Renal System 1

Question 1

What is the function of the kidneys?

Answer 1

• Eliminating metabolic waste
• Regulating fluid & electrolyte balance
• Influencing acid-base balance
• Production of some hormones (renin, erythropoietin)

Question 2

How do patients with renal disease present?

Answer 2

• Acute renal failure= generally unwell, rapid rise in creatinine & urea
• Nephrotic syndrome= Oedema, proteinuria & hypoalbuminaemia
• Acute nephritis= Oedema, proteinuria, renal failure & haematuria
• Chronic renal failure= slow decline in renal function

Question 3

In the kidneys, what element allows filtration?

Answer 3

Podocytes, endothelial cells & basement membrane

Question 4

What can cause damage to the kidney basement membrane? What does this ultimately lead to?

Answer 4

• Circulating immune complexes & antigens deposit in glomerulus
• Lupus nephritis
• IgA nephropathy
• Anti- GBM disease
• Antibodies to basement membrane or other components
• All lead to complement & neutrophil activation & reactive O2 species and clotting factors causing glomerular damage

Question 5

What non-immunological mechanisms can cause glomerular damage?

Answer 5

Damage to vessel- Injury to endothelium of vessels, altered bm due to hyperglycaemia in DM
Damage to BM- Abnormal bm or podocytes due to inherited disease, deposition of abnormal proteins in the kidney (amyloid)

Question 6

What ischaemic factors can lead to tubular damage?

Answer 6

• Hypotension/ shock
• Damage to vessels within kidney
• Glomerular damage
• All lead to reduced blood supply to tubules

Question 7

What toxic factors can lead to tubular damage?

Answer 7

• Direct toxins
• Hypersensitivity reactions (drugs)
• Deposition of crystals or abnormal proteins in tubules
• All lead to direct tubular damage

Question 8

What factors can cause vascular damage to the kidneys?

Answer 8

• Hypertension
• Diabetes
• Atheroma (renal artery stenosis)
• Vasculitis
• Thrombotic microangiopathy

Question 9

How does vasculitis damage blood vessels in the kidneys?

Answer 9

• Acute/chronic inflammation of vessel walls
• Obliteration of lumen by inflammation of glomerular vessels leading to clotting & destruction of glomerulus
• Different types affect different vessels
• Inflammation of larger arterioles within kidney can lead to hypoxia of tubules
• Often affects other vessels so rash, joint & muscle pain
• E.g Wegener’s granulomatosis

Question 10

How does thrombotic microangiopathy lead to vascular damage in the kidneys?

Answer 10

• Thrombi in capillaries & small arterioles
• Due to damaged endothelium by bacterial toxins, drugs, abnormalities in complement or clotting system
• E.g Haemolytic uraemic syndrome

Question 11

Give the:
-Complications
-Signs
-Causes
of nephrotic syndrome

Answer 11

Causes= always due to damage to glomerulus- membranous nephropathy, FSGS, minimal change disease, other 
Signs= Oedema, proteinuria (>3g), hypoalbuminaemia
Comp= infection, thrombosis

Question 12

What are the signs of acute nephritis?

Answer 12

• Oedema
• Haematuria
• Proteinuria
• Hypertension
• Acute renal failure

Question 13

What are the causes of acute nephritis in adults &children?

Answer 13

A=
Post-infective glomerulonephritis
(after strep throat, complete recovery)
IgA nephropathy (upto 50%= renal failure, teens/y.adults w/ haematuria)
Vasculitis (fever, unwell, rash, myalgia, arthralgia)
Lupus (autoimmune, y.women)

C=Post-infective glomerulonephritis
IgA nephropathy
Henoch-Schonlein purpura (Specific IgA nephropathy, y.boys w/abdo pain, arthralgia,rash, haematuria, acute renal failure)
Haemolytic-uraemic syndrome (E.Coli infection, acute nephritis, haemolysis, thrombocytopaenia)

Question 14

How is acute renal failure diagnosed?

