Poststreptococcal glomerulonephritis

In nephrology, post-streptococcal glomerulonephritis is a disorder of the glomeruli (glomerulonephritis), or small blood vessels in the kidneys, following an streptococci infection. This condition is essentially defined as an inflammation of the kidneys.

A closely related term is "post-infectious glomerulonephritis", which accounts for infections by other agents. However, this term is used much less frequently.

It can be a risk factor for future albuminuria.

Pathophysiology
The exact pathology remains unclear, but it is believed to be Type III hypersensitivity reaction. Immune complexes (antigen-antibody complexes formed during an infection) become lodged in the glomerular basement membrane. Complement activation leads to destruction of the basement membrane. It has also been proposed that specific antigens from certain nephrotoxic streptococcal infections have a high affinity for basement membrane proteins, giving rise to particularly severe, long lasting antibody response.

Presentation

 * Hematuria:
 * It may be microscopic and not identified by the patient.
 * It may be macroscopic and lead to dark brown or smoky urine.
 * Frank hematuria may occur in severe case.


 * Oliguria
 * It means urine output is less than 400 ml/day (normally 600 to 2500 ml/day).
 * May be not observed by the patient.


 * Edema
 * Acute Onset.
 * Mild to modest severity.
 * Pitting edema.
 * Starts in the eye lids and face then the lower and upper limbs then generalized ( Hydrocele,ascites.Pericardial and pleural effusion ).
 * It may be migratory : appear in eye lid in the morning ,disaapear in the afternoon and reappear around the ankle in the ambulant patients by the end of the day.


 * Hypertension
 * It is usually mild to moderate.
 * Hypertensive encephalopathy,heart failure and acute pulmonary edema may occur in severe cases.
 * Pulmonary congestion and congested neck veins may be present, but usually due to salt and water retention and less commonly heart failure.


 * General
 * Fever, headache, malaise, anorexia, nausea and vomiting.
 * Pallor due to edema and/or anemia.


 * Acute renal necrosis due to injury of capillary or capillary thrombosis.
 * Acute tubular obstruction by cast

Mechanism of Edema

 * Decreased glomerular permeability.
 * Secondary hyperaldosteronism.
 * Hypoalbuminemia.

Causes
Post-infectious glomerulonephritis can be a complication of streptococcal pharyngitis (strep throat).

Diagnosis
Diagnosis rarely requires a renal biopsy since there is usually a classical clinical presentation. There will be elevated levels of ASOT Ab and low complement levels in the blood.

Differential Diagnosis

 * 1) Other causes of acute glomerulonephritis with hypocomplementaemia:
 * 2) *Lupus nephritis
 * 3) *Type 1 membranoproliferative glomerulonephritis.
 * 4) *Bacterial endocarditis.
 * 5) *Shunt nephritis
 * 6) *Cryoglobulinemia
 * 7) Nephrotic syndrome.
 * 8) Other causes of generalized edema:
 * 9) *Malnutrition
 * 10) *Malabsorption
 * 11) *Renal affection
 * 12) *Liver cell failure.
 * 13) *Right side heart failure.
 * 14) *Angioneurotic edema
 * 15) Other causes of hematuria.