Abnormal/unsteady gait
Underpinning
Sciences
Basic Medical Sciences
Structure and function of CNS, spinal cord and peripheral nerves
particularly motor and extra pyramidal systems.
Control mechanisms within nervous system.
Biochemistry of nervous system function and dysfunction.
Factors effecting development of nervous system.
Physiology of nerve conduction.
Functional anatomy and blood supply of brain and spinal cord.
Understand role neuro-transmitters in CNS.
Understand control of voluntary movement.
Understand upper and lower motor neurone pathologies.
Clinical Sciences
Pathophysiology of upper/lower motor neurone disorders; disorders of extra
pyramidal system and cerebellum; disorders of muscles and peripheral
nerves.
Features of spinal cord disorders and compression.
Developmental milestones in children.
Understand upper and lower motor neurone pathologies.
Behavioural Sciences
Factors underlying non-organic causes.
Population Health
Sciences
Screening of CDH.
Epidemiology of common neurological causes (e.g. stroke, MS, cerebral
palsy).
NSF for falls in the elderly.
Index Conditions
Common or less
common but dangerous
Stroke.
Childhood hip disorders.
Parkinsons disease.
Cerebral palsy.
Multiple sclerosis.
Spinal cord compression.
Joint disorders.
Uncommon but
illustrative
Cerebellar disorders.
Peripheral neuropathies.
Myopathies/Dystrophies
Non-organic causes
Spinal cord disorders (e.g. Guillain Barre Syndrome, polio).
Motor neurone disease
Structure and function of CNS, spinal cord and peripheral nerves
The brain is divided into 2 halve, which are connected in the midline by the corpus
callosum and the anterior and posterior commissures (which are anterior and posterior
to the callosum). Each of the hemispheres in then divided into 4 lobes frontal, parietal,
temporal and occipital, so named after the overlying bones. The hemispheres are
composed of grey matter (peripherally) and white matter (centrally). Anywhere within
the cerebral hemispheres where there is a density of grey matter is called a nucleus.
Examples of these are the thalamus, caudate nucleus. These are areas where neurones
are synapsing in significant density, these are surrounded by white matter in the brain,
where myelinated neurones are passing in between centres of the brain.
Glutamate is the major excitatory neurotransmitter in the CNS, whereas GABA is the
main inhibitory neurotransmitter in the CNS.
The spinal cord is the opposite of the brain with the grey matter (area of all the
synapses) is in the centre of the cord and the white matter on the periphery of the
cord. The sensory information leaves the cord posteriorly through the posterior root,
the cell bodies are in the dorsal root ganglion outside of the cord, these join the
anterior roots to form the spinal nerve. There are also grey and white rami which
leave/enter the spinal cord and communicate with the sympathetic chain.
The motor system is carried in the anterior part of the spinal cord, the main one of
these is the corticospinal tract, but there are others, for example the reticulospinal tract
and the rubrospinal tract. The corticospinal tract is involved in the control of
voluntary movement, the others are involved in things like posture control head
movements. The corticospinal tracts start in the motor cortex in the posterior frontal
lobe, and they commence from layer 5 of the cortex from the Betz cells. They run
down from the cortex, through the reticular formation and the internal capsule and
then synapse with various nuclei in the brain (e.g. the basal ganglia and the
cerebellum), for coordination of the movement. The corticospinal tract mostly (85%)
decussates in the medulla (pyramids) forming the lateral corticospinal tract, although
15% remains uncrossed and forms the anterior corticospinal tract.
Organisation of the motor system (3 main):
1. The corticospinal (or pyramidal) system originates in the frontal lobe in the cortex
and delivers information to spinal cord anterior horn cells. This is the system
which allows purposeful, skilled, intricate, strong and organised movement to
occur. Defective function of this system leads to loss of skilled movements,
spasticity and reflex change. This is seen in hemiplegia.
2. The extrapyramidal system facilitates fast, fluid movements that the corticospinal
system has generated. Defective function is recognised usually by slowness
(bbadykinesia), stiffness (rigidity) and/or disorders of movement (rest tremor,
chorea and other dyskinesias). Frequently, one sign (e.g. stiffness, tremor or
