nephrotic syndrome

Question 1

def nephrotic syndrome

Answer 1

Characterized by proteinuria (>3 g/24 h), hypoalbuminaemia (<30g/L),oedema and hypercholesterolaemia.

for proteinuria (P:CR >300mg/mmol, A:CR>250mg/mmol)

Question 2

primary causes of nephrotic syndrome

Answer 2

commonest cause - minimal change glomerulonephritis in children

all forms of glomerulonephritis can cause it

Question 3

secondary causes of nephrotic syndrome

Answer 3

• dm
• sickle cell disease
• amyloidosis
• malignancies - lung and GI adenocarcinomas
• drugs - NSAIDS
• alport’s syndrome
• HIV infection
• lupus nephritis
• myeloma
• pre-eclampsia

Question 4

path nephrotic syndrome

Answer 4

filtration barrier of kidney is formed by podocytes - the GBM and endothelial cells

proteinuria happens because of podocyte pathology

• abnormal function in minimal change disease
• immune-mediated damage in membranous nephropathy
• podocyte injury/death in FSGS

or from pathology in the GBM/endothelial cell - membranoproliferative GN

Question 5

epi nephrotic syndrome

Answer 5

Most common cause of nephrotic syndrome in children (90%): minimal change glomerulonephritis (usually seen in boys<5 years, rare in black populations).

Most common causes of nephrotic syndrome in adults: diabetes mellitus, membranous glomerulonephritis

Question 6

sx nephrotic syndrome

Answer 6

Family history of atopy in those with minimal change glomerulonephritis, family history of renal disease.

generalised pitting oedema which can be rapid and severe - ankles, sacrum, periorbitally (area of low resistance)

Swelling of face, abdomen, limbs, genitalia

Symptoms of the underlying cause (e.g. SLE).

Symptoms of complications (e.g. renal vein thrombosis: loin pain, haematuria).

ask about systemic symptoms eg joint/skin, malignancy, chronic infection

Question 7

pathogenesis of nephrotic syndrome

Answer 7

Structural damage to the basement membrane or the reduction in the negatively charged components within it reduces the filtration of large protein molecules by the glomerulus, causing proteinuria and hypoalbuminaemia.

Question 8

signs nephrotic syndrome

Answer 8

Oedema: Periorbital, peripheral, genital.

ascites - fluid thrill, shifting dullness

Question 9

bloods nephrotic syndrome

Answer 9

• FBC
• UE
• LFT - low albumin
• ESR/CRP
• glucose
• lipid profile - secondary hyperlipidaemia
• immunoglobulins
• complement -C3, C4

Question 10

ix for cause of nephrotic syndrome

Answer 10

SLE - ANA, anti-dsDNA

infections - Group Ab-haemolytic streptococcal infection (ASO titre), HBV infection (serology), plasmodium malariae (blood films).

Goodpastures syndrome: Anti-glomerular basement membrane antibodies

Vasculitides: e.g. Wegener’s and microscopic polyarteritis (ANCA).

Urine: Urinalysis (protein, blood), microscopy, culture, sensitivity, 24-h collection (to calculate creatinine clearance and 24-h protein excretion).

Renal ultrasound: Excludes other renal diseases that may cause proteinuria, e.g. reflux nephropathy.

Renal biopsy: In all adults and in children who have unusual features or do not respond to steroids.

Other imaging: Doppler ultrasound, renal angiogram, CT or MRI are options if renal vein thrombosis is suspected.