Urinary Flashcards
Which animals have a multilobar kidney?
Cow
Pig
Marine mammals
Which animals have a unilobar kidney?
Carnivores
Small ruminants
Horses
How much of cardiac output, body’s o2 needs go to the kidneys?
25% of CO
10% of body O2
What are the roles of the kidneys?
-Regulation of electrolytes
-conservation of water
-Acid-base regulation
-excretion of waste
-endocrine roles (EPO)
What should the normal cortex : medulla ratio be?
2:1 / 3:1
On a radiograph which kidney is more cranial + can be hidden behind the gastrointestinal tract?
Right Kidney
If nephrons are lost what happens to the tubules?
Compensatory hypertrophy - but limited capacity
If exceeded = renal failure
What are the 4 different types of congenital/ inherited diseases of the urinary system?
1.Ectopic - in abnormal location (fused horse-shoe kidneys can be fully
functional)
2.Dysplasia - other kidney = compensatory hypertrophy
3.Familial renal disease = chronic renal failure in <2y/o dogs
4. Cystic renal disease = polycystic kidneys - persian cats/bull terriers
What can induce dysplasia?
viral infections in utero - canine herpes virus, feline panleukopenia, BVD
How does polycystic kidneys cause damage?
blocked tubules = filtrate build-up = pressure = atrophy of renal tissue
What are the 3 types of circulatory diseases?
1.Haemorrhage - trauma, septicaemia, DIC
2.Infarction - 2* to vascular occlusion by embolus
3.Cortical ischaemia - i). Acute tubular necrosis
ii). Renal cortical necrosis
What are examples of traumatic injuries?
RTA
Dog bite trauma - cat kidney attacked
What does the kidney look like grossly with infarction?
wedge shaped pale tan sunken tissue
What does haemoglobin/myoglobin in the filtrate cause?
Acute tubular necrosis - causes copper toxicity in sheep
What are the degenerative diseases of the urinary system? (3)
1.Amyloidosis
2.Hydronephrosis - due to partially obstructed blood flow
3.Hypercalcaemic nephropathy - 2* to hypercalcaemia
What does histology of amyloidosis look like?
What stain picks up amyloid?
loss of structure + flattened (pressure)
high protein due to beta-pleated sheets of amyloid
Congo red stain
Causes of hydronephrosis?
Congenital ureteral anomalies
Calculi
lower urinary tract inflammation
Neoplasia
bladder paralysis
What are the causes of hypercalcaemic nephropathy?
Paraneoplastic syndrome
hypervitaminosis D
increased PTH
hypoadrenocorticism
osteolysis
CRF
What stain picks up Ca2+?
Von kossa
What are the 3 infectious/inflammatory urinary tract diseases?
1.Glomerulonephritis - immune mediated damage(hypersensititvity iii)
2.Tubulointerstitial nephritis
3.Pyelonephritis
What causes the different types of tubulointerstitial nephritis?
-Suppurative interstitial nephritis - E.coli - (‘white spot kidney’ - cattle)
-Granulomatous interstitial nephritis - FIP (cats), Mycobacteria (cattle)
What is the Parasite that affect the urinary system?
Toxocara Canis - larvae = granulomatous nephritis
Why are kidneys prone to toxic injury?
high exposure and sensitivity
What are examples of toxins that affect the kidneys?
*Oxalates - ethylene glycol poisoning
*Mycotoxins
*Heavy metals (Hg, Pb, arsenic)
*Antibiotics (aminoglycosides, monesin, tetracyclines)
*Endogenous pigments (haemoglobin, myoglobin)
*Enterotoxaemia - C. Perfringes
*grapes/raisins in dogs
What do the kidneys look like in ethylene glycol poisoning?
Red + swollen
What sheep are more prone to pulpy kidneys disease?
aged 3-10weeks with sudden change in diet
What toxin causes pulpy kidney disease?
Clostridium Perfringens type D
Epsilon toxin
What does pulpy kidney look like?
Soft + mushy
mutifocal to coalescing
What does epsilon toxin cause?
*decreased intestinal motility
*allows uptake to circulation via portal capillaries
*damage to epithelium = oedema + haemorrhage
*damage to kidney tubular epithelium = ATN
What is the congenital disease of the lower urinary tract (LUT)?
Ectopic ureters => chronic urinary incompetence
=> Ureters to urethra - bypass bladder = no storage
What are the circulatory diseases of the LUT?
