151 - Tubular Damage

Question 1

Normal interstitium in kindey

Answer 1

Very thin, difficult to see

Question 2

Acute reason for tubular interstitial swelling

Answer 2

Oedema

Question 3

Chronic reason for tubular interstitial swelling

Answer 3

Fibrosis, scarring

Question 4

Are tubulointerstitial or glomerular diseases more common?

Answer 4

Tubulointerstitial

Question 5

Most important tubulointerstitial diseases
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3

Answer 5

1) Acute tubular necrosis
2) Acute pyelonephritis
3) Acute or chronic tubulointerstitial disease

Question 6

Acute pyelonephritis

Answer 6

Acute pyelonephritis

Question 7

Acute tubular necrosis 
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Answer 7

1) Usually due to ischaemia (or acute hypo-perfusion of kidney)
2) Epithelial cells die, detach from tubular basement membrane, slough off into lumen
3) GFR falls because tubules aren’t working
4) Reversible lesion. With support, can fully recover

Question 8

Blood effects of ATN

Answer 8

Without functioning epithelium the tubule can no longer fulfil its functions: the glomerular filtration rate falls, electrolyte balance fails, urea and creatinine accumulate in blood

Question 9

What is associated with recovery from ATN?

Answer 9

Phase of increased urine production

Question 10

Supportive therapy that might be needed when recovering from ATN

Answer 10

Dialysis

Question 11

Most vulnerable areas of kidney to infarction

Answer 11

As blood supply falls tubular epithelium dies before other components of the kidney: glomeruli, blood vessels and interstitium survive longer

Question 12

Things that must be considered when trying to explain poorly-functioning renal transplants 
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Answer 12

–Problems due to the transplantation procedure (particularly ischaemia)
–Early rejection (can happen very early)
–Drug toxicity (many immunosuppressive drugs unfortunately potent nephrotoxins)
–Recurrent primary disease (though it would be very early )

Question 13

Difference between hypoperfusion and ischaemic ATN

Answer 13

Hypoperfusion is where there is too little blood (EG: lost blood, hypotension), and there is transient acute kidney failure. If the tubular epithelium survives, it is not ATN.

Ischaemic ATN is where there is prolonged hypoperfusion, leading to death of tubular epithelial cells.

Question 14

Toxic tubular necrosis
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3

Answer 14

•Very similar appearance and outcome to Ischaemic ATN

•Seen with toxins that affect tubular epithelium
–Heavy metals (esp. mercury)
–Some antibiotics
–Some cancer chemotherapy drugs

•Many act by disturbing mitochondrial function and oxidative phosphorylation

Question 15

Acute interstitial nephritis
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2
3

Answer 15

• Interstitium and tubules infiltrated by inflammatory cells (lymphocyte-mediated), often with many eosinophils
• Often fever, maybe a rash
• Very often due to drug allergy (e.g. antibiotics)

Question 16

How does acute interstitial nephritis present?

Answer 16

Usually presents as acute renal failure, sometimes with some blood or protein in urine

Question 17

Examples of organs where acute inflammation is lymphocyte-mediated, not neutrophil-mediated

Answer 17

Liver and kidneys

Question 18

Pyelonephritis

Answer 18

Bacterial infection of the kidney that affects the:
–Parenchyma of the kidney
–Calyces
–Renal pelvis

Question 19

How do organisms reach the kidney to cause pyelonephritis?

Answer 19

Ascend from the lower urinary tract to reach the kidney

Question 20

Variable features of pyelonephritis

Answer 20

Can be acute or chronic.

Can occur with or without blockage to urine flow.

Question 21

Type of bacteria that often cause pyelonephritis

Answer 21

G-
–E. coli
–Klebsiella sp.
–Proteus sp.
–Pseudomonas sp.

Question 22

Typical presentation of acute pyelonephritis in adults
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5

Answer 22

–Acute onset
–Fever, chills, lumbar tenderness and pain
–Discomfort when urinating (and frequency)
•Renal function usually preserved. Hypertension not a component
•Urine contains organisms, white blood cells

Question 23

Presentation of acute pyelonephritis in children

Answer 23

In children symptoms often less clearly renal – abdominal pain, vomiting, fever

Question 24

What often kills in acute pyelonephritis?

Answer 24

Extremely high fever (with rigors, delirium, sweats)

Question 25

Difference in inflammation between pyelonephritis and interstitial nephritis

Answer 25

In interstitial nephritis, whole kidneys is full of lymphocytes and eosinophils.

In pyelonephritis, there are inflammatory foci of lymphocytes, neutrophils. Not the blanket coverage with immune cells that you get in interstitial nephritis

Question 26

What can lead to chronic pyelonephritis?

Answer 26

Obstruction, repeated infection.

Question 27

Appearance of chronic pyelonephritis

Answer 27

Results in interstitial scarring, tubular atrophy, depressed ‘saddle shaped’ scars visible on the renal surface

Question 28

Analgesic nephropathy

Answer 28

Longterm use of compound analgesics (phenacitin, caffeine, aspirin).
Drugs have now been banned

Question 29

End stage kidney disease

Answer 29

End result of some kidney diseases that don’t resolve.

Kidneys aren’t able to perform function, particularly maintenance of creatinine, urea levels in the blood.

Question 30

Treatment for end stage kidney disease
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2

Answer 30

1) Transplant
2) Dialysis
Without these, death.

Question 31

Common features of long-term, irreversible renal diseass

Answer 31

Glomerular scarring, tubular atrophy, interstitial fibrosis.
Macroscopically the result is a shrunken, pitted and scarred kidney.
Leads to chronic renal failure

Question 32

Presentation of chronic renal failure 
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Answer 32

•Insufficient glomerular filtration to
–Eliminate metabolic wastes
–Maintain water and solute homeostasis
•GFR

Question 33

Proportion of causes of chronic renal failure in Australia

Answer 33

–32% diabetic nephropathy
–24% glomerulonephritis
–14% hypertension
– other include Analgesic Nephropathy, inherited conditions, chronic pyelonephritis, reflux nephropathy

Question 34

Why is chronic renal failure hard to pick up early?

Answer 34

Can lose 80-85% of kidney mass without showing symptoms.

By the time symptoms show, patient is in serious renal failure