Renal syndromes leading to abnormal kidney function:
An abnormality in kidney function can be detected by the following:
1) changes in serum creatinine concentration, reflecting changes in GFR
2) abnormalities in urinalysis
3) altered renal homeostatic mechanisms: for example, abnormal volume regulation,
hypertension, abnormal electrolyte profiles, metabolic acidosis, abnormal calcium
phosphorus metabolism, anemia.
4) abnormal renal imaging studies
Although there are numerous disease states and conditions which can lead to altered kidney
function, there are relatively few renal syndromes. Any condition affecting the function of the
kidney should address the following questions:
1) does this represent an acute or chronic process?
2) is the process primarily glomerular, tubular, or vascular in origin?
3) is the process inflammatory or noninflammatory?
4) is the process associated with an underlying systemic disease?
5) is this prerenal, intrinsic renal, or postrenal in origin?
The following is a list of syndromes associated with intrinsic renal disease. Disease
processes that alter kidney function must cause abnormalities in one of the following structures:
glomeruli, tubules or interstitial areas (tubulointerstitial areas), or renal vasculature.
Glomerular syndromes:
nephrotic syndrome
nephritic syndrome
rapidly progressive glomerulonephritis (the most severe form of the nephritic syndrome)
mixed nephritic nephrotic syndrome
mesangial pattern
chronic glomerular disease
Tubular syndromes:
noninflammatory tubular interstitial changes
inflammatory tubular interstitial changes
acute pyelonephritis
allergic interstitial nephritis (a form of inflammatory tubular interstitial disease)
chronic interstitial disease
Vascular syndromes:
prerenal azotemia (reduced renal blood flow or reduced renal perfusion pressure)
renal artery stenosis (unilateral or bilateral)
hypertensive nephrosclerosis (ischemic nephropathy)
vasculitis (typically presents as nephritic syndrome)
, Typical Features of the Main Renal Syndromes
Glomerular Syndromes:
I) Nephrotic syndrome: the pathognomonic abnormality is abnormal permeability of the
glomerular capillary wall to protein, leading to proteinuria. Since the major serum protein is
albumin the majority of urinary protein excretion in nephrotic syndrome will be albumin.
Clinical definition: proteinuria, hypoalbuminemia, edema formation, lipiduria. To produce this
syndrome, urinary protein excretion is typically > 3 g per day, corresponding to a spot urine
protein creatinine ratio of > 3, and urinary dipstick 3+ to 4+ positive for protein. This level of
proteinuria can be thought of as nephrotic range proteinuria. Patients with this level of proteinuria
have glomerular disease. Many patients, however, may have this degree of proteinuria without
the development of the complete clinical syndrome:i.e., they may have minimal or no edema and
relatively normal serum albumin concentration.
Patients with pure nephrotic syndrome typically have normal glomerular filtration rate, normal
blood pressure, normal acid-base status. The edema is a consequence of avid sodium retention
by the kidney as a result of enhanced renal tubular sodium reabsorption (particularly in the distal
tubule). The retained salt and water is primarily restricted to extracellular fluid volume. Because
of decreased plasma oncotic pressure (due to albuminuria), there is disproportionate increase in
the size of the interstitial fluid volume. The plasma volume remains normal, until there is
profound hypoalbuminemia (<2g/dl). There may be associated pleural effusions and ascites with
severe volume retention. Since intravascular volume remains normal, pulmonary edema is not a
feature of nephrotic syndrome. Hypercholesterolemia is frequently present with nephrotic
syndrome.
Typical urinary findings: 3+ to 4+ positive dipstick for protein (dipstick is specific for albumin).
Remainder of the dipstick tests are normal. Urinary concentration is intact. Urinary sediment:
generally unremarkable. There may be oval fat bodies and fatty casts related to lipiduria.
Clinical examples: most common cause in children is minimal change disease. Most common
intrinsic glomerular disease leading to nephrotic syndrome in Caucasian adults is membranous
glomerulopathy. Most common cause in African-American adults is focal segmental
glomerulosclerosis and second leading cause in this population is membranous glomerulopathy.
Some of the diseases leading to nephrotic syndrome can progress to chronic renal insufficiency.
This is particularly true for focal segmental glomerulosclerosis, but may also occur with
membranous glomerulopathy. Chronic renal disease is extremely unusual with minimal change
disease.
The most common cause of nephrotic syndrome in adults is diabetic nephropathy. Diabetic
nephropathy is a slowly developing noninflammatory process which is first clinically detected by
the presence of microalbuminuria and later with overt proteinuria, frequently leading to nephrotic
syndrome. By the time heavy proteinuria is present there is also decreasing glomerular filtration
rate. The disease progresses to chronic renal insufficiency and ultimately end-stage renal
disease. Diabetic nephropathy is the most common etiology for end-stage renal disease in the
United States.
