Tubular injury

Question 1

What parts of the kidney fall under intrinsic renal damage?

Answer 1

Glomerulus and tubules

Found in the connective tissue of the kidney - interstitium

Question 2

What 3 categories can we divide renal injury into?

Answer 2

Pre - renal kidney injury

Injury to the interstitium

Tubular injury

Question 3

Why are the tubules often the site of kidney injury?

Answer 3

Problems that affect the blood supply affects the tubule disproportionately

Tubular cells are very metabolically active

Tubules have major role in movement of molecules from urine to the blood

Tubules may become blocked

Question 4

How does the role of the tubules make them more predisposed to tubular injury?

Answer 4

The movement of molecules from the urine to the blood sometimes includes toxins

These toxins are often found in high concentration in the tubules

Cause damage in the tubules

Question 5

How does the fact that the tubules are very metabolically active make them predisposed to tubular injury?

Answer 5

Cells require lots of energy to perform normal function

Any reduction in the substrates that provide energy to the cells lead to kidney injury

Question 6

How may tubules become blocked?

Answer 6

Substances can precipitate in the urine

May lead to inflammatory response and damage

Question 7

What does the biopsy of a healthy kidney look like?

Answer 7

Tubules are preserved

Tubular cells are large and healthy

Tubular cells have little gaps between them

Question 8

What does the biopsy of a diseased kidney look like?

Answer 8

Gaps in tubules - cells that line the tubules are unhealthy/died

Space between the tubules - oedema

Glomerulus is preserved - no major problems

Question 9

Does the glomerulus remain preserved after tubular injury?

Answer 9

Yes

Kidney biopsies see no major structural problems in the glomerulus of a kidney with tubular injury

Question 10

What causes tubular injury?

Answer 10

Impaired perfusion - pre-renal injury that continues for long enough causes tubular injury

Toxins - concentrate in tubular cells

Substances that precipitate - causes inflammatory response

Question 11

What are the two types of toxins that can lead to tubular injury?

Answer 11

Endogenous - myoglobin or hemoglobin

Exogenous - antibiotics, antiretrovirals, iodinated radiocontrast

Question 12

What are the two types of substances that can precipitate and cause tubular injury?

Answer 12

Endogenous substances - uric acid, immunoglobulin light chains

Exogenous substances - antivirals

Question 13

What condition can lead to tubular injury by production of substances that precipitate?

Answer 13

Myeloma

Plasma cell cancer

Increases antibody production

Antibodies precipitate and lead to tubular injury