Renal Flashcards
What are the 9 functions of the kidney?
Elimination of metabolic waste, water homeostasis, electrolyte homeostasis, acid-base balance, BP control, vitamin D synthesis, EPO synthesis, renin synthesis, drug excretion.
How is CKD characterised?
eGFR <60 or pathological kidney damage (proteinuria) for > 3 months.
Which stage of CKD can a patient present with symptoms due to impaired kidney function?
4 & 5
What are the causes of CKD?
Diabetes, hypertension, glomerulonephritis, atherosclerosis (renal artery stenosis), drugs (e.g. NSAIDs), infection, polycystic kidney disease, obstructive uropathy.
What are the complications of CKD?
CV disease, hypertension, salt/water retention, electrolyte abnormalities (e.g. hyperkalaemia), metabolic acidosis, renal bone disease, anaemia (EPO), uraemia, altered drug metabolism, peripheral neuropathy.
How is CKD managed?
Treat underlying cause, control BP, reduce proteinuria (ACEi/ARB), avoid nephrotoxic drugs, manage complications, renal replacement therapy.
How do ACEi/ARBs reduce proteinuria?
Lower intraglomerular pressure so reduce filtration.
How do ACEi decrease glomerular filtration?
They cause vasodilation of efferent arteriole.
How is AKI characterised?
Increase serum creatinine within hours/days or decrease urine output > 6 hours.
Name some nephrotoxic drugs
Diuretics, ACEi/ARBs, NSAIDs, gentamicin, vancomycin, chemotherapy.
What are the causes of AKI?
Pre-renal: perfusion failure.
Renal: damage to kidney tissue.
Post-renal: obstruction.
How is AKI treated?
Treat underlying cause, fluid balance, dietary restriction, stop nephrotoxic drugs, dialysis.
What are the signs of nephrotic syndrome?
Heavy proteinuria, peripheral oedema, hypoalbuminaemia, hyperlipidaemia.
Which part of the glomerular filtration barrier is damaged in nephrotic syndrome?
Podocytes and basement membrane.
Give some examples of diseases that cause nephrotic syndrome
Primary: focal segmental glomerulosclerosis, membranous nephropathy, minimal change disease.
Secondary: SLE, diabetes, amyloidosis, HIV.
What are the complications of nephrotic syndrome?
Thromboembolism, infection, hyperlipidaemia, malnutrition, CKD/AKI.
Treatment of nephrotic syndrome?
Treat underlying cause, loop diuretics, salt restriction, ACEi/ARB, thrombo-prophylaxis.
What are the signs of nephritic syndrome?
Proteinuria, haematuria, hypertension, impaired kidney function and oedema.
How is the glomerular endothelium damaged in nephritic syndrome?
By inflammation or immune mediated processes.
Give examples of diseases causing nephritic syndrome
ANCA vasculitis, anti-glomerular basement membrane disease (good pasture syndrome), post-streptococcal glomerulonephritis, IgA nephropathy, lupus nephritis.
Why is there haematuria in nephritic syndrome?
The damage to the endothelium allows RBC, albumin and large molecules to be filtered into urine.
How are the kidneys commonly imaged?
Ultrasound.
What are the risk factors for AKI?
Age > 65, Hx of AKI, CKD, HF, diabetes, liver disease, nephrotoxic drugs.
Name the pre-renal causes of AKI
Hypoperfusion such as dehydration, hypotension/shock, cardiac failure, hypovolaemia.
Name the renal causes of AKI
Intrinsic kidney disease such as acute tubular necrosis, interstitial nephritis, glomerulonephritis, renal vascular damage.
Name the post-renal causes of AKI
Obstruction such as stones, tumours in pelvis/abdomen, ureter strictures, BPH/prostate cancer, blocked catheter.
List the main investigations for AKI
Urinalysis: blood, protein, glucose, nitrites, leukocytes.
Bloods: FBC, U&Es, bone profile, blood gas.
Imaging: ultrasound, CXR.
ECG.
What are the additional blood tests for an AKI?
CK, vasculitis screen (ANCA, ANA), blood film, blood/urine culture, virology (HBV, HCV), clotting, complement, immunoglobulins, serum electrophoresis.
What are the complications of AKI?
Hyperkalaemia, metabolic acidosis, fluid overload and uraemia.
What is the common presentation of minimal change disease?
Child, oedema (puffy face, swollen ankles), proteinuria (frothy urine), normal BP, no haematuria.
What is the commonest cause of nephrotic syndrome in adults and children?
Adults - focal segmental glomerulosclerosis.
Children - minimal change disease.
What is the most common type of glomerulonephritis overall?
Membranous nephropathy.
What is the histology of membranous nephropathy?
IgG and complement deposits on basement membrane.
Thickened basement membrane on light microscopy and sub-epithelial spikes on silver staining.
