Urinary 1, 2 and 3 Flashcards
What should grossly be observes about kidneys at necropsy?
Examine shape, position, and size
Contours/adherence of capsule
Cortex is finely radially striated and dark red
Cortex: medula 2:1
R kidney more cranial
How can you distinguish between proximal and distal convoluted tubules in histology?
Proximal- cuboidal, bigger- as more metabolically active
Distal- flatter
What is abnormal about this kidney slide?
Severe glomerular damage has led to fibrosis
Cannot be replaced- loss of entire nephron
What is the response to injury of the tubular epithelium when
- Basement membrane remains intact
- Nephrons are lost
- Damaged to basement membtane
- Cells regenerate
- Remaining tubules undergo compensatory hypertrophy- but limited capacity and if exceeded causes renal failure
- Diffuse ishcaemic necrosis- entire nephron lost
What are the 4 congenital/inherited diseases of kidneys?
- Ectopic/ fused kidneys- can be functional if blood supply not disrupted
- Dysplasia- anomalous differentiation
- Familial renal disease- under 2yo, leds to loss of nephrons- fibrosis and proteinuria
- Cystic renal disease- single or multiple, blocked tubule, filtrate build up
- Aplasia- Fail to form- rare
- Hypoplasia- incomplete development
What can cause renal haemorrhage?
Trauma
Septicaemia- salmonellosis, erysipelas, CSF, canine herpes in pups
DIC
What causes renal infarction?
What does the severity depend on?
Coagulative necrosis of renal parenchyma secondary to vascular occlusion by embolus
Severity depends on-
Level of vascular obstruction
Nature of thrombus- septic, neoplastic
Common with endocardial thrombosis
How does renal infarction grossly and histologically appear?
How does a chronic infarct appear?
Bonus question (Coffee if correct)- what are the arteries of the kidneys biggest to smallest?
Gross- wedge shaped pale tan, sunken tissue with apex pointing to site of vascular obstruction
Histo- central necrosis and congestion with PCT necrosis at edges, glomeruli often spared
Chronic infarct- replacment of necrotic tissue by fibosis causes contaction and depression of cortical lesion
Arteries- Renal, interlobar, arcuate, interlobar, afferent arterioles, efferent
What is renal papillary necrosis secondary to and what can cause it?
Secondary to reduced blood flow, often due to NSAIDs with or without prostolgandin production
Ishaemic necrosis of medulla
Rarely causes progressive renal disease unless large, sloughed sections lodge in ureter and cause blockage
What are the two types of renal cortical ishaemia and what is the difference?
Acute tubular necrosis- results from reduced blood flow or toxins- multifocal to diffuse ischaemia, mainly PCT affected
Renal cortical necrosis- gram -ve septicaemia or DIC leads to microthrombi causing multifocal to diffuse necrotising damage- rare
Describe the process of necrosis with Acute tubular necrosis?
- Toxic or ischaemic damage causes PCT loss and tubules fille with cell debris
- Oligouria (small volume of urine) as cell debris blocks, urine leaks into intersitium
- Can regenerate if BM intact
What endogenous toxins can cause acute tubular necrosis?
Hypoperfused kidneys with Hb-aemia- secondary to Cu tox
Myoglobinaemia
Serum Hb/Mb are increased and pass into filtrate- Houses Leg
Necropsy shows dark red cortices
What are the three types of degenerative renal diseases?
Amyloidosis
Hydronephrosis
Hypercalcaemic neuropathy
What is amyloidosis and what causes it?
Modified protein deposits as beta-pleated sheets which is proteolysis resistant
Serum amyloid A (amyloid AA)- idiopathic
Imunoglobulin light chain (Amyloid AL)
Some secondary to neoplasia or chronic inflammation
Where can amyloidosis cause deposits?
Glomerular deposition- common site
Pressure atrophy of glomerulus- proteinuria to CRF
Medullary deposition- cats, asymptomatic at first, then papillary necrosis due to ischaemia to CRF
Can you identify the following 5 conditions grossly?
- Acute renal infarct
- Cat amyloidosis
- Polycystic kidney
- Pig with DIC haemorrhage
- Dog renal Dysplaysia
Can you identify the conditions from these two slides?
- Acute tubular necrosis
- Renal infarct
What is hydronephrosis and what causes it?
Dilation of nephron due to partially obstructed urine flow
Urine pressure build up leading to reduced local medullary blood flow- ischaemie dilation of renal pelvis
In severe cases leads to cortical atrophy leading to urine filled sac in end stage
Caused by slowly developing partial blockages (Congenital abnormalities, ureteral obstruction, LUT inflam, neoplasia, bladder paralysis)
Or
Secondary to infection
What is hypercalcaemic neuropathy?
