Poststreptococcal Glomerulonephritis- Causes, Symptoms, and Management

Introduction

A rapid deterioration of the physiological functions of the kidney characterizes post-streptococcal glomerulonephritis. It occurs due to an inflammatory type III hypersensitivity reaction following the infection with certain streptococcal bacterial species strains. This disease specifically results from certain bacterial strains of group A beta-hemolytic streptococci, also known as nephrogenic streptococci. The disease primarily affects the renal glomeruli and kidneys' tiny blood vessels. It is most commonly seen in children one to two weeks after encountering a sore throat or six weeks post skin infection. It is mainly associated with decreased urine production, blood in the urine, high blood pressure, and edema.

What Are the Causes of Poststreptococcal Glomerulonephritis?

Post-streptococcal glomerulonephritis is a type of glomerulonephritis. An infection caused by a strain of streptococcus bacteria. The disorder usually develops after infections caused by group A Streptococcus (group A strep) bacterial species. These infections include:

• Strep throat (streptococcal infection in the throat and tonsils).

• Scarlet fever (bright red rash covering almost the entire body, with strep throat and high fever).

• Impetigo (highly contagious streptococcal skin infection of infants and young children).

Therefore, post-streptococcal glomerulonephritis is not a bacterial infection of the kidneys. Instead, it occurs due to the body’s immune system defending against strep throat, scarlet fever, or impetigo.

After the appearance of scarlet fever symptoms, usually, ten days are required for the disease to develop. After initiating impetigo symptoms, it takes approximately three weeks for poly streptococcal glomerulonephritis to develop. Other etiologic factors of post-streptococcal glomerulonephritis include bacterial infections such as:

• Endocarditis (inflammation and infection of the heart's inner lining).

• Enterocolitis (infection of both intestines).

• Pneumonia.

• Intraventricular shunt infections.

• Viral (hepatitis B and C infections, human immunodeficiency virus, cytomegalovirus, Epstein Barr virus).

• Fungal infections (coccidioidomycosis, histoplasmosis).

• Parasitic infections (malaria, leishmania, and toxoplasmosis).

Risk Factors:

• Poor Personal Hygiene - If the person is not practicing good personal hygiene, he may be a source of bacterial infection.

• Overcrowded Places - Overcrowded places are prone to more infections due to a lack of hygiene and improperly cleaned places.

• Low Socioeconomic Status (Poor People) - People below the poverty line cannot keep good hygiene practices and, therefore, can catch infections easily.

These factors are important predisposing factors for streptococcal infection outbreaks. This explains a higher incidence of post-streptococcal glomerulonephritis in developing countries.

• Genetic factors play a role since about 40 % of patients with the disease report a positive family history. However, there is no specific gene found to cause post-streptococcal glomerulonephritis.

What Is the Epidemiology of Poststreptococcal Glomerulonephritis?

The disease may develop in people of any age, but it most frequently affects children between six to ten years of age. Skin and throat infections are relatively common in children. But, post-streptococcal glomerulonephritis is a rare complication of these infections. This disease causes the small blood vessels to be inflamed in the filtering units of the kidneys (glomeruli). Hence, the kidneys filter less urine.

The condition is not commonly seen today in developed countries like the United States of America, the United Kingdom, Japan, and Central Europe because antibiotic prophylaxis and personal hygiene have improved patient conditions.

Poststreptococcal glomerulonephritisis the most frequent cause of kidney injury in young children, especially in the Middle East, Africa, Australia, and worldwide. The clinical symptoms of the disease are more frequently seen in males than females. Racial factors are not found to play any role in the occurrence of the disease.

What Are the Symptoms of Poststreptococcal Glomerulonephritis?

Clinical symptoms may include any of the following:

• Reduced urine output.

• Rust-colored or dark reddish-brown urine.

• Swelling (generalized edema), abdominal swelling, swollen face or eyes, swollen feet, ankles, and hands.

• Hematuria (visible blood in the urine).

• Joint pain (arthralgia).

• Stiffness or swelling of the joints.

• Decreased tendency to pee.

• Exhaustion and fatigue.

• Anemia.

• Hypertension (high blood pressure).

• Weight loss.

• Malaise.

• Nausea and vomiting.

• Anorexia.

Some of the children are mildly symptomatic or completely asymptomatic. Hematuria, edema, and high blood pressure are the classic triad of glomerulonephritis. Most patients have a history of recently encountered streptococcal infections like pharyngitis, tonsillitis, or impetigo.

What Are the Diagnostic Tests for Poststreptococcal Glomerulonephritis?

• Medical History - The family and medical history of the affected patient should be thoroughly investigated carefully.

• Physical Examination - A complete physical examination shows facial swelling (edema), especially around the eyes. Abnormal sounds may be produced in the heart and lungs that can be heard with a stethoscope. High blood pressure is usually observed.

• Anti-DNase B Test - A blood test is done to check for antibodies to a proteinaceous substance produced by group A streptococcus bacteria.

• Serum ASO (and Streptolysin O) Titer Test - This blood test checks for a strep infection.

• Serum Complement Levels - High serum complement levels suggest the level of inflammation in the body.

• Urinalysis - The physical, biochemical, and microscopic urine examination is usually carried out.

• Throat Cultures - An important investigation for the affected patient and family members.

What Is the Treatment of Poststreptococcal Glomerulonephritis?

There is no specific therapeutic cure for this disorder. It is a self-limiting disease. Treatment is mainly aimed at relieving the symptoms.

• Decreasing edematous swelling by reducing salt and water intake.

• Bed rest and immobilization are usually preferred in the initial days of the condition.

• Diuretics (medication that increases urine flow) are usually prescribed.

• Managing hypertension through blood pressure drugs.

• Antibiotics are prescribed to destroy any persistent streptococcal bacteria in the body.

• Corticosteroids and other immunosuppressive drugs are not found to be effective.

What Is the Prognosis of Poststreptococcal Glomerulonephritis?

Poststreptococcal glomerulonephritis is a self-limiting condition that usually goes away by itself after a few weeks to several months. It has an excellent prognosis in children. However, it may worsen and lead to long-term (chronic) kidney failure in a few adult patients. Rarely can it progress to end-stage renal disease, which requires dialysis and kidney transplantation.

Conclusion

Poststreptococcal glomerulonephritis is a kidney disease with a good prognosis, especially in children. But in a few cases, the disease can progress to end-stage kidney disease or nephrotic syndrome. A team of a specialized team of doctors should be consulted for the treatment of this disease and extend good patient care. Avoiding crowded places and maintaining personal hygiene are two very important precautions that a person should take to prevent infection. The patient should immediately consult the healthcare professional on the appearance of the clinical symptoms.