Urinary Pathology

Question 1

Define aplasia of the kidney

Answer 1

failure of development, no recognisable tissue present. Often presents as only one kidney and often an incidental finding

Question 2

Define hypoplasia of the kidney

Answer 2

incomplete development, fewer nephrons at birth and a smaller kidney than expected.

Question 3

Define dysplasia of the kidney

Answer 3

altered structural organisation
kidney will be small, misshapen and +/- fibrosis
cells will have an undifferentiated mesenchyme, immature glomeruli, fibrosis, immature tubules and dilation of the collection tubules

Question 4

Define ectopic kidney

Answer 4

kidney is misplaced from the normal location due to abnormal migration during foetal development

Question 5

Define renal cysts

Answer 5

spherical, thin-walled distensions of the cortex/medulla filled with clear fluid.
can be primary or associated with renal dysplasia, often incidental

polycystic kidneys = multiple cysts on one kidney, sporadic or inherited

PKD = inherited autosomal dominant mutated gene, leading to altered function of related proteins

Question 6

Define hyperaemia

Answer 6

increase in arterial blood flow, can be caused by nephritis/septicaemia/toxaemia
active !

Question 7

Define congestion

Answer 7

increase in venal blood pooling, can be physiological, passive, shock induced or caused by cardiac insufficiency
inactive !

Question 8

Define renal infarction and name the 3 different types

Answer 8

local ischaemia of vascular occlusion, usually due to thromboembolism

acute = swollen and haemorrhagic. focal, wedge-shaped area affected, bulges above the capsule due to swelling

subacute = pale, surrounded by a zone of hyperaemia and haemorrhage, swelling has subsided

chronic = focal, pale, wedge-shaped scar of shrunken and fibrotic connective tissue, surface is below that of a normal kidney

Question 9

Define hydronephrosis

Answer 9

dilation of the renal pelvis, potentially accompanied by atrophy and cystic enlargement (also hydroureter, distension of the bladder)

unilateral or bilateral

caused by urinary obstruction

Question 10

Define glomerulitis

Answer 10

inflammation of the glomeruli

Question 11

Define glomerulonephritis and name the 4 patterns

Answer 11

glomerular inflammation accompanied by secondary tubulointerstitial vascular changes

complicated topic due to many causes, but most commonly deposition of immune complexes

• proliferative = many nuclei due to proliferation
• membranous = thickening of BM by eosinophilic material
• membranoproliferative = combination of both
• glomerulosclerosis = increased connective tissue and mesangial matrix with a loss of capillaries (end stage)

Question 12

Define glomerulopathy

Answer 12

glomerular disease without inflammation

Question 13

Define acute suppurative (embolic) glomerulitis

Answer 13

micro-abscesses in the cortex, normally caused by bacteraemia

Question 14

Define and describe what you see with glomerular amyloidosis

Answer 14

deposition of insoluble proteins in the glomeruli, often associated with chronic inflammation, sometimes neoplasia

grossly, enlarged kidney, pale brown in colour, smooth/finely granular surface

histologically, accumulation of pale, eosinophilic material replacing normal glomerular architecture

Question 15

Define acute tubular necrosis (ATN)

Answer 15

acute necrosis of the tubules characterised by cellular swelling, pyknosis, karyorrhexis and karyolysis

a cause of acute renal failure, caused by a hypoxic/ischaemic injury or a nephrotoxic injury

Question 16

Name then two types of ATN and their main causes

Answer 16

nephrotoxic –> sloughing of epithelial cells into tubulars but BM remains intact - reversible.
caused by nephrotoxins (i.e. drugs, antifreeze, lily toxicity, grapes and raisins) or nephrotoxic pigments (i.e. haemoglobin (kidney is red-brown with haemoglobin casts microscopically))

ischaemic –> sloughing of epithelial cells and necrosis of the BM - irreversible. caused by hypotension and/or ischameia (i.e. heat stroke, dehydration, anaemia)

Question 17

Define interstitial/tubulointerstitial nephritis and name the 2 types

Answer 17

nephritis affecting the interstitium/interstitium and tubules.

suppurative –> bacterial, may be haematogenous or ascending infection

nonsuppurative –> acute or chronic, see fibrosis and atrophy

Question 18

Name some common causes of interstitial nephritis

Answer 18

leptospirosis
Encephalitozoon cuniculi
“white spotted kidney”
FIP

Question 19

Define pyelitis

Answer 19

inflammation of the renal pelvis

Question 20

Define pyelonephritis

Answer 20

inflammation of the renal pelvis and renal parenchyma

Question 21

Define renal gout

Answer 21

deposition of urate crystals (common in birds/humans/repitiles due to lack of uricase enzyme) causing severe dehydration, renal disease, urolithiasis and neoplasia

Question 22

Name the most common renal neoplasms and their features

Answer 22

Renal adenoma –> benign and rare, small and usually incidental

Renal carcinoma –> most common, only affects one pole, palpable mass, commonly metastasizes

Nephroblastoma –> most common in pigs and chickens, large masses, multiple, unilateral, soft, spongy, grey-white

Question 23

Name common systemic changes associated with uraemia
(“non-renal lesions of uraemia”)

Answer 23

increased vascular permeability, leading to pulmonary oedema and fibrinous pericarditis

ammonia secretion, leading to ulcerative gastritis/stomatitis

endothelial damage, leading to thrombosis

lack of erythropoietin production (weak RBCs), leading to anaemia

altered Ca-P metabolism, leading to soft-tissue mineralization, fibrous osteodystrophy and potential parathyroid hyperplasia