chorea) will predominate. Mixtures of these features, and lack of localised
pathological anatomy makes classification difficult.
3. The cerebellum and its connections have a role in coordinating smooth
movements initiated by the corticospinal system, and the regulation of balance.
Cerebellar disease leads to unsteadiness and jerkiness of movement (ataxia), with
characteristic physical signs of past pointing, action tremor and incoordination.
Each of these three motor controllers also relies upon connections with the other two,
and with sensory input, from proprioception, reticular formation, vestibular system
and special senses.
Characteristics of pyramidal/UMN lesions: weakness, spasticity (remember acutely
the limbs may be flaccid and tendon reflexes lost- then becomes spastic with claspknife effect), changes in superficial reflexes (extensor plantar response, cremasteric
reflex lost), drift of an upper limb (downward, medially, with pronation and finger
flexion), weakness and loss of a skilled movement (if above decussation=
contralateral to the lesion- in the upper limb flexors remain stronger, the lower limbs
the extensors remain stronger), muscle wasting is not a feature and have normal
electrical excitability. There are 2 main patterns of UMN lesions, hemiparesis (brain
lesion) and paraparesis (spinal cord lesion):
 Hemiparesis=
o Motor cortex: weakness and/or loss of skilled movement confined to
one contralateral limb or part of a limb is typical of an isolated motor
cortex lesion (e.g. a secondary neoplasm) a defect in higher cortical
function and focal epilepsy may occur
o Internal capsule: since all the fibres are tightly packed, a small lesion
causes a large deficit, and may cause a sudden, dense, contralateral
hemiplegia
o Pons: rarely only confined to the corticospinal tract, may have
localising signs e.g. 6th or 7th nerve lesions.
o Spinal cord: would cause an ipsilateral lesion, there may be presence of
Brown-Sequard syndrome.
 Paraparesis=
o Bilateral damage of the corticospinal tracts, may be due to spinal cord
compression, but cerebral disease may cause paraparesis (e.g. midline
skull vault meningioma).
Extrapyramidal system:
Refers to the basal ganglia i.e. corpus striatum (caudate nucleus, globus pallidus and
putamen), subthalamic nucleus, substantia nigra and parts of the thalamus.
Extrapyramidal disorders are classified broadly into akinetic-rigid syndromes (in
which poverty of movement predominates) and dyskinesias (where there are various
involuntary movements). The most common extrapyramidal disorder is Parkinson’s
disease.
In many involuntary movement disorders there are substantial and specific changes in
neurotransmitters, rather than anatomical lesions. The main neurotransmitters in the
extrapyramidal system are dopamine, GABA, norepinephrine, serotonin, GAD
(glutamic acid decarboxylase), acetylcholine.
Cerebellum:
This modulates coordination rather than speed. Ataxia is characteristic when it
malfunctions. The cerebellum receives afferent fibres from:
 Proprioceptive receptors in joints and muscles
 Vestibular nuclei
 Basal ganglia
 The corticospinal system
 Olivary nucleus
Efferent fibres pass from the cerebellum to:
 Each red nucleus
 Vestibular nuclei
 Basal Ganglia
 Corticospinal system.
Each ipsilateral cerebellar lobe coordinates movement of the ipsilateral limbs. The
vermis (a midline structure) is concerned with maintenance of axial (midline) posture
and balance.
Lesions in the lateral lobes of the cerebellum cause ipsilateral symptoms with
problems of posture and gait, tremor and ataxia, nystagmus, dysarthria, other signs
(titubation- rhythmic head tremor, hypotonia, depression of reflexes).
Midline cerebellar lesions affect the truncal muscles with difficulty standing
unsupported and a rolling, broad, ataxic gait. Lesions of the flocculonodular region of
the cerebellum cause vertigo, vomiting and gait ataxia.
Physiology of nerve conduction
The nerve relies on action potentials to transmit information. This is reliant on sodium
and potassium movement into and out of the cells. The resting potential of the neuron
is normally around -65- -75mV. This is altered when the action potential is initiated
and the sodium channels are opened and sodium enters the cell, making the potential
less negative. As the potential becomes negative, this causes voltage-gated potassium
channels to open. The action potential will reach a potential of around +35-40mV.
