Tubulointerstitial Diseases

Question 1

What are the features of normal interstitium?

Answer 1

• CT in which glomeruli, tubules, and blood vessels lie
• tiny amount of collagen between tubular BMs
  
  • contains the peritubular capillaries
• in disease can swell (oedema) or expand and fibrose (interstitial fibrosis)

Question 2

Which is more common, tubulointerstitial diseases or glomerular diseases?

Answer 2

tubulointerstitial

most pt with acute renal failure will have TID

will also cause in patients

Question 3

What are the most important problems of TI injury?

Answer 3

• ischaemic or toxic injury of tubular epithelium –> acute tubular necrosis (ATN)
• infection of the tubules and interstitium –> acute pyelonephritis
• acute or chronic TI nephritis

Question 4

What is the commonest renal cause of ARF?

Answer 4

acute tubular necrosis (ATN)

Question 5

What is acute tubular necrosis?

Answer 5

• commonest renal cause of ARF
• acute injury to tubular epithelial cells
  
  • usually due to ischaemia
  • cells die and slough off into the tubule
    
    • leaves naked non-functional BM
    • blocks tubule
• reversible on re-perfusion, cells brow back

Question 6

What is acute interstitial nephritis?

Answer 6

• this is the one you will cause
  
  • allergic interstial nephritis due to drugs/antibiotics
• presents as ARF sometimes with blood or protein in urine
• interstitium and tubules are infiltrated with inflammatory cells
  
  • bc allergic, eosinophils present

Question 7

What is pyelonephritis?

Answer 7

• bacterial infection of the kidneys affecting:
  
  • parenchyma
  • calyces
  • renal pelvis
• can be acute or chronic
• can occr with or without obstruction
• ascension of organisms from LRT (Gram negatives - Pseudomonas, E coli, Klebsiella, Proteus)
• systemic, febrile illness
• presents acutely, with fever, chills/rigors, increased frequency of urination, discomfort, lumbar tenderness and pain
• renal function is usually preserved

Question 8

How does PN present histologically?

Answer 8

• dark purple accumulations of bacteria/casts in the tubules
• foci of acute inflammation - neutrophils damaging tubule tissue
• macroscopically white streaks of pus radiating through medulla

Question 9

What is chronic PN?

Answer 9

• recurrent lower-grade infection
• may or may not have obstruction
• results in scarred, contracted kidney

Question 10

What is reflux nephropathy?

Answer 10

• vesico-ureteric reflux
  
  • backflow of urine from lower tract
  • can be sterile or infective
• causes chronic renal damage, scarring

Question 11

Chronic renal injury presents macroscopically as

Answer 11

• shrunken, pitted, rubbery, scarred kidneys
• difficult to determine cause
  
  • GN, toxins, chronic PN or allergic interstitial nephritis all end up this way
• irreversible

Question 12

What are the complications of chronic renal failure?

Answer 12

• insufficient GFR to maintain water and solute homeostasis and eliminate wastes
• may have proteinuria
• often accompanying hypertension that gets worse

Question 13

What are the common causes of CRF?

Answer 13

• diabetic neuropathy
• GN
• hypertension
• others:
  
  • analgesic nephropathy, inherited conditions, chronic PN, reflux nephropathy