ACUTE GLOMERNEPHRITIS IN CHILDREN
DEFINITION
Glomerulopathies form the heterogeneous group of kidney diseases with
initial glomerular lesion. The secondary involvement of other components of renal
tissue (tubules, vessels or interstitium) may be observed later on. There is a huge
variety of causes, pathogenetic patterns, clinical presentations and morphological
features, as well as course (natural history) and outcome in the group of
glomerulopathies.
CLASSIFICATION GLOMERULONEPHRITIS
All glomerulopathies are divided in:
– primary or idiopathic — glomerular lesion occurs primarily in absence of
any systemic condition, which may cause kidney disease;
– secondary — glomerular lesion is a result of systemic illness (more often
systemic disease of connective tissue, for example systemic lupus erythematosus,
systemic vasculitis, etc.).
According to the disease course glomerulopathy can be:
– acute (e.g. endocapillary glomerulonephritis (GN));
– chronic (e.g. membranoproliferative GN, IgA nephropathy, focal
segmental glomerulosclerosis, etc.);
– rapidly progressive (extracapillary GN).
There are clinical classifications of glomerulopathies, which are based on
clinical presentation and course of the disease, and morphological one, which is
considered to be a ―gold standard‖, predominantly in case of chronic illness.
However, not always morphological diagnostics is needed (especially in case of
acute illness or hormone sensitive nephrotic syndrome). That is why both
classifications, based on clinical manifestations and morphological diagnosis,
remain of importance in clinical practice.
3
, Often there isn’t strong correlation between clinical pattern and
morphological changes found on kidney biopsy. However, some clinical patterns
may be designated:
1. Nephritic syndrome, which is the most characteristic for acute
poststreptococcal or post infectious (endocapillary) GN.
2. Nephrotic syndrome, which in young children is predominantly due to
minimal changes disease.
3. Rapidly progressive GN, with nephrotic syndrome with hematuria and/or
hypertension at presentation is characteristic for crescentic (extracapillary) GN.
4. Recurrent macroscopic hematuria (with or without proteinuria), which is
often a sign of Berge’s nephropathy.
According to the type of initial glomerular lesion glomerulopathies can be
(figure 1).
Glomerular lesion
Non-inflammatory Inflammatory (glomerulonephritis)
Minimal changes Acute poststreptococcal/postinfectious GN
Membranous nephropathy Chronic GN:
Focal-segmental glomerulosclerosis – proliferative (crescentic or extracapillary);
Thin membranes disease – membranous proliferative;
Diabetic nephropathy – mesangial proliferative GN;
Amyloid nephropathy – fibroplastic (sclerotic) GN (focal, diffuse)
Ischemic nephropathy
Fig. 1. Types of glomerular lesions
Non-inflammatory glomerulopathies are characterized by parenchymatous
dystrophy or/and changes of glomerular basement membrane (GBM),
disorganization or sclerosis of mesangial matrix. No or minimal signs of
proliferation or glomerular infiltration can be observed. These caused by, in
majority of cases, non immune-mediated damage, for example, amyloid deposition.
In case of immune injury (in minimal changes nephrotic syndrome),
the attack is targeted at visceral epithelial cells, which are called podocytes, and
the type of lesion is called podocytopathy.
In inflammatory glomerulopathies (true glomerulonephritis) immune attack is
targeted at endothelial cells, mesangium, epi-, peri- and intramembranous
structures. Classical signs of inflammation are observed: infiltration, proliferation,
exudation, alteration and function impairment. Immune mediated injury involves
immunoglobulin’s deposition and inflammatory cells migration from blood flow
in glomerulus, these both may be resulting in direct damage to glomerular cells
and in inflammatory response of residential glomerular cells, mesangial
proliferation and hyperproduction of mesangial matrix, thickening of glomerular
basement membrane, proliferation of parietal epithelial cells with crescents
formation.
4
DEFINITION
Glomerulopathies form the heterogeneous group of kidney diseases with
initial glomerular lesion. The secondary involvement of other components of renal
tissue (tubules, vessels or interstitium) may be observed later on. There is a huge
variety of causes, pathogenetic patterns, clinical presentations and morphological
features, as well as course (natural history) and outcome in the group of
glomerulopathies.
CLASSIFICATION GLOMERULONEPHRITIS
All glomerulopathies are divided in:
– primary or idiopathic — glomerular lesion occurs primarily in absence of
any systemic condition, which may cause kidney disease;
– secondary — glomerular lesion is a result of systemic illness (more often
systemic disease of connective tissue, for example systemic lupus erythematosus,
systemic vasculitis, etc.).
According to the disease course glomerulopathy can be:
– acute (e.g. endocapillary glomerulonephritis (GN));
– chronic (e.g. membranoproliferative GN, IgA nephropathy, focal
segmental glomerulosclerosis, etc.);
– rapidly progressive (extracapillary GN).
There are clinical classifications of glomerulopathies, which are based on
clinical presentation and course of the disease, and morphological one, which is
considered to be a ―gold standard‖, predominantly in case of chronic illness.
However, not always morphological diagnostics is needed (especially in case of
acute illness or hormone sensitive nephrotic syndrome). That is why both
classifications, based on clinical manifestations and morphological diagnosis,
remain of importance in clinical practice.
3
, Often there isn’t strong correlation between clinical pattern and
morphological changes found on kidney biopsy. However, some clinical patterns
may be designated:
1. Nephritic syndrome, which is the most characteristic for acute
poststreptococcal or post infectious (endocapillary) GN.
2. Nephrotic syndrome, which in young children is predominantly due to
minimal changes disease.
3. Rapidly progressive GN, with nephrotic syndrome with hematuria and/or
hypertension at presentation is characteristic for crescentic (extracapillary) GN.
4. Recurrent macroscopic hematuria (with or without proteinuria), which is
often a sign of Berge’s nephropathy.
According to the type of initial glomerular lesion glomerulopathies can be
(figure 1).
Glomerular lesion
Non-inflammatory Inflammatory (glomerulonephritis)
Minimal changes Acute poststreptococcal/postinfectious GN
Membranous nephropathy Chronic GN:
Focal-segmental glomerulosclerosis – proliferative (crescentic or extracapillary);
Thin membranes disease – membranous proliferative;
Diabetic nephropathy – mesangial proliferative GN;
Amyloid nephropathy – fibroplastic (sclerotic) GN (focal, diffuse)
Ischemic nephropathy
Fig. 1. Types of glomerular lesions
Non-inflammatory glomerulopathies are characterized by parenchymatous
dystrophy or/and changes of glomerular basement membrane (GBM),
disorganization or sclerosis of mesangial matrix. No or minimal signs of
proliferation or glomerular infiltration can be observed. These caused by, in
majority of cases, non immune-mediated damage, for example, amyloid deposition.
In case of immune injury (in minimal changes nephrotic syndrome),
the attack is targeted at visceral epithelial cells, which are called podocytes, and
the type of lesion is called podocytopathy.
In inflammatory glomerulopathies (true glomerulonephritis) immune attack is
targeted at endothelial cells, mesangium, epi-, peri- and intramembranous
structures. Classical signs of inflammation are observed: infiltration, proliferation,
exudation, alteration and function impairment. Immune mediated injury involves
immunoglobulin’s deposition and inflammatory cells migration from blood flow
in glomerulus, these both may be resulting in direct damage to glomerular cells
and in inflammatory response of residential glomerular cells, mesangial
proliferation and hyperproduction of mesangial matrix, thickening of glomerular
basement membrane, proliferation of parietal epithelial cells with crescents
formation.
4