This is when depolarisation along the nerve occurs. As this depolarisation causes the
sodium channels around the site to also become depolarised, and the action potential
is transmitted along the nerve. If the nerve is myelinated, then this means the action
potential has to ‘jump’ along the nerve in between the myelin sheaths (the gaps are
the nodes of Ranvier) and this type of nerve transmission is Saltatory conduction.
When the nerve reaches the pre-synaptic terminal, the transmission of the action
potential would stop unless there is some way to transfer the potential to the postsynaptic bulb. This is allowed with by the use of neurotransmitters. When the action
potential reaches the terminal bulb, calcium channels open in the bulb and calcium
therefore influxes into the cell. These then bind to vesicles in the neurone, which then
move to fuse with the cell membrane and are released into the junction between the
pre-and post-synaptic bulb. The neurotransmitters then join with receptors at the post
synaptic membrane, and open sodium channels to allow potentiation along the postsynaptic neurone.
Upper and Lower motor neurone lesions
Upper motor neurone:
The lesion is anywhere above the anterior horn cell. The signs of this lesion is that
everything goes up (up going plantars-extensor, brisk reflexes, increased muscle tone
and no muscle wasting).
Lower motor neurone:
This is the converse of the above, so the lesion is everything below the level of the
anterior horn cell including the muscles. The signs of this is that everything goes
down (muscle wasting, no reflexes, flaccid tone, fasciculations, trophic skin and nail
changes).
Difficulty walking and falls
Change in gait is a common presenting complaint in neurology. Arthritis and muscle
pains also alter gait, making walking stiff and slow (antalgia). Falls, especially in the
elderly, are a common cause of morbidity. The pattern of abnormal gait is valuable
diagnostically.
Spasticity: more pronounced in extensor muscles, with or without weakness, causes
walking to be stiff and jerky. Toes of shoes become scuffed, catching level ground.
Pace is shortened an narrow base maintained. Clonus may be noticed. When the
problem is predominantly unilateral and weakness is marked (in a hemiparesis), the
stiff weak leg drags and is circumducted.
Parkinson’s: Muscular rigidity throughout extensor and flexor muscles, power is
preserved but walking slows. The pace shortens and is shuffling with a narrow base.
The patient becomes stooped and diminished arm swinging is seen. Gait becomes
festinate, with small rapid steps, with the patient tripping over themselves.
Retropulsions= small backward steps taken involuntarily when a patient is halted.
Cerebellar Ataxia: disease of the lateral cerebellar lobes, stance is broad based and
unstable and tremulous. Walking tends to veer towards the more affected cerebellar
lobe. If disease is only in the midline then only the trunk will be ataxic, with the arms
and legs unaffected.
Sensory Ataxia: broad high-stepping gait is seen in peripheral neuropathy due to loss
of proprioception. Ataxia is worsened by the removal of additional sensory input- see
in positive Romberg’s test.
Lower limb weakness: in distal weakness, the leg must be lifted over obstacles. If
dorsiflexors are weak e.g. in common peroneal nerve palsy, the feet return to the
ground with a slapping sound. In proximal weakness (e.g. polymyositis, muscular
dystrophy) leads to difficulty in rising from sitting and climbing stairs. When walking
the patient may have a waddling gait, as the hip muscles are weak and therefore it is
unstable.
Gait apraxia: with frontal lobe disease (e.g. tumour, hydrocephalus, infarction), the
acquired skill of walking becomes disorganised. Leg movement is normal when
sitting or lying but initiation and organisation of walking fail. This is gait apraxia a
failure of the skilled act of walking. Shuffling small steps, difficulty initiating walking
or undue hesitancy may predominate. Urinary incontinence and dementia are often
present with frontal lobe disease.
Falls: especially in the elderly can be problematic-e.g. following hip or upper limb
fracture. Often no cause can be found. An MDT approach is necessary e.g. reviewing
risk factors and need for home aid.
Features of spinal cord disease and compression
The cord extends from C1 to the vertebral body of L1 where it becomes the conus
medullaris.
Principle features of chronic and subacute cord compression are spastic paraparesis or
tetraparesis, radicular pain at the level of compression and sensory loss below the
