Lower motor disorders

Amr Hassan, M.D.
Associate professor of Neurology - Cairo University
LOWER MOTOR
DISORDERS

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1. The anterior (ventral) horn cell
2. The radicle (root).
3. The peripheral nerve.
4. The neuromuscular junction.
5. The muscle.
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Disorders of the AHC
Motor Neurone Diseases (MNDs)
Definition:
• A group of purely motor degenerative
disorders that involve selective loss of the
function of upper and/or lower motor
neurons innervating the voluntary
musculature of the limb and bulbar regions.

Motor Neurone Diseases (MNDs)
Classification :
• Combined LMN and UMN involovement
Amyotrophic lateral sclerosis
• Pure UMN involovement
Primary lateral sclerosis
Hereditary spastic paraplegia
• Pure LMN involovement =Spinal muscular atrophy (SMA)
Acute infantile SMA (Werdnig-Hoffmann syndrome).
Bulbo-SMA (Kennedy's syndrome).
Chronic childhood SMA (Kugelberg-Welander syndrome).
Distal SMA.

MND
UMNL
primary
Lateral
sclerosis
Hereditary
spastic
paraplegia
LMNL
Acute infantile
SMA (Werdnig-
Hoffmann
syndrome
Bulbo-SMA
(Kennedy's
syndrome
Chronic
childhood
SMA
(Kugelberg-
Welander
syndrome).
Distal
SMA.
COMBINED
Amyotrophic
lateral sclerosis

Pure UMNL Pure LMNL
Bulbar (cranial
nerves)
Pseudo bulbar
palsy
True bulbar palsy
Limbs Spastic
quadriplegia
Progressive muscular
atrophy

Pseudo bulbar palsy True bulbar palsy
Bulbar symptoms: Dysphagia,dysarthria,
hoarseness of voice
recurrent choking attacks.
Dysphagia,dysarthria,
hoarseness of voice,
nasal tone of voice,
nasal regurgitation.
Platal and pharyngeal reflex Exaggerated Lost
Emotional lability Commonly present Absent
Jaw reflex Exaggerated Normal

Definition:
• Motor degenerative disorders that involve selective
loss of the function of upper and lower motor
neurons.
Pathogenesis:
• Oxidative stress theory: Disruption of cell
detoxification mechanismsoxidative stress on
neurons  neuronal degeneration.
• Loss of certain neurotrphic factors: These factors are
responsible for maintenance and survival of neurons.

• Lou Gehrig was a Major League
Baseball player who played first
base for the New York Yankees
from 1923-1939. Gehrig set the
records for most grand slams in
a season and most consecutive
games played. Gehrig was
stricken with amyotrophic
lateral sclerosis, now
commonly known as Lou
Gehrig's disease.

Clinical picture: ALS has gradual onset and
progressive course.
Cranial nerves examination:
• Oculomotor nerves: are usually spared
• Pseudobulbar palsy

Motor system examination:
Weakness both U.L.s and L.L.s, usually starts at U.L.
Weakness of neck muscles  chin drop.
= Tonic Atrophy
Combined features of UMNL and LMNL: UMNL: +ve Babinski sign,
hyperreflexia.
N.B. Sensory system examination: Normal (as purely motor disorder)
LMNL:wasting(D>P), fasiculations (tongue &bulky muscle).

Diagnosis: can be made on clinical bases.
Electrophysiological studies:
• Nerve conduction studies are also required to
exclude motor neuropathy & to provide
evidence of chronic denervation.
Neuroimaging studies: to exclude conditions
which may cause UMN and/or LMN signs that
may simulate ALS e.g. focal quadriparesis due
to cervical cause.

Treatment:
A) Non -Pharmacological:
Speech therapy. d) Physiotherapy.
Nutritional support. e) Occupational therapy.
Respiratory therapy. f) Mental health care.
B) Pharmacological:
1. Symptomatic treatment: e.g. muscle relaxant for treatment of stiffness.
2. Potentially disease modifying drugs:
Glutamate antagonists: Riluzole: 50-200 mg / d.
Antioxidant drugs : e.g. Vitamin E.
Neurotrphic factors: e.g. Nerve growth factor.
Other lines of treatment:e.g. Stem cell therapy, gene therapy.

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5. The muscle.
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II. Disorders of The Spinal Roots
(Radiculopathies)
Intervertebral Disc and Its Disorders
• The intervertebral disc = central gelatinous
part, "the nucleus pulposus," surrounded by a
fibrous tissue ring, "the annulus fibrosus" and
covered from above and below by a
cartilaginous plate.

