Post-streptococcal Glomerulonephritis Information
Acute proliferative glomerulonephritis is a disorder of the glomeruli (glomerulonephritis), or small blood vessels in the kidneys. It is a common complication of infections, typically streptococcal skin infection (impetigo) rather than streptococcal pharyngitis, for which it is also known as postinfectious or poststreptococcal glomerulonephritis.[1]
It can be a risk factor for future albuminuria.[2]
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Causes
Acute proliferative glomerulonephritis can be a complication of streptococcal pharyngitis (strep throat) and impetigo.
Pathophysiology
Schematic representation.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 below the podocyte foot processes. This creates a lumpy bumpy appearance on light microscopy and subepithelial humps on electron microscopy. 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.
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 (C3 and C4) in the blood.
Presentation
- May be microscopic and not identified by the patient.
- May be macroscopic and lead to dark brown or smoky urine.
- Frank hematuria may occur in severe case.
2) Oliguria
- Urine output is less than 400 ml/day (normally 600 to 2500 ml/day). In children less than 0.5 mL/ kg/ hr.
- May not be observed by the patient.
3) Edema
- Acute onset.
- Mild to modest severity.
- Pitting edema.
- Starts in the eyelids and face then the lower and upper limbs then generalized (Hydrocele, ascites. Pericardial and pleural effusion.)
- It may be migratory: appear in eyelid in the morning, disappear in the afternoon and reappear around the ankle in the ambulant patients by the end of the day.
4) 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.
5) General
- Fever, headache, malaise, anorexia, nausea and vomiting.
- Pallor due to edema and/or anemia.
6) Acute renal necrosis due to injury of capillary or capillary thrombosis.
- Acute tubular obstruction by cast.
Mechanism of edema
Diffuse Proliferative Glomerulonephritis (DPGN) is a nephritic syndrome; therefore, it causes edema through an increase in hydrostatic pressure and fluid overload secondary to inflammatory damage. Examples of nephritic syndrome include: DPGN, IgA nephropathy, Lupus nephritis, and MPGN.
Hypoalbuminemia is the cause of edema in nephrotic syndrome (characterized by heavy proteinuria—greater than 3.5g/day). Examples include: Minimal Change Disease (MCD), Membranous Glomerulonephritis (MGN), Focal Segmental Glomerulosclerosis (FSGS), Lupus, Amyloidosis, and Diabetes.
Differential diagnosis
- Other causes of acute glomerulonephritis:
- IgA Nephropathy
- Lupus nephritis
- Type 1 membranoproliferative glomerulonephritis
- Bacterial endocarditis
- Shunt nephritis
- Cryoglobulinemia
- Nephrotic syndrome
- Other causes of generalized edema:
- Malnutrition
- Malabsorption
- Renal affection
- Liver cell failure
- Right side heart failure
- Angioedema
- Other causes of hematuria
Complications
Possible complications of acute proliferative glomerulonephritis include renal failure and hypertensive encephalopathy.
References
- ^ Baltimore RS (February 2010). "Re-evaluation of antibiotic treatment of streptococcal pharyngitis". Curr. Opin. Pediatr. 22 (1): 77–82. doi:10.1097/MOP.0b013e32833502e7. PMID 19996970.
- ^ White AV, Hoy WE, McCredie DA (May 2001). "Childhood post-streptococcal glomerulonephritis as a risk factor for chronic renal disease in later life". Med. J. Aust. 174 (10): 492–6. PMID 11419767. http://www.mja.com.au/public/issues/174_10_210501/white/white.html.
- ^ Sung HY, Lim CH, Shin MJ, et al. (December 2007). "A case of post-streptococcal glomerulonephritis with diffuse alveolar hemorrhage". J. Korean Med. Sci. 22 (6): 1074–8. doi:10.3346/jkms.2007.22.6.1074. PMID 18162726. http://jkms.org/contents/jkms.php?pubyear=2007&vol=22&fpage=1074.
External links
- Post-infectious glomerulonephritis - Mayo Clinic
- Group A Streptococcal Infections - National Institute of Allergy and Infectious Diseases
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