compression. For example, in compression at T4 a band of pain radiates around the
thorax, characteristically worse on coughing and straining. Spastic paraparesis
develops over months, days or hours, depending upon the underlying pathology.
Numbness commencing in the feet rises to the level of compression, this is the
sensory level. Urinary retention and constipation develop.
Cord compression is a medical emergency, it is sometimes hard to spot as pain may
be absent.
Causes of spinal cord compression:
 Spinal cord neoplasms
 Epidural haemorrhage
 Disc and vertebral lesions
 Rarities
o Chronic degenerative
o Paget’s disease,
o Trauma
scoliosis, epithelial
endothelial and parasitic
 Inflammatory
cysts, aneurysmal bone
o Epidural abscess
cyst, vertebral angioma,
o Tuberculosis
haematomyelia,
o Granuloma
arachonoiditis,
 Vertebral neoplasms
osteoporosis, AVM.
o Metastasis
o Myeloma
Spinal cord neoplasms
Pathophysiology of upper and lower motor neurone diseases
The commonest cause of an upper motor neuron lesion is a stroke, where the lesion is
most commonly in the motor cortex of the brain, but can also be in the internal
capsule, medulla or spinal cord.
Multiple sclerosis causes upper motor neuron lesions if a plaque develops in the
motor system. Multiple sclerosis does not cause a lower motor neurone lesion as the
plaques only occur in the CNS. These symptoms may be transient, in the acute
episode of inflammation, and may fully recover, however some motor deficit may
remain following this acute attack leading to chronic disability.
Other upper motor neuron causes might be motor neuron disease, and this can
exclusively affect the upper motor neurons in Primary lateral sclerosis. There is a
progressive tetraparesis with terminal pseudobulbar palsy. This is a progressive
degenerative disease.
Another cause could be a spinal cord compression, of any of the causes listed above.
Tumours in the CNS may also be a cause of a motor neuron disorder, a syrinx (fluid
filled cavity) in the cervical or thorax cord.
Metabolic and toxic cord diseases: Vitamin B12 deficiency, Lathyrism, Acute
transverse myelopathy, anterior spinal artery occlusion and radiation myelopathy are
all very rare caused of upper motor neuron diseases. In order to localise the lesion to a
part of the nervous system, it is important to look at the other symptoms present.
Lower motor neuron diseases are anywhere downward from the anterior horn cell,
and this includes the neuro-muscular junction and the muscles.
At the level of the cranial nerve nuclei and anterior horn cell: Bell’s palsy, motor
neurone disease, poliomyelitis.
At the level of the spinal root: cervical and lumbar disc protrusion, neuralgic
amyotrophy.
At the level of the peripheral (or cranial) nerve: nerve trauma or entrapment,
mononeuritis multiplex (lesion in the vasa nervorum).
At the level of the motor end plate (NMJ): myasthenia gravis, Eaton-Lambery
syndrome
At the level of the muscle: myopathies and muscular dystrophies.
Screening for CDH (or DDH) and its management
DDH is a spectrum of disorders ranging from dysplasia to subluxation through frank
dislocation of the hip. Early detection is important as it usually responds to
conservative treatment; late diagnosis is usually associated with hip dysplasia which
requires complex treatment often including surgery. Neonatal screening is performed
as part of the routine examination of the newborn, by checking if the hip can be
dislocated posteriorly out of the acetabulum (Barlow’s manoeuvre) or can be
relocated back into the acetabulum on abduction (Ortolani’s manoeuvre).
REMEMBER AS BARLOW’S MANOEUVRE IS PUSHING THE LEG
BACKWARDS. These tests are repeated at routine surveillance at 8 weeks of age.
Thereafter, presentation of the condition may be with detection of asymmetry of the
hip, shortening of the affected leg or limp or abnormal gait.
On screening a hip abnormality is detected in about 6-10 per 1000 live births. The true
prevalence of DDH is about 1.5 per 1000, clinical neonatal screening misses some
cases. If DDH is suspected, a specialist orthopaedic opinion should be obtained, an
ultrasound performed and this allows detailed assessment of the hip, quantifying the
degree of dysplasia and whether there is subluxation or dislocation. If the initial
ultrasound is abnormal, the infant may be placed in a positioning device, which puts
the hips in abduction (e.g. Craig splint), or in a restraining device (e.g. Pavlik harness)
