Internal medicine (urinary) Flashcards
what is acute kidney injury?
spectrum of disease associated with a sudden onset of renal parenchymal injury
how much GFR has to be lost before an animal presents as azotaemic?
75%
what are the four main causes of acute kidney injury?
decreased renal blood flow
toxins
intrinsic renal disease
systemic disease
what are some possible toxins that can lead to acute kidney injury?
antibacterials (aminoglycosides)
NSAIDs
ethylene glycol
lillies (cats)
grapes (dogs)
why are kidneys predisposed to toxin damage?
high blood flow
high metabolic activity
epithelial cells absorb things
what are the main aminoglycosides used in smallies?
gentamicin and amikasin
what are the four pathophysiological phases of acute kidney injury?
initiation
extension
maintenance
recovery
what happens in the initiation phase of acute kidney injury?
damage to the kidney begins
what pathophysiology occurs in the extension phase of acute kidney injury?
ischaemia, hypoxia, inflammatory response, ongoing cellular injury and death
after day 90 what is acute kidney disease called?
chronic kidney disease
what are signs of acute kidney injury on physical exam?
uraemia breath
hypothermia
kidney pain/enlargement
tachycardia (dehydration/pain)
bradycardia (hyperkalaemia)
what effect does hyperkalaemia often have on the heart?
bradycardia
what are the features of haematology of acute kidney injury cases?
azotaemia
increased phosphate
hyperkalaemia
calcium variable
what can be seen on urinalysis of acute kidney injury cases?
isosthenuric
glucosuria, haematuria
sediment, casts and WBCs
what is the normal size of a kidney on radiograph in dogs?
2.5-3.5 times L2
what is the normal size of a kidney on radiograph in cats?
2-3 times L2
how does the body condition of AKI and CKD patients compare?
AKI - good condition
CKD - weight loss/poor condition
how will the size/shape of the kidneys differ in AKI and CKD cases?
AKI - enlarged (painful)
CKD - small, firm, irregular
will anaemia be present with AKI and CKD?
non-regenerative anaemia present with CKD
(AKI aren’t anaemic)
in regards to the azotaemia, how sick will AKI and CKD patients present?
AKI - disproportionally sick for degree of azotaemia
CKD - surprisingly well for degree of azotaemia
how does the hair coat of animals with AKI and CKD compare?
AKI - good
CKD - poor
what potassium levels are expected with CKD and AKI patients?
AKI - hyperkalaemia
CKD - normal/low potassium
is sediment more commonly seen with AKI and CKD?
AKI
what plant is very poisonous to cats?
lillies (entire plant leaves, pollen, stem…)
what is the goals of fluid resuscitation for acute kidney injury?
optimise intravascular circulating volume and increase cardiac output to improve renal blood flow, oxygen supply and GFR
how aggressive should fluid therapy be given for acute kidney injury?
don’t give aggressively (don’t flush) just give at a normal rate
what is oliguria?
abnormally small amounts of urine being produced (<2ml/kg/hr)
what is the goal for urine output?
> 2ml/kg/hr
if you have given fluid therapy to an AKI animal and they are still oliguric what should be done?
give 3-5% body weight IVFT if not over hydrated then reassess
if an AKI animal is still oliguric after giving 3-5% bodyweight IVFT what should be done?
reduce IVFT (otherwise damage will occur), place a urinary catheter and start treatment to increase urine output (furosemide)
what drug is used to increase urine output of oliguric patients?
furosemide
does furosemide increase GFR?
no
should IVFT be continued when giving furosemide to increase urine output?
yes continue IVFT
what are some possible adverse effects of giving furosemide and IVFT to treat oliguria in AKI patients?
polyuria
acid-base/electrolyte abnormalities (metabolic acidosis…)
hyperkalaemia
how does hyperkalaemia look on an ECG?
flattened P wave
slow HR
spike T waves
what is the best anti-emetic?
maropitant
what is the prognosis for AKI patients?
fair (50% mortality)
are urinary tract infections more common in dogs or cats?
dogs
are urinary tract infections more common in males or females?
females
what is pyuria?
white blood cells in urine
what is a urinary tract infection?
adherence, multiplication and persistence of an infectious agent within the urinary system
what is the difference between a bacteraemia and urinary tract infection?
bacteraemia is when they are just sat there but UTI is when they are adhering and multiplying
what are the clinical signs of cystitis?
dysuria, pollakiuria, haematuria, urinary incontinence
what is cystitis?
inflammation of bladder
what results should be ignored on a dipstick?
leucocytes
nitrites
how is sporadic bacterial cystitis treated?
antibiotics for 3-5 days (amoxicillin, cephalexin, trimethoprim)
NSAIDs
how long should you treat pyelonephritis with antibiotics for?
