PATHOLOGY - Lower Urinary Tract Disease Flashcards
What is gross/macroscopic haematuria?
Gross/macroscopic haematuria is where there is sufficient enough blood in the urine that it can be seen macroscopically. The urine will typically appear red to brownish
What is occlut/microscopic haematuria?
Occult/microscopic haematuia is where there are erythrocytes in the urine but they cannot be visualised macroscopically
What is pseudohaematuria?
Pseudohaematuria is where the urine appears red to brownish but there are no erythrocytes present in the urine
What can cause pseudohaematuria?
Haemaglobinuria
Myoglobinuria
How can you differentiate between true haematuria and pseudohaematuria?
Urine sediment examination - erythrocytes will be visible if there is true haematuria but they will not be visible if it is pseudohaematuria
Centrifuge the urine - the erythrocytes will seperate from the urine if it is true haematuria but they will not if it is pseudohaematuria
What are the generalised causes of haematuria?
Systemic disease
Renal/ureteral disease
Bladder/urethral disease
Genital tract
Which history questions can be useful to determine if haematuria is systemic or urogenital?
Has there been bleeding at other sites?
Has there been any recent trauma?
Has there been any exposure to anticoagulant rodenticides?
When does the bleeding start during urination?
Describe the appearance of the urine?
Which factors should you be aware of on clinical examination which could help to determine if haematuria is systemic or urogenital?
Determine if there are any other sites of haemorrhage
Determine if there are any signs of anaemia
Rectal examination
Palpate the kidneys
Palpate the muscles
What are the distinguishing factors of haematuria due to systemic disease?
Haematuria due to systemic disease typically presents with bleeding elsewhere and there is unlikely to be signs of a lower urinary tract disease
What are the systemic causes of haematuria?
Primary haemostasis
Secondary haemostasis
Tertiary haemostasis
What are the distinguishing features of haematuria due to renal/ureteral disease?
Bleeding can occur throughout urination, at the end of urination or intermittently
Typically there will be no signs of lower urinary tract disease
May be concurrent haemaglobinuria
Why can there be concurrent haemaglobinuria with haematuria due to renal/ureteral disease?
Renal/ureteral disease can decrease the concentrating abilities of the kidneys resulting in the production of dilute urine. Erythrocytes within dilute urine can be lysed due to osmosis resulting in haemaglobinuria
What are some of the causes of renal/ureteral haematuria?
Pyelonephritis
Neoplasia
Caliculi
Trauma
Infarction
Cysts
Glomerulonephritis
Idiopathic renal haematuria
What are the distinguishing features of haematuria due to bladder/urethral disease?
Bleeding can occur throughout urination or at the start of urination
Signs of lower urinary tract disease
What are some of the causes of bladder/urethral haematuria?
Cystitis
Neoplasia
Polyps
Caliculi
Trauma
Cyclophosphamide administration
Feline idiopathic cystitis
What are the distinguishing features of haematuria due to genital disease?
Bleeding can occur throughout urination, at the start of urination or be unrelated to urination
May or may not have signs of lower urinary tract disease
What are some of the causes of genital haematuria?
Prostatic disease
Oestrus
Infection
Neoplasia
Trauma
What are some of the diagnostic tests which can be done to investigate haematuria?
Haematology
Biochemistry
Urinalysis
Coagulation profile
Diagnostic imaging
Cystoscopy
Vaginoscopy
Vaginal cytology
Prostatic wash
What are the key clinical signs of lower urinary tract disease?
Dysuria
Stranguria
Pollakiuria
What is dysuria?
Dysuria is difficult and/or painful urination
What is stranguria?
Stranguria is slow and painful urination or straining to urinate
What is pollakuria?
Pollakuria is the abnormally frequent passage small volumes of urine
What are the two general mechanisms of dysuria?
Mucosal irritation or inflammation of the lower urinary tract Narrowing or obstruction of the urethra or bladder neck
What are the differential diagnoses for dysuria involving the bladder?
Cystitis
Neoplasia
Polyp
Bladder rupture
Reflex dyssynergia
What are the differential diagnoses for dysuria involving the urethra?
Bladder urethritis
Granulomatous urethritis
Urethral caliculi
Urethral plugs (in cats)
Urethral stricture
Neoplasia
Urethral rupture
Reflex dyssynergia
What are the differential diagnoses for dysuria involving the prostate?
Benign prostatic hyperplasia
Prostatitis
Prostatic abscess
Prostatic cyst
Neoplasia
What are the differential diagnoses for dysuria involving the penis, prepuce or vagina?
Neoplasia
Which history questions are useful to ask when investigating patients with dysuria?
Are they passing any urine?
How much urine is being passed?
How often is urine being passed?
Is the patient painful on urination?
Describe the appearance of the urine?
Where is the animal urinating?
Is the patient licking their penis or vulva?
Has this happened before?
How long has this been going on for?
Has there been any recent trauma?
Which factors should you assess carefully on clinical examination in patients with dysuria?
Abdominal palpation
Bladder palpation
Rectal examination
Examination of the perineum and external genitalia
If possible, watch the animal urinate and take a sample
What are some of the diagnostic tests which can be done to investigate dysuria?