for several months. Progress needs to be monitored by ultrasound or X-ray. The
splinting must be done expertly, as necrosis of the femoral head is a potential
complication. If all conservative measures fail then open reduction and derotation
femoral osteotomy will be required if conservative measures fail.
Other hip conditions in children:
Transient synovitis: most common cause of acute hip pain in children. Occurs in the
ages 2-12 years and often follows or accompanies a viral infection. Presents with a
sudden onset of hip pain or limp, no pain at rest but decreased range of movement,
particularly external rotation. Child does not appear ill, and blood cultures are
negative. Management is with bed rest and sometimes skin traction.
Perthes disease: due to ischaemia of the femoral epiphysis, resulting in avascular
necrosis, followed by revascularisation and reossification over 18-36 months, it
mainly affects boys (5:1) of 5-10 years old. Presentation is insidious with the onset of
limp or hip pain. The condition may be initially mistaken for transient synovitis. It is
bilateral in 10-20%. X-ray shows increased density in the femoral head, but it may be
normal, the patient may require a bone scan or MRI. In most the prognosis is good
(best is in <6 years with < half the femoral head controlled.) If over 6 with more
damage then the child risks degenerative arthritis in adult life. Management is with
bed rest and traction, in more severe disease the femoral head needs to be covered by
the acetabulum to act as a mould for the reossifying epiphysis. This is achieved by
maintaining the hip in abduction with plaster or calipers or by performing femoral or
pelvic osteotomy.
Slipped upper femoral epiphysis: there is displacement of the epiphysis of the head
postero-inferiorly. It is most common at 10-15 years during the adolescent growth
spurt, particularly in obese boys. Presentation is with limp or hip pain, which may be
referred to the knee. There is restricted abduction and internal rotation of the hip. The
onset may be acute, following minor trauma. In 20% it is bilateral. The diagnosis is
confirmed on X-ray. The management is surgical, usually with pin fixation in situ.
Severe slips may require subsequent corrective realignment osteotomy once the
epiphysis has fused or, rarely, open reduction of the hip, but this carries a risk of
avascular necrosis.
Septic arthritis: This is the opposite to transient synovitis, there is sudden onset of
hip pain or limp. The affected joint may be red and swollen and hot to the touch.
There may be a detectable effusion. The child will appear unwell and may have a
systemic temperature. The child will hold the limb still and refuse passive movement.
In up to 15% there is associated osteomyelitis. The white cell count will be increased
and acute-phase reactants. Ultrasound is helpful to identify an effusion. X-rays are
initially normal, apart from widening of the joint space and soft tissue swelling.
Aspiration of the effusion under ultrasound for culture will give the definitive
diagnosis. Management is with a prolonged course of antibiotics, usually IV (e.g.
flucloxacillin combined with a third-generation cephalosporin to cover H. influenzae).
Joint wash out or surgical drainage may be required.
Usual organisms= Staph. aureus and H. influenzae prior to Hib vaccination.
Osteomyelitis: may present with hip pain
Juvenile idiopathic arthritis: may cause hip pain, presenting with persistent joint
swelling presenting before 16 years of age in the absence of infection or a defined
cause. Newly presenting JIA is rare. It has a prevalence of 1 in 1000 children. There
are at least 7 different forms of the disease. Complications of these are: chronic
anterior uveitis, flexion contractures of the joints, growth failure, amyloidosis
(causing proteinuria and subsequent renal failure).
Management is with NSAIDs, intra-articular steroids, systemic steroids, DMARDs
(methotrexate is effective in 70% of children), and biological if not controlled by
methotrexate.
Cerebral Palsy
Definition: is a disorder of movement and posture due a non-progressive lesion of
motor pathways in the developing brain. Although the lesion is non-progressive, the
clinical manifestations emerge over time, reflecting the difference between normal
and abnormal cerebral maturation. Cerebral palsy is the most common cause of motor
impairment in children, affect 2 per 1000 live births. Children with cerebral palsy
often have other problems reflecting more widespread brain dysfunction:

