Urology Flashcards
What is the normal water consumption for a dog vs a cat?
Dog: 50-100mL/kg/day
Cat: 30-50ml/kg/day
What is the normal urine production for a dog vs a cat?
Dog: 50ml/kg/day
Cat: 25-50ml/kg/day
List 3 general clinical signs that can be associated with an upper urinary tract infection
- Inability to concentrate urine (with PUPD)
- Failure to produce urine
- Systemically unwell (pyrexia, anorexia)
Define polyuria
Producing more than 2 ml/kg/hour of urine
Define anuria
Producing less than 0.25 ml/kg/hour of urine
Define oliguria
Producing less than 1 ml/kg/hour of urine
Define uraemia
The group of clinical signs associated with nephron loss
Uraemia is the clinical signs of azotaemia
List 5 classical clinical signs that present as uraemia
- Urine smelling breath
- Oral ulceration
- Anorexia
- Vomiting
- Neurological signs
List 2 general clinical signs that can be associated with a lower urinary tract infection
- Inability to store urine
- Inability to void urine
List the clinical terms associated with an inability to store urine
- Incontinence
- Pollakiuria
- Periuria
List the clinical terms associated with the inability to void urine
- Dysuria
- Stranguria
What are some general things you want to obtain from a Hx when presented with an animal with urinary issues?
- Quatifiy the polydipsia (is it true/how much/was there a change in diet)
- Establish a urination pattern (volume, frequency, discomfort, location)
- Is there discolouration or an odour
- Is the animal aware
What does a urine protein to creatinine ratio tell us?
How much protein is in the urine irrespective of the urine concentration
Dipstick protein can be unreliable because it doesn’t consider {}
What is a normal UP:C ratio for dogs and cats
Dogs: less than 0.5
Cats: less than 0.4
What does a UP:C ratio of more than 2 tell us?
There is a problem in the glomerulus and protein is leaking out
What does a specific gravity tell us?
The concentration of the urine (how much pee weighs compared to the same amount of water)
Key indicator of kidney function
Define hyposthenuria
When the urine is dilute compared to plasma concentration (less than 1.007 SG)
Define isothenuria
When the urine is the same concentration as plasma (1.008-1.012 SG)
Means the kidneys are doing nothing (kidney disease)
Define hypersthenuria
When the urine is more concentrated than the plasma (more than 1.013 SG)
This is what we want bc it means the kidneys are filtering
What is a normal SG for a dog?
~1.030
What is normal SG for a cat?
~1.035
Define azotaemia
Elevated blood levels of nitrogenous waste products (creatine and urea)
Describe where urea comes from in the body
When you eat a high protein meal, protein is broken down into ammonia in the GI tract, then it goes to the liver where it is converted to urea. Most of the urea is peed out, but some is kept by the kidney to make it concentrated (contributes to tonicity)
What does a high urea with a normal creatinine indicate?
A GI bleed
(stomach is digesting blood as if it was from a high protein meal, converting ammonia to urea)
What does a low urea with a normal creatinine indicate?
The animal hasn’t been eating
What is the gold standard parameter for assessing GFR?
Blood creatinine
Its released from the muscle into the blood and filtered right away
What happens to the kidneys in a pre-renal azotaemia?
The kidneys are not getting enough blood for them to filter it
Ex. animal is haemorrhaging, hypovolaemic, dehydrated
What does the USG look like for pre-renal azotaemia?
Usually high (greater than 1.030)
Kidneys are concentrating urine to reduce water losses
What happens to the kidneys in a renal azotaemia?
The blood reaches the kidneys but they’re not working
Ex. AKI, CKD
What does the USG look like for a renal azotaemia?
Isothenuric (1.007-1.012)
What happens to the kidneys in post renal azotaemia?
Theres a block somewhere past the kidneys, so the body can’t expel the urine causing a back up of pressure, and then the kidneys will stop filtering (bc it can’t go anywhere)
What does the USG look like for a post renal azotaemia?
Variable - not a good indicator
How much of kidney function do you have to lose before the kidneys can’t filter anymore?
2/3
What does SDMA test for?
Can detect CKD with only 25% of function lost, irrespective of muscle mass
Why is SDMA a better indicator for CKD than creatinine?
Creatinine is dependent on muscle mass, so it is not always reliable in thin animals
Can be falsly low, just bc they’re skinny
Which section of the kidney can you biopsy?
The cortex (not the medulla)
What condition would be an indication for doing a renal biopsy?
Protein losing nephropathies (there’s lots of cons, so we want to avoid doing it if we can)
How is chronic kidney disease classified?
It is irreversible and progressive, and present for at least 3 months
List 5 conditions/causes that can progress to CKD?
- Metabolic dysfunction
- AKI
- Hypoperfusion
- Infection
- Drugs/toxins
Describe the progression to CKD
Inflammation in the kidney causes fibrosis (inflammatory cells promote fibrosis), decreasing functional nephron numbers, thus reducing GFR
What are 6 clinical signs of CKD?
