How is rheumatic fever diagnosed?

Having a purulent Sore throat or measles (scarlet fever) following an infection with a special bacterium called Streptococcus (Streptococcus pyogenes) can lead to an inflammatory disease called rheumatic fever in a group of people (especially children and adolescents).

Acute rheumatic fever can cause symptoms in the heart, brain and joints, etc. Diagnosis of rheumatic fever is important because without treatment, rheumatic fever can lead to permanent heart failure or permanent heart valve dysfunction. But How is rheumatic fever diagnosed?

Before we learn about how to diagnose rheumatic fever, let’s get acquainted with the causes and symptoms of this inflammatory disease:

 

 

Causes of rheumatic fever

A group of bacteria called group streptococcus A are the main culprits in the formation of acute rheumatic fever. This group, also called strep pyogenes, can cause the following diseases:

• Throat
• infection
• Measles or scarlet fever
• Skin infections, jaundice and cellulite, etc.
• Infections of other parts of the body

But it is interesting to know that throat infections with strep pyogenes are the most common cause of rheumatic fever. After a throat infection, measles can cause RF in some people, but other than these two, Strep infections on the skin and other parts of the body can rarely cause rheumatic fever.

This is because strep pyogenes have a special protein that the immune system mobilizes against to kill the bacteria. This protein is very similar to the proteins that are found naturally on the surface of cells in the heart wall and other parts of our body (nervous system, skin and joints). Therefore, the immune system of a person with a throat strep infection mistakenly causes damage to heart cells and so on.

Proper medication and completion of treatment for purulent sorethroat and measles will greatly reduce your child’s chances of developing acute rheumatic fever and its complications.

Of course, the relationship between group streptococcal infections and rheumatic fever is not completely clear and precise, but what we described above is still expressed as a process Immune system damage to the heart, and … following purulent sore throat and measles.

 

Who is most at risk for acute rheumatic fever?

Rheumatic fever is less common in developed countries today, despite appropriate and timely antibiotic treatments, but its incidence is still high in developing countries.

The following increases the risk of developing rheumatic fever:

• Type of bacteria:

It seems that a group of strep A bacteria are more associated with rheumatic fever than other types of this group.

• Genetics and family history:

Some families have genes that make them more susceptible to rheumatic fever.

Repeated exposure to Streptococcus pyogenes can also increase the incidence and risk of rheumatic fever.

In general, children over the age of five and adolescents under the age of 15 are the main affected groups, but rheumatic fever can affect younger or older ages.

 

Symptoms of acute rheumatic fever

Symptoms usually appear two to four days after a purulent sorethroat or measles. A person can have only a limited number of the following symptoms. Sometimes a person with rheumatic fever experiences a large number of the following clinical symptoms. Rheumatic fever Symptoms  can change during illness.

Inflammation in the heart, joints, cells of the nervous system, skin, etc. leads to the following symptoms:

• Fever

• Joint involvement: (especially, knees, wrists, elbows and ankles)
• Joints become painful.
• Joint tenderness (when the joint is touched or pressed slightly, the patient feels pain).
• Redness and warmth of the joint.
• Swelling of the joints.
• Inflammation and joint pain in rheumatic fever can migrate from one joint to another.
• Skin involvement:

Prominent and painless subcutaneous lesions (subcutaneous nodules)

In the form of flat or slightly raised skin and pink color that extends from the margins and can disappear in the first place and appear on another part of the skin.

And are called migratory erythema.

• Fatigue

• Cardiac symptoms:
• Chest pain

Symptoms of rheumatic fever include a new heart sound that can be heard by a doctor(Heart murmur).

• Symptoms in the nervous system:
• Sydenham chorea (SC): jumps and movements of the head, neck, arms and legs, which are uncontrollable.
• Behavioral changes and inappropriate behaviors in inappropriate and unusual situations, such as inappropriate laughter or crying.
• Bad handwriting of affected children.

 

What are the complications of rheumatic fever?

Rheumatic heart disease can become permanent (rheumatic heart disease), These lesions usually become institutionalized in the heart of a person with rheumatic fever about ten years later, But children with severe rheumatic fever develop valvular problems at the same time as the symptoms.

Cardiac complications of rheumatic fever include:

• Cardiac valve disorders (especially mitral valve):
• Valve stenosis
• Valve failure
• Inflammation of the heart muscle can lead to muscle weakness and the heart’s inability to pump blood, leading to heart failure.
• Cardiac arrhythmias

 

How is rheumatic fever diagnosed?

It is not possible to name a specific test to diagnose 100% of rheumatic fever.

The patient’s history, in addition to clinical examination such as listening to heart sounds and skin examination, are very important for seeing the characteristic conflicts of rheumatic fever.

