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Chapter 6: Disorders of the kidney 243

Table 6.7 Causes of nephrotic syndrome Acute renal failure may occur due to hypovolaemia
(often diuretic-induced), or in some cases there is
Approx.
Cause percentage both glomerular and tubular damage. Most causes of
nephrotic syndrome do not cause ARF.
Secondary, e.g. DM, SLE, amyloidosis, 35%
Loss of specific binding proteins, e.g. transferrin, lead-
drugs, pre-eclampsia etc.
Membranous glomerulonephritis 20% ing to iron-resistant hypochromic anaemia.
Focal segmental glomerulosclerosis (FSGS) 20% Protein malnutrition.
Minimal change disease 10%
Any proliferative glomerulonephritis, e.g. 10%
IgA nephropathy Investigations
Mesangiocapillary glomerulonephritis 5% Measured or calculated creatinine clearance and total
protein.
Urine microscopy.

Haematuria and renal failure are therefore usually minor Bence Jones protein (to look for myeloma).
or absent.Albumin is the main protein lost, but clotting BloodforU&Es,albumin,cholesterol,FBC,ESR,CRP.
factors, transferrin and other proteins may be lost as Avariety of other blood tests may be able to suggest
well. The liver is able to synthesise enough albumin to a diagnosis, such as serum protein electrophoresis,
compensate for the losses initially, but if protein losses ANA, anti-dsDNA, C 3 ,C 4 .
are large, hypoalbuminaemia results. Peripheral oedema Renal biopsy is indicated in most cases, but children
is the result of a fall in plasma oncotic pressure, so that and teenagers without haematuria, hypertension or
fluid stays in the tissues, and also sodium retention by renal impairment are very likely to have minimal
the kidney. change disease, so if a trial of steroids leads to full
remission, biopsy may be avoided.
Clinical features
Gradual development of swelling of eyelids, peripheral Management
oedema, ascites and pleural effusions. The urine may be Treatment of the underlying cause.
frothy due to proteinuria. There may be relevant history ACE-inhibitors are used to lower intraglomerular
of drugs, other past medical history or a family history pressure. This reduces the proteinuria and slows pro-
of renal disease. gression of renal disease.
Sodium restriction and diuretics are used to relieve

oedema, but with care to avoid precipitating prerenal
Complications
failure, due to intravascular hypovolaemia.
Venous thrombosis and pulmonary embolism due to

Dietary protein must be sufficient to compensate for
loss of antithrombin III in the urine, lowered plasma
urinary losses.
volume and increased clotting factors (II, V, VII, VIII
Treat complications: Hyperlipidaemia responds to
and X).
treatment of the nephrotic syndrome, although HMG
Renal vein thrombosis may occur particularly in pa-

CoAreductase inhibitors (statins) are often needed.
tients with a very low serum albumin (<20 g/L) or
Consider anticoagulation and prophylactic penicillin.
membranous nephropathy. This is usually asymp-
tomatic, the first sign may be a pulmonary embolus,
or it may present acutely due to venous infarction with Nephritic syndrome
flank pain, haematuria and renal impairment.
Infection, particularly streptococcal infections, possi-
Definition
bly due to low levels of IgG. Nephritic syndrome is characterised by hypertension,
Hypercholesterolaemia is thought to occur due to
haematuria and acute renal failure.
increased hepatic lipoprotein synthesis as a re-
sponse to decreased plasma oncotic pressure. Reduced Aetiology
metabolism also plays a part in hypercholesterolaemia Acute diffuse proliferative, e.g. post-streptococcal glo-
and hypertriglyceridaemia. merulonephritis.