What is the histology of IgA nephropathy?
IgA deposits and glomerular mesangial proliferation.
Describe the classical presentation of IgA nephropathy
Individual in 20s presents with visible haematuria 1-2 days after URTI.
Name the condition with a mutation in GBM type 4 collagen
Alport syndrome.
Post-streptococcal glomerulonephritis is also known as…
Diffuse proliferate glomerulonephritis.
Describe the classical presentation of post-streptococcal glomerulonephritis
Child presents with haematuria, proteinuria and oedema 10-14 days after a throat or skin infection.
Name the subsets of rapidly progressive glomerulonephritis/ANCA-associated vasculitis
Granulomatosis with polyangitis (Wegener’s).
Microscopic polyangitis.
Describe the clinical presentation of anti-glomerular basement membrane disease (Goodpasture syndrome)
AKI (glomerulonephritis) and haemoptysis (pulmonary haemorrhage).
How would you distinguish between granulomatosis with polyangitis and anti-GBM disease?
Granulomatosis would present with wheeze, sinusitis and saddle-shaped nose as well as haemoptysis and AKI. Anti-GBM disease just haemoptysis and AKI.
What is the general treatment for glomerulonephritis?
Immunesuppression - steroids.
BP control - ACEi/ARBs.
What are the 2 types of fluids?
Crystalloids - electrolytes in water e.g. saline, dextrose saline, 5% dextrose, Hartmann’s.
Colloids - fluids with high molecular weight molecules - natural e.g. blood, albumin and synthetic e.g. gelatins, dextrans and hydroxyethyl starches (HES).
What is the pathophysiology of pyelonephritis?
Bacteria ascend from lower urinary tract or directly enter kidney from bloodstream.
What is the most common cause of pyelonephritis?
E.coli
What are the causes of catheter-associated pyelonephritis?
Enterococcus, Pseudomonas aeruginosa and Staphylococcus aureus.
Risk factors for pyelonephritis?
Female, structural abnormalities, vesico-uretic reflux, diabetes, immune compromised, catheters and recent sexual intercourse.
What are the main symptoms of pyelonephritis?
Fever, loin pain and nausea/vomiting. As well as dysuria, suprapubic pain, increased frequency and urgency.
What are the investigations for pyelonephritis?
Urine dipstick, midstream urine, bloods and imaging.
What is the management for pyelonephritis?
Antibiotics for 7-10 days: cefalexin, co-amoxiclav, trimethoprim, ciprofloxacin.
Sepsis six if admitted to hospital.
Describe sepsis six
3 in: IV fluids, IV antibiotics, oxygen.
3 out: lactate, blood cultures and urine output.
What are the complications of pyelonephritis?
Urosepsis and chronic pyelonephritis (leading to CKD).
Define polyuria
Abnormally high urine output.
Define oliguria
Abnormally low urine output - <400mls/day or <0.5ml/kg(body weight)/hour.
Define anuria
No urine output - <50mls/day.
How do NSAIDs contribute towards an AKI?
They reduce GFR by inhibiting the prostaglandin-mediated vasodilation of the afferent arteriole.
What is the pathophysiology of uraemia and what are the symptoms/signs?
Kidneys fail to remove metabolic waste so urea builds up in the blood to toxic levels.
Symptoms/signs - anorexia, change in taste, nausea/vomiting, pruritis, neuropathy, pericarditis, confusion, encephalopathy and coma.
What is the pathophysiology of sodium retention in kidney failure?
Production of renin and failure to regulate sodium and water homeostasis leads to oedema and hypertension. Treatment - loop diuretic and salt restriction.
What is the pathophysiology of anaemia in kidney failure?
Reduction in EPO production —> decreased rbc synthesis.
What is the pathophysiology of bone disease in kidney failure?
Increased phosphate in blood and decreased production of vitamin D in kidney failure stimulates PTH to release calcium from bones into the blood. This leads to vascular calcification and renal osteodystrophy.
What are the changes seen in diabetic nephropathy?
Mesangial cell expansion, podocytopathy, GBM thickening and sclerosis.
CKD patients are usually asymptomatic - true or false?
True - incidental finding.
What are the symptoms of CKD?
Anorexia, nausea, fatigue, weakness, muscle cramps, pruritus, dyspnoea, oedema.
What are the signs of CKD?
Pallor, hypertension, fluid overload, skin pigmentation, excoriation marks, peripheral neuropathy.
End stage renal failure is classified by a GFR of…
<15
Describe the main investigations for CKD
Urine dipstick, ACR, U&Es, FBC, bone profile, renal USS.
Why does renal bone disease occur with CKD?
Decreased vitamin D synthesis —> hypocalaemia —> increased PTH production —> bone resorption/osteoclast activity.
Which drug can control BP and reduce proteinuria in CKD?
ACEi