Session 5 - Motor Disorders (Urinary Incontinence)

Question 1

What are two classes of upper motor neurone disorders?

Answer 1

Pyramidal and extra-pyramidal

Question 2

Outline some signs of pyramidal lesions

Answer 2

o Reduction of motor tone
o Loss of fractionation of finger movements
o Almost similar to LMN signs, but not for the same reasons
o Lesions are extremely rare

Question 3

Outline the innervation of the bladder

Answer 3

Detrusor
Parasympathetic
o	Pelvic Nerve (S2-S4)
o	Ach M3 Receptors
o	Contraction
Sympathetic
o	Hypogastric Nerve (T10-L2)
o	NA  3 Receptors
o	Relaxation

Internal Urethral Sphincter
Sympathetic
o	Hypogastric Nerve (T10-L2)
o	NA  1 Receptors
o	Contraction

External Urethral Sphincter
Somatic
o	Pudendal Nerve (S2-S4)
o	Spinal motor outflow from Onof’s Nucleus of the ventral horn of the cord
o	Ach  Nicotinic Receptor
o	Contraction

Afferent Stretch Receptors
o S2-S4
o Bladder wall stretch – feeling of fullness

Question 4

How does an autonomous bladder occur?

Answer 4

when the Sacral (S2-S4) spinal cord is damaged bilaterally

Question 5

What do you lose in bilateral sacral spine damage (autonomous bladder)

Answer 5

o Parasymapthetic
 Pelvic Nerve (S2-S4)
 Contraction of the Detrusor

o Somatic
 Pudendal Nerve (S2-S4)
 Contraction of External Urethral Sphincter
o Afferent Stretch Receptors
 S2-S4
 Activated when bladder wall is stretched

Question 6

What do you retain in autonomous bladder?

Answer 6

o Sympathetic
 Hypogastric Nerve (T10-L2)
 Relaxation of the Detrusor
 Contraction of Internal Urethral Sphincter

Question 7

What occurs in autonomous bladder?

Answer 7

Unopposed action of the SNS (Hypogastric Nerve, T10-L2) means that the bladder capacity increases, it fills to capacity but cannot empty. This results in overflow incontinence. Comparable to LMN signs (Flaccid, Hyporeflexic, Paralysed).

Question 8

What is the automatic reflex bladder?

Answer 8

The automatic reflex bladder occurs when the spinal cord is damaged above the sacral level, resulting in the loss of descending voluntary control. Reflex voiding of the bladder is preserved.

Question 9

What is lost in the automatic reflex bladder, and what is preserved?

Answer 9

Lost
o Somatic
 Pudendal Nerve (S2-S4)
 Contraction of External Urethral Sphincter

Preserved
o	Parasymapthetic 
	Pelvic Nerve (S2-S4)
	Contraction of the Detrusor
o	Sympathetic
	Hypogastric Nerve (T10-L2)
	Relaxation of the Detrusor
	Contraction of Internal Urethral Sphincter
o	Afferent Stretch Receptors 
	S2-S4
	Activated when bladder wall is stretched

Question 10

Why is the automatic reflex bladder named thus?

Answer 10

Bladder fills to the point where every 1-4 hours afferent stretch receptors are activated and stimulates the automatic voiding of the bladder. Injury to the spinal cord means loss of voluntary control (contraction of external urethral sphincter), meaning the patient is completely unable to prevent this.
This is comparable to an UMN lesion, spastic and hyper-reflexic bladder.

Question 11

What happens in damage to higher spinal cord?

Answer 11

Damage to the higher spinal cord (T12-L2) means there is a loss of sympathetic outflow, and failure of the internal urethral sphincter to contract. This results in a constant dribbling of urine (parasympathetic and afferent stretch fibres would be intact, but will not become active as bladder doesn’t fill enough).

Question 12

What is lost in damage to higher spinal cord?

Answer 12

o Sympathetic
 Hypogastric Nerve (T10-L2)
 Relaxation of the Detrusor
 Contraction of Internal Urethral Sphincter
o Somatic
 Pudendal Nerve (S2-S4)
 Contraction of External Urethral Sphincter

Question 13

What is retained in damage to the higher spinal cord?

Answer 13

o	Parasymapthetic 
	Pelvic Nerve (S2-S4)
	Contraction of the Detrusor
o	Afferent Stretch Receptors 
	S2-S4
	Activated when bladder wall is stretched

Question 14

Describe the anatomy of the cerebellum

Answer 14

The cerebellum is highly folded, with a grey matter cortex and white matter core (in contrast to the spinal cord, which has a white matter periphery and grey matter core).

Question 15

What are the three zones of the cerebellum?

Answer 15

Vestibulocerebellum
Spinocerebellum
Cerebrocerebellum

Question 16

What is the o Vestibulocerebellum

Answer 16

 Main input is from the vestibular system

 Involved in balance and ocular reflexes

Question 17

o Spinocerebellum

Answer 17

 Main input is from the Spinocerebellar ascending tract

 Involved in unconscious proprioception, error correction

Question 18

o Cerebrocerebellum

Answer 18

 Main input is from contralateral cerebral cortex
 Involved in fine motor control (e.g. finger movements), movement planning and motor learning
 Particularly in relation to visually guided movements and coordination of muscle activation

Question 19

Give some signs associated with cerebellar dysfunction

Answer 19

Incoordination of movement
Ataxic gait
Ataxic, dysartric speech
Abnormal Eye Movements
Hypotonia

Question 20

What is dysdiadochokinesia?

Answer 20

the inability to carry out rapid alternating movements with regularity, resulting from the inability to control antagonist muscle groups

Question 21

What is dysmetria?

Answer 21

the inability to control smooth and accurate targeted movements. Movements are jerky, with overshooting of the target. Can be manifested in the finger-nose and heel-shin tests

Question 22

What are four symptoms of cerebellar incoordination of movement?

Answer 22

o Dysdiadochokinesia – the inability to carry out rapid alternating movements with regularity, resulting from the inability to control antagonist muscle groups
o Dysmetria – the inability to control smooth and accurate targeted movements. Movements are jerky, with overshooting of the target. Can be manifested in the finger-nose and heel-shin tests
o Cannot learn new movements
o No muscle atrophy/weakness

Question 23

What is an ataxic gait?

Answer 23

o Patient walks with a staggering gait, may later develop a wide-based gait
o In mild cases, the unsteadiness may be apparent only when walking heel-to-toe

Question 24

What is ataxic, dysarthric speech?

Answer 24

o Speech can be slow, slurred and scanning in quality

o Scanning speech is monotone and words may be broken up into syllables

Question 25

Give an abnormal eye movement

Answer 25

o Coarse Nystagmus, which is maximal on gaze towards the side of the lesion

Question 26

What is hypotonia?

Answer 26

o Resistance to passive movement
o Rebound phenomenon – Patients outstretched arms are pressed down for a few seconds hen abruptly released by the examiner. The arms rebound upwards much further than would be expected

Question 27

Give three common causes of cerebellar dysfunction

Answer 27

o Tumours
o Cerebrovascular disease
o Genetic – E.g. Friedrich’s Ataxia