PATHOLOGY - Urethral Obstruction Flashcards

(89 cards)

1
Q

Why are male animals more prone to urethral obstructions?

A

Male animals have a longer urethra and there is considerable narrowing of the urethral lumen at the os penis in male dogs and cats

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the potential causes of urethral obstruction in dogs?

A

Urolithiasis
Urethritis
Retroflexed bladder into a perineal hernia
Prostatic disease
Urethral spasm
Neoplasia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the most common cause of urethral obstruction in dogs?

A

Urolithiasis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which signalement is most prone to urethral obstruction?

A

Young, male cats

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the potential causes of urethral obstruction in cats?

A

Feline idiopathic cystitis
Urolithiasis
Urethral stricture
Prostatic disease
Neoplasia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the most common cause of urethral obstruction in cats?

A

Feline idiopathic cystitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How does feline idiopathic cystitis cause urethral obstruction?

A

Feline idiopathic cystitis can result in the formation of urethral plugs or cause urethral spasm resulting in urethral obstruction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the clinical signs of a urethral obstruction?

A

Dysuria
Stranguria
Pollakuria
Haematuria
Large, tense bladder on palpation
Posturing to urinate
Urine dripping
Can be bright to lethargic/collapsed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What should you make sure to assess on clinical examination of a patient with a potential urethral obstruction?

A

Abdominal palpation to feel the bladder
Assess the penis
Rectal examination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Why is it important to assess the penis in patients with a potential urethral obstruction?

A

You should assess the penis as there may be a distal plug or urolith that can be removed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Why is it important to do a rectal examination in patients with a potential urethral obstruction?

A

You should do a rectal examination as neoplasia and prostatic disease can cause compression of the urethra and this can be felt via the rectum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Which diagnostic tests should you do when presented with a patient with urethral obstruction?

A

Urinalysis and culture
Haematology and biochemistry
Diagnostic imaging

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What should you assess on haematology and biochemistry in patients with urethral obstruction?

A

Assess renal function
Assess potassium levels
Assess for any other underlying causes of obstruction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which diagnostic imaging can you do in patients with a urethral obstruction?

A

Ultrasound
Radiography
Contrast radiography

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the three main consequences of urethral obstruction?

A

Post-renal azotaemia
Hyperkalaemia
Metabolic acidosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the first thing you should do when treating a urethral obstruction?

A

Stabilise the patient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How do you treat a urethral obstruction?

A

Analgesia
Intravenous fluid therapy
Manage hyperkalaemia
Relieve the urethral obstruction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Which analgesia should you provide patients with a urethral obstruction?

A

Full μ agonst opioid as the patient will possibly have to go for surgery and it is a very painful condition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Why should you avoid NSAIDs in patients with a urinary obstruction?

A

Patients with urethral obstruction are usually both hypovolaemic and have reduced renal perfusion so NSAIDs are contraindicated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the purposes of intravenous fluid therapy when treating a urethral obstruction?

A

Restore circulatory blood volume
Restore renal perfusion
Correct hyperkalaemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Which fluids should you use when treating a urethral obstruction?

A

Isotonic crystalloid fluids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is one of the main consequences of hyperkalaemia?

A

Bradycardia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How do you manage hyperkalaemia?

A

Intravenous fluid therapy
Calcium gluconate
Glucose
Insulin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Why is calcium gluconate used in the management of hyperkalaemia?

A

Calcium gluconate does not directly lower serum potassium levels, however it is cardioprotective and can mitigate the immediate effects of hyperkalaemia on the heart, giving time for other treatments to lower the potassium more effectively

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Why is glucose used in the management of hyperkalaemia?
When glucose is administered this stimulates the release of insulin which moves the glucose from the bloodstream into the cells. When glucose is moved into the cells, potassium and phosphate move with it which can help to correct the hyperkalaemia | Be aware you will have to monitor for hypoglycaemia
26
Why is insulin used in the management of hyperkalaemia?
When insulin is administered, this will move glucose, along with potassium and phosphate, into the cells which can help to correct the hyperkalaemia | Be aware you will have to monitor for hypoglycaemia
27
How can you relieve a urethral obstruction?
Catheterisation and retrograde hydropulsion Surgical intervention
28
What are the benefits of a cystocentesis when attempting to relieve a urethral obstruction?
Cystocentesis can relieve the pressure on the bladder and thus make urinary catheterisation easier
29
What is the main risk of a cystocentesis in a patients with a urethral obstruction?
Uroabdomen
30
Which type of catheter can be placed as an indwelling catheter in cats?
KatKath catheter
31
Which type of catheter can be placed as an indwelling catheter in dogs?
Foley catheter
32
How do you carry out urinary catheterisation on a patient with a urethral obstruction?
1. Sedate your patient or put them under general anaesthesia 2. Assess the penis for any distal plugs or uroliths 3. Aseptically clip and prep the perinuem 4. Pass the urinary catheter aseptically. The majority of obstructions are due to urethral spasm or due to urethral plugs so catheter placement should be relatively unopposed or may require some peri-rectal massage and gentle saline flushing 5. If this is unsuccessful, retrograde hydropulsion can be attempted especially if there is a focal obstruction *(i.e. a urolith)*
33
How do you carry out retrograde hydropulsion?
Flush the urinary catheter with sterile saline and lubricant in a pulsatile fashion in an attempt to push the obstruction from the urethra into the bladder. Use rectal palpation to assist in dislodging the obstruction. Make sure to **not** push the obstruction with the catheter as you risk iatrogenic urethral rupture. Remember to monitor the bladder as it may require cystocentesis as there is a risk of it becoming excessively distended and can rupture
34
What should be done after retrograde hydropulsion?
Cystotomy to remove the obstructive substance from the bladder or medical dissolution with careful monitoring for reobstruction *(bit risky as they have already obstructed once)*
35
What should be done post catheterisation?
1. Take a urine sample via the catheter 2. Once the urethra is patent, flush it thoroughly to ensure all debris removed and then advance the catheter into the bladder to flush and drain the bladder to remove any debris *(blood clots etc)* 3. If you used an indwelling catheter attach a closed collection system to prevent the patient getting covered in urine in recovery 4. Diagnostic imaging to ensure there are no other potential causes of obstruction 5. For cats, sometimes it can be best to flush thoroughly, remove the catheter, put them on prazosin and send the cat home to reduce stress which can increase risk of re-obstruction
36
What can be done if you are unable to catheterise a patient with a urethral obstruction?
Stabilisation and referral for surgery Cystostomy tube placement Euthanasia
37
What is a cystostomy tube?
A cystostomy tube placement involves surgically placing a foley catheter through the abdominal wall and into the bladder to allow urine to bypass the urethra
38
What is a cystotomy?
A cystotomy is a surgical incision into the bladder
39
How do you carry out a cystotomy?
