Urinary Tract Obstruction Flashcards
Where are upper urinary tract obstructions?
Kidneys (uncommon but can occur in the renal pelvis)
Ureters
What can cause a urinary tract obstruction? (4)
Urolithiasis (dogs)
Urethral spasm (cats)
Organ displacement
Intra (calculi, tumours, inflammation) /extra (trauma, bladder masses, prostatic disease) urethral lesions
What is a functional urethral obstruction?
aka reflex dyssynergia - failure to co-ordinate the relaxation of the urethra when there isn’t an anatomic reason for obstruction
What are the most common sites of urethral obstruction in male dogs? (2)
Base of Os penis
Where the urethra narrows at the ischiac arch
What is the most common site of urethral obstruction diagnosed in cats?
At the base of the penis
What effects does a urinary tract obstruction have on the bladder? (3)
Overdistension
Causes increased pressure which prevents ureteral emptying
High pressures can also cause bladder mucosa to slough off and cause further obstruction
How can we detect Hyperkalaemia on an ECG?
Prolonged PR interval or peaked T waves
Bradycardia (wide QRS complexes)
How long until a full urinary tract obstruction kills?
72 hours
How do we treat Bradycardia caused by Hyperkalaemia? (2)
Fluid therapy
Calcium Gluconate to stabilise myocardium
When is Decompressive Cystocentesis indicated?
prior to removal of the full obstruction- it allows stabilisation of the patient due to temporary relief of the obstruction
also allows us to reduce the hydrostatic pressure within the bladder to facilitate catheterisation
What is decompressive cystocentesis?
Needle is inserted into the bladder and urine is drained via a syringe
What is a Retrograde Hydropropulsion?
Using a catheter and saline to flush urethral calculi back into the bladder so they can be removed via a cystotomy
After unblocking the urethra, what are the next steps? (3)
Save some urine or the plug for analysis
Bladder lavage with warm saline and flush until the urine is clear
After catheter removal, express bladder and evaluate urine stream- if good leave without catheter
After unblocking, if we are to leave a catheter in what features of the catheter should we aim for? (3)
Soft and flexible
Retained by sutures or an inflatable bulb
Attached to a closed collection system
What forms of Pharmacological Therapy can we use in cases of Urinary Tract Obstruction?
Smooth Muscle Relaxants
Alpha adrenergic blockers (dilation)
Skeletal Muscle Relaxants
