Urinary - medicine Flashcards
What is azotemia?
Increased urea +/- increased creatinine in the blood
What is uraemia?
The clinical syndrome arising from azotemia
What causes a pre-renal azotemia?
Reduction in renal blood flow - less filtration
What causes a renal azotemia?
Fewer functional nephrons
What causes a post renal azotemia?
Urinary tract obstruction - back pressure
Urinary tract rupture - urine leakage and reabsorption of waste products
How do you identify a uroabdomen?
Creatinine in the abdominal fluid is higher than creatinine in the blood serum
How do you tell an azotemia is pre-renal?
Azotemia with concentrated urine (still have the nephrons to concentrate it)
USG >1.030
How do you tell it is a renal azotemia?
Azotemia with dilute urine
USG < 1.030
How do you tell that it is a post renal azotemia?
Evidence of urinary obstruction or rupture - on imaging or clinically
What is the most common result of severe acute kidney injury?
Anuria/oliguria - epithelial cells slough into tubules and block them
What are the physiological consequences of acute kidney injury?
Failure of excretion of nitrogenous waste products
Acid base disturbances
Electrolyte disturbances - hyperkalaemia
What is the clinical presentation of acute kidney injury?
Uraemic
Dehydrated
Lethargic
Nauseous
Diarrhoea
Tremors - hypocalaemia
What are the 3 main aetiologies of acute kidney injury?
Toxic
Ischaemia
Infectious - lepto, pyelonephritis
What is an acute kidney injury disease that is accompanied by skin lesions?
Cutaneous and renal glomerular vasculopathy - alabama rot
What are some specific urinalysis findings of acute kidney injury?
Dilute urine
Casts and crystals in sediment exam
Cytology - inflammatory cells, bacteria
What can be seen on imaging for acute kidney injury?
Exclude post renal causes - pelvic dilation or free fluid
Renal size
Radio-opaque uroliths
What infectious disease should you test for on acute kidney injury?
Leptospirosis
How do you manage acute kidney injury?
Remove underlying cause eg. stop nephrotoxic drugs
Supportive care - fluids
What are the risks with fluids in cases of acute kidney injury?
Anuria/oliguria cases - may cause volume overload as cant excrete fluid
What is the normal urine output for a dog or cat on fluids?
1-2ml/kg/hr
How do you determine an anuria/oliguria vs polyuria?
Measure fluid ins and outs - closed urinary catheter system or weigh urine
How do you manage hyperkalaemia?
Restore renal perfusion
Calcium gluconate - IV (redistributes potassium intracellularly)
Glucose/insulin
What specific drug can you give for NSAID induced acute kidney injury?
Misoprostol
What specific drug can you give for pyelonephritis induced acute kidney injury?
Amoxyclav
What specific drug can you give for lepto induced acute kidney injury?
Amoxyclav and then doxycycline
What specific drug can you give for ethylene glycol induced acute kidney injury?
Ethanol
What can you give if there is persistent anuria?
Frusemide - diuretic
(if no obstruction and is euvolaemic)
What are the indications for euthanasia/renal replacement following acute kidney injury?
Persistent anuria
Volume overload
Unmanageable hyperkalaemia
What is chronic kidney disease?
Gradual progressive irreversible nephron loss
What species is CKD very common in?
Cats
What percentage of nephrons can be lost before any clinical disease is detected?
67%
What disease is caused by a subclinical toxic injury that happened a while ago causing CKD?
Chronic interstitial nephritis
What breed are predisposed to polycystic kidney disease
Persian cats - autosomal dominant
What is the pathogenesis of chronic kidney disease?
Asymptomatic/undiagnosed initial insult reduces glomerular filtration rate
Compensatory hypertrophy of remaining loss - more susceptible to damage, so progressive nephron loss
What are the three major differentials for cats with PUPD and weight loss?
Diabetes mellitus
Hyperthyroidism
Chronic kidney disease
What is the main sign of hypokalaemia?
