What is Post-Streptococcal Glomerulonephritis?
Post-streptococcal glomerulonephritis (PSGN) is an inflammatory kidney disorder that occurs as a complication following infection with certain strains of
group A Streptococcus, particularly those causing throat or skin infections. This condition is characterized by the sudden onset of symptoms such as
hematuria,
proteinuria, edema, and hypertension. PSGN is considered a classic example of a
post-infectious glomerulonephritis, where the immune response to the infection subsequently affects the kidneys.
How Does PSGN Develop?
PSGN develops due to an
immune-mediated response following a streptococcal infection. The pathogenesis involves the deposition of immune complexes in the glomeruli, leading to inflammation and damage. This immune response is triggered by
antigens from the streptococcal bacteria which stimulate the production of
antibodies. These antibodies form complexes with the antigens, depositing in the renal glomeruli and activating the
complement system, which results in glomerular injury.
PSGN most commonly affects children between the ages of 5 and 12, but it can occur in adults as well. Factors increasing the risk of developing PSGN include
recent streptococcal infections, overcrowded living conditions, and poor hygiene. Individuals with a history of
streptococcal pharyngitis or skin infections such as
impetigo are particularly susceptible.
The symptoms of PSGN typically appear 1 to 2 weeks after a streptococcal throat infection or 3 to 6 weeks after a skin infection. Common symptoms include:
Hematuria (blood in urine, often giving it a tea or cola color)
Proteinuria (excess protein in urine)
Edema (swelling, especially in the face, hands, and feet)
Hypertension (high blood pressure)
Fatigue and malaise
How is PSGN Diagnosed?
Diagnosis of PSGN is based on clinical presentation, history of recent streptococcal infection, and supportive laboratory tests. Key diagnostic tests include:
Urinalysis showing hematuria and proteinuria
Blood tests revealing elevated
anti-streptolysin O (ASO) titers
Decreased serum complement levels, particularly
C3 Renal biopsy, although rarely needed, may show the characteristic histological changes
Treatment for PSGN is primarily supportive as the condition is usually self-limiting. Management focuses on relieving symptoms and preventing complications:
Control of hypertension using antihypertensive medications
Diuretics to manage edema
Restriction of dietary sodium and fluids if necessary
In severe cases, dialysis may be required
Antibiotics are not used to treat PSGN itself but may be given to ensure eradication of the streptococcal infection.
What are the Prognosis and Complications?
The prognosis for PSGN is generally good, especially in children, with most recovering fully without long-term kidney damage. However, some individuals may experience persistent hypertension or
chronic kidney disease. Complications are more common in adults and may include nephrotic syndrome, acute renal failure, or progressive glomerulonephritis.
Can PSGN be Prevented?
Prevention of PSGN involves early and effective treatment of streptococcal infections. Prompt administration of appropriate
antibiotics for streptococcal pharyngitis can reduce the risk of developing PSGN. Public health measures aimed at improving hygiene and reducing overcrowding can also help decrease the incidence of streptococcal infections and subsequent PSGN.
