Nephrotic syndrome Flashcards
What is nephrotic syndrome?
Presence of proteinuria (>3.5g/24h)
Hypoalbuminaemia (<30g/L)
Peripheral oedema
What other 2 features are commonly seen in nephrotic syndrome other than the diagnostic features?
Hyperlipidaemia
Thrombotic disease
What is nephritic syndrome?
Presence of AKI
HTN
Active urinary sediment (red cells and red cell casts)
Does the urine in nephrotic syndrome contain casts?
Very few.
If a patient presents with isolated heavy proteinuria but no other features of nephrotic syndrome, what can this be called?
Nephrotic-range proteinuria
What is the most common cause of nephrotic syndrome in children?
Minimal change disease
What is the most common cause of nephrotic syndrome in adult males?
Primary glomerular diseases
What is the most common cause of nephrotic syndrome in adult females?
Secondary glomerular disease
What is the most common cause of nephrotic syndrome in younger adults?
FSGS (focal segmental glomerulosclerosis)
What is the most common cause of nephrotic syndrome in older adults?
Membranous nephropathy
What is the most common cause of nephrotic syndrome in diabetics?
Diabetic nephropathy
Is nephrotic or nephritic syndrome more common in pts with IgA nephropathy, membranoproliferative glomerulonephritis, and post-infectious glomerulonephritis?
Nephritic
but both possible
When can minimal change disease occur in adults?
Idiopathic
Relation to NSAID use
Hodgkin’s lymphoma
Why is it called minimal change disease?
Light microscopy finds normal glomeruli or mild mesangial proliferation
What does electron microscopy show in minimal change disease?
Diffuse effacement of the epithelial cell foot processes
What does immunofluorescence show in minimal change disease?
No immune complex deposition
How is minimal change disease treated?
Steroids
What does light microscopy show in FSGS?
Segmental areas of mesangial collapse and sclerosis affecting some but not all glomeruli
What causes primary FSGS?
Idiopathic - unknown
What can cause secondary FSGS?
HIV
Obesity
Reflux nephropathy
How is primary FSGS treated?
Immunospression
How is secondary FSGS treated?
Reducing intraglomerular pressure (renin-angiotensin blockade)
How does FSGS commonly present?
Haematuria
HTN
Reduced renal function
How is FSGS diagnosed?
Renal biopsy
What does light microscopy show in membranous nephropathy?
basement membrane thickening without assoc. cellular proliferation or infiltration
What does immunofluoresence show in membranous nephropathy?
Diffuse, granular IgG deposition throughout the capillary walls
What does electron microscopy show in membranous nephropathy?
Electron-dense deposits in the subepithelial space
New basement membrane growth between subepithelial immune deposits leads to the classic ‘spike and dome’ appearance
Membranous nephropathy is usually idiopathic, but what may it be due to?
Hep B
AI disease
Malignancy
Adverse drug reactions
How does diabetic nephropathy usually present?
Microalbuminuria
Prgrssive fall in eGFR
How does diabetic nephropathy present in microscopy?
Mesangial expansion, glomerular basement membrane thickening, and glomerular sclerosis leading to the development of Kimmelstiel-Wilson nodules
Amyloidosis is responsible for what % of nephrotic syndrome cases?
~10%
How is Amyloidosis investigated?
Presence of a monoclonal paraprotein in urine or plasma
What is the primary insult leading to the development of nephrotic syndrome?
High-grade glomerular proteinuria
- heavier protein loss the more likely the development of the full-blown syndrome
Why do patients become hypoalbuminaemic in nephrotic syndrome?
Albumin is lost in urine
What does the liver do in hypoalbuminaemia?
Synthesises albumin, LDL, VLDL, and lipoprotein
How does lipiduria appear in nephrotic syndrome?
lipid sediment, fatty casts, oval fat bodies, or free fat droplets in teh urine
How does hypercoagulability occur in nephrotic syndrome?
Loss of coagulation inhibitors in the urine
Increased synthesis of procoagulatory factors by the liver
How does the oedema occur in nephrotic syndrome?
Decreased oncotic pressure from the hypoalbumiaemia as well as primary renal sodium retention in the collecting tubules
Why are patients with nephrotic syndrome at increased risk of infection?
Loss of immunoglobulins and complement in the urine
Nephrotic syndrome is 1 of the 3 causes of severe oedema (anasarca); what are the other 2?
CHF
Severe hepatic disease
What are the complications of nephrotic syndrome?
Proteinuria and oedema, which can become generalised (anasarca)
Protein malnutrition, with a negative nitrogen balance due to marked proteinuria
Hypovolaemia due to over-diuresis, particularly in the presence of hypoalbuminaemia
Acute kidney injury secondary to hypovolaemia, ischaemic injury, non-steroidal anti-inflammatory drugs
Hyperlipidaemia and accelerated atherosclerosis
Hypercoagulability causing arterial plus venous thrombosis.
Immunocompromised state and infections
Rapidly progressive glomerulonephritis
What is the basis for diagnosing nephrotic syndrome?
Hx and examination Quantification of proteinuria Urinalysis for casts Serological studies Renal biopsy
What features should be included in taking a history in someone with suspected nephrotic syndrome?
PMH
Full medication history
FH of causative diseases
Previous know renal disease
What features should be included in an examination of someone with suspected nephrotic syndrome?
Assessment of oedema and severity Features of hypoalbuminaemia Protein malnutrition Xanthelasmata Any additional features depending on ?cause
What investigations should be done in someone with suspected nephrotic syndrome?
Proteinuria quantification Evaluation of fresh urine sampel for casts Renal function FBC Lipid profile Serum albumin TFTs HIV test Serum complement Any other tests depending on presenting features and clinical suspicians
What imaging should be done in someone with suspected nephrotic syndrome?
Appropriate imaging of any suspected malignancies
Renal USS esp. if renal biopsy taken
What group of patients with nephrotic syndrome do not usually need a renal biopsy?
Children
-90% minimal change disease so nothing will be seen on biopsy that aids diagnosis
Biopsy only for refractory cases
What are the contraindications for percutaeous renal biopsy in nephrotic syndrome?
Bleeding diathesis resistant to correction
Multiple, bilateral renal cysts
Renal tumour Hydronephrosis
Active renal infection
Small kidneys secondary to chronic irreversible disease
Severe and resistant hypertension.