Neck ventroflexion - head down
Why does chronic kidney disease cause renal secondary hyperparathyroidism?
Increased serum phosphate
PTH secretion increases to encourage more phosphate excretion at the kidneys
But PTH also causes bone resorption
How do you diagnose chronic kidney disease?
Azotemia with submaximally concentrated urine
What do you use to measure urine concentration?
Refractometer
What are the two ways of measuring renal filtration?
GFR
SDMA
What changes are seen on serum biochemistry in chronic kidney disease cases?
Azotemia - high urea, creatinine
Increased phosphorus
Increased calcium
Decreased potassium (euthanased before increased potassium like in acute kidney disease)
What size are the kidneys in chronic kidney disease?
Small and irregular
What do you use to know how to treat CKD?
IRIS staging
What is IRIS staging?
Use to know how to treat CKD, only once reversible problems have been addressed so there is no active underlying component
1 - CReatinine
2 - substage by proteinuria
3 - substage by blood pressure
How do you delay progression of CKD?
Feed renal diet
Control hypertension, proteinuria, hyperphosphataemia, hypokalaemia
Avoid further insults eg. keep hydrated
Maropitant/mirtazapine
What should you avoid in caloric management of CKD?
Avoid protein calorie malnutrition - must eat enough calories
Avoid introducing prescription diets in the hospital - will associate with hospital so wont eat
Avoid syringe feeding
What do renal diets have?
Restricted protein, phosphorus and sodium
Potassium supplement
What should you examine to monitor hypertension other than bp?
Retinal exam
For oedema and haemorrhage on retina
What is the prognosis of CKD?
Depends on the IRIS stage and whether it is being managed properly
Cats do much better than dogs
What are the two main regulators of blood pressure?
Baroreceptors
Renin-angiotensin-aldosterone system
What are the main causes of systemic hypertension in cats and dogs? What species is more common for each one?
Primary - rare (no high salt diet)
Secondary -
Kidney disease (most common in cats)
Endocrinopathies (most common in dogs)
Situational hypertension - stress
Increased intracranial pressure
What are the main consequences of systemic hypertension?
Ocular
Renal - CKD progression
Cardiac - LV concentric hypertrophy
Neurological - stroke
What is the normal systolic blood pressure?
120-140mmHg
Above what systolic blood pressure is considered hypertensive?
160mmHg and above
Above 180mmHg is severe
How can you measure blood pressure?
Doppler
Oscillometric - automated inflation and deflation
When should you treat hypertension?
If BP >180mmHg
If BP >160nnHg with evidence of target organ disease or is sustained
What is the medical treatment for systemic hypertension in cats? How does it work?
Amlodipine first choice
Calcium channel blocker so causes vasodilation
What is the medical treatment for systemic hypertension in dogs? How does it work?
Benazepril
ACE inhibitor, prevents production of angiotensin II
What are some causes of proteinuria?
Pre-renal -
Increased proteins in the blood
Pyrexia
Muscles - post exercise, seizure
Renal -
Intrinsic renal disease
Post renal -
Inflammatory or neoplastic disease in urinary tract
Urinary tract haemorrhage
Repro tract disease
How do you diagnose proteinuria?
Urine protein:creatinine ratio
(Dipstix - qualitative, not fully reliable)
What is a normal urine protein:creatinine ratio?
Less than 0.2
What is a proteinuric (abnormal) urine protein:creatinine ratio?
> 0.4 - cat
0.5 - dog
What is a renal proteinuria? What is it due to?
Protein losing nephropathy
Marked renal proteinuria (>2) is due to GLOMERULAR disease
What are the consequences of glomerular disease?
NOT necessarily azotemic and may retain urine concentrating ability - tubules still intact
Progressive proteinuria - hypoalbuminaemia, oedema
Hyperchloesterolaemia
What causes secondary glomerular disease?
Immune complexes fighting inflammation elsewhere in the body get stick in the glomerulus
Amyloid deposition
Drug/toxin
What breed is predisposed to amyloidosis?
