Renal Pathology

Question 1

What does pre-renal functional problems cause?

Answer 1

Compromised renal perfusion - Reduced RBF leading to Renal Ischemia

Question 2

What does functional problems intrarenally cause?

Answer 2

Compromised kidney function

Question 3

What does post-renal functional problems cause?

Answer 3

Obstruction of urine outflow

Question 4

When does acute renal failure occur?

Answer 4

When over 75% of renal function is abruptly impared

Question 5

What are the main signs of acute renal failure?

Answer 5

Azotaemia - Cardiac dysrrythmia (due to to K retention) - Muscle tremors and coma (due to phosphate retention) - Metabolic acidosis (due to failure of pH control) - Hypertension - Oliguria

Question 6

What is chronic renal failure characterised by?

Answer 6

Prolonged signs of uraemia

Question 7

Define azotemia. How is it caused?

Answer 7

Retention of nitrogenous metabolites - Insufficient glomerular filtration

Question 8

What are the clinical signs of chronic renal disease?

Answer 8

Polyuria - Isosthenuria - Polydipsia - Halitosis - Dribbling - Lank coat - Weight loss

Question 9

Define uraemia

Answer 9

Urea in the blood

Question 10

Give the progression of normal renal function to uraemia

Answer 10

1- Diminished renal reserve, GFR 50% of normal 2- Renal reserve, GFR 20-50%, azotaemic and polyuric 3- Renal failure, 20-25%, kidneys can’t maintain homeostasis = uraemia 4- End-stage renal disease, 5%, terminal stages of uraemia

Question 11

What are the systemic effects of uraemia?

Answer 11

Causes retention of electrolytes (esp Ca) - Plasma protein loss - Hyperphosphataemia - Secondary renal hyperparathyroidism - Reduced erythropoietin - Hypertension

Question 12

How does uraemia cause Secondary renal hyperparathyroidism?

Answer 12

Reduced GFR - inadequate secretion of phosphate - Precipitation of ionised calcium concentration - Reduced activation of Vit D - Reduced Ca absorption - PTH stimulated - Osteoclastic bone resorption

Question 13

How does uraemia cause non-renal lesions?

Answer 13

Endothelial degeneration and necrosis = vasculitis and secondary thrombosis Large amounts of ammonia/bacteria in saliva

Question 14

What are the portals of entry for infection into the kidney?

Answer 14

Haematogenous - Glomerular infiltrate - Ascending ureter - Direct penetration

Question 15

What are the defence mechanisms within the kidney?

Answer 15

Urine flow flushes out bacteria - pH of urine - basement membrane

Question 16

What are the categories of renal disorders?

Answer 16

Glomerular - Tubular - Interstitial - Vascular system

Question 17

What condition is affecting these kidneys?

Answer 17

Hydronephrosis

Question 18

What is the pathogenesis of hydronephrosis?

Answer 18

Obstruction of outflow tract - Increased pressure in renal pelvis - Tubules undergo necrosis and atrophy - Interstitial fibrosis - Pale radiatiing rays

Question 19

What is the condition of this cows kidney? What are the gross problems?

Answer 19

Pyelonephritis - Renal calyces contain supprative exudate bordered by red rim of haemorrhage

Question 20

What infectious agents are involved in pyelonephrotitis in cows?

Answer 20

E. coli - Arcanobacterium pyogens - Cornyebacterium renale

Question 21

When are cows most likely to get pyelonephrititis? What other species is susceptible?

Answer 21

Post-partum period - Sows

Question 22

What is this condition called? What are the microscopic features of this disease?

Answer 22

Acute tubular necrosis - Diffuse degeneration and necrosis of epithelial cells of convoluted tubules

Question 23

What can cause acute tubular necrosis?

Answer 23

Ischaemia - Nephrotoxins - Inflammation - Certain infectious agents

Question 24

What causes chronic renal failure?

Answer 24

Uraemia

Question 25

This is a histological section of a cat's pancreas - What has happened and what could cause it?

Answer 25

Vacuolated beta cell islets consistent with hydropic degeneration - Type 2 diabetes

Question 26

This is the bladder of a cat with type 2 diabetes - what has caused this?

Answer 26

Glycosuria in diabetes mellitus enhances bacterial growth

Question 27

What is the common name for this disease? What can cause it?

Answer 27

Renal infarction - Blockage of artery (neoplasia, embolism), damage of vasculature (toxins)

Question 28

Describe the gross appearance of this kidney

Answer 28

Multifocal small pale/white nectrotic foci

Question 29

Describe what is in these microscopic images of the kidney with multifocal white/red lesions. What is this condition know as?