Disease states which lead to nephrotic syndrome and chronic renal insufficiency are frequently
An abnormality in kidney function can be detected by the following:
1) changes in serum creatinine concentration, reflecting changes in GFR
2) abnormalities in urinalysis
3) altered renal homeostatic mechanisms: for example, abnormal volume regulation,
hypertension, abnormal electrolyte profiles, metabolic acidosis, abnormal calcium
phosphorus metabolism, anemia.
4) abnormal renal imaging studies
Although there are numerous disease states and conditions which can lead to altered kidney
function, there are relatively few renal syndromes. Any condition affecting the function of the
kidney should address the following questions:
1) does this represent an acute or chronic process?
2) is the process primarily glomerular, tubular, or vascular in origin?
3) is the process inflammatory or noninflammatory?
4) is the process associated with an underlying systemic disease?
5) is this prerenal, intrinsic renal, or postrenal in origin?
The following is a list of syndromes associated with intrinsic renal disease. Disease
processes that alter kidney function must cause abnormalities in one of the following structures:
glomeruli, tubules or interstitial areas (tubulointerstitial areas), or renal vasculature.
Glomerular syndromes:
nephrotic syndrome
nephritic syndrome
rapidly progressive glomerulonephritis (the most severe form of the nephritic syndrome)
mixed nephritic nephrotic syndrome
mesangial pattern
chronic glomerular disease
Tubular syndromes:
noninflammatory tubular interstitial changes
inflammatory tubular interstitial changes
acute pyelonephritis
allergic interstitial nephritis (a form of inflammatory tubular interstitial disease)
chronic interstitial disease
Vascular syndromes:
prerenal azotemia (reduced renal blood flow or reduced renal perfusion pressure)
renal artery stenosis (unilateral or bilateral)
hypertensive nephrosclerosis (ischemic nephropathy)
vasculitis (typically presents as nephritic syndrome)
, Typical Features of the Main Renal Syndromes
Glomerular Syndromes:
I) Nephrotic syndrome: the pathognomonic abnormality is abnormal permeability of the
glomerular capillary wall to protein, leading to proteinuria. Since the major serum protein is
albumin the majority of urinary protein excretion in nephrotic syndrome will be albumin.
Clinical definition: proteinuria, hypoalbuminemia, edema formation, lipiduria. To produce this
syndrome, urinary protein excretion is typically > 3 g per day, corresponding to a spot urine
protein creatinine ratio of > 3, and urinary dipstick 3+ to 4+ positive for protein. This level of
proteinuria can be thought of as nephrotic range proteinuria. Patients with this level of proteinuria
have glomerular disease. Many patients, however, may have this degree of proteinuria without
the development of the complete clinical syndrome:i.e., they may have minimal or no edema and
relatively normal serum albumin concentration.
Patients with pure nephrotic syndrome typically have normal glomerular filtration rate, normal
blood pressure, normal acid-base status. The edema is a consequence of avid sodium retention
by the kidney as a result of enhanced renal tubular sodium reabsorption (particularly in the distal
tubule). The retained salt and water is primarily restricted to extracellular fluid volume. Because
of decreased plasma oncotic pressure (due to albuminuria), there is disproportionate increase in
the size of the interstitial fluid volume. The plasma volume remains normal, until there is
profound hypoalbuminemia (<2g/dl). There may be associated pleural effusions and ascites with
severe volume retention. Since intravascular volume remains normal, pulmonary edema is not a
feature of nephrotic syndrome. Hypercholesterolemia is frequently present with nephrotic
syndrome.
Typical urinary findings: 3+ to 4+ positive dipstick for protein (dipstick is specific for albumin).
Remainder of the dipstick tests are normal. Urinary concentration is intact. Urinary sediment:
generally unremarkable. There may be oval fat bodies and fatty casts related to lipiduria.
Clinical examples: most common cause in children is minimal change disease. Most common
intrinsic glomerular disease leading to nephrotic syndrome in Caucasian adults is membranous
glomerulopathy. Most common cause in African-American adults is focal segmental
glomerulosclerosis and second leading cause in this population is membranous glomerulopathy.
Some of the diseases leading to nephrotic syndrome can progress to chronic renal insufficiency.
This is particularly true for focal segmental glomerulosclerosis, but may also occur with
membranous glomerulopathy. Chronic renal disease is extremely unusual with minimal change
disease.
The most common cause of nephrotic syndrome in adults is diabetic nephropathy. Diabetic
nephropathy is a slowly developing noninflammatory process which is first clinically detected by
the presence of microalbuminuria and later with overt proteinuria, frequently leading to nephrotic
syndrome. By the time heavy proteinuria is present there is also decreasing glomerular filtration
rate. The disease progresses to chronic renal insufficiency and ultimately end-stage renal
disease. Diabetic nephropathy is the most common etiology for end-stage renal disease in the
United States.
Disease states which lead to nephrotic syndrome and chronic renal insufficiency are frequently
