Pathology of the Urinary Tract 1 Flashcards
(111 cards)
1
Q
Multipyramidal (Multilobar) kidneys are present in which species?
A
pigs, cattle
2
Q
What animal species has external lobulations of the kidney?
A
Cattle
3
Q
What species have unipyramidal (unilobar) kidneys?
A
Cats, dogs, small ruminants, horses
4
Q
What is unique about equine kidneys?
A
- mucous glands in the medulla
- mucus & crystals normally present in renal pelvis
5
Q
What is unique about mature cat kidneys?
A
cortex is often yellow due to large lipid content of tubular epithelial cells
6
Q
kidneys autolyze quickly after…
A
death
7
Q
Autolysed tissues make it so it is not possible to detect…
A
ACUTE tubular necrosis
8
Q
sampling of ocular fluid from the anterior chamber for urea lvls w/i 24 hr of death indicates…
A
acute renal failure
9
Q
The interlobular artery extends into the cortex forming glomerular arterioles where…
A
high pressure favors filtration
10
Q
Efferent glomerular arterioles close to subcapsular region create peritubular capillary network where…
A
low pressure favours reabsorption
11
Q
Why is the medulla especially sensitive to ischaemia?
A
Due to relative avascularity & low HCT in the medullary capillaries
12
Q
How much cardiac output is received in the kidneys?
A
up to 25%
13
Q
How much oxygen content do the kidneys receive?
A
about 10% of the whole body
14
Q
Why do kidneys receive so much oxygen?
A
Needed for resorption of essential solutes predominantly cortical function
15
Q
Kidneys self-regulate the balance of…, ensuring stable…
A
BP
GFR
16
Q
Renal artery & its branches are…
A
end-arteries so goes into cortex then to glomeruli for urinary filtration –> interstitium –> venous flow
17
Q
Medulla receives…
A
very little blood flow (primarily for reabsorption)
18
Q
Glomerular arterioles have high pressure that favours…
A
filtration
19
Q
Efferent arterioles favor low pressure which favours
A
reabsorption
20
Q
Each nephron functions on an…
A
all or none basis
21
Q
Components of a nephron
A
- Glomerulus
- Bowman’s Capsule
- Proximal Convoluting Tubule
- Loop of Henle
- Distal Convoluting Tubule
22
Q
if the glomerulus is gone, then the blood supply is gone, meaning there is…
A
a decrease in urine production
22
Q
In progressive renal disease, remaining nephrons respond by…
A
hyperplasia & hypertrophy causing an increase in glomerular filtration & tubular function
23
Q
Damage to tubule but basement membrane is intact means…
A
regeneration can occur
24
What happens when a nephron is defective?
Function is impaired causing essential substances wasted in urine
25
uriniferous tubule consists of...
nephron & collecting duct
26
Macula densa is used for...
sodium concentration & BP
27
why does the glomerulus need high BP?
for filtration purposes
28
Renal corpuscle consists of...
glomerulus & Bowman's capsule
29
Glomerulus produces ultrafiltrate as a result of...
difference btw higher systemic hydrostatic BP & lower hydrostatic pressure in tubules
30
What plasma proteins are excluded from filtration in the glomerulus?
Albumin & higher molecular weight plasma proteins
31
What are the 3 main features of the proximal convoluted tubules?
1. microvilli w/ brush border
2. tight jxns
3. lots of mitochondria
32
What are key features of the distal convoluted tubule & collecting ducts?
1. Principal cells - receptors for ADH & aldosterone
2. Intercalated cells - role in blood pH homeostasis
3. Absorption
4. Tight Jxns
33
The interstitium consists of...
blood vessels, CT
34
The interstitium expands in disease such as
oedema in acute dz or fibrosis in chronic dz
35
Selective reabsorption occurs in
specialised tubular epithelial cells
36
The cells of proximal convoluted tubule are prone to...
ischaemia
37
Loop of Henle leads to...
* hypotonic filtrate produced via countercurrent exchange
* close association w/ peritubular capillary network
* Na & K ATPase pumps absorb Na & Cl ions
38
When does the interstitium become abnormal?
Oedema
Cellular infiltration
Amyloid depositions
Fibrosis
39
What are the basic functions of the kidneys?
* Excretion of waste products
* control of blood volume
* blood pressure
* body fluid pH
* body fluid isotonicity
* Regulation of acid-base balance
* endocrine functions
40
What triggers the renin-angiotensin system?
