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NEPHROTIC SYNDROME
The
nephrotic syndrome is a common mode of presentation
of glomerular disease. It is not a diagnosis but
rather a term used to describe a clinical syndrome
that arises when the urinary protein excretion is
sufficient to produce hypoproteinaemic oedema. The
correlation between urinary protein excretion,
plasma albumin concentration, and the presence of
oedema is poor.
In
adults it is uncommon to develop oedema unless the
plasma albumin is less than 30 g/l, but many
patients will remain oedema-free with a plasma
protein of less than 25 g/l. Similarly, the degree
of proteinuria needed to cause hypoprotinaemia is
variable: some quote a urinary protein excretion of
3.5 g/day as being 'nephrotic', but it is best to
avoid a particular value as some patients develop
oedema with an excretion of less than 3.5 g/day,
whereas others will excrete greater amounts and
remain oedema-free.
The presence of the nephrotic syndrome indicates
that the patient has at least one of a wide range of
glomerular pathologies, which may reflect primary or
secondary renal disease. The different conditions
have very variable responses to treatment, get
precise diagnosis is essential to guide management.
Aside from the estimation of GFR (usually estimated
from serum creatinine by the Cockcroft and Gault
formula, or from a 24-h creatinine clearance),
quantitation of proteinuria, and measurement of
serum albumin, the routine investigation of all
patients with the nephrotic syndrome should include
a full blood count, tests for systemic lupus
erythematosus (SLE) (antinuclear antibody tests,
anti-double-stranded DNA (-dsDNA), estimation of
serum complement, hepatitis B and hepatitis C
serology, serum immunoglobulins, and protein
electrophoresis. a precise diagnosis of most cases
of the nephrotic syndrome can only be made
histologically, and renal biopsy should be performed
after checking platelets and a coagulation screen,
and imaging—usually by ultrasonography—to confirm
the presence of two anatomically normal kidneys.
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