Urinary

Question 1

What % of blood plasma becomes glomerular filtrate?

Answer 1

16%

Question 2

How do the kidneys affect vitamin D?

Answer 2

Convert vitamin D to active form, facilitating Ca2+ absorption from intestines

Question 3

Where is renin produced?

Answer 3

Juxtaglomerular cells

Question 4

How big should a kidney be?

Answer 4

2.5-3 x length of a lumbar vertebrae

Question 5

What is an ectopic kidney?

Answer 5

Abnormal kidney migration eg in pelvic region
Mainly unilateral
Dogs, pigs

Question 6

What is the difference between aplasia, hypoplasia, and dysplasia regarding kidneys?

Answer 6

Aplasia: kidneys never developed (agenesis)
Hypoplasia: incomplete development (fewer nephrons and lobules)
Dysplasia: small, misshapen, fibrosed, cystic kidneys. Structures are primitive for their age

Question 7

Polycystic kidney disease affects which cat breed in particular?

Answer 7

Persians

Question 8

Congenital tubular function abnormalities affect which species?

Answer 8

Dog

Question 9

Autoregulation of renal blood flow is under the control of what?

Answer 9

Prostaglandins

Question 10

How would a kidney with infarction appear histologically?

Answer 10

Central necrosis, mild inflammation with congested capillaries. Replacement of necrotic tissue by fibrosis -> depressed scar

Question 11

What is infarction of the kidney?

Answer 11

Coagulative necrosis of the parenchyma due to vascular occlusion by emboli

Question 12

What name is given to the capillaries supplying the medulla of the kidneys?

Answer 12

Vasa recta renis

Question 13

How can treatment with NSAIDs cause papillary necrosis?

Answer 13

NSAIDs inhibit prostaglandin synthesis, prostaglandins regulate renal blood flow
Papillary necrosis occurs due to impaired blood flow in the vasa recta capillaries supplying the medulla

Question 14

Give the 2 types of necrosis that can result from cortical ischaemia of the kidney

Answer 14

Renal cortical necrosis (diffuse cortical damage)
Acute tubular necrosis (tubular epithelium of PCT-cells die, slough and occlude the tubular lumen -> oliguric renal failure)

Question 15

What is meant by oliguria?

Answer 15

Production of very small amounts of/almost no urine

Question 16

What is amyloidosis?

Answer 16

The deposition of insoluble, proteolysis-resistant, beta-pleated sheets of protein, derived from modified forms of circulating proteins

Question 17

What are the 2 kinds of amyloid that cause amyloidosis, and what are they formed from?

Answer 17

Amyloid AL: formed from immunoglobulin light chains

Amyloid AA: formed from serum amyloid A (hepatic acute phase protein)

Question 18

What is the main site of deposition of amyloid plaques in the kidney?

Answer 18

Glomeruli

Question 19

Amyloid depositions in the kidneys can result in what?

Answer 19

Proteinuria
Hypoproteinaemia (nephrotic syndrome)
Increased glomerular permeability 
Pressure atrophy of the glomerular tuft
Nephron atrophy
Chronic renal failure

Question 20

How does a kidney with amyloidosis appear grossly?

Answer 20

Enlarged, pale, ‘waxy’ kidneys, with glomeruli possibly standing out as dots, which stain positive with Lugol’s iodine

Question 21

Which other organs (besides kidneys) can be affected by amyloid deposition?

Answer 21

Pancreas (cat)
Liver (esp Siamese cats)
Spleen and skin (horse)
Coronary artery (dog)

Question 22

What is hydronephrosis?

Answer 22

Dilation of the renal pelvis secondary to any obstruction of urine flow.
Fluid builds up -> pressure -> occlusion of blood vessels -> ischaemia of medulla

Question 23

Describe hypercalcaemic nephropathy

Answer 23

High Ca2+ impairs Na+ transport, leading to natriuresis (excretion of sodium in urine), and interferes with action of ADH on tubules (ADH causes water to be reabsorbed) -> nephrogenic diabetes insipidus
PU/PD, although this is reversible at this stage
More common in dogs

Question 24

What 3 things does filtration depend on in the glomerulus?

Answer 24

Size, charge (anions are repelled by the negative charge of the barrier) and adequate blood pressure in the glomerulus

Question 25

What make up the filtration barrier of the glomerulus?

Answer 25

Fenestrated epithelium Glomerular basement membrane (inc mesangial cells which are phagocytic and secrete cytokines) Epithelial cells with podocyte processes forming slit pores (non-regenerative)

Question 26

Give the 2 main consequences of glomerular damage

Answer 26

Increased permeability | Reduced perfusion of downstream parts of the tubule

Question 27

Which kind of conditions cause glomerulitis?

Answer 27

Acute septicaemia | Viral glomerulitis

Question 28

Glomerulonephritis in animals is usually what type?