Answer 29

Microabscesses centered on glomeruli - Bacterial, neutrophils and necrotic debris - Suppurative glomerulitis (embolic nephritis)

Question 30

What causes supprative glomerulitis?

Answer 30

Bacterial invasion - Haematogenous route and lodge in capillaries of glomeruli - Replicate and induce necrosis & inflammation

Question 31

How can immune mediated glomreulonephritis occur?

Answer 31

Formation of antibodies against entrapped nonspecific antigens withing the glomerular basement membrane

Question 32

What is glomerular amyloidosis commonly associated with? Why?

Answer 32

Chronic inflammatory disorders, systemic infectious diseases or neoplasia - Acute phase proteins cause amyloid deposits in glomeruli

Question 33

How can you diagnose that there is amyloid deposition in the kidney?

Answer 33

Stain with congo red - Amyloid is apple green when viewed under polarised light

Question 34

What is acute supprative glomerulitis also known as?

Answer 34

Bacterial or embolic nephritis

Question 35

What is seen in the kidney during acute suppurative glomerulitis?

Answer 35

Formation of microabscesses throughout the cortex

Question 36

What is glomerulosclerosis?

Answer 36

Reduction in number of functional glomeruli

Question 37

What is the most common cause of tubular disease?

Answer 37

Ischemia

Question 38

What is the response of tubules to injury?

Answer 38

Degeneration - Necrosis - Apoptosis - Cells slough into lumen forming cellular casts - Compensatory hypertrophy

Question 39

Why is it detrimental if the basement membrane undergoes necrosis as well as the tubule?

Answer 39

Nephrons don't regenerate

Question 40

Name 3 congenital disorders of renal tubular function

Answer 40

Primary renal glycosuria (reduced glucose reabsorption) - Fanconi syndrome (reduced protein, glucose, phosphate and amino acid reabsorption) - Cystinuria (calculus formation & obstruction in male dogs)

Question 41

What is the most important cause of acute renal nacrosis? What causes it?

Answer 41

Acute tubular necrosis - Nephrotoxic or ischemic injury

Question 42

Why can muscle damage cause acute tubular necrosis?

Answer 42

Myoglobinuric nephrosis released from damaged muscle cells - Amplifies effects of toxins in combination with ischemia

Question 43

Give examples of toxins that can cause acute tubular necrosis

Answer 43

Heavy metal - Pharmaceutical agents (NSAIDs) - Fungal and plant toxins - Ethylene glycol (antifreeze) - Vitamin D - Bacterial toxins

Question 44

What is the renal interstitium?

Answer 44

Fibrovascular stroma that surrounds the nephron

Question 45

What can cause renal interstitial disease?

Answer 45

Ascending infection (pylonephritis) - Haematogenous (E. coli, Leptospira, Canine adenovirus) - Secondary to injury of vasculature/tubules/glomeruli

Question 46

What are the responses to interstitial injury?

Answer 46

Oedema - Haemorrhage - Inflammation - Fibrosis

Question 47

Why is any disease or damage to the renal vascular system detrimental?

Answer 47

Arterial blood supply to the cortex is terminal (no anastomoses) so will have a knock on effect to nephron blood supply

Question 48

What is the difference between hyperaemia and congestion?

Answer 48

Hyperaemia is an active processs where arterial dilation causes increased blood flow (inflammatory response) - Congestion is a passive process where blood accumulates in venous system (secondary to hypovolaemic shock/cardiac insufficiency/hypostatic)

Question 49

What is Virchow's triad?

Answer 49

Major determinants of thrombosis - Endothelial injury, Dynamics of blood flow, Hypercoagulability of blood

Question 50

What is disseminated intravascular coagulation? What can cause it?

Answer 50

Serious manifestation of abnormal coagulation, generation of excess thrombin - Complication of any condition associated with widespread thrombin activation

Question 51

Whata re the main diseases of the renal pelvis?

Answer 51

Hydronephrosis - Pyelonephritis - Papillary necrosis

Question 52

What is the main cause of hydronephrosis?

Answer 52

Obstruction of urine outflow

Question 53

What has occured on this photo?

Answer 53

Hydronephrosis

Question 54

What is pyelonephritis?

Answer 54

Bacterial infection of the renal pelvis

Question 55

What has occured on this photo?

Answer 55

Pyelonephritis