Mineralisation of tubular basement membrane in the epithelium and glomerulus leading to necrosis
Tubular obstruction and loss- renal failure
Secondary to hypercalcaemia
Paraneoplastic, hypervitaminosis D, hyperparathyroidism, hypoadrenocorticism, otesolysis
What stain is used to identify hypercalcaemic neuropathy and what does it show?
Von Kossa stain- calcium is highlighted black
What happens when a glomeruli is damaged?
Not capable of regeneration but can hypertrophy to extent
Glomerular damage:
- increases permeability
- Reduced perfusion of the downstream parts of the tubule
- Proteinuria (osmotic diuresis)
- Nephrotic syndrome- hypoproteinaemia/cholesterolaemia- oedema and thrombosis
What is glomerulonephritis and what are the two causes?
Indlammation of glomeruli with secondary damage to other parts of the nephron
Caused by:
- Immune mediated damage
- Immune complexes deposited in glomeruli
- Physical action- obstruction to filtration slits
- Biological acvtivity- type III hypersensitivity
What prolonged infections can form immune complexes and therefore glomerulonephritis in dogs, cats, pigs, cattle?
Dogs- ICHep, Pyometra, Chronic skin disease, SLE, AIHA, neoplasia
Cats- FeLV, FIP, neoplasia
Pigs- CSF, PRRS, PDNA
Cattle- BVD
Can be acute or chronic
What causes post-weaning multisystemic wasting syndrome in pigs?
-mouthful am I right?
What other condition can it lead to?
What does it lead to and where?
Caused by porcine circovirus 2
Can lead to PDNS- porcine dermatitis, nephropathy syndrome
Leads to necrogranulomatous hepatitis, interstitial pneumonia and IN inclusion bodies
Liver/Lung/Lymph nodes
How does PDNS appear in animals?
How is biochemistry of the animal affected?
Causes systemic necrotising vasculitis of skin and kidneys
Kidneys appear enlarged, pale brown with petechial haemorrhages
Multifocal to coalescing erythematous skin lesions, some progressing to necrosis
Raised serum urea, creatinine, gamma globulin levels and proteinuria
What is tubulointerstitial nephritis?
Disease that caused inflammation that affects tubules and interstitium
damage to one triggers the other
Interstitial inflammation and fibrosis results in tubular atrophy and degeneration with secondary damage to glomeruli and vessels
Tubular damage stimulates inflammation which spills into intersitium
Both lead to chronic renal disease
What are the different categories of tubulointerstitial nephritis?
Acute interstital nephritis
Supprative intersitial nephritis
Granulomatous interstitial nephritis
What can cause acute tubulointerstitial nephritis in dogs, cattle and pigs?
Dogs- Leptospires, ICHV
Cattle- MCF, L.hardjo/pomona
Pigs- L.pomona
What is the source of canine leptospirosis?
How can it be primary or secondary exposure?
Source of infection- Rats
Primary- indirect exposure via contaminated water source, soil food
Secondary- direct via infected urine, bite wounds
Describe the development of canine leptospirosis?
In an acute case how do the kidneys appear?
Describe the histology
- Skin abrasions/mm allow entry causing leptospiraemia
- Localisation in intersitial capillaries
- Migration to tubular lumen
Kidneys appear swollen and reddened
Histo- leptospiras associate with microvilli of D/PCT cause cause necrosis. Secondary intersitial inflammation with lympocytes, plasma cells and macrophages
What happens if a dog survives from canine leptospirosis?
Regeneration of tubules is possible
Leptospiras can persist in renal tubules without causing disease but excreted in usine for long periods of time
What is the zoonotic form of leptospirosis?
What animal can it affect and what does it cause?
L. hardjo
Cattle- causes a transient milk drop
What are the diffent causes of supprative interstitial nephritis?
What different organisms can cause it?
Pyogenic (cause pus) organisms either haematogenously or ascening up pelvis
E.coli- white spot kidney
Actinobacillus
Erysipelas
Truperalla pyogenes
What agents can cause granulomatous interstitial nephritis?
Cats- FIP
Mycobacteria- M.Bovis
Fungi- rare
Dogs- systemic encephalitozoan cuniculi
- What are the alternative names for pyelonephritis?
- Pyelitis/ Pyonephritis
- What causes pyelonephritis?
- Why is the medulla predisposed?
- What agents can cause pyelonephritis
- Usually ascending LUT infection- Bacteria
females predisposed, urine stasis, retrograde flow, local trauma - Medulla hypertonicity inbitis neutrophil influx and NH3 inhibitory complement
- All species- E.coli, Staphylocci, Strep
Cattle- Corynebacterium renale
Foals- actinobacillus equi
What parasitic disorders can and how do they affect the kidney?
Toxocara canis- Dogs
Migration of ascarid larvae, producing granulomatous nephritis
Dictophyma renale-
Pelvic and peritoneal location
Parenchyma destroyed by pressure atrophy
Zoonotic
Why are renal tubules highly susceptible to toxic damage?
Which part of the kidney is particularly susceptible?
What exacerbates damage?