Answer 28

Immune-complex type, ie results from immune complexes deposited directly from circulation or developed in-situ after entrapment of an antigen

Question 29

Describe porcine dermatitis and nephropathy syndrome

Answer 29

Growing/finishing pigs Results in a severe fibrino-necrotising glomerulonephritis and necrotising vasculitits, with haemorrhages in the skin and other organs (suggesting an immune complex-based pathogenesis)

Question 30

How may a dog acquire canine leptospirosis?

Answer 30

Direct transmission: infected urine, venereal/placental transfer, bite wounds, ingestion of infected tissues Indirect transmission: exposure to contaminated water sources, soil, food, bedding Rat urine is a common source of infection

Question 31

Which organism is responsible for 'white spot kidney' in cattle?

Answer 31

E.coli

Question 32

How does suppurative interstitial nephritis occur?

Answer 32

Pyogenic organisms localise in the kidney either haematogenously due to bacteraemia, or in infected emboli which lodge in the renal vasculature Formation of foci of pus/abscesses scattered through the kidney

Question 33

What is pyelonephritis?

Answer 33

Inflammation of pelvis and renal parenchyma

Question 34

Why are cells of the PCT particularly susceptible to damage by toxins?

Answer 34

High metabolic activity

Question 35

How does antifreeze poisoning result in renal failure?

Answer 35

``` Ethylene glycol (antifreeze) is oxidised to glycoaldehyde, glycolic acid, glyoxylate and oxalate by the liver Oxalate combines with calcium -> hypocalcaemia -> calcium oxalate crystals precipitate in renal tubules -> acute renal failure by obstruction ```

Question 36

What are the clinical signs of ethylene glycol poisoning?

Answer 36

Ataxia, convulsions, vomiting, uraemia but no fever

Question 37

What clinical signs would you see with calciferol poisoning?

Answer 37

Calciferol=vit D | Hypercalcaemia, hyperphosphataemia, soft tissue mineralisation

Question 38

Describe oak tannin poisoning

Answer 38

Oak tannins cause irritation to the GI tract Tannins and their metabolites are also nephrotoxic and hepatotoxic Signs: colic, anorexia, constipation followed by scant dark faeces with blood in, icterus, dehydration PM: pale enlarged kidneys surrounded by gelatinous blood-tinged oedema and haemorrhages in the capsule and peri-renal fat

Question 39

'Purple kidney disease' affects which species? What is it caused by? What are the clinical signs?

Answer 39

Sheep (lambs) Caused by Clostridium perfringens type D Acute, infectious, non-contagious disease of lambs; convulsions, hyperglycaemia, sudden death Epsilon enterotoxin causes damage to vascular endothelium in lungs, brain, kidneys

Question 40

Are males and females more prone to infection or obstruction regarding their lower urinary tract? Why?

Answer 40

Females: infection due to close proximity to rectum, and short wide urethra Males: obstruction due to narrow tortuous urethra and its associated structures

Question 41

In which animals is patent urachus most common?

Answer 41

Foals and calves

Question 42

Give 3 causes of bladder haemorrhage

Answer 42

Severe haemorrhage: ventral trauma eg being kicked Treatment with the chemotherapeutic agent cyclophosphamide can cause a sterile haemorrhagic cystitis in dogs Petechiation or ecchymoses are a feature of septicaemic or toxaemic conditions eg classical swine fever

Question 43

What is hydroureter/hydrourethra?

Answer 43

Dilation of the ureter/urethra due to an obstruction of urine outflow by blockage eg calculi, chronic inflammation, neoplasia, strictures

Question 44

What is urolithiasis?

Answer 44

Formation of calculi within the urinary tract causes obstruction, pressure necrosis with ulceration at site of impaction, and acute heamorrhagic cystitis, urethritis or nephritis due to bacterial overgrowth in the static urine

Question 45

Give some factors which predispose an animal to urolithiasis

Answer 45

pH: acidic= oxalates, alkaline= struvite Bacterial infection Dietary factors: high phosphate diets, oxalate-rich plants, dehydration, vit A defiency Hereditary: urates in dalmations Sex Species: calcium carbonate (horses), struvite (dogs)

Question 46

Describe feline urologic syndrome

Answer 46

Obstructive urethral urolithiasis Male neutered cats Dry diets, alkaline urine Urethral obstruction -> post-renal azotaemia, dysuria, haematuria Secondary bacterial infection causes severe haemorrhagic transmural cystitis. Rupture and uroperitoneum may occur Grossly, the bladder is distended and haemorrhagic

Question 47

Give the 4 types of cystitis

Answer 47

Acute: haemorrhage, necrosis, catarrhal exudate Chronic: polypoid mucosal changes, squamous metaplasia, thickening of bladder wall Emphysematous: bacterial fermentation of glucose-loaded urine (diabetes mellitus) Granulomatous: rare, can occasionally occur with tuberculosis or other granulomatous organisms

Question 48

Give 4 factors which protect against cystitis

Answer 48

Urethral sphincters Frequent voiding of urine Antibacterial properties of urine (urea, high osmolarity, organic acids) Secretory IgG and mucin (mucosal defences against colonisation)

Question 49

Give some factors that predispose an animal to cystitis

Answer 49

