Renal Flashcards
What is the pathogenesis of diabetic nephropathy?
Increased glomerular capillary pressure
Non-enzymatic glycosylation of the BM
What is seen on histology of diabetic nephropathy
BM thickening
Kimmelstiel-Wilson nodules (nodular glomerulosclerosis)
Hyaline arteriosclerosis
What genetic predisposition may lead to diabetic nephropathy?
ACE gene polymorphisms
What are the stages of diabetic nephropathy?
- Hyperfiltration
- Silent (GFR remains elevated)
- Microalbuminaemia 30-300mg/day, dipstick -ve
- Overt nephropathy: albumin>300mg/d, dipstick +ve, HTN usually present
- ESRF
What type of renal stone does proteus mirabilis predispose to?
Struvite
Why is there a small rise in creatinine following ACEI introduction?
Reduced filtration pressure
Greater rise - underlying renovascular disease
What has the best sensitivity for detecting proteinuria in CKD?
Albumin:creatinine ratio
How is proteinuria diagnosed in CKD?
First pass morning ACR sample
3-70mg/mmol - repeat
>70 - confirmed
What are the indications to refer to nephrologist in CKD?
Urinary ACR>70 unless known to be caused by diabetes
Urinary ACR >30 + haematuria
Urinary ACR 3-29, persistent haematuria, declining eGFR
What causes bone disease in CKD?
Low vitamin D
As hydroxylation normally occurs in the kidneys
High phosphate due to decreased excretion
What are the clinical manifestations of renal bone disease?
Osteitis fibrosa cystica
Osteomalacia
Osteoporosis
What is the most common histological pattern of lupus nephritis?
Diffuse proliferative glomerulonephritis (also the most severe pain)
Other - rapidly progressive GN
What are the histological features of lupus nephritis?
Wire loop appearance (endothelial and mesangial proliferation)
Thickened capillary wall secondary to immune complex deposits
What is Henoch-Schonlein purpura?
IA mediated small vessel vasculitis
What are the symptoms of HSP?
Palpable purpuric rash with localised oedema over buttocks and extensor surfaces of arms and legs
Abdominal pain
Polyarthritis
Features of IgA nephropathy - haematuria and renal failure
What percentage of HSP patients relapse?
1/3
What is the triad of haemolytic uraemic syndrome?
AKI
Microangiopathic anaemia
Thrombocytopenia
What are the causes of HUS?
Verotoxigenic/enterohaemorrhagic e.coli
Also shigella
Primary - atypical (not related to diarrhoea) = complement dysregulation
What is the treatment of HUS?
Supportive Fluids Dialysis Blood transfusion Atypical - plasma exchange
What is Goodpasture’s disease?
Small vessel vasculitis associated with pulmonary haemorrhage and rapidly progressive glomerulonephritis
What is the cause of Goodpasture’s syndrome?
Anti-GBM antibodies against type 4 collagen
Associated with HLA DR2
How is Goodpasture’s syndrome diagnosed?
Linear IgG deposits on GBM on renal biopsy
Increased TLCO
What is the management of Goodpasture’s syndrome and a common complication
Plasmaphresis
Complication - hypocalcaemia
Also steroids, CYC
What are 8 indications for plasma exchange?
GBS Myasthenia gravis Goodpasture's syndrome TTP HUS Cryoglobulinaemia ANCA +ve vasculitis if severe Hyperviscosity syndrome
What are 4 complications of plasmaphresis?
Hypocalcaemia (due to presence of citrate used as anticoagulant for extra-corporeal system which binds to calcium)
Metabolic alkalosis
Remove of systemic medications
Coag factor/Ig depletion
What is the inheritance of PKD?
Autosomal dominant
T1 - 85% = chromosome 16 which encodes for polycystin 1
T2 - 15% = chromosome 4
How is PKD screened for?
Abdominal ultrasound - good pickup rate of type 1
However if wanting to donate a kidney therefore screening for type 2 needed as well - genetic screening
What is the management of PKD?
Manage HTN
Tolvaptan
How does tolvaptan work in PKD?
Vasopressin receptor 2 antagonist - binds to V2 receptors in collecting ducts to reduced cell proliferation, cyst formation, fluid excretion
What are the extra-renal manifestations of PKD?
Liver cysts
Berry aneurysms
MV prolapse
Aortic root dilation and aortic dissection
What is fibromuscular dysplasia?
Non-atherosclerotic non-inflammatory disease of blood vessels that causes abnormal growth in the wall of an artery
What are the features of fibromuscular dysplasia?
Hypertension
CKD/AKI secondary to ACEI initiation
Flash pulm oedema secondary to fluid retention and diastolic ventricular dysfunction
What percentage of renal artery stenosis is caused by fibromuscular dysplasia?
10%
How is fibromuscular dysplasia diagnosed?
USS - asymmetric kidneys
Duplex USS
Contrast catheter angiography of the renal artery
What hormones do testicular teratomas secrete?
hCH and AFP
What scan is used to diagnose reflux nephropathy?
Micturating cystography
What scan is used to diagnose renal scarring?
DMSA scan
What is the mechanism of action of ciclosporin?
Inhibits calcineurin which is a phosphatase involved in T cell activation
What are the side effects of tacrolimus?
Impaired glucose tolerance
What is the mechanism of action of MMF?
Blocks purine synthesis by inhibition of IMPDH, therefore inhibits proliferation of B and T cells
When does CMV syndrome occur post renal transplant?
Between 1st and 6th month
What is the diagnosis and treatment of CMV syndrome?
PCR
Ganaciclovir
What is the pathophysiology of hyperacute organ rejection?
Pre-formed antibody such as ABO incompatibility or HLA mismatch
What are the features of hyperacute organ rejection?
Kidney becomes mottled, dusky, vessels thrombose following completion of vascular anastamosis.
If left in - abscess formation
What are the characteristics of acute organ rejection?
Occurs during first 6 months
T cell mediated
Medical management
What are the features of renal artery thrombosis, a complication of renal transplant?
Sudden complete loss of urine output
What would suggest a urine leak post renal transplant?
Diminished urine output Rising creatinine Fever Abdo pain USS --> perigraft collection, necrosis of ureter tip
What are the complications of peritoneal dialysis?
Coagulase -ve staph peritonitis (epidermis)
Sclerosing peritonitis
What is the diagnosis of renal vascular disaese?
MR angiography
What are the biochemical features of renal artery stenosis?
High aldosterone
High renin
Low K
Why is renin low in primary hypoaldsteronism?
Resulting hypertension causes excessive renal perfusion, which results in decreased renin production
What are 4 risk factors for Wilm’s tumour?
Beckith-Wiedemann syndrome
WAGR syndrome
Hemihypertrophy
Mutation in WT1 gene on chromosome 11