High exposure and sensitivity
PCT- high metabolic activity
Shock and dehydration
Describe the pathogenesis of renal toxic disease?
Leads to acute tubular necrosis
Many toxins alter ion pump in epithelium- reducing Na reabsorption and increased excretions- stimulates RAAS, causing vasoconstriction and ischaemia
Obstruction by cell debrin and intersitial oedema
Impaired glomerular permeability
What toxins can cause acute tubular necrosis?
Oxalates- Ethylene glycol
Vitamin D compounds
Oak tannins
Myotoxins
Heavy metals
Antibiotics
Endogenous pigments- Hb
Enterotoxaemias- Clostrid perfringens
Describe the pathogenesis of ethylene glycol toxicity?
How do kidneys grossly appear?
What can be done to cytology samples for diagnosis?
- Effects CNS
- Insoluble Ca2+ oxlalate crystals form in PCT- obstruction
- Metabolic acidosis
- Azotaemia, hypocalcaemia, hyperkalaemia, renal failure
Grossly appear-red and swollen with white/yellow striated cortex
Polarised light shoes the oxalate crystals
What agent causes pulpy kidney disease?
How does it affect lambs and sheep
Where is C. perfringens found and who is most susceptible?
Clostridium perfringens D enterotoxaemia
Lambs- Acute, non-contagious disease in lambs- convulsion/sudden death
Older sheep- die after few days of mild GI signs some CNS signs (ataxia)
Found in soil, manure, intestinal commensal in ruminants
All ages- but 3-10 week old fast growers with sudden change in feed
How does C. perfringens cause enterotoxaemia?
- Ingest spores which activate in SI, if consumption of undigested starch high (milk) it provides substrate for overgrowth
- Multiplying bacteria produce inactive protoxin which is activated by trypsin into epsilon toxin
- Toxin decreases intestinal motility and allows uptake into circulation
- Systemic circulation causes vascular endothelial degeneration- glucosuria, oedema, haemorrhage
What renal neoplasias are common and uncommon?
Primary neoplasia uncommon
Epithelial/mesenchymal origin
Metastatic tumours
What epithelial neoplasms can form in the kidneys?
Adenoma- rare, well circumcised, cortical mass
Adenocarcinoma- most frequent in dogs, cattle, sheep
Large, necrotic, haemorrhagic
Vascular metastasis to lung
May produce erythropoietin- polycythaemia
Transitional cell carcinoma- renal pelvis
What mesenchymal neoplasms can originate from the kidney?
Lymphosarcoma- cats, cattle, dogs
Primary or secondary
Nodular or diffuse
Haemangiosacrcoma, fibrosarcoma- rare
What epithelium makes up the lower urinary tract?
Stratified squamous epithelium
What congenital disease can affeft the lower urinary tract?
Ectopic ureters- ureters terminate somewhere different (more caudal) to bladder
Leads to chronic urinary incompetence and UTI common
Patent urachus- urine from the navel
What circulatory diseases can affect the LUT?
Haemorrhage- trauma, septicaemia, Viraemia
Infarction- torsion, prolapse
What degenerative conditions affect the LUT?
Hydroureter/urethra-
Dilation of urter or urethre secondary to partial obstruction
If unilateral distal to bladder, bilateral proximal
Acquires anatomic variatoins-
displacment, torsion, dilation, rupture, herniation
Urolithiasis
What can commonly cause bladder rupture, Dilation, Displacement?
Rupture-
Ruminants- urethral obstruction
Dogs/Cats- pelvic trauma
Foals- parturition
Dilation- obstructive- can lead to muscle tone loss
Dislacement- abdominal masses, pregnancy
What is urolithiasis?
What are its effects?
Formation and presence of particles- kidney stones
Effects
- Partial/complete obstruction
- Pressure necrosis/ulceration
- Acute haemorrhagic inflammation with bacterial overgrowth
- Possible rupture of bladder/urethra
What can urolithiasis particles be composed of?
Variable mineral content-
Struvite, Calcium carbonate, Silicate, Oxalate
Variable organis content-
Role in formation
What are the predisposing factors to urolithiasis?
pH- acid (oxalates), alkaline (struvite)
Bacterial infection- urea to NH4++ by bacteria elevates pH
Diet- high phosphorus, oxalate, vit A deficiency
Hereditary
Sex
Species- cats
What are the different potential sites of urolithiasis?
Renal- pelvic- painful
Ureteral
Cystic- cystitis
Urethral- Os penis dogs, sigmoid flexure
What is feline urologic syndrome?
What is it predisposed by?
Describe its pathogenesis?
Obstructive urethral urolitheriasis
Predisposed by- neutered males, dry diets, alkalkine urine pH, increased urination intervals
Urethral obstruction to dysuria, haematuria and post renal azotaemia
2nd bacterial infectoin to severe haemorrhagic, transmural cystitis
can lead to rupture or acute renal failure