Chinese shar pei
What causes amyloid production?
Chronic inflammatory disease - production of serum amyloid A which is deposited in tissue and polymerises to insoluble state
What is the standard therapy for glomerular disease?
Treat underlying disease
Treat the proteinuria - ACE inhibitors
Renal diet
Treat hypertension
Treat hypercoagulability - anti-platelets eg. clopidogrel
What is the name of proximal tubular disease and what is the main feature?
Fanconi syndrome
Glucose high in urine but not high in the blood
Not diabetes mellitus
What structures are involved in lower urinary tract disease?
Bladder nad urethra
What is pollakiuria?
Increased frequency of urination
What is stranguria?
Straining to urinate
What is periuria?
Voiding in inappropriate places - eg. cats not wanting to use litter tray as associate it with pain
What is the most common disease of lower urinary tract disease in cats?
Feline idiopathic cystitis
What is the most common disease of lower urinary tract in dogs (male and female)?
Bacterial UTI - most common in female dogs
Prostatic disease - most common in male dogs
What are the two main diseases of the lower urinary tract in cats?
Feline idiopathic cystitis
Urolithiasis
What are the 4 main diseases of the lower urinary tract in dogs?
Bacterial UTI
Prostatic disease
Urolithiasis
Neoplasia
What cats are predisposed to feline idiopathic cystitis?
Younger
Indoor
Overweight
Dry food diet - more calorific
Multi-cat household
What dogs are affected by prostatic neoplasia?
Almost exclusively neutered male dogs
What complications are associated with urinary obstruction?
Hyperkalaemia - bradydysrhythmias
Back pressure on kidneys - post renal azotemia
What tube do you use for sediment/crystal examination of urinalysis?
Plain tube
What crystals are square with a cross on for urinalysis?
Calcium oxalate dihydrate
What crystals are coffin shaped on urinalysis?
Struvite
When should you treat bacteriuria?
Only if there are clinical signs - common to find bacteria in the urine with no adverse reactions
How do you treat a bacterial UTI?
Ideally on culture and sensitivity
Amoxicillin or trimethoprim sulphonamide
NSAIDs
Lots of water
Clean vulva
What is the most common bacteria found in UTIs?
E. coli
What are the possible complications of UTIs?
Struvite uroliths - from bacteria breaking down urea into ammonia
Pyelonephritis
Polypoid cystitis
What count as complicated UTIs?
Recurrent cases, male dogs, cats
What can cause urethral obstruction?
Urethral spasm
Urethral plug
What is feline idiopathic cystitis?
Lower urinary tract disease in stressed cats - from neuroendocrine modulation
What is the emergency management of hyperkalaemia?
Alleviate obstruction - urinary catheterisation
Fluid therapy
Calcium gluconate, glucose, insulin
Analgesia
What is the medical management of feline idiopathic cystitis?
Analgesia - buprenorphine, NSAIDs
Gabapentin - anxiolytic
Feliway
Encourage water intake
Avoid obesity
Address stressful cat - cat interactions
Antispasmodics - prazosin, dantrolene
What is a urolith?
Macroscopic urinary stone - organised crystal aggregates of minerals in small amounts of organic matrix
What is crystalluria?
Crystals in the urine - microscopic mineral precipitate
Can occur with uroliths or separately - not necessarily the same constituents
What are promotors of crystal formation?
concentration of a compound in urine
USG
Urine pH
Urine stasis
What is the term for when it is no longer possible to hold the compound in solution?
Formation product (Kf)
What is the term for how saturated the urine is with a compound?
Solubility product
When can uroliths be symptomatic of lower urinary tract disease?
Urethroliths - obstruction
Cystoliths - cause cystitis
When can uroliths be symptomatic of upper urinary tract disease?
Nephroliths - pain, pyelonephritis
Ureteroliths - obstruction
What are the sizes of the kidneys when blocked with a ureterolith?
Little - chronic kidney disease, non blocked
Big - ureteric obstruction, backup of fluid in renal pelvis
How do you treat a urethral urolith?