In your examination and history, your doctor will consider the following:

Examines your joints for swelling, pain and tenderness, and redness and warmth.

Examination of the skin is important in diagnosing rheumatic fever:

People with rheumatic fever can develop subcutaneous masses that are painless and visible on the bumps on the bones around the elbow, or on the forearm, or on the back of the head.

Another type of skin involvement in these people is a slightly raised or flat skin lesion that usually extends from the margins and the center is white and light. These lesions can be seen on the body or hands, arms, thighs and legs.

Interestingly, one of the manifestations of nervous system involvement in children with rheumatic fever is their bad handwriting.

In addition to a history and examination, the following tests can help diagnose acute rheumatic fever.

 

Laboratory tests:

Evaluation of blood samples for the presence of Strep Pyogen antibacterial antibodies (Group A streptococcus)

Examination and measurement of blood markers that indicate the presence of inflammation in the body, such as: ESR, CRP

If a patient with a purulent throat infection has undergone a throat swab test and is diagnosed with strep pyogenesis or group A streptococcus, and now has seen a doctor with suspicious symptoms, It is no longer necessary to perform laboratory tests above.

 

ECG or EKG or  electrocardiogram :

Your doctor can take an ECG to check the electrical activity of the heart muscle, and if a part of the heart changes due to rheumatic fever, it will leave a mark on the ECG.

For example, if your heart has an enlargement following rheumatic fever, your doctor will notice a problem by looking at your ECG.(?)

 

Echo of the heart:

Your doctor will do a cardiac echo to monitor the activity of your heart muscle as well as the function of your heart valves.

Also, with cardiac echo in a person who is suspicious of having rheumatic fever, the doctor notices narrowing or failure of the heart valves.

Doctors around the world have defined the same diagnostic criteria in order to take the same approach to diagnosing rheumatic fever, and therefore the diagnosis of rheumatic fever will be the same everywhere in the world.

 

What are the criteria for diagnosing rheumatic fever?

Two categories of diagnostic criteria are defined:

1. Major diagnostic criteria for rheumatic fever
2. Minor diagnostic criteria for rheumatic fever

 

1. Major diagnostic criteria for rheumatic fever which are:

• Carditis (inflammation of the heart)
• Arthritis (joint inflammations): Involvement of more than two joints or polyarthritis
• Sydenham chorea (SC) (a symptom that indicates inflammation of the nervous system and is in the form of uncontrollable movements of the head, arms and legs)
• Erythema migrans (described above)
• Subcutaneous nodules (described above)

 

2. Minor diagnostic criteria for rheumatic fever are:

• Arthritis: Involvement of two joints or less (oligoarthritis).
• Fever (greater than or equal to thirty-eight and a half degrees Celsius).
• ESR greater than or equal to sixty (millimeters) or CRP greater than or equal to three (milligrams per deciliter).
• A type of change observed in an infected person’s ECG that is called a prolonged PR interval.

The diagnostic criteria for rheumatic fever mentioned above is called Jones Criteria.

Now the question is, how do doctors use these criteria to diagnose rheumatic fever?

When is the diagnosis of rheumatic fever definitive?

• There are at least two major criteria.
• There should be one major criterion plus two sub-criteria plus a history of a group A strep throat infection.

 

How long does rheumatic fever last?

Rheumatic fever usually occurs two to six weeks after a purulent Sore throat and can last for six weeks to six months.

 

When is it necessary to see a doctor?

• If you see skin lesions characteristic of rheumatic fever, you should see a doctor.
• If you have migratory pain, swelling, and inflammation of your joints.
• If you have chest pain and a recent history of throat infection.

We note that rheumatic fever is common in the age group of five to fifteen years, so if you see the mentioned symptoms, the child should be examined by a doctor to reduce the risk of heart complications with medical interventions.

 

Prevention of rheumatic fever

The only way to prevent it is to take the correct antibiotic treatment for purulent sore throat or measles and complete the course of treatment.

The discovery of penicillin has reduced the incidence of rheumatic fever and its complications in a large group of the world’s population.

 

Treatment of rheumatic fever

After the definitive diagnosis of rheumatic fever and the rejection of differential diagnoses such as rheumatoid arthritis in  adolescents , lupus, etc., the person is hospitalized and receives steroids (corticosteroids) in case of heart conflict. Penicillin is also needed to kill strep pyogenic bacteria.

Depending on the condition of the patient, penicillin should be taken once in a month sometimes up to a certain age (for example, forty-five years old) and sometimes up to the end of life. If the treatment is not completed, the person will have recurrent purulent sore throat with group A strep, causing recurrence of rheumatic fever and symptoms of rheumatic heart disease.