1. Ventral midline laparotomy from the umbilicus to the pubis 2. Isolate the bladder using moistened surgical swabs 3. Place a stay suture at the apex of the bladder 4. Drain the bladder using cystocentesis 5. Incise the ventral midline of the bladder using a stab incision and extend the incision with metzenbaum scissors 6. If you are performing cystotomy for removal of urolithiasis ensure you catheterise the urethra and flush thoroughly to ensure all uroliths are removed 7. Flush the bladder with sterile saline to remove any debris before closure 8. Close in one or two layers using an appositional or inverting suture pattern. Use a monofilament, absorbable synthetic suture material. Make sure to catch the submucosa in your sutures as this is your strength holding layer 9. Avoid placing sutures through the mucosa and into the lumen as exposed suture will act as a nidus for infection 10. Place an omental wrap 11. Repeat diagnostic imaging after to ensure all uroliths and debris have been removed 12. Always send uroliths away for analysis at the Minnesota urolith centre
40
What is a urethrotomy?
A urethrotomy is a surgical incision into the urethra
41
How do you carry out a urethrotomy?
1. Place a urinary catheter to the level of the obstruction 2. Make a skin incision directly over the obstruction 3. Reflect the retractor penis muscle laterally to expose corpus spongiosum *(this will bleed a lot)* and make a midline incision to expose the urethra 4. Make a midline incision into the urethral over the obstruction 5. Remove the obstruction and advance the urinary catheter into the bladder to flush any debris 6. Carry out primary closure or allow to heal by second intention
42
What is a urethrostomy?
A urethrostomy is a surgical procedure in which a permanent stoma is created directly in the urethra to allow urine to exit the body
43
What are the indications for a urethrostomy?
Unable to dislodge a urethral obstruction Urethral structure formation Recurrent urethral obstructions
44
What is the best location for a urethrostomy?
Scrotal urethrostomy
45
What are the complications of a scrotal urethrostomy?
Haemorrhage Urine scalding Lower urinary tract infections
46
What are the complications of a perineal urethrostomy?
Haemorrhage Urine scalding Lower urinary tract infections Stricture Dehiscence
47
What is crystalluria?
Crystalluria is where there is crystals present in the urine, indicating very saturated urine. Crystalluria can be normal and abnormal
48
What are uroliths?
Uroliths are stones in the urine and are always abnormal
49
What is required for a urolith to form?
Substrate Supersaturation Nidus
50
What can determine supersaturation of the urine?
Urine pH Urine concentration Infection
51
What are the most commonly seen uroliths?
Struvite uroliths Calcium oxalate uroliths Purine uroliths
52
What is struvite urolith formation associated with?
Neutral to alkaline urine Infection *(in dogs)*
53
What is calcium oxalate urolith formation associated with?
Acidic to neutral urine
54
What are the risk factors for calcium oxalate urolith formation?
Chronic kidney disease (CKD) Hypercalcaemia
55
What are purine uroliths?
Purine uroliths are uroliths made up of purines such as urate, uric acid and/xanthine
56
What is purine urolith formation associated with?
Acidic to neutral urine
57
What are the risk factors for purine urolith formation?
Hepatic dysfunction *(mainly portosystemic shunts)* Autosomal recessive congenital impairment of uric acid metabolism
58
Which dog breeds have an autosomal recessive congenital impairment of uric acid metabolism?
Dalmations Bulldogs Russian Terriers
59
Which cat breeds have an autosomal recessive congenital impairment of uric acid metabolism?
Siamese Egyption Mau Birman
60
What are the clinical signs of a urethrolith?
Clinical signs of lower urinay tract inflammation Clinical signs of urethral obstruction
61
What are the clinical signs of a urocystolith?
Asymptomatic Haematuria Recurrent lower urinary tract infections Clinical signs of lower urinay tract inflammation
62
What are the clinical signs of a uterolith or nephrolith?
Asymptomatic Azotaemia Uraemia Abdominal pain Systemic clinical signs
63
How can you diagnose urolithiasis?
Radiography *(plain and contrast)* Ultrasound Urinalysis and culture
64
Why should you do a urine culture on patients that you suspect have urolithiasis?
Urolithiasis can predispose patients to a urinary tract infection and urinary tract infections can cause struvite uroliths
65
What are the treatment options for urolithiasis?
Urinary catheter retrieval Lithotripsy Surgical retrieval Medical dissolution
66
What is lithotripsy?
Lithotripsy is a procedure used to break down uroliths into smaller pieces so they can more easily pass through the urinary tract
67
When is medical dissolution of uroliths contraindicated?
Calcium oxalate uroliths *(cannot be dissolved)* Urethral obstructions Patients at high risk of obstruction Patients in pain
68
How do you carry out medical dissolution of uroliths?
Undersaturate the urine to achieve correct USG Dietary modification
69
How do you undersaturate the urine to achieve the correct USG for dissolution?
Increase water intake Increase frequency of urination
70
How do you carry out medical dissolution of struvite uroliths?
Undersaturate the urine to achieve correct USG Dietary modification *(s/d diet)* Antibiotics *(if infection present)*
71
Which dietary modifications are required for medical dissolution of struvite uroliths?
Acidifying diet Decrease renal excretion of magnesium and phosphate Increase water intake
72
Why is it beneficial to decrease renal excretion of magnesium and phosphate when managing struvite uroliths?
It is beneficial to decrease renal excretion of magnesium and phosphate when managing struvite uroliths as struvite crystals are formed when there is an abundance of magnesium and phosphate in the urine. Decreasing excretion decreases the concentration of these ions in the urine and thus decreases the risk of struvite urolith formation
73
How do you carry out medical dissolution of urate uroliths?
Treat underlying liver disease if possible Dietary modification Allopurinol
74
Which dietary modifications are required for medical dissolution of urate uroliths?
Alkalising diet Low purine diet Increase water intake
75
What is allopurinol?
Allopurinol decreases serum uric acid levels
76
How do you prevent calcium oxalate urolith formation?
Treat hypercalcaemia Alkalising diet Low protein, oxalate, calcium and sodium diet Sufficient phosphorus and magnesium in the diet
77
Why is it so important to monitor patients that have had urolithiasis?
Urolithaisis very commonly recurs so it is very important to monitor these patients
78
How should you monitor struvite and urate uroliths?
Struvite and urate uroliths develop rapidly so you should monitor patients closely and do weekly urinalysis until they are clear of struvite or urate crystals. When the patient is clear of crystals, do a urinalysis every 2 to 4 weeks. Do recheck radiography at 2 to 4 weeks, 3 months and 6 months
79
How should you monitor calcium oxalate uroliths?
Calcium oxalate uroliths develop slowly so you can do a urinalysis monthly until they are clear of calcium oxalate crystals. When the patient is clear of crystals, do a urinalysis every 3 months. Do recheck radiography at 2 to 4 weeks, 3 months and 6 months
80
Which signalement typically presents with feline idiopathic cystitis?
Young to middle aged cats
81
Which signalement typically presents with urethral obstruction secondary to feline idiopathic cystitis?
Young to middle aged neutered male cats
82
What are the risk factors for feline idiopathic cystitis?
Stress *(main risk factor)* Overweight Indoor cat Multicat household Dry diet
83
What are the clinical signs of feline idiopathic cystitis?
Dysuria Stranguria Pollakuria Haematuria May have signs of urethral obstruction
84
How do you diagnose feline idiopathic cystitis?
Feline idiopathic cystitis is a diagnosis of exclusion
85
What are the three forms of feline idiopathic cystitis?
Acute non-obstructive feline idiopathic cystitis Chronic non-obstructive feline idiopathic cystitis Acute obstructive feline idiopathic cystitis
86
How do you manage acute non-obstructive feline idiopathic cystitis?
Acute non-obstructive feline idiopathic cystitis is self-limiting and should begin to improve within 2 - 4 days and resolve within a week. You should give the patient analgesia as this is a painful condition
87
How do you manage chronic non-obstructive feline idiopathic cystitis?
1. Confirm diagnosis and rule out any other concurrent conditons 2. Dietary modification 3. Multimodal environment modification (MEMO) 4. Pheromones *(reduces stress)* 5. Behaviour modifying drugs *(tricyclic antidepressants)*
88
Which dietary modifications should be made to manage chronic non-obstructive feline idiopathic cystitis?
Prescription urinary diet Increased water intake | Change diet gradually to reduce stress
89
What should owners be aware of when broaching management of feline idiopathic cystitis?
Owners need to be aware that this is a recurrent condition and can be expensive to manage, with management and environmental factors often having to be modified long term