+what are the causes?
a). Haemorrhage - from trauma, septicaemia, viraemia
b). Infarction - from torsion / prolapse
What are the degenerative diseases of the LUT?
a). Hydroureter/Hydrourethra
b). Acquired anatomic variations of the bladder
c). Urolithiasis - kidney stones
What causes hydroureter/ hydrourethra?
secondary to partial obstruction + build up of pressure
Hydronephrosis = complete obstruction + anuria
What are the 3 different acquired anatomic variations of bladder?
*Displacement
*dilation
*rupture
What causes displacement of bladder?
*abdominal masses
*pregnancy
What causes dilation of the bladder?
obstruction - can cause loss of muscle tone => 2* bacterial cystitis
What causes rupture of the bladder?
Dilation
Trauma = RTA (Dog + Cat)
= 2 to obstruction - urolithiasis (ruminants)
= Foals = at parturition, rupture of urachus/ 2 to umbilical
abscessation
What does urine in the body cavity cause?
Irritant = peritonitis + thickened + reddened omentum
What can urolithiasis (kidney stones) lead to?
*partial / complete obstruction
*pressure necrosis/ulceration
*acute haemorrhagic inflammation with bacterial overgrowth.
*possible rupture of bladder / urethra
What are the different content/minerals of kidney stones?
*Struvite = most common
*Calcium Carbonate
*Silicate
*Oxalate
*Urate/cystine
What are the predisposing factors of kidney stones?
Heredity
Diet
pH
Sex
Species - cats more likely
What are the common sites of urolithiasis?
Renal pelvis = v painful
ureteral
cystic
urethral = most common
What is the LUT inflammatory disease?
Cystitis = acute = catarrhal, haemorrhagic, necrotic
= Chronic = polypoid, follicular, metaplastic
What are the predisposing factors of cystitis?
urine stasis
incomplete voiding
trauma
glucosuria
dilute urine / increased pH
short urethra
What are the protective factors from cystitis?
frequent voiding
effective urethral sphincters
low pH, high osmolarity
secretory IgA + mucin
What are the predisposing factors of Feline Urologic Syndrome?
neutered males
dry diets
alkaline urine (struvite)
long intervals between urination
What bacterial agent can cause cystitis?
E. coli
streptococcus
staphylococcus
What toxic infection can cause damage to the LUT?
Enzootic haematuria - cattle - bracken associated toxins
What damage do these toxins cause to the animal? - bracken
epithelial hyperplasia/metaplasia + haemorrhagic cystitis
chronic squamous metaplasia=>dysplasia=>benign=> malignant
haematuria => tumours ulcerate + bleed into lumen
chronic weight loss
sheep = blindness
What is needed for proper renal function?
1.Adequate blood flow
2. Sufficient functioning nephrons
3. unimpaired drainage/ expulsion of continuous urinary output
What are the 3 types of renal failure + causes?
1.Pre-renal failure = inadequate blood flow (haemorrhage, shock, cardiac failure, trauma)
2.Intrinsic renal failure = inflammatory, toxic, neoplasia, fibrosis,
congenital defects
3.Post-renal = LUT obstruction, inflamed bladder, dysfunction,
bladder rupture
How much renal capacity can you lose without failure, when does the kidneys become insufficient/failure?
Can lose up to 50% of capacity
insufficient when 50-70% loss
Failure when over 70% of kidneys lost
But there is compensatory hypertrophy but this has a capacity
What is acute renal failure? causes?
Sudden loss of 70-100% of kidneys - ischaemia, toxins, obstructions
rapidly progressive but reversible
What is chronic renal failure?
gradual loss of renal capacity - irreversible
looks shrunken, fibrosis, scarring
What is the effect of chronic renal failure?
*build up of metabolic waste
*failure of acid base regulation
*failure of fluid volume regulation
*electrolyte + endocrine disturbances
What are the reasons for death following chronic renal failure?
*dehydration
*acidosis
*hyperkalaemia
*hypocalcaemia
*pulmonary oedema
What is uraemia and what are the clinical signs?
uraemia = urea in blood = toxic
signs = PUPD, pale pink MM, anorexia, lethargy, weakness, muscle
wasting, hypothermia, mouth ulcers, vomiting, melaena,
non-regenerative anaemia, renal pain, ataxia, coma
What are the secondary pathological lesions?