Learning
difficulties

Epilepsy

Squints

Visual
impairment

Hearing
impairment

Speech and
language disorders

Behavioural
disorders

Feeding
problems

Joint
contractures, hip subluxation, scoliosis.
Cause of CP:
80% is antenatal in origin: vascular occlusion, cortical migration disorders or
structural maldevelopment of the brain during gestation, some problems are linked to
gene deletions, congenital infection
10% are due to hypoxic-ischaemic injury at birth.
10% postnatal in origin. Pre term infants are especially vulnerable to brain damage
from periventricular leukomalacia secondary to ischaemia and/or severe
intraventricular haemorrhage. Other postnatal causes are infection (meningitis,
encephalitis, encephalopathy from brain trauma, symptomatic hypoglycaemia,
hydrocephalus and hyperbilirubinaemia.
Check for clotting disordered in neonatal stroke.
There are 3 main types of CP spastic (70%), ataxia hypotonic (10%), dyskinetic
(10%) and there may be a mixed pattern (10%). This can be thought of as cortical,
basal ganglia and cerebellar patterns.
There is nothing medical that can be given to manage CP, it is important the parents
are made aware of the nature of the disease and that there is an MDT approach to
assessment and management.
It is an important cause of missed milestones in childhood.
Parkinson’s Disease
In the pars compacta of the substania nigra, progressive cell degeneration and
neuronal eosinophilic inclusion bodies (Lewy bodies) are seen. These contain protein
filaments of ubiquitin and alpha-synulcein. Degeneration also occurs in other basal
ganglia nuclei. Biochemically there is loss of dopamine (and melanin) in the striatum.
This correlates well with cell loss and with the degree of akinesia.
Symptoms: combination of tremor, rigidity and akinesia develops slowly, over
several months or years, together with changes in posture. The most common initial
symptoms are tremor and slowness. Patients may complain of stiffness in the limbs
and joints. Fine movements become difficult and slowness causes characteristic
difficulty in rising from a chair or getting in/out of bed. There is micrographia (small
and spidery writing), and tends to tail off. It is almost always initially more prominent
on one side.
Signs: Tremor= 4-7Hz pill-rolling tremor at rest, decreasing with action. Rigidity=
stiffness throughout range of movement, and equal in opposing muscle groups. There
is ‘lead pipe’ increase in tone- usually more marked on one side. It is also present in
the neck and axial muscles. When stiffness occurs with tremor, smooth ‘lead pipe’
rigidity is broken up into a jerky resistance to passive movement- known as
cogwheeling. Akinesia= poverty and slowing of movement (bradykinesia) is an
additional handicap, distinct from rigidity. There is difficulty initiating movement.
Rapid fine finger movements e.g. piano-playing, become indistinct, slow and
tremulous. Facial immobility gives a mask-like semblance of depression. The
frequency of spontaneous blinking is reduced. Postural changes= a stoop is
characteristic. Gait becomes, hurrying (festinant) and shuffling with poor arm
swinging. Balace deteriortates, falls are common. Speech= pronunciation is initially a
monotone but progresses to characteristic tremulous slurring dysarthria, the result of
combined akinesia, tremor and rigidity. Speech may eventually be completely lost.
GI and other symptoms= include heartburn, dribbling, dysphagia, constipation and
weight loss. Urinary difficulties are common, especially in men. Skin is greasy and
sweating excessive.
Natural History: worsens over years, beginning as a mild inconvenience but slowly
progressing. Remissions are unknown except for rare and remarkable short-lived
periods of release. These tend to occur at times of great emotion, fear or excitement,
when the sufferer is released for seconds or minutes and able to move quickly. While
bradykinesia and tremor worsen, power remains normal until immobility makes its
assessment difficult. Patients often complain bitterly of limb and joint discomfort.
There is no sensory loss, reflexes are brisk. Cognitive function is preserved early on,
dementia often develops in the late stages. Anxiety and depression are common.
Usually the course is over 10-15 years, with death resulting from bronchopneumonia.
Treatment: No drugs alter the course of PD, levodopa and/or dopaminergic
agonists produce striking initial symptomatic improvement. Avoid drugs until
clinically necessary because of delayed unwanted effects. Catechol-O-methyl
transferase inhibitors are also used as supplementary therapy. Selegeline, a
monoamine oxidase B inhibitor, may delay the need for levodopa therapy by some
months. Antioxidants are also used, but their value is unproved.
Levodopa is combined with an aromatic amino acid decarboxylase inhibitorbenserazide (Madopar) or carbidopa (Sinemet), reduces the peripheral side-effects,
principally nausea, of levodopa and it’s metabolites. Levodopa is commenced and
gradually increased. The great majority of patients with idiopathic PD improve
initially with levodopa. The response in severe, previously untreated idiopathic PD is
sometimes dramatic. Unwanted effects= nausea and vomiting, confusion, formed
visual pseudo-hallucinations and chorea also occur. There are difficult issues with
long-term therapy (levodopa induced involuntary movements). After several years
levodopa gradually becomes ineffective, even with increasing doses. As treatment
continues, episodes of immobility develop (freezing). Falls are common. Fluctuation
in response to levodopa also appears, its effect apparently turning ‘on and off’,
causing freezing alternating with dopa-induced dyskinesias, chorea and dystonic
movements. Levodopa’s duration of action shrinks, with dyskinesia become several
hours after a dose. The patient also begins to suffer from a chronic levodopa-induced
movement disorder. Approaches to treatment of these complications include:

Shortening
the interval between levodopa doses and increasing each dose

Selegiline, a
type B monoamine oxidase inhibitor, inhibits catabolism of dopamine in the
brain. This sometimes smooths out the selegeline response.

