Renal disease in a child: Nephrotic syndrome Flashcards
Define nephrotic syndrome.
Characerised by hypoalbuminaemia, proteinureia and oedema.
Explain the aetiology of nephrotic syndrome.
All causes of glomerulonephritis (GN) can cause nephrotic syndrome.
What is primary nephrotic syndrome?
Described by histology; Minimal change disease (MCD), focal segmental glomeruloscelrosis (FSGS) and membranous nephropathy (MN)
What are causes of secondary nephrotic syndrome?
SLE, post-infectious (group A B-haemolytic streptococcus, syphilis, malaria, TB, varicella, hepatitis B, HIV, EBV), collagen vascular disease, HSP, hereditary nephritis (Alport syndrome), sickle cell disease
What is the pathophysiology of nephrotic syndrome?
Proteinuria: Structural damage to the glomerular membrane and reduction of its negatively charged componenets prevent the action of repelling negatively charged proteins, which are therefore excreted in excess.
Hypoalbuminaemia: Secondary to proteinuria and increase breakdown of albumin in the kidney.
Oedema: Hypoalbuminuria leads to decreased intravascular colloid osmotic pressure.
Summarise the epidemiology of nephrotic syndrome.
Developed countries: 2-7/100,000/year (UK). MCD is the cause of nephrotic syndrome in 90% of children; most common in boys < 5 years; Peak age: 2-4 years
Developing countries: Infectious cause of GN: malaria (40%), HBV infection (6%) and group A B-haemolytic streptococcal infection (rare)
What are signs and symptoms of nephrotic syndrome?
General: Anorexia, lethargy, oliguria, hypertension GI: Diarrhoea, poor feeding, abdominal pain.
Oedema: Swelling of face, ascites, oedema of legs/scrotum Symptoms of complications: Infectious, renal vein thrombosis, loin pain, haematuria.
What are investigations for nephrotic syndrome?
Bloods: U&E, decrease albumin, increase ESR/CRP, lipid profile (secondary hyperlipidaemia).
Post-infectious nephropathy: Plasmodium falciparum (thick and thin blood films), ASOT, HBV/EBV/HIV serology, HIV, PCR.
Urine dipstick: 3/4 + protein, microscopic haematuria
MSU: MC&S
24-hour urine collection: Creatinine clearance and 24-hour protein excretion
Renal USS: Other renal diseases may cause proteinuria, e.g. Polycystic kidney disease
Renal biopsy: Reserved for older children with haematuria, increase BP, renal impairment, steroid-resistant patients
Doppler USS, renal angiogram, CT, MRI: If renal thrombosis is suspected
How is nephrotic syndrome treated symptomatically?
Limit oedema with low-sodium diet and diuretics
What should be monitored when treating nephrotic syndrome?
BP, U&E, Ca2+, weight, fluid balance
How should the initial presentation of nephrotic syndrome be treated?
Longer duration (6 months) of initial prednisolone treatment is associated with fewer relapses and lower total prednisolone dose over the first 2 years
How should a relapse of nephrotic syndrome be treated?
Prednisolone daily unit in remission, then a slow gradual reduction of dosage
How should steroid-resistant patients be treated?
Alternate-day prednisolone with long-term cyclosporine or cyclophosphamide. Steroid-sensitive patients (85-90% cases) respond after 4 weeks, steroid-resistant (10-15% cases) have no remission after 4 weeks
How should hypertension in nephrotic syndrome patients be treated?
ACE inhibitors are drug of choice
How should complications in nephrotic syndrome be treated?
Penicillin prophylaxis to prevent pneumococcal peritonitis and septicaemia, mobilisation/TED stockings to prevent thrombosis.