31 Urinary diseases 1

Question 1

What are the functions of the kidney? (4)

Answer 1

Eliminating waster products.
Regulating fluid and electrolyte levels.
Influencing acid-base balance.
Production of erythropoietin and renin.

Question 2

Which three structures allow filtration in the kidney?

Answer 2

Podocyte foot processes.
Basement membrane.
Endothelial cells.

Question 3

What are the immunological mechanisms of glomerular damage? (2).

Answer 3

Deposition of circulating immune complexes/ antigens.

Autoantibodies to components of glomerulus.

Question 4

What are the non immunological mechanisms of glomerular damage? (4).

Answer 4

Injury to endothelium.
Altered basement membrane due to hyperglycaemia in diabetes.
Abnormal basement membrane/podocyte structure.
Deposition of abnormal proteins.

Question 5

What are the mechanisms of tubular damage in the kidney? (7)

Answer 5

Ischaemic: hypotension, damage to vessels, glomerular damage.
Toxic: direct, hypersensitivity, protein deposition, crystal deposition (gout).

Question 6

Describe how microthrombotic angiopathy induces vascular damage in the kidney.

Answer 6

Damage to endothelial wall leads to thrombi in capillaries and small arterioles.
Abnormal clotting proteins, bacterial drugs and toxins.

Question 7

What is nephrotic syndrome?

Simple cause?

Answer 7

Oedema, proteinuria, hypoalbuminaemia.
±hypertension ± hyperlipidaemia
Always due to glomerular damage.

Question 8

What are the common causes of nephrotic syndrome in adults? (6).

Answer 8

Membranous nephropathy. M>F. Most common.
Focal segmental glomerulosclerosis. M>F.
Minimal change disease.
Amyloid, diabetes, lupus nephritis.

Question 9

What are the most common causes of nephrotic syndrome in children? (2).

Answer 9

Minimal change disease. Most common.

Focal segmental glomerulosclerosis.

Question 10

What is acute nephritis? (5)

Answer 10

Oedema.
Haematuria.
Proteinuria.
Hypertension.
Acute renal failure.

Question 11

What are the most common causes of acute nephritis in adults? (4).

Answer 11

Post-infective glomerulonephritis (strep throat).
IgA nephropathy (teens with haematuria).
Vasculitis (+ rash, myalgia, arthralgia).
Lupus (young women).

Question 12

What are the common causes of acute nephritis in children? (4).

Answer 12

Post-infective glomerulonephritis.
IgA neuropathy.
Henonch-Schonlein purpura. Specific IgA nephropathy. M>F.
Haemolytic uraemia syndrome (E.coli O157 enteritis + haemolysis + thrombocytopenia).

Question 13

What is the diagnostic criteria for acute renal failure?

Answer 13

Anuria/oliguria and raised serum creatinine/urea.

Question 14

What are the general causes of acute renal failure? (4)

Answer 14

Pre renal: dehydration, any hypotensive cause.
Renal.
Post renal: urinary obstruction: tumour, bladder stones, prostate enlargement.

Question 15

What do biopsies of kidneys with acute renal failure show?

Answer 15

Acute tubular necrosis.

Question 16

What are three causes of acute renal failure in adults?

Answer 16

Vasculitis.
Acute interstitial nephritis.
Acute tubulointerstitial nephritis (mostly drug rxns).

Question 17

What are the three causes of acute renal failure in children?

Answer 17

Henonch-Schonlein purpura.
Haemolytic uraemic syndrome.
Acute interstitial nephritis.

Question 18

What are the complications of acute renal failure? (5).

Answer 18

Cardiac failure (fluid overload).
Arrythmias (electrolyte imbalance).
GI bleeding.
Jaundice (hepatic venous congestion).
Infection, especially lung and urinary tract.

Question 19

What is chronic renal failure?

Answer 19

Permanently reduced glomerular filtrate rate.

Reduced number of nephrons.

Question 20

What are the common causes of chronic renal failure in adults?

Answer 20

Diabetes.
Glomerulonephritis.
Reflux nephropathy (reflux-infection-scarring).

Question 21

Why is a biopsy unhelpful in end stage renal disease?

Answer 21

Will show the same regardless of cause.

Scarring with loss of glomeruli and tubules.

Question 22

What are the systemic effects of chronic renal failure?

Answer 22

Reduced excretion - oedema, hypertension.
Reduced toxic metabolite excretion.
Reduced production of erythropoietin - anaemia.
Renal bone disease.

Question 23

What are the causes of isolated haematuria ± proteinuria with normal kidney function? (3).

Answer 23

IgA nephropathy.
Thin basement membrane disease.
Alport type hereditary nephropathy. Collagen IV defect. ± deafness, ± ocular problems.

Question 24

What are the causes of isolated proteinuria?

3 benign, 4 diseases

Answer 24

Benign: postural, pyrexia, exercise.
Disease: FSGS, Diabetes, Lupus, Henoch-Schonlein purpura.

Question 25

What is acute pyelonephritis associated with?

Answer 25

Women.
Diabetes.
Structural urinary tract abnormalities.

Question 26

What is chronic pyelonephritis associated with?

Answer 26

Obstruction of urinary tract and fibrosis.

Question 27

How does renal artery stenosis affect the kidney? (2)

Answer 27

Causes infarction, killing kidney tissue.

Activates RAAS system, causing hypertension.

Question 28

How does hypertension affect the kidney? (3)

Answer 28

Damages vessel walls leading to increased thickness and reduction in lumen.
Induces chronic hypoxia which leads to loss of renal tubules.
Reduction in flow activates RAAS, exacerbating the hypoxia.

Question 29

How does diabetes affect the kidney? (3)

Answer 29

Hyperglycaemia damages the basement membrane, becoming thicker.
Glomerulus produces extra extracellular matrix, forming nodules.
Small vessel damage leading to ischaemia.

Question 30

How does myeloma affect the kidney?

Answer 30

Excess immunoglobulin production. Deposition in the kidney tubules, causing inflammation and fibrosis.
Renal impairment is irreversible.

Question 31

Name toxins that directly damage kidney tubules (6).

Answer 31

Drugs e.g. antibiotics, NSAIDs.
Organic solvents.
Heavy metals.
Ethylene glycol (anti-freeze).
Pesticides.
Iodine containing radiographic contrast medium.