``` Urine stasis Incomplete voiding of urine Bladder trauma (catheterisation) Glycosuria (diabetes mellitus) Urine of dilute concentration or high pH Short wide urethra (female) ```

Question 50

Give some agents which cause cystitis

Answer 50

``` E.coli Proteus Streptococci Staphylococci Eubacterium suis (pigs) ```

Question 51

Enzootic haematuria occurs in cattle due to chronic ingestion of what?

Answer 51

Bracken

Question 52

What is the commonest bladder tumour in dogs?

Answer 52

Transitional cell carcinoma

Question 53

What is uraemia?

Answer 53

The clinical syndrome of toxicosis from renal failure

Question 54

What is azotaemia?

Answer 54

Higher than normal blood urea (or other nitrogen-containing compounds)

Question 55

What is isosthenuria?

Answer 55

Specific gravity of urine is the same as protein-free plasma. It is fixed at around 1.010, irrespective of fluid intake

Question 56

What is hyposthenuria?

Answer 56

Urine of low specific gravity

Question 57

Give some causes of pre-renal renal failure

Answer 57

``` Hypoperfusion due to: hypovolaemia by haemorrhage dehydration shock trauma cardiac failure ```

Question 58

Give some causes of intrinsic renal failure

Answer 58

``` Renal infections Nephrotoxicity eg drugs, ethylene glycol, Hb, heavy metals Neoplasia Inflammation Fibrosis Congenital disease ```

Question 59

Give some causes of post-renal renal failure

Answer 59

Acute lower urinary tract obstruction Bladder rupture Bladder dysfunction

Question 60

Describe acute renal failure

Answer 60

Sudden loss of 70-100% of nephron capacity Caused by: ischaemia, nephrotoxins, complete outflow obstruction Kidneys are often painful and swollen Animals are typically anuric or oliguric. Urine tends to be isosthenuric. Prognosis depends on degree to which regeneration is possible

Question 61

Describe chronic renal failure

Answer 61

Gradual and progressive loss of nephrons: -Interstitial nephritis -Glomerulonephritis -Pyelonephritis -Amyloidosis Results from persistent disease process. Overloading of residual tubules -> poor concentrating ability -> hyposthenuria, PUPD

Question 62

How can you use urine to differentiate between acute and chronic renal failure?

Answer 62

Acute will be isosthenuric | Chronic will be hyposthenuric

Question 63

What are the effects of renal failure?

Answer 63

Build up of waste products -> azotaemia (urea, creatinine, phenols etc) Failure of acid base regulation -> metabolic acidosis Failure of fluid volume regulation (dehydration, PU with hyposthenuria and secondary PD) Electrolyte disturbances (phosphate and K+ retention, Ca2+ loss with secondary hyperparathyroidism) Endocrine disturbances (reduced erythropoietin -> anaemia; activation of RAAS -> high blood pressure; failure of vit D conversion -> hypocalcaemia)

Question 64

Give some clinical signs of uraemia

Answer 64

PUPD, pallor, anorexia, lethargy, weakness, muscle wasting, hypothermia, mouth and tongue ulcers, vomiting (+/- blood), melaena (blood in faeces), non-regenerative anaemia, skeletal softening (rubber jaw) Terminal CNS signs: dullness, drowsiness, tremors, ataxia, coma

Question 65

Give some conditions that can occur as a result of uraemia | state why they occur

Answer 65

Cachexia (prolonged catabolic state) Haemorrhagic gastritis (ammonia secretion) Soft tissue mineralisation (hyperparathyroidism) Non-regenerative anaemia (decreased erythropoietin)

Question 66

How does renal failure lead to 'rubber jaw'?

Answer 66

RETENTION OF PHOSPHATE Reduction in GFR -> retention of phosphate; hyperphosphataemia Hyperphosphataemia inhibits renal conversion of Vit D to calcitriol -> reduced intestinal calcium absorption High phosphate precipitates out calcium in tissues Hypocalcaemia Increased PTH secretion, parathyroid glands become hyperplastic Chronic PTH secretion -> resorption of mineralised bone Softening, enlargement and rarefaction of bones, esp facial and mandibular - 'rubber jaw'

Question 67

What are the functions of the kidneys?

Answer 67

Excretion of waste products, particularly nitrogenous waste, by the formation of urine Conservation of water (loop of Henle, urea gradient, ADH) Acid-base regulation (bicarbonate reclamation) Electrolyte regulation (Na+/K+ -RAAS, phosphate) Endocrine roles (erythropoietin, vit D conversion)