Micturition Disorders

What are the phases of micturition?

Storage phase

Voiding/emptying phase

What nervous system causes you to pee?

Parasympathetic

What nervous system causes you to store?

Sympathetic and somatic

What gives you voluntary control of the external urethral sphincter muscle?

Skeletal/striated muscle

What gives you involuntary control of the internal urethral sphincter muscle?

Smooth muscle

What is the detrusor muscle?

Muscle around the bladder that helps contract and expand it

Where does the hypogastric nerve leave the spinal cord?

L1-4

Where does the pelvic and pudendal nerve leave the spinal cord?

S1-3

What part of your brain decides to pee and sends it down to the bladder?

Cerebral cortex

What kind of NS is the pelvic nerve?

Parasympathetic

Where does the pelvic nerve go?

Detrusor muscle

What happens if the pelvic nerve is stimulated?

Bladder contraction

What happens if the pelvic nerve is inhibited?

Bladder relaxes

What type of nerve is the hypogastric nerve?

Sympathetic

Where does the hypogastric nerve go?

Detrusor and internal urethral sphincter

What happens if the hypogastric nerve is stimulated?

Store, bladder relaxes and urethral sphincter contracts

What happens if the hypogastric nerve is inhibited?

Urination

What type of nerve is the pudendal?

Somatic

Where does the pudendal nerve go?

External uyrethral sphincter

What happens if the pudendal nerve is stimulated?

Urethral sphincter contracts

What happens if the pudendal nerve is inhibited?

Urination

Draw the map of the storage phase

OK

Draw the map of the voiding phase

OK

What are some storage disorders?

urethral sphincter mechanism incompetence (USMI)

ectopic ureters

detrusor instability / overactive bladder

lmn bladder

What are some voiding disorders?

Detrusor atony

Functional outflow obstruction (FOO)

Mechanical outflow obstruction (MOO)

UMN bladder

What do you need to figure out in the history during a micturition problem?

Is the animal aware of inappropriate urination?

Age of onset

Duration of problem

Is problem getting worse?

Was problem there before neutering?

Able to posture and urinate normally?

Able to empty the bladder completely?

What is the most important part of the physical exam for a micturition problem/

Observation of urination

What is everything you should look for when watching an animal urinate?

Urine stream

Stranguria

Duration of voiding

Involuntary leakage immediately after urinating

Posture and presence of discomfort

What areas should you exam during a micturition problem/

Perineal area

Rectal area

Preputial area

When feeling the bladder what should you look for?

Position within the abdomen

Degree of distention

Bladder tone

Presence of pain

If the bladder is full after voiding what should you think?

Voiding disorder

If the bladder is empty after voiding what should you think?

Storage disorder

What is a normal amount of urine left in the bladder after voiding?

0.2-1mL/kg

What does >3mL/kg of urine left in bladder mean/

That is an abnormal amount

What should you look for during a neuro exam?

Behavior, level of consciousness , cranial nerves, gait, pastural reactions, presence of spinal pain

T/F every patient should get a urinalysis?

True

When do you do a culture?

If bacteriuria is detected, if there are lower UTI signs, before undergoing interventional urinary procedures

What are the main diagnostic images you would want?

Radiographs, US, CT, cystoscopy

What diagnostic imaging technique can be used to exclude mechanical reasons for voiding disorders?

Survey and contrast radiogrpahs

What are survey and contrast radiographs good for diagnosing?

Uroliths, mineralized mural lesions, strictures, mural lesions, anatomical abnormalities of LUT

What are US good for?

Evaluation of upper and lower urinary tract

Good sensitivity and specificity for detecting ectopic ureters, but cannot be ruled out based on US alone?T

T/F you can rule out ectopic ureters with US?

False

What is a CT good for?

A detailed overview and can identify ectopic ureters

What is cystoscopy good for?

Evaluate LUT

Ectopic ureters

Ablation therapy for ectopic ureters

Collection of biopsies

What is the best way to diagnose ectopic ureters?

Cystoscopy

What causes USMI (urethral sphincter mechanism incompetence)?