Answer 14

Anuria/oliguria & raised creatinine & urea

Question 15

What are the causes of acute renal failure? (outside of the kidney)

Answer 15

Pre-renal= reduced blood flow to kidneys, severe dehydration, hypotension (septic shock, bleeding, LVF)- renal biopsy not helpful
Post-renal= tumours in pelvis or urinary tract, bladder stones, prostatic enlargement- renal biopsy helpful
Intrinsic= damage to the glomeruli, renal tubules, or interstitium

Question 16

What are causes of acute renal failure within the kidney?

Answer 16

Adults=Vasculitis, Acute interstitial nephritis (by drug reactions)
Children= Acute interstitial nephritis, Henoch-Schonlein purport, Haemolytic uraemic syndrome

Question 17

What are complications of acute renal failure and how is it treated?

Answer 17

• Cardiac failure (fluid overload)
• Arrythmias (electrolyte imbalance)
• GI bleeding
• Jaundice (hepatic venous congextion)
• Infection
• Short term dialysis & treat underlying cause

Question 18

What are causes of chronic renal failure?

Answer 18

Adults= Diabetes, glomerulonephritis, reflux nephropathy
Children= glomerulonephritis, reflux nephropathy, developmental abnormalities/malformations

Question 19

What are the effects of chronic renal failure?

Answer 19

-Reduced excretion of H2O & electrolytes= oedema & hypertension
-Reduced excretion of metabolites
-Renal bone disease
-Reduced production of erythropoietin= anaemia

Question 20

Describe acute pyelonephritis and its complications

Answer 20

• More common in women& diabetics
• Bacterial lower UTI which tracks back up to the kidneys
• Abscess formation

Question 21

Describe chronic pyelonephritis and its complications

Answer 21

• Most associated with obstruction of urinary tract & reflux of urine
• Leads to scarring of kidneys and can lead to chronic renal failure

Question 22

Describe renal artery stenosis

Answer 22

• Due to atheroma or arterial dysplasia
• Leads to ischaemia of affected kidney
• Activation of renin-angiotensin-aldosterone system= hypertension
• Loss of renal tissue due to ischaemia= reduced renal function

Question 23

How does hypertension damage the kidneys?

Answer 23

• Damages renal vessels
• Leads to thickening of vessel wall & reduction in lumen size
• Produces chronic hypoxia leading to loss of renal tubules & reduced renal function
• Reduced blood flow in kidney activates renin-angiotensin-aldosterone system exacerbating hypertension

Question 24

How does diabetes damage the kidneys?

Answer 24

• Commonest cause of end stage renal failure
• Hyperglycaemia main cause of diabetic nephropathy by damaging basement membrane
• BM becomes thicker & glomerulus produces excess ECM which forms nodules
• Also damages small vessels leading to ischamia & damage to renal tubules

Question 25

How does a myeloma damage the kidneys?

Answer 25

- Tumour of plasma cells producing immunoglobulins - Excess deposited in kidney tubules - Tubules become damaged & inflamed & fibrosis occurs - Loss of renal tubules leads to decline in kidney function - Renal impairment usually reversible

Question 26

Clinical presentation of glomerulonephritis

Answer 26

Nephrotic=Proteinuria, oedema, hypoalbuminaemia, hyperlipidaemia Nephritic=Haematuria, hypertension, proteinuria, low urine volume

Question 27

What are primary and secondary causes of nephrotic syndrome?

Answer 27

- 1=minimal-change nephropathy, membranous nephropathy, and focal glomerulosclerosis - 2=diabetes mellitus, lupus erythematosus, and amyloidosis.

Question 28

What are primary and secondary causes of nephritic syndrome?

Answer 28

- 1=IgA nephropathy, Post-streptococcal glomerulonephritis | - 2=Vasculitis, Goodpasture's, SLE, Hep B&C

Question 29

What are the clinical features & causes of interstitial nephritis?

Answer 29

-Cause= drug effects/allergy, hypokalaemia, hypercalcaemia/ uric acid, infection, autoimmune (SLE, kawasaki, wegener) -Features=haematuria, fever Inc/dec urine, Mental changes, Nausea/vomiting, rash, swelling/oedema

Question 30

Describe inherited kidney disease

Answer 30

- ADPKD or ARPKD - fluid-filled cysts develop, multiply and grow in kidneys - abdo pain, recurrent UTI haematuria, kidney stones & kidney failure - may have cysts in liver, pancreas, spleen, ovaries, and large bowel