Glomerular disease Flashcards
What is glomerulonephritis?
Broad term that refers to a group of parenchymal kidney diseases that all result in the inflammation of the glomeruli and nephrons
What can glomerulonephritis cause?
- Damage to the filtration mechanism –> Haematuria and Proteinuria
- Damage to the glomerulus restricts blood flow –> compensatory Hypertension
- Loss of the usual filtration capacity –> Acute Kidney Injury
How can glomerulonephritis present?
- Acute Nephritic Syndrome (Acute glomerulonephritis)
- Nephrotic syndrome
- Asymptomatic urinary abnormalities
- Haematuria, proteinuria or both
- Chronic kidney disease (CKD)
What is the most common primary cause of acute nephritic syndrome?
IgA nephropathy
Describe the pathophysiology of IgA nephropathy
IgA immune complexes get deposited in the mesangium which result in a type III hypersensitivity reaction and lead to destruction of the glomerulus
Describe how infection can lead to acute nephritic syndrome?
Immune complexes become trapped in the BM –> inflammation and damage to the glomerulus
What is the most common infection leading to acute nephritic syndrome?
Streptococcal infection e.g Streptococcus pyogenes
How can SLE lead to acute nephritic syndrome?
Anti-nuclear antibodies form immune complexes which travel to the glomerulus where and deposit in the BM.
What is goodpastures syndrome?
A disease in which circulating anti-bodies are directed against collagen in the BM of both the kidneys and the lungs –> progressive kidney failure
What are the signs of acute nephritic syndrome?
P - Proteinuria - usually <3.5g /day (nephrotic = >3.5g/day)
H - Haematuria -mild macrocytic
A - Azotemia - inc creatinine and urea - symptoms of
anorexia, rash, lethargy and nausea
R - RBC casts
O - Oliguria - little urine
H - Hypertension (moderate-severe increase) and oedema
(periorbital (around eyes), leg or sacral) caused by salt
and water retention
What investigations would you do in acute nephritic syndrome?
Measure eGFR, proteinuria, serum urea & electrolytes and albumin - to determine current status and monitor progress
Culture - swab from throat or infected skin
Urine dipstick - to detect proteinuria and haematuria
Renal biopsy if necessary
What triad of symptoms define nephrotic syndrome?
- Proteinuria > 3.5g/24 hours
- Hypoalbuminemia
- Oedema
What are the main primary causes of nephrotic syndrome?
- Membranous neuropathy
- Minimal change diseases
- Focal segmental glomerulosclerosis
What are the secondary causes of nephrotic syndrome?
- Diabetes mellitus MOST COMMON SECONDARY CAUSE
- Amyloidosis - protein deposit
- Infections e.g. Hep B or C and HIV
- SLE, RA
- Drugs e.g. gold, penicillamine, NSAIDs and ACE-
inhibitors - Malignancy
Briefly describe the pathophysiology of membranous neuropathy?
Can be idiopathic or secondary to:
- Drugs e.g. penicillamine, gold or NSAIDs
- Autoimmune - SLE, thyroiditis
- Infection e.g. hepatitis B or C, schistomiasis
- Neoplasia e.g. lung, colon, stomach and breast
There is deposition of IgG and C3 (SPIKES) along outer aspect of glomerular basement membrane
NB: most common cause of nephrotic syndrome in adults
What is minimal change disease?
Minimal change seen to the glomeruli - so only seen on electron microscopy where you can see fusion of the podocytes. Immature differentiating CD35 stem cells appear to be responsible for the pathogenesis
What is the clinical presentation of minimal change disease?
- Proteinuria
- Oedema, predominantly around the face
- Fatigue
- Frothy urine
What is the treatment for minimal change disease?
High dose corticosteroids e.g. Prednisolone - can reverse proteinuria in 95% cases - however the majority relapse
What is focal segmental glomerulosclerosis?
CD80 in podocytes resulting in increased permeability in glomeruli and thus proteinuria and haematuria. The scarring is focal and only some of the glomeruli are affected. It’s also segmental affecting only some of the glomerulus.
What is the treatment for focal segmental glomerulosclerosis?
Treat with corticosteroids and immunosuppressants e.g. cyclophosphamide or ciclosporin
What are some secondary causes of nephrotic syndrome?
- Diabetes mellitus MOST COMMON SECONDARY CAUSE
- Amyloidosis - protein deposit
- Infections e.g. Hep B or C and HIV
- SLE, RA
- Drugs e.g. gold, penicillamine, NSAIDs and ACE-inhibitors
- Malignancy
Why does diabetes cause nephrotic syndrome?
Glucose gets stuck to the BM of the glomerulus and causes damage.
What is the epidemiology of minimal change disease in relation to nephrotic syndrome?
Minimal change disease account for 10-25% of nephrotic syndrome in adults and is the commonest cause of nephrotic syndrome in children
What are the signs of nephrotic syndrome?
- Normal-mild increase in BP
- Proteinuria > 3.5g/day
- Normal-mild decrease in GFR
- Hypoalbuniaemia
- Pitting oedema of ankles, genital, abdominal wall and sometimes face (periorbital)
- Frothy urine - due to protein?
