Is post-streptococcal glomerulonephritis contagious?

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Post-streptococcal glomerulonephritis itself is not contagious. However, group A streptococcus bacteria - the cause of the disease can be transmitted from person to person. Therefore, the best way to avoid post-streptococcal glomerulonephritis is to maintain good hygiene and encourage everyone to do the same.

1. Cause

Post-streptococcal glomerulonephritis (PSGN) is a late immune-mediated sequelae of pharyngitis or skin infection. Immunity-mediated is an immune response that does not involve antibodies.
Disease caused by strains of Streptococcus pyogenes, also known as S. pyogenes / Group A Streptococcus / strep. According to reported data, cases of acute glomerulonephritis following infection with group C streptococci are very rare.
S. pyogenes are gram-positive cocci, growing in chains. They exhibit beta hemolysis (complete hemolysis) when cultured on isolated blood agar. This bacterium belongs to group A in the Lancefield classification system for streptococci and is therefore also known as group A streptococci.

2. Characteristics

Signs of acute glomerulonephritis after streptococcal infection include:
Edema, mainly in the face and eye bags, especially in the morning after waking up; Hypertension ; Proteinuria ; Macroscopic hematuria, presenting with dark, reddish-brown urine; The person is lethargic, tired or anorexia. In terms of clinical examination, laboratory examination usually shows:
Mild red blood cell isochromic anemia; Mild hypoproteinemia; Increased blood urea nitrogen and creatinine; The erythrocyte sedimentation rate is high; Whole hemolysis and low C3 complement. Patients often have decreased urine output. Urine examination revealed protein (approximately < 3 grams per day) and hemoglobin with red blood cell waste.
There are cases that still find the subclinical indicators of glomerulonephritis after streptococcal infection even though the external signs are so mild that the patient does not need medical attention.

3. Is glomerulonephritis contagious after a streptococcal infection?

As a late sequelae of group A strep infection, post-streptococcal glomerulonephritis itself is not contagious. However, people often spread group A strep from person to person through direct contact.
Usually, the main route of transmission is through saliva or nasal secretions from an infected person. Symptomatic patients are much more likely to transmit the bacteria than asymptomatic carriers. Crowded gathering places - such as schools, daycare centers, or military training camps - often facilitate the spread of bacteria.
Although rare, group A strep infections can also be spread through food if not handled properly. Commonly found carriers, such as utensils, dishes, or toys, are unlikely to spread this bacteria. Humans are the main reservoir of group A strep, and there is no evidence that pets can transmit the bacteria to humans.
Post-streptococcal glomerulonephritis occurs after an incubation period of about 10 days, counting from the time of recovery from group A streptococcal pharyngitis. Thus, acute glomerulonephritis usually appears about 3 weeks after the onset of streptococcal infection. strep bacteria.

4. Risk factors

The risk factors for post-streptococcal glomerulonephritis are the same as those for pharyngitis or impetigo caused by group A streptococcal infections. It is more common in children, but can also occur in adults. . Acute glomerulonephritis associated with pharyngitis is most common in school-age children, while post-infectious skin disease is more common in preschool-aged children.
There are no specific risk factors for acute post-streptococcal glomerulonephritis. However, the risk is increased if a strain of group A kidney disease bacteria enters the household.
A 1960 study found that the rate of developing acute glomerulonephritis following a sore throat or skin infection caused by a group A nephritogen strain was between 10 and 15%. There are an estimated 470,000 cases of post-streptococcal glomerulonephritis worldwide each year and 5,000 deaths.

5. Diagnosis and treatment

For the differential diagnosis of acute glomerulonephritis after streptococcal infection, it should be based on whether the cause of acute glomerulonephritis is infectious or non-infectious. Through the test can also detect:
Group A strep bacteria from the throat; Isolation of group A strep from skin lesions; Streptococcus antibodies are elevated. Treatment of post-streptococcal glomerulonephritis focuses on controlling hypertension and edema. In addition, patients should take penicillin (preferably penicillin G benzathine) to eliminate the strain of kidney disease, which helps prevent it from spreading to others.
The prognosis of post-streptococcal glomerulonephritis in children is very good, more than 90% of children recover completely. Adults with acute glomerulonephritis due to streptococcal infection are at increased risk of worsening of renal function.

6. Prevention

Antibiotics are not effective in preventing acute glomerulonephritis from developing in people with a streptococcal infection (which causes impetigo or sore throat). So it's important to prevent group A strep infections or sore throats. However, treating patients with acute post-streptococcal glomerulonephritis with antibiotics can prevent a strain of the bacteria that causes kidney disease that runs in the family.
Hand and nose-throat hygiene is a way to reduce the spread of all types of group A strep infections. Hand washing with soap is especially important after coughing and sneezing, as well as before cooking. or dine. Cover your mouth when sneezing or coughing with your elbow or towel. Infected people need to be treated with antibiotics for at least 24 hours to rule out the possibility of bacterial transmission. Therefore, people with sore throats or impetigo caused by group A strep infections should stay home, not go to work, school or daycare until:
No more fever and fatigue; Have been treated with appropriate antibiotics for at least 24 hours. Acute streptococcal glomerulonephritis is a slow-growing sequelae of pharyngitis or skin infections, caused by strains of S. pyogenes. Once it has progressed to acute glomerulonephritis, it is not contagious, but someone with a previous strep throat or impetigo can pass the bacteria on to others. Keeping hands clean, covering coughs and sneezes, isolating people with sore throats or skin infections, combined with antibiotic treatment for 24 hours or more can prevent disease transmission between related members. closeness in family and community.
Post-streptococcal glomerulonephritis itself is not contagious. However, group A streptococcus bacteria - the cause of the disease can be transmitted from person to person. Therefore, people with respiratory diseases such as sore throat or skin infections should pay attention and limit contact to avoid spreading to the community. Accordingly, it is necessary to visit medical centers for examination and appropriate treatment, to avoid possible dangerous complications.
Vinmec International General Hospital is a general hospital with the function of examining, diagnosing and treating many diseases. At Vinmec, there are all necessary medical equipment to perform simple to complex treatment methods such as medical treatment, surgery, medical intervention, research,... Especially, at Vinmec. Vinmec always has a team of highly qualified doctors and nurses who have undergone training and are technically certified, able to handle quickly and effectively, especially in cases of urgent emergency. Therefore, patients can be assured of a strict, methodical and effective treatment process at Vinmec.

References: cdc.gov, ada.com

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