Nephrotic Syndrome Flashcards
What is nephrotic syndrome?
Heavy proteinuria results in hypoalbuminaemia and oedema.
PCR>200mg/mmol
Albumin < 25g/L
What causes nephrotic syndrome?
90% unknown cause
Can be secondary to nephritis, Henoch-Shonlein purport, vasculitis SLE, infections or allergens
Nephrosis is the process of leaking protein from a damaged glomerulus, distinguishing it from nephritis, which is inflammation that can involve any part of the nephron or interstitium. The glomerular basement membrane is made up of specialised epithelial cells (podocytes) which normally fuse together and prevent proteins albumin-sized or larger from being filtered; in nephrotic syndrome, they become flattened and start to allow the leaking of these proteins.
The most common cause of nephrotic syndrome in children is minimal change disease, so-named because on biopsy there is little change to see. The other, rarer causes include congenital nephrotic syndromes, focal segmental glomerulosclerosis and mesangiocapillary glomerulonephritis.
What are clinical features of nephrotic syndrome?
Periorbital oedema - earliest sign usually on waking
Scrotal or vulval, leg and ankle oedema
Ascites
Breathlessness due to pleural effusions and abdo distension
Infection such as peritonitis, septic arthritis or sepsis due to loss of protective immunoglobulins in the urine
Irritability
Anorexia
GI disturbance
What investigations in nephrotic syndrome?
Bedside:
Urine dip - ++++ protein, frothy, alchumious casuts
Bloods: Blood albumin decreased FBC ESR U&E generally normal urea and creatinine Complement lebels
Micro
Urine MC&S
Urine sodium conc - secondary hyperaldosteronism causing reduced sodium in urine
Urine PCR
Renal biopsy if haematuria, hypertension, raised urea, protein loss is unselective and treatment failure
How is nephrotic syndrome classified?
Steroid sensitive 90%
Steroid dependent
Steroid resistant
What features suggest steroid sensitive nephrotic syndrome?
What often precipitates this?
1-10 yo No macroscopic haematuria Normal BP Normal complement Normal renal function
Precipitate by respiratory infections
More common in boys, Asians
What is management for nephrotic syndrome?
Oral high dose corticosteroids - prednisolone 60mg/m2/day
for 4 weeks then reduce to 40 for 4 weeks then wean
Takes 11 days to become free of protein
Conservative;
Eat healthy with no added salt and no high protein - LOW salt diet
Prophylactic antibiotics - leak of immunoglobulins increases infection risk
Fluid restrict to 800-1000ml/day
Diuretics if Very oedematous and no evidence of hypovolaemia
Albumin infusion only in symptomatic hypovolaemia
When should renal biopsy be performed?
Do not respond to corticosteroid therapy Atypical features Haematuria HTN Increased urea Unseletive protein loss <1 or >12
Describe renal histology in steroid sensitive nephrotic syndrome
Usually normal
Fusion of podocytes
- minimal change disease
What are complications of nephrotic syndrome?
Hypovolaemia
Intravascular compartment may become volume depleted - abdominal pain and may feel faint
Peripheral vasoconstriction and urinary sodium retention
Low urinary sodium due to secondary hyperaldosteronism an high packed red cells are indications of hypovolaemia
Urgen IV fluids 0.9% saline 4.5% albumin as child is at risk of thrombosis and shock
Thrombosis
Hypercoagulanle state due to urainary losses of antithrombin III, thrombocytosis which may be exacerbated by steroids, increased synthesis of clotting factors, and increased blood viscosity from raised haematocrit all predispose to thrombosis
Infection - pneumococcus, vaccination is recommended
Hypercholesterolaemia - correlates inversely with serum albumin
Why is there thrombosis risk in nephrotic syndrome?
Hypercoagulanle state due to urainary losses of antithrombin III, thrombocytosis which may be exacerbated by steroids, increased synthesis of clotting factors, and increased blood viscosity from raised haematocrit all predispose to thrombosis
What infection are they at risk of?
Pneumococcal peritonitis due to loss of immunoglobulins
What can be used in steroid toxicity and relapsing NS?
Cyclophosphamide as steroid sparing agents, calcenurin inhibitorssuch as tacrolimus, cyclosporin A
What is steroid dependent NS?
Frequent relapses requires long term steroids or cyclosporin * note cyclosporin is nephrotoxic
How is steroid resistant NS managed?
Management of the oedema is by diuretic therapy, salt restriction, angiotensin-converting enzyme inhibitors, and sometimes nonsteroidal anti-inflammatory drugs, which may reduce proteinuria.
Genetic testing for steroid-resistant nephrotic syndrome is available and helps in the management of children