Haematology
Biochemistry
Urinalysis
Coagulation profile
Diagnostic imaging
Cystoscopy
Vaginoscopy
Vaginal cytology
Prostatic wash
Describe the physiological mechanism of urine storage
The sympathetic nervous system stimulates the hypogastric nerve to relax the detrusor muscle via β2 receptors and contract the internal urethral sphincter via α1 receptors
Describe the physiological mechanism of micturition
The parasympathetic nervous system stimulates the pelvic nerve to contract the detrusor muscle via M3 receptors and relax the internal urethral sphincter via the M2 receptors, allowing for the voiding of the bladder
What is the role of the pudendal nerve in micturition?
The pudendal nerve mediates the external urethral sphincter which is made up of skeletal muscle and is thus mediated under voluntary control
What are the potential causes of urinary retention?
Obstruction
Detrusor atony
Failure of relaxation of the internal urethral sphincter
Reflex dyssynergia
How do you approach investigation of causes of urinary retention?
History and clinical signs
Clinical examination
Neurological examination
Diagnostic imaging
What is detrusor atony?
Detrusor atony is where there is a loss of detrusor muscle tone resulting in incomplete bladder emptying or urinary storage
What are some of the causes of primary detrusor atony?
Primary detrusor atony is rare
Dysautonomia
Lower motor neurone disease between S1 to S3 (where the pelvic nerve arises)
What causes secondary detrusor atony?
Secondary detrusor atony is more common than primary
Secondary detrusor atony is due to chronic overstetching of the bladder
What are the key clinical signs of secondary detrusor atony?
Weak or absent urinary stream
Distended, flaccid bladder on palpation
How do you treat detrusor atony?
Bethanecol
Place an indwelling urinary catheter to rest the detrusor
What is reflex dyssynergia?
Reflex dyssynergia is where there is a loss of coordination between the detrusor muscle and the urethral sphincters resulting in delayed bladder emptying or urinary retention
What is the main cause of reflex dyssynergia?
Reflex dyssynergia is idiopathic
Which signalement is more prone to reflex dyssynergia?
Middle aged, large breed dogs
Which dog breed is particularly prone to reflex dyssynergia?
Labradors
What are the key clinical signs of reflex dyssynergia?
Urine stream intiated by not maintained
Difficult to manually express the bladder
What can reflex dyssynergia progress to?
Reflex dyssynergia can eventually cause detrusor atony
How do you diagnose reflex dyssynergia?
Reflex dyssynergia is a diagnosis based on the exclusion of all other causes of these clinical signs
What are the aims of treatment for reflex dyssynergia?
Decrease internal urethral sphincter tone
Decrease external urethral sphincter tone
Increase detrusor contraction
Which drugs can be used to decrease internal urethral sphincter tone?
Prazosin
Phenoxybenzamine
Which drugs can be used to decrease external urethral sphincter tone?
Diazepam
Dantrolene
Which drug can be used to increase detrusor contraction?
Bethanecol
What are the potential causes of urinary incontinence?
Decreased detrusor compliance
Urethral sphincter mechanism incontinence (USMI)
Overflow incontinence
Ectopic ureters
How do you approach investigation of causes of urinary incontinence?
History and clinical signs
Clinical examination
Neurological examination
Urinalysis
Diagnostic imaging
Which conditions can be commonly mistaken as urinary incontinence by owners?
Polyuria
Pollakuria
Periuria
What is periuria?
Periuria is urinating in inappropriate places
Which history questions are beneficial to ask to determine if an animal is truly urinary incontinent?
At what age did the incontinence begin?
When does the owner percieve the animal to be incontinent?
Are the able to urinate normally?
How aware are the pets of this incontinence?
What are the key signs of true urinary incontinence?
Urinary incontinence at rest
Normal urination outside of incontinence
Animal unaware of incontinence
Why is it important to do urine culture and sensitivity on patients with urinary incontinence?
It is important to do a urine culture and sensitivity on patients with urinary incontinence as there are at an increased risk of a lower urinary tract infection due to being regularly covered in urine
(T/F) Urethral sphincter mechanism incontinence (USMI) is more commonly congenital than acquired
FALSE. Urinary sphincter mechanism incontinence (USMI) is more commonly acquired
Which signalement typically presents with urethral sphincter mechanism incontinence (USMI)?
Female dogs within three years of being spayed
How does spaying cause urethral sphincter mechanism incontinence (USMI)?
Spaying causes a reduction in oestrogen which results in downregulation of the α1 adrenergic receptors at the internal urethral sphincter, resulting in decreased sphincter tone and urinary incontinence
What are some of the other causes of acquired urethral sphincter mechanism incontinence (USMI)?
Decreased urethral sphincter tone
Decreased number or responsiveness of α1 receptors
Changes in periurethral tissues
Obesity
Abnormal morphology of the bladder
Abnormal morphology of the urethra
Vaginal structural abnormalities
Breed predispositions
What are the clinical signs of urethral sphincter mechanism incontinence (USMI)?
Urinary incontinence
How do you diagnose urethral sphincter mechanism incontinence (USMI)?
Urethral sphincter mechanism incontinence is a diagnosis based on the exclusion of all other causes of these clinical signs
How can you medically manage urethral sphincter mechanism incontinence (USMI)?
Phenylpropanolamine
Ephedrine
Estriol
What is the mechanism of action of phenylpropanolamine?
Phenylpropanolamine is a sympathomimetic drug which can bind to the α1 adrenergic receptors at the internal urethral sphincter, increasing internal urethral spincter tone