Dopaminergi
c agonists are added, or replace levodopa

Entacapone
is used

Drug
holidays are occasionally helpful .
Dopamine receptor agonists: Bromocriptine, lisuridem pergolide, cabergoline (ergot
derivatives), pramipexole and ropinerole are oral directly acting dopamine receptor
agonists, acting principally on D1 and D2 receptors. The ergot derivatives are
associated with retroperitoneal and pericardial fibrotic reactions. Apomorphine, a
potent D1 and D2 agonist given by subcutaneous metered infusion is an effective
method of smoothing out fluctuations in response to levodopa. Vomiting is common
with apomorphine, and haemolytic anaemia is an unusual side-effect. DRA are in
general less effective than levodopa, but cause fewer late unwanted dyskinesias.
Stereotactic neurosurgery: used less frequently with newer drugs but still improves
tremor and dyskinesia. Thalamic stimulation is used.
Physiotherapy and physical aids.
Multiple Sclerosis
MS is a chronic inflammatory disorder of the CNS. There are multiple plaques of
demyelination within the brain and spinal cord. Plaques are ‘disseminated in time and
place’, hence the old name disseminated sclerosis. Plaques of demyelination, initially
2-10mm in size are the cardinal feature. Plaques are perivenular with a predilection
for distinct CNS sites: optic nerves, the periventricular region, brainstem and it’s
cerebellar connections and the cervical spinal cord (corticospinal tracts and posterior
columns). Acute relapses are caused by focal inflammatory demyelination, which
causes a conduction block. Inflammation induces local production of nitric oxide by
macrophages, which damages central nerve fibres. Remission follows as
inflammation subsides. Remyelination occurs and helps recovery. When damage is
severe, secondary permanent axonal destruction occurs. In the cord, plaques rarely
destroy large groups of anterior horn cells- thus focal muscle wasting (e.g. small hand
muslces) is unusual. MS plaques are not seen in myelin sheaths of peripheral nerves.
Clinical Features: The commonest age of onset is between 20 and 45 years, a
diagnosis before puberty or after 60 years is rare. MS is more common in women. No
single group of signs or symptoms is absolutely diagnostic. Despite this, MS is often
recognisable clinically by different patterns:

Relapsing
and remitting MS (80-90%)

Primary
progressive MS (10-20% of cases)

Secondary
progressive MS- this follows on from relapsing-remitting disease

Occasionally
(10%) MS runs a fulminating course over some months (fulminant MS).
Presentation which would cause a change in the gait would be from a lesion in the
spinal cord which might cause a spastic paraparesis developing over days or weeks
and is typically a result of a plaque in the cervical or thoracic cord, causing
difficulty in walking and numbness. Lhermitte’s sign may be present. Urinary
symptoms are common. Brainstem demyelination commonly causes combinations
of diplopia, vertigo, facial numbness/weakness, dysarthria or dysphagia. Pyramidal
signs in the limbs occur when the corticospinal tracts are involved (greater weakness
in the extensors of the lower limb).
Management: none medical= practical advice at work, on walking aids, wheelchairs,
car conversions, alterations to houses and gardens is needed, from professionals with
experience of rehabilitation. Wide-ranging support- for fear, reactive depression and
sexual difficulties- is also helpful. MDT liaison between patient, carers, doctors and
therapists is essential. Treat all infections. Urinary infection frequently exacerbates
symptoms. Physiotherapy is of particular value in reducing pain and discomfort of
spasticity, particularly lower limb flexor spasms. Muscle relaxants (e.g. baclofen,
BDZs, dantrolene and tizanidine) are sometimes helpful. Injected botulinum toxin is
used for painful spasms. Prevention of pressure sores is vital.