Acute disc prolapse:
• There is sudden rupture of the annulus
fibrosis followed by bulging (herniation) of the
nucleus pulposus; this compresses the spinal
roots.
• It may occur at any age and usually follows
trauma, as lifting heavy objects or jumping to
the floor from a height.

B) Spondylosis:
• Definition:
It is the gradual, progressive degeneration of the
intervertebral discs, specially those which are freely mobile as
they are more subjected to the process of wear and tear. The
freely mobile discs are mainly found in the cervical and
lumbar regions.

B) Spondylosis:
• Predisposing factors: Old age and excessive mobility of the
spine as in labourers.
• Pathology:
• In spondylosis, there is degeneration of the annulus fibrosus,
leading to herniation of the nucleus pulposus with
subsequent compression of adjacent structures. As the
weakest parts of the annulus fibrosus are the lateral and
posterior parts, the herniation will be either lateral, posterior
or posterolateral.

Acute disc prolapse Lumbar spondylosis
Age Any age Middle and old age
Cause Traumatic Degenerative
Onset Acute Gradual
X-ray Narrowed intervertebral space. Narrowed intervertebral space sclerosis,
lipping & osteophytes.

Selected Radiculopathies
Cauda Equina

Cauda Equina
Causes of cauda equina lesions:
• Congenital: Spinabifida.
• Traumatic:
• Fracture or fracture dislocation of
• the lumbar vertebrae.
• Post traumatic disc prolapse.
• Inflammatory: Pott's disease of the
• lumbar vertebrae.
• Neoplastic.
• Degenerative: lumbar spondylosis.

Cauda Equina
Clinical picture of cauda equina lesions:
Motor manifestations:
L.M.N.

Cauda Equina
Root Action Muscles
L2 Flexor of the hip Ileopsoas.
L3 Extensor of the knee Quadriceps
L4 Dorsiflexion of the ankle Anterior tibial group
L5 Dorsiflexion of the toes Anterior tibial group & glutei
S1 Plantar flexion of the ankle and toes Calf muscles & glutei
S2 Flexor of the knee Hamstrings
S3, 4, 5 Anal contraction Anal and perianal muscles

Cauda Equina
Sensory manifestations:
• The sensory impairment affects both
superficial and deep sensations. Initially 
irritative lesion  radicular pain destructive
lesion hyposthesia or anaesthesia in the
dermatome supplied by the affected root.

Cauda Equina
Root Sensory
L1 Upper third of the front of the thigh.
L2 Middle third of the front of the thigh
L3 Lower third of the front of the thigh.
L4 Antero-lateral aspect of the thigh, Front of the knee, of the knee , Antero - Medial
aspect of the leg, medial aspect of the dorsum of the foot and the foot and big toe.
L5 Lateral aspect of the thigh and leg, Middle third of the dorsum of the foot and
Middle three toes.
S1 Postero-lateral aspect of the thigh and leg, Lateral third and little toe .
S2 Posterior aspect of the thigh and leg and sole of the foot.
S 3,4, 5 Anal, perianal and gluteal region (saddle-shaped area).

Cauda Equina
Autonomic manifestations:
• Sphincteric manifestations are usually late
unless the lesion is bilateral and affects mainly
S2,S3,S4 roots (roots of innervation of the
bladder). The Sphincteric disturbances are in
the form of: sensory atonic bladder,Motor
atonic bladder or Autonomic bladder.
• Vasomotor changes and trophic ulcers may
occur in the L.L.

Cauda Equina
Investigations:
1) Plain X-ray:
Narrowing of the intervertebral disc spaces.
Sclerosis of the adjacent surfaces of the vertebrae.
Lipping or osteophytic formations due to calcification of the
prolapsed parts and ligaments
Straightening of the spines (loss of lordosis).
2) M.R.I
can visualize the intervertebral discs, degree of disc
herniation, vertebrae, the facet joints, the nerves, and the
ligaments in the spine and can reliably diagnose nerve
compression.

Cauda Equina
Treatment:
There is no treatment to reverse the process of spondylosis,
because it is a degenerative process.
The treatments of spondylosis target the back pain and neck
pain.Available treatments fall into several categories:
General measures:
• Bed rest prolongs the time to recovery. Therefore, it is
recommended to continue normal or near normal activities.
However, do not do anything that could exacerbate the
problem, such as heavy lifting.
• Some people find heat and/or ice to be helpful for back and
neck pain caused by spondylosis.

Cauda Equina
Medical: Analgesics &muscle relaxants.
Physiotherapy.
Adjunctive therapies.
Chiropractic spinal manipulation may be helpful to
some people, especially within the first month of
pain.
Acupuncture.
Injections and Minimally Invasive Procedures for
Spondylosis:Steroids (cortisone) can be injected into
the epidural space (the space surrounding the spinal
cord). This is known as an epidural injection.