Reduced blood supply at juxtaglomerular apparatus
41
Angiotensin II
* causes vasoconstriction
* induces aldosterone release in adrenal gland --> reduces excretion of NaCl
* Activates ADH in the hypothalamus --> fluid retention
42
What is the outcome of Renin-Angiotensin System?
Increased BP, salt & water retention
43
The Renin-Angiotensin system...
maintains BP
Regulates Na Balance
44
What are the main renal hormones?
EPO
Vit D Metabolism
Hypothalamus & ADH
45
Fxnl characteristics of kidney
* large amts of primary urine produced, most reabsorbed
* enormous reserve capacity (70% lost before clin signs)
* Regeneration of renal tissue
* glomerular malfunction (causes tubular & interstitial malfunction)
* tubular & interstitial malfunction (causes glomerular malfunction)
46
What are the portals of entry of injurious stimul & agents?
* Ascension from lower UT
* Haematogenous (infarction, embolic, glomerular tufts, interstitial vessels)
* metabolic (toxic or metabolic substances secreted into filtrate)
47
What are the kidney defence mechanisms?
* barrier system: glomerular & tubular basement membranes
* monocyte-macrophage system: glomerular mesangium & interstitium
* immune system: innate, humoral, cellular
48
How does the glomeruli response to injury?
* cellular proliferation
* leukocytic infiltration
* thickening of basement membrane
* hyalinization
* sclerosis
49
How do the renal tubules respond to injury?
* necrosis, esp of lining of prox tubules
* basement membrane thickening
* cell regeneration if basement membrane intact
* compensatory hypertrophy
50
How does the renal interstitium respond to injury?
* oedema, haemorrhage, inflammation
* fibrosis
51
How do the blood vessels of the kidney respond to injury?
* arteritis
* arteriosclerosis
* thrombosis
52
How does the renal medulla respond to injury?
* accumulation of protein casts
* papilla (inflammation pyelonephritis, amyloid, necrosis)
53
What are the essential requirements for normal renal fxn that can go wrong and lead to renal failure?
* Adeq perfusion w/ blood (incl BP)
* Adeq fxnl renal rissue
* Normal elim of urine thru UT
54
What is the index of failure for renal fxn?
* amt of urea retained
55
Azotaemia is a biochemical abnormality that consists of what parameters?
* increased urea
* increased creatinine
* w/ no clin manifestation of renal dz
56
Uraemia is a clinical syndrome of renal failure due to...
biochemical disturbances, often due to extra-renal multisystemic lesions
57
What are the 4 steps of renal insufficiency to renal failure?
1. Diminished renal reserve (GFR >50%) -> asymptomatic
2. Renal insufficiency (GFR 20-50% of normal) -> azotaemia & polyuria
3. Renal failure (GFR 20-25% of normal) -> uraemia w// GI, CV, resp, skeletal complications
4. End-stage renal dz (<5% normal) -> terminal stages of uraemia
58
What is unable to be regulated in kidney failure?
* fluid volume (leads to dehydration)
* Electrolytes (PO4, Ca, Na, K)
* Acid-base balance (metabolic acidosis)
* Metabolic waste excretion
* Endocrine fxns (secondary hyperparathyroidism, non-regn anaemia)
* hypertension
* non-specific effects of uraemic toxins
59
Failure of Ca to regulate renal failure looks like...
* increased hypercalcaemic nephropathy
* decreased tetany
* osteodystrophy
60
Failure of Na regulation due to renal failure looks like...
* increased oedema
* decreased dehydration
61
Failure to regulate K in renal failure looks like...
* increased cardiotoxicity
* decreased muscle weakness
62
Metabolic acidosis due to renal failure looks like...
* decreased production of ammonia in distal & collecting tubules
* increased retention of H+
* impaired resorption of HCO3-
63
What are the causes of acute prerenal renal failure?
* sudden & severe BP drop (shock/ischaemia) -OR- interruption of blood flow to kidneys from severe injury or illness
Due to:
* Decreased CO: CHF, arrhythmia, cardiac tamponade
* Shock: systemic vasodilation, anaphylaxis, sepsis
* Hypovolaemia: dehydration, V/D, burns, blood loss
* Vascular ischaemia/obstruction: toxins, thrombi, vasculitis, bacterial emboli
64
What are the causes of acute intrarenal failure?
* Sudden compromised kidney fxn, direct damage to kidneys by inflammation, toxins, drugs, infection, or reduced blood supply
Due to:
* nephrotoxins & drugs
* infectious agents
* vascular obstruction/ischaemia
* immune-mediated
* tumours
65
What are the causes of post-renal renal failure?