Briefly explain why these signs are present
- PU with compensatory PD (loss of concentrating ability, urine volume increases)
- Anorexia (urea and PTH suppress appetite)
- Weight loss (decreased intake and protein loss)
- Vomiting (uraemic gastritis)
- Muscle weakness (hypokalaemia, uraemia, anaemia)
- Constipation (dehyrdation from excess water loss)
Similar for AKI
List the 5 steps to approaching a patient with kidney disease
- Confirm its the kidneys
- Is it acute or chronic
- Is it chronic, but has an acute flare up?
- Staging
- Consider secondary consequences
What are 3 top ddx for PU/PD?
That is not CKD
- Diabetes mellitus
- Hypoadrenocorticism
- Hyperadrenocorticism
List 3 parameters you can measure to diagnose CKD
- Reduced concentration ability
- Azotaemia
- Elevated SDMA
How can you differentiate between acute and chronic kidney disease?
- Duration of clinical signs (4-5 weeks consider chronic)
- BCS (no muscle condition consider chronic)
- Tolerance of azotaemia (good tolerance consider chronic)
- Kidney size (irregular or stretched)
- Renal pain (painful consider chronic)
What does it mean to have an acute on chronic kidney injury?
A chronic patient can be stable for a long time, but when they have a flare up of clinical signs they are considered acute-on-chronic
For the consequence of CKD, why does it happen and list a treatment
Dehydration
Why: the animal can’t concentrate urine and conserve any water
Treatment: add water to diet, fluid therapy (at home or in hospital)
What is the dose and duration of at home SQ fluids for a cat?
75-125 mL SC for 1-3 days
For the consequence of CKD, why does it happen and list a treatment
Cachexia
Why: anorexia and inflammation
Treatment: dietary management (restrict protein, increase fat and B vitamins)
Can try a renal diet
For the consequence of CKD, why does it happen and list a treatment
Hyperphosphataemia
Why: Decreased GFR means not enough PO4 is excreted, this stimulates PTH, PTH stimulates Ca release from bone (secondary renal hyperparathyroidism)
Treatment: restrict phosphate in the diet or use phosphate binders (reduces PO4 absorption from GI tract)
When should you reassess phosphate levels after starting treatment (dietary or drugs) in a patient with hyperphosphataemia?
After 4 weeks
For the consequence of CKD, why does it happen and list a treatment
Proteinuria
Why: damage to glomeruli and tubules causes protein to leak through (viscious circle - the more protein they lose the worse it gets)
Treatment: ACE inhibitors (dilate efferent arteriole to decrease the pressure in the glomeruli) or angiotensin receptor blockers (treats whole body hypertension)
What is a risk of giving ACE inhibitors for proteinuria?
It can worse azotaemia (urea and creatinine are retained bc decreased GFR)
For the consequence of CKD, why does it happen and list a treatment
Hypertension
Why: Altered renal BF, activation of RAAS, sympathetic drive for hypertension
Treatment: ACE inhibitors/ARBs, amlodipine besylate (Ca channel blocker for cats)
For the consequence of CKD, why does it happen and list a treatment
Urinary tract infections
Why: Dilute urine, polyuria and immunodeficiency
Treatment: Abx or appropriate management
For the consequence of CKD, why does it happen and list a treatment
Hypokalaemia
Why: Polyuria, anorexia, and fluid therapy
Treatment: K+ supplementation
For the consequence of CKD, why does it happen and list a treatment
Anaemia
Why: decreased EPO, GI blood loss, and iron deficiency
Treatment: blood transfusion or erythrocyte stimulating agents (2-8 weeks to effect)
What is a risk of giving erythrocyte stimulating agents for anaemia?
They are a synthetic form of EPO, so you can risk the animal developing an immune response to them and shutting down their own EPO production
Define IRIS stage I kidney disease
Creatinine & SDMA
No clinical signs
Creatinine normal
SDMA > 14
Define IRIS stage II kidney disease
Creatinine & SDMA
Mild clinical signs
Creatinine below 250
SDMA 18-35 dogs (18-25 cats)
Define IRIS stage III kidney disease
Creatinine & SDMA
Clinical signs present
Creatinine 251-440
SDMA 36-54 dogs (26-38 cats)
Define IRIS stage IV kidney disease
Creatinine & SDMA
Severe clinical signs
Creatinine greater than 440
SDMA greater than 54 dogs (>38 cats)
A BP greater than __ is considered severely hypertensive
180
UP:C less than __ is considered non-proteinuric
0.2
In which stage of AKI does irreversible damage occur?
Maintenance - the kidney learns to adapt
How much of the cardiac output do the kidneys receive?
25%
List 2 reasons why the kidneys are very susceptible to injury
- They receive 25% of the blood supply
- They have a large metabolic and oxygen demand
List 3 possible causes of AKI
- Hypotension
- Anaesthesia
- Post-renal obstruction