Cauda Equina
Surgical: Surgery is rarely necessary in patients with
acute back pain, unless progressive neurologic
problems develop,surgical interference is indicated in
cases of:
1. Severe intolerable pain.
2. Bladder disturbances (in cases of cervical
spondylosis), denoting severe cord compression.
3. Motor weakness.
4. Marked Sensory deficit.

Conus lesion Epiconus lesion
Anatomically lowermost three segments of the
spinal cord S3,S4,S5
L4,L5,S1,S2
Motor affection No motor disability in L.Ls Weakness or paralysis in L.Ls, in the
muscles supplied by L4S2. revise
table. )
Sensory affection No sensory loss in the lower limbs.
- ↓ sensations in saddle-shaped
area.
↓ sensations from L4 to S2 segment.
Sphincteric
affection
Early urinary incontinence
(autonomic bladder) and faecal
incontinence.
- Impotence.
Precipitancy may occur

B.Sciatica
Definition: It is radicular pain along the
distribution of the sciatic nerve (L4,5,S1,2,3) i.e.
along the back of the thigh, leg and foot.
The most common causes of sciatica are:
• Acute disc prolapse.
• Lumbar spondylosis.

B.Sciatica
Spinal canal at the
lumbosacral regions
Intervertebral
foramina
Pelvis Sciatic nerve
- Acute lumbar disc
prolapse.
- Fracture dislocation.
- Lumbar spondylosis.
- Pott's disease or
tumours.
- Neurofibroma
- Ankylosing
spondylitis.
- Radiculitis.
Compression of
sciatic plexus over
the sacro-iliac joint
by:
- Malignant
tumours of the
bladder,rectum..
- Pelvic abscess.
- Pregnant
retroverted
uterus.
- Neuritis as diabetic,
alcoholic and
rheumatic.
- Pressure on the nerve
by dislocated head of
femur.
- Wrong injection into
the nerve.

B.Sciatica
Clinical picture of sciatica:
• Sensory manifestations: Pain and paraesthesias
along the course of the sciatic nerve, aggravated by
walking which stretches the nerve and also by
coughing, straining or sneezing. Tenderness on direct
pressure on the sciatic nerve.
• Motor: Slight L.M.N. weakness in the muscles
supplied by the nerve The paravertebral muscles may
be spastic; resulting in loss of lumbar lordosis.
• Signs of meningeal irritation: +ve Kernig, Lassegue &
Brudzinski signs.

B.Sciatica
• Investigations: M.R.I. lumbosacral spine
• Treatment: Treatment of the cause.

C. Cervical Spondylosis
It may present by one of the 3 following manifestations
depending on the direction of prolapse of the disc.
1. Manifestations of root compression (lateral
prolapse):
a) Ventral root compression: There is motor weakness
or paralysis in one or both lower limbs of a L.M.N.
nature involving the muscles which are supplied by
the affected root. The function of each root can be
easily tested in the following muscles:

Root Action Muscle
C l,2 Lateral movement of neck Sternomastoid & trapezius
C 3.4 Elevation of shoulder Supra and infraspinatus
C5 Abduction of shoulder Deltoid
C 5,6 Flexion of elbow Biceps & brachioradialis
C 6,7 Extension of elbow Triceps
C 7.8 Extension of wrist Extensors of wrist
C 8,T 1 Flexion of wrist & movement of small ms of
hands
Flexors of wrist

• Posterior root compression:The sensory impairment
affects both superficial and deep sensations. Initially
 irritative lesion  radicular pain destructive
lesion hyposthesia or anaesthesia in the
dermatome supplied by the affected root.

Root Sensory distribution
C2 Lateral aspect of neck
C3,4 Shoulder down to manubrium anteriorly
C5 Lateral aspect of arm
C6 Lateral aspect of forearm, thenar eminence & thumb
C7 Middle aspect of forearm, middle of palm, middle 3 fingers
C8 Medial aspect of forearm, hypothenar eminence & little finger
T1 Medial aspect of arm

2. Manifestations of cord compression (Posteroir
prolapse):
This results in weakness or paralysis with signs of
U.M.N.L.
3. Manifestations of root and cord compression
(Postero–lateral prolapse):
Combined features of UMNL and LMNL: In the lower
limbs ,UMNL: +ve Babinski sign, hyperreflexia.
In the upper limb ,LMNL:wasting(D>P), fasiculations
(tongue &bulky muscle).

D.Brachial Neuralgia
Definition: It is radicular pain along the distribution of
the brachial plexus (C5 —> Tl) i.e. in the shoulder and
U.L.
Causes:
• It may be due to:
• