Tubular & Interstitial Diseases Flashcards
1
Q
Tubular & interstitial urogenital diseases
A
- Acute tubular necrosis
- Acute interstitial nephritis
- Acute pyelonephritis
- Chronic pyelonephritis
- Xanthogranulomatous pyelonephritis
- Renal tuberculosis
2
Q
Features of acute tubular necrosis
A
- common cause of acute renal failure
- tubular epithelial cell injury/death resulting in reduction/loss of tubular fn
- reversible, damaged/dead tubular epithelial cells can be replaced by regenerating residual viable cells (as long as BM remains)
- not associated w necrosis of glomeruli/adj renal cortical tissue
3
Q
Causes of acute tubular necrosis (2)
A
- Ischemic - resulting in hypotension and/or hypovolemia - reduced renal perfusion
- shock
- hemorrhage
- major surgery
- severe burns
- dehydration - Toxic - direct damage to tubules
- endogenous products
- drugs
- heavy metals
- organic solvents
- other toxins
4
Q
Pathogenesis of acute tubular necrosis (3)
A
- Oliguric phase
- ischemia - vasoconstriction (reduced GFR) + tubule cell injury
- (a) tubule cell injury - sloughed endothelial cells - obstruction - increased intratubular pressure + tubular backleak (causing reduced tubular flow)
- (b) tubule cell injury - loss of polarity - tubuloglomerular feedback increases
- (c) tubule cel linjury - necrosis & apoptosis - obstruction/backleak
- reduced GFR - oliguria - Polyuric phase
- clearance of sloughed off epithelial cells - GFR goes back to normal
- tubular cells are regenerating but not fully recovered - impaired reabsorption of filtrate - urine is not concentrating - polyuria, possible dehydration, hypokalemia - Recovering phase
5
Q
Morphology of acute tubular necrosis
A
- varying degrees of swelling, vacuolation, flattening, sloughing, loss of PAS positive brush border, necrosis
- may also have tubular dilation & interstitial edema
6
Q
Features of acute interstitial nephritis
A
- acute tubulointerstitial nephritis
- does not include infections of the kidney
- can affect any age group
7
Q
Causes of acute interstitial nephritis
A
- mainly due to drugs
- others: toxins , metabolic causes, autoimmune disease, ifnections, idiopathic
8
Q
Features of drug-induced acute interstitial nephritis
A
- usually a form of allergic or T cell mediated hypersensitivity reaction
- most commonly antibiotics, diuretics, NSAIDs, also traditional, herbal remedies
- symptoms usually develop 1-2w after starting the drug
9
Q
Effects of acute interstitial nephritis
A
- variable degrees of renal impairment
- RBCs, WBCs, eosinophils in urine (hematuria, eosinophilia)
- may have mild proteinuria
- fever, rash
10
Q
Causes of acute pyelonephritis
A
- usually bacterial infection
- bacteria from
1. Ascending (retrograde) spread from bladder) - predisposed by UTO, vesicoureteric reflux, DM, pregnancy
2. Hematogenous spread
11
Q
Clinical features of acute pyelonephritis
A
- chills, fever
- flank tenderness, pain
- dysuria, increased freq of micturition
- often >100,000/ml bacteria in urine
- pyuria, may have pus casts
12
Q
Complications of acute pyelonephritis (4)
A
- Acute renal failure
- Septicaemia
- Pyonephrosis
- Perinephric abscess
13
Q
Definition of chronic pyelonephritis
A
- chronic tubulointerstitial inflammation & renal scarring
- associated with pathologic involvement of the calyces & pelvis
14
Q
Causes of chronic pyelonephritis (2)
A
- predisposition to recurrent kidney inflammation/infection & progressive scarring
1. Reflux (vesico-ureteric) - usually begins in childhood - congenital abnormality rendering physiological valve incompetent
- damage, scarring due to pressure, often subclinical
2. Obstruction
15
Q
Features of xanthogranulomatous pyelonephritis
A
- rare, but clinically significant as it mimics renal carcinoma
- caused by proteus, urinary tract obstruction usually present