Decrease in estrogen and increase in LH and FSH

What breeds are predisposed to USMI?

Large and giant breed

When is urinary incontinence most severe with USMI?

At rest

When does USMI symptoms begin?

As an adult after neutering or spaying

T/F they can urinate normally and completely empty the bladder with USMI?

True

What usually leads to a USMI diagnosis?

A UTI or PU/PD associated disorder because they owner will not realize it until there is another problem and they are susceptible to UTIs

How do you treat USMIs?

Estrogen or alpha agonists

How does estrogens, like DES and estriol treat a USMI?

It increases responsiveness to norepinephrine to sensitize the urethral sphincter to alpha-adrenergic stimulation

How do alpha-agonists like PPA (phenylpropanolamine) treat USMIs?

Stimulation of alpha-receptors

How can you treat USMIs in males?

Androgen supplement like testosterone cypionate

How do androgen supplements treat USMIs in males?

Tone the urethra and bladder smooth muscle

causes prostatic hypertrophy

Describe how you treat USMI in males?

Start with a PPA and if that fails try a androgen supplement

What causes a lower motor neuron bladder?

Secondary to a spinal cord injury or disease in the S1-S2 region

What are the signs of lower motor neuron bladder?

Neurological deficits

Bladder easy to express

What can cause detrusor instability?

Loss of bladder compliance and capacity

What are signs of detrusor instability?

Increased urgency to urinate

Urine dribbling after urination

More frequent urination

What needs to rule out before deciding detrusor instability?

Underlying UTI and LUT disorders

What causes ectopic ureters?

Congenital

What is more likely to get ectopic ureters?

Females and predisposed breeds like labs and retrievers

What are the types of ectopic ureters?

Intramural

Extramural

Combined

What are signs of ectopic ureters?

Incontinence at all times

Juvenile onset

Can posture and urinate normally

What is the presenting complaint for ectopic ureters?

Poorly house trained

What are the 2 types of detrusor atony?

Neurogenic

Non-neurogenic

Describe a neurogenic detrusor atony

Injury to S1-S3 or pelvic nerves

Large, easily expressed bladder

Poor perineal reflexes

Describe a non-neurogenic detrusor atony

Direct damage to the detrusor muscle due to overdistention

How do you treat detrusor atony?

Keep bladder empty and use parasympathomimetic drugs like bethanechol to stimulate detrusor contraction

What is bethanechol?

Parasympathomimetic drug used to stimulate detrusor contraction

What is detrusor atony?

Detrusor muscle is not able to contract

What causes FOO (functional outflow obstruction)?

Thoracolumbar spinal cord disfunction that causes a lack of inhibition of the pudendal and hypogastric nerves

What is predisposed to FOO?

Middle aged, large and giant MALE breed dogs

How do you diagnose FOO?

Observation of urination and to rule out MOO

What does it look like with a dog with FOO urinates?

An initial nice stream that stops very quickly and the patient keeps trying to urinate

How do you treat FOO?

Maintain an empty bladder

Alpha-1 antagonists

Skeletal muscle relaxants

Parasympathomimetic drugs if secondary bladder atony is present

What alpha-1 antagonists can be used to treat FOO?

Prazosin and tamsulosin

What skeletal muscle relaxants can be used to treat FOO?

Diazepam, methocarbamol, dantrolene

Where can the obstructions cause with MOO?

Intraluminal

Intramural

Extraluminal

What are intraluminal causes of MOO?

Urolithiasis

Blood clots

Urethral foreign bodies

Inflammatory debris

What are intramural causes of MOO?

Neoplasia

Urethritis

Stricture

What are extraluminal causes of MOO?

Prostatic disease

Caudal/abdominal perineal tumors

Trauma

Howe do you treat MOO?

Specific treatment to relieve obstruction

What are complications of MOO?

Managing AKI

Urinary tract rupture

What is UMN bladder?

Loss of inhibitory signals to the hypogastric and pudendal nerves

What causes UMN bladder?

Spinal cord lesion cranial to the sacral segment

What are signs of UMN bladder?

Unable to urinate normally

Bladder is difficult to express

There are other neurologic deficits