10-14 days
how long should subclinical bacteriuria be treated for?
treatment isn’t recommended
does cystitis cause PUPD?
no (causes stranguria and pollakiuria)
what is chronic kidney disease?
structural/functional abnormalities of one or both kidneys that have been there for 3 months or longer
is CKD reversible?
no - slowly progressive irreversible disease
what are some congenital causes of CKD?
renal dysplasia
polycystic kidney disease
amyloidosis
fanconi-like syndrome
what breed is predisposed to polycystic kidney disease?
Persian cats
what are the main two acquired causes of CKD?
idiopathic tubulointerstitial nephritis
glomerular disease
is glomerular disease more common in cats or dogs?
dogs
is idiopathic tubulointerstitial nephritis more common in cats or dogs?
cats
what are the possible reasons CKD progresses in the absence of the initial disease?
intraglomerular hypertension - loss of nephrons so blood forced through remaining ones at a higher pressure
proteinuria - high levels of tubular protein is harmful
phosphorous - precipitates with calcium in tubules to cause damage
why is staging CKD useful?
determines treatment
can predict clinical signs for owners (easier for owner understanding)
what are some possible clinical signs of CKD?
weight loss/poor appetite
dullness/lethargy
PUPD
dehydration
vomiting
constipation
poor hair coat
neurological signs
hypertension (associated signs)
what are the criteria for staging CKD?
creatinine
proteinuria
blood pressure
what is the first way of staging CKD?
creatinine
what is the most important parameter to look at on haematology of CKD animals?
haematocrit/RBC count (need to treat anaemia)
what does urea correlate with on haematology of CKD patients?
severity of clinical signs
what does creatinine correlate with on haematology of CKD patients?
GFR
in cats with CKD is potassium usually increased/decreased?
decreased
what is increased phosphorous linked to in CKD cases?
increased progression and mortality
what extra-renal causes should be ruled out before blaming the kidneys for inadequately concentrated urine?
hypercalcaemia
Addisons
drugs - furosemide
what are the aims for treating CKD?
provide good quality of life, reduce severity of clinical signs, minimise progression (can’t cure it)
what is a uraemia crisis?
a CKD patient that destabilises acutely
what is done first when treating a uraemia crisis?
IVFT (don’t flush)
what stage CKD aren’t azotaemic?
stage 1
what are the initial actions needed to treat stage 1 CKD?
stop all nephrotoxic drugs
identify/eliminate ongoing disease
measure BP and UPCR
treat
what is UPCR?
urine protein creatinine ratio
how can proteinuria be reduced in stage 1 CKD cases?
inhibit RAAS
reduce dietary protein
antiplatelet drugs if severe (clopidogrel)
why should ACE inhibitors not be used on dehydrated/hypovolaemic patients?
dilates the efferent arteriole causing a drop in GFR
what needs to be treated in stage 1 CKD?
control/prevent dehydration
control blood pressure
control proteinuria (if present)
what drugs can be used to control hypertension in stage 1 CKD?
ACE inhibitors
telmisartan (angiotensin receptor blocker)
amlodipine
what is the most important treatment that starts in stage 2 CKD?
begin a renal diet
what are the beneficial features of a renal diet?
restricted protein (reduces uraemia crisis…)
restricted phosphate
omega 3 fatty acids
fibre
low sodium
water soluble vitamins
what are the benefits of the restricted protein of a renal diet?
reduction in clinical sings
less risk of uraemia crisis
reduced proteinuria
reduced PUPD
reduced acid load
what stages of CKD in cats and dogs is a renal diet recommended for?
cats - stage 2, 3, 4
dogs - stage 3, 4
what can be added if a renal diet doesn’t reduce phosphate enough?
phosphate binder (ipakitine)
what are the treatment recommendations for stage 2 CKD?
same as stage 1 (control, dehydration, hypertension, proteinuria)
start renal diet
control phosphate
supplement potassium if needed
what stage of CKD do clinical signs begin to worsen?
stage 3
what are the recommendations for treated stage 3 CKD?
same as stage 1 and 2
treat nausea/vomiting
consider erythropoetin
control metabolic acidosis
consider subcutaneous fluid
what drugs can be used to stimulate an animals appetite?
mirtazapine
capromorelin
what drugs are available to control vomiting, poor appetite and GI signs in stage 3 CKD patients?
anti-emetics
appetite stimulants
reduce mastic acid secretion
sucralfate
(feeding tube considered)
what drug is used as an erythropoietin replacer?
darbepoeitin
what always needs to be given with darbepoetin?
iron supplements
what is the major side effect of erythropoietin treatment?
they develop antibodies to them - can cross react with the patients own erythropoietin (hence only use in severe anaemia)
what are the recommendations for treating stage 4 CKD?
same as stage 1, 2, 3 but phosphate control is more relaxed
what are the things to control to minimise progression of CKD?
phosphate
proteinuria
blood pressure
(use renal diet)
do congenital or acquired CKD cases progress quicker?
acquired tend to progress quicker
what are the three most common uroliths?
struvite
calcium oxalate
urate (purine)
what is the shape of calcium oxalate crystals?
envelopes
what is the shape of struvite crystals?
coffin lid
what is the shape of irate crystals?
thorn apples
what uroliths form in acidic urine?
calcium oxalate
urate
cystine
what uroliths form in alkaline urine?
struvite
what is the centre of a urolith called?
nidus
what uroliths can be resolved by medical dissolution?
struvite
urate
cystine
what are the disadvantages of using medical dissolution to treat uroliths?
can block the urethra when smaller
some don’t dissolve
needs repeated radiographs/urinalysis
need sooner compliance with the diet
what are some indications for removal of uroliths?
if its causing obstruction
persistant clinical signs
lack of response to medical therapy
if uroliths are increasing in number/size
what is a non-surgical method of removing uroliths?
voiding urohydropropulsion - sedate and fill bladder with saline then position them to massage the uroliths out
what are struvite uroliths associated with?
urinary tract infections
are struvite stones viable on X-rays?
yes - they are radiopaque
what type of uroliths do urinary tract infections predispose to?
strivite
why do urinary tract infections predispose to struvite uroliths?
bacteria produce urease that converts urea to ammonia and bicarbonate, this ammonia then binds with magnesium and phosphorus in the diet to form struvite
how are struvite stones treated?
feed a reduced protein, phosphorous and magnesium diet that promotes acidic urine to dissolve them
treat UTI as well
when do animals need monitoring for struvite dissolution?
every 4-6 weeks after the start of treatment until there has been radiographic cure for at least 2-4 weeks
what are some possible reasons for failure of struvite treatment?
UTI isn’t controlled
core of urolith is oxalate
diet not followed
what is the best way to prevent struvite stones?
rapid treatment of bacterial UTIs
what pH urine to calcium oxalate crystals form in?
neutral to acidic
what condition predisposed to calcium oxalate stones?
hypercalcaemia
are calcium oxalate uroliths visible on radiographs?
yes - they are radiodense
are calcium oxalate crystals more common seen in males or females?
males
how are calcium oxalate uroliths treated?
removal (often reoccur)
how can calcium oxalate crystals be prevented?
rule out underlying cause - hypercalcaemia, metabolic acidosis, excess vitamin D
increase urine volume - dilute solute
what pH urine do urate stones form in?
acidic
are urate stones visible on radiographs?
no - they are radiolucent
what are the two situations in which dogs get urate stones?
inherited alteration of rate transporter
portosystemic shunts
how are urate stones treated?
low protein and purine diet that produce alkaline urine to dissolve them
allopurinol (only with diet)
are cystine stones visible of radiographs?
no - they are radiolucent
what uroliths can be prevented by neutering?
cystine
which urolith is more commonly seen in females?
struvite
what intervention is important when treating/preventing all uroliths?
increase water intake (dilutes the urine solution)
what is feline idiopathic cystitis?
abnormal voiding behaviour after exclusion of other disorders
persistent, chronic or recurrent with no obvious cause
what are the two forms of feline lower urinary tract disease?
non-obstructive (mainly female)
obstructive
what is FLUTD?
feline lower urinary tract disease
what is the most common cause of non-obstructive FLUTD?
idiopathic cystitis
what is the most common cause of obstructive FLUTD?
urethral plug
are non-obstructive or obstructive FLUTD more common in males?
obstructive more in males
non-obstructive more in females
what age cats is FLUTD most commonly seen in?
2-6 year old neutered cats
what predisposes cats to FLUTD?
obesity
indoor/sedentary cats
dry diet
multi-cat household (stress)
what are the clinical signs of FLUTD?
dysuria (difficulty)
pollakiuria (increased frequency)
haematuria
inability to urinate (obstruction)
behavioural changes
appear to lose letterbox training (periuria)
what is periuria?
urinating in inappropriate places
what is done to treat non-obstructive FLUTD?
nothing - self-limiting and resolves in around a week
what are the features of a bladder of cats with non-obstructive FLUTD?
small, firm, painful
how does the bladder appear in cases of cats with obstructive FLUTD?
large, painful
what is FIC?
feline idiopathic/interstitial cystitis
what pathology is seen with cases of FIC?
increased mast cells and oedema on submucosa
neurogenic inflammation leading to increased sensitivity
reduced glycosaminoglycan layer - reduced protection
what is the main predisposing factor of feline idiopathic/interstitial cystitis?
stress (can’t deal with it properly)
what are the main constituents of a urethral plug due to FLUTD?
mucus and glycoprotein matrix (weeping from bladder)
is struvite associated with UTIs in cats?
no - they are usually sterile
is blood sampling more important for obstructed or non-obstructed FLUTD cats?
very important in obstructed
unremarkable in non-obstructed
what are possible features of a haematology of obstructed FLUTD cats?
hyperkalaemia
hyperphosphataemia
metabolic acidosis
azotaemia
how common are crystals in cat urine?
very - don’t over interpret
what uroliths in cats require surgical removal?
calcium oxalate
how often does FIC reoccur?
chronically reoccurring but self-resolving
what is the main way to reduce/prevent FIC?
reduce stress - environment, household, pets, neighbours
what needs to be done to assess stress in FIC patients?
multimodal environmental modification
what drugs can be used to treat FIC?
glycosaminoglycan supplements
analgesics - buprenorphine, NSAIDs
tricyclic antidepressant - amitriptyline (reduce stress??)
if using amitriptyline to treat FIC what needs to be monitored closely?
bloods
what is the most important thing to check in a cat presenting with LUT signs?
bladder size
what are the three layers of the glomerular filtration barrier?
fenestrated endothelial cells
glomerular basement membrane
podocytes
what is the hallmark sign of a glomerulopathy?
proteinuria
are glomerulopathies more common in dogs or cats?
dogs
what are the two main categories of the pathogenesis of glomerulopathies?
immune mediated
non-immune mediated
what is the cause of immune mediated glomerulopathies?
type 3 hypersensitivity reactions - immunoglobulin complexes get stuck in-between the barriers causing inflammation due to complement
how fast do familial glomerulopathies progress?
rapidly (present at a young age)
what is the main breed associated with glomerulopathy due toamyloidosis?
shar-pei
what are the clinical signs of amyloidosis in shar-peis?
shar-pei fever - swollen joints. hyperthermia
when would a glomerulopathy be suspected?
unexpected proteinuria on urinalysis
differential for renal disease
unknown hypertension
hypoalbuminaemia/hypercholesterolaemia
thromboembolic diseases
what needs to be done when suspecting a glomerulopathy to confirm diagnosis?
confirm proteinuria (dipstick)
quantify proteinuria - protein creatinine ratio (UPCR)
determine if proteinuria is pre-renal, renal, post-renal
confirm proteinuria is persistent - 3 tests 2 weeks apart
what is the gold standard for confirming a renal proteinuria?
renal biopsy - needs specific sample and pathologist centres (rarely performed)
what is the marker used to assess if a proteinuria is a renal or not?
UPCR >2 is probably renal
UPCR <2 is problem tubulointerstital
what is the standard treatment used for proteinuria?
RAAS blockade - ACE inhibitor or angiotensin receptor blockers
what is the most common ACE inhibitor used for proteinuria treatment?
benazepril (then telmisartan if ineffective)
can steroids (immunosuppressives) be used as a treatment for glomerulopathies?
yes but needs a biopsy to confirm it is an immune mediated glomerulopathy so is rarely used
what are some complications of glomerulopathies that need treating?
thromboembolism
azotaemia (CKD)
systemic hypertension
oedema
what is used to treat thromboembolism in glomerulopathy cases?
antiplatelets - clopidogrel
anticoagulants - apixaban or rivaroxaban
what needs to be monitored closely if using a anti-coagulants in the treatment of glomerulopathies?
signs of bleeding
what is used to treat hypertension in glomerulopathy cases?
dogs - benazepril (then amlodipine)
cats - amlodipine or telmisartan
what is nephrotic syndrome?
a combination of hypoalbuminaemia, proteinuria, hypercholesterolaemia and oedema
what is usually the reason for oedema formation in glomerulopathy cases?
associated with renal sodium retention
what is used to treat oedema associated with glomerulopathies?
furosemide (pulmonary oedema)
spironolactone (pleural/abdominal oedema)
what is the major disadvantage of using diuretics to treat oedema associated with glomerulopathies?
can cause severe azotaemia