* sudden obstruction of urine flow (obstruction of ureter by urolithiasis, congenital, injury, bladder tumour, nephrolithiasis)
66
Acute renal failure can be...
reversible
67
Clinical signs of renal failure
* rapid onset of oliguria or anuria
* azotaemia
* disturbance in electrolyte balance
* accumulation of metabolic waste
* extra-renal lesions (rare) due to severity of uraemic lesions (stomatitis, gastritis, enteritis, vasculitis --> fibrinoid necrosis of vasc wall (often lung) --> increased permeability --> severe pulm oedema)
68
Animals die of acute renal failure b/c:
* metabolic acidosis
* hyperkalaemia --> cardiotoxicity
* +/- severe pulm oedema
69
Chronic renal failure is the end-result of ...
Chronic renal dz's
70
Chronic renal failure is usually
irreversible
71
What characterises chronic renal failure?
* prolonged duration & signs of uraemia which are progressive
* death imminent
72
What are the clinical effects of chronic renal failure?
* D/V/anorexia
* altered Ca/P metabolism
* potential secondary renal PTH
* non-regen anaemia of EPO
* heart (angiotensin-induced hypertension leading to L ventricular hypertrophy; mineralisation of atria; myocardial degeneration; vasculitis; fibrinous pericarditis)
* NS: lethargy, drowsiness, NM twitches, convulsions
* Lung: alveolar wall mineralisation, pulm oedema
* Metabolic acidosis: cachexia, oedema
73
Non-renal lesions of uraemia
* dehydration
* oedema
* pulmonary oedema
* ulcerative stomatitis, glossitis
* ulcerative, haemorrhagic gastritis
* ulcerative, haemorrhagic enteritis
* fibrinous pericarditis, hydropericardium
* atrial/aortic lesions, ulcerations
* myocardial degeneration
* congestive heart failure, L ventricle hypertrophy
* Vascular lesions
* anaemia, nonregenerative
* mineralisation of soft tissue/stomach
* fibrous osteodystrophy
* secondary hyperparathyroidism
* uraemic encephalopathies
* cachexia
74
What is the pathomechanism of dehydration causing uraemia?
* PU, V, D
75
What is the pathomechanism of oedema causing uraemia?
* proteinuria
* Hypoalbuminaemia
* leads to increased glomerular permeability nephrotic syndrome
76
What is the pathomechanism of pulmonary oedema leading to uraemia?
* vascular damage, increased permeability
77
What is the pathomechanism of ulcerative stomatitis, glossitis leading to uraemia?
* vascular damage
* ammonia
* ammonia production by bacteria from urea in saliva
78
What is the pathomechanism of ulcerative, haemorrhagic gastritis leading to uraemia?
* ammonia
* vascular damage
* initially non-inflammatory
* may get infected
79
What is the pathomechanism of ulcerative, haemorrhagic enteritis leading to uraemia?
* ammonia
* vascular damage
* colitis, oedema in stomach & prox SI
80
What is the pathomechanism of fibrinous pericarditis, hydropericardium leading to uraemia?
* vascular damage
81
What is the pathomechanism of atrial/aortic lesions, ulcerations leading to uraemia?
* endothelial/subendothelial damage
82
What is the pathomechanism of myocardial degeneration leading to uraemia?
* vascular damage
* high K lvls
83
What is the pathomechanism of CHF, L Ventricle hypertrophy leading to uraemia?
* hypertension, RAAS
84
What are the pathomechanisms of vascular lesions that lead to uraemia?
* endothelial damage
* secondary thrombosis
* infarction in variety of tissues
85
What are the pathomechanisms of nonregenerative anaemia leading to uraemia?
* EPO deficiency
86
What is the pathomechanism of mineralisation of soft tissue/stomach leading to uraemia?
* altered Ca-P metabolism
87
What is the pathomechanism of fibrous osteodystrophy leading to uraemia?
* altered Ca-P metabolism
* increased syntehsis of PTH
88
What is the pathomechanism of secondary hyperparathyroidism leading to uraemia?
* altered Ca-P metablism
89
What is the pathomechanism of uremic encephalopathies leading to uraemia?
* metablic acidosis
* toxic waste products
90
What pathomechanism of cachexia causes uraemia?
* anorexia
* v/d
91
What is nephrotic syndrome?