Retropulsion to bladder, then removal
How do you treat a ureteral urolith?
Place an artificial silicone ureter as a bypass - referral
How do you treat cystoliths?
Dissolution - medical therapy
Cystotomy
How do you treat nephroliths?
Dissolution if possible
Referral
How should you manage longer term urolith formation/recurrence?
Classify stone composition - submit for analysis
What type of uroliths are radioopaque?
Calcium oxalate
Struvite
(You can C/See them)
What stones are radiolucent?
Urate
How big do uroliths need to be to visualise on radiograph?
> 2-3mm
How do you look for a radiolucent urolith?
Contrast/double contrast - radiograph
Or use ultrasound
What is ultrasound useful for evaluating related to uroliths?
Can visualise both radio-opaque and radio-lucent - use Doppler, look like a disco ball)
Can evaluate renal pelvic dilation
What do urate crystals look like on urinalysis?
Round holographic crystals
What uroliths form in acidic pH?
Urate
(Calcium oxalate - acidic to neutral)
What uroliths form in alkaline pH?
Struvite
What uroliths form in acidic to neutral pH?
Calcium oxalate
What is the most common urolith in dogs? What are the most common sites?
Struvite - infection associated
Cystoliths and urethroliths most common sites
What is the most common urolith in cats? Where are they found?
Struvite most common
But calcium oxalate is most common in upper urinary tract
Increased incidence of ureteroliths and nephroliths
What are the general principles for urolith management?
Dilute urine - so supersaturation is not possible
Encourage voiding
Avoid obesity
What are the different classes of drugs used in the management of urinary tract disease?
ACE inhibitors
Diuretics
Drugs affecting bladder (detrusor muscle)
Drugs affecting urethral sphincter pressure
What drugs are anti-proteinurics?
ACE inhibitors
What does angiotensin II do?
Causes vasoconstriction of EFFERENT arterioles and stimulates aldosterone secretion - increases preload
How do ACE inhibitors reduce proteinuria?
Block angiotensin II so prevents vasoconstriction of the efferent arterioles
Reduces transcapillary pressure in the glomerulus so reduces degree of proteinuria
What does ACE stand for in ACE inhibitors?
Angiotensin converting enzyme inhibitors
What are the 3 indications for ACE inhibitors?
Reduce glomerular pressure - proteinuria
Reduce pre/afterload in heart failure
Reduces blood pressure in hypertension
When are ACE inhibitors contraindicated?
Hypovolaemia
Hypotenison
Acute kidney injury
When are angiotensin receptor blockers given?
Reduces proteinuria in chronic kidney disease
Which arm of the autonomic nervous system controls the detrusor muscle contracting to empty the bladder?
Parasympathetic
(P - Pee, S - storage)
What drugs act on the bladder detrusor muscle? When are they needed
Parasympathomimetics
Used in bladder atony - when the bladder is distended for a long time so loses its elasticity in transitional epithelium
What are the side effects of parasympathomimetics?
Cholinergic side effects
DUMBBELS
Diarrhoea
Urination
Myosis
Bradycardia
Bronchoconstriction
Emesis
Lacrimation
Salivation
What muscles make up the urethra?
Smooth muscle internal sphincter
Skeletal muscle of urethra - urethralis muscle
What phase of the autonomic nervous system controls storage of urine, keeps the internal urethral sphincter closed?
Sympathetic control
(P - Pee, S - storage)
What drugs are used to treat urinary sphincter mechanism incompetence (common in spayed bitches)?
Alpha-adrenergic agonists
Sympathomimetics
Oestrogens
What are the side effects of the drugs used to treat urinary sphincter mechanism incompetence?
Sympathetic effect - increased heart rate, overstimulation
Oestrogens - as if on heat
What drugs are used to treat urethral spasm in cats?
Smooth muscle - alpha adrenergic antagonists - prazosin
Skeletal muscle - dantrolene, diazepam
