usually temporary, repeated episodes can cause long-term joint problems or chronic pain in rare cases. 

6. Neurological Complications 

• Sydenham’s chorea (involuntary movements caused by inflammation in the nervous system) can interfere with daily activities and emotional stability. 
• Persistent neurological symptoms may occur in rare cases. 

7. Recurrent Rheumatic Fever 

• Without proper secondary prophylaxis (e.g., regular antibiotic treatment), patients are at high risk of recurrent attacks, worsening complications like heart disease. 

8. Pregnancy-Related Complications 

• Women with rheumatic heart disease may face complications during pregnancy and childbirth due to the additional strain on the heart. 

9. Reduced Quality of Life 

• Chronic complications like heart failure or valvular disease can limit physical activity, reduce life expectancy, and require lifelong medical care or surgery. 

Prevention of Complications 

• Early Treatment: Treating group A streptococcal throat infections promptly can prevent rheumatic fever. 
• Secondary Prophylaxis: Long-term antibiotics to prevent recurrence. 
• Regular Follow-Up: Monitoring for heart complications in patients with a history of rheumatic fever. 

Addressing rheumatic fever early is essential to avoid these potentially severe complications.