Protein-losing nephropathy
92
Nephrotic syndrome has damaged...
glomeruli in the presence of normally fxning tubules
93
What are signs of nephrotic syndrome?
* proteinuria +++
* hypoproteinaemia
* generalised oedema
* hypercholesteraemia/hyperlipidaemia
94
Clinical syndrome of nephrotic syndrome is characterised by...
* hypoalbuminaemia
* generalised oedema
* hypercholesterolaemia
95
Proteinuria in absence of UT inflammation is indicative of
glomerular damage
96
Oedema is the result of...
decreased plasma colloid osmotic pressure, stimulation of RAAS, and release of ADH in response to hypovolaemia
97
What is the hepatic response to hypoproteinaemia?
* generalised increase in production of proteins incl lipoproteins
* leads to hyperlipoproteinaemia & hypercholesterolaemia
98
Dependent oedema
Hypoalbuminaemia --> plasma colloid osmotic pressure decreases --> interstitial fluid increases --> circulating vol decreases --> angiotensin activated (ADH release), Na retention increases --> dependent oedema increases
99
dependent oedema is often seen in...
vental abd & legs due to gravity
100
Renal aplasia
| What is it? Predisposed breeds, assoc'd w/ ?
* absence of kidney/renal tissue (bilateral = incompatible w/ life, unilateral = remaining kidney compensatory hyperplasia and increased vulnerability)
* Predisposed: beagle, doberman, shetland sheepdog
* Assoc'd w/: ureter aplasia, absent vas deferens/epididymis/uterine horns
101
Renal Hypoplasia
| What is it? species affected
* kidney abnormally small but morphologically normal
* species: cats
* fxnl capacity lower to start w/ b/c one is smaller
102
Renal Ectopia
| What is it? Species affected, Predisposed to:
* kidneys misplaced in pelvic cavity or inguinal region
* unilateral in pigs/cats/dogs
* Predisposed to: ureteral obstruction, hydronephrosis, pyelonephritis
103
Renal Fusion
| Significance, appearance
* Appearance: horseshoe kidney
* Significance: no clinical pathological significance
104
Renal cysts
| What is it? species affected? acquired how? Mechanism?
* Cysts variable sized fluid-filled spaces lined by flattened epithelium anywhere in nephron
* Species: All
* Acquired by: chronic interstitial lesion, steroid txt, dialysis, assoc'd w/ renal dysplasia, chronic renal dz
* Mechanism: obstruction of nephron, saccular dilation of tubules due to defective basement membrane, focal tubular epithelial hyperplasia
105
Polycystic kidney dz
| Species/breeds; associations, commonly leads to
* species/breeds: cats (persians), dogs (Cairn terriers, WHWT), lambs, pigs, calves, foals
* Associations: cystic bile ducts, pancreatic cysts, bile duct proliferation
* Commonly leads to: stillbirth, neonatal death, chronic renal failure in 1st few wks of life
106
Familial Renal Dz's in dogs includes Progressive Juvenile Nephropathy. What is it?
* aka Renal dysplasia
* non-inflammatory, degenerative, or dvlpmtl chronic renal dz, nephron impacted of obscure pathogenesis in young animals
* inbred lines of animals (mostly dogs)
* young dogs: 4 mos to 5 yrs
* progressive renal failure
107
Renal dysplasia
| What is it? Causes? Consequences?
* Altered structural organisation that results from abnromal renal dvlpmt/differentiation
* causes: familial renal dz in dogs or inherited renal dz in Suffolk shep, Japanese black cattle; foetal infection by teratogenic virus; in utero ureteral obstruction; hypovitaminosis A in piglets; anything that disrupts organogenesis
* Consequences: diffuse & bilateral --> fxnl overloading of renal excretory capacity w/ time causes uraemia in 1st yr or 2 in life; any superimposed inflammation will hasten onset & dvlpmt of clin syndrome; ureteral anomalies concomitant, dysplastic kidneys abnormally susc to pyelonephritis
108
What are specific tubular dysfxns of multiple transport defects?
* Fanconi syndrome: Basenjis
* Poor reabsorption of glucose/PO4/Na/K/Uric Acid/ AA's from prox tubules --> PU, progressive renal failure
109
What are specific tubular dysfxn due to single transport defects?
* glucose --> Norwegian Elkhounds
* Cystine --> some male dogs
* No morphological changes
110
Nephrogenic Diabetes insipidus
* dogs, foals
* Lack of responsiveness of cells of distal tubules & collecting ducts to ADH
* congenital or acq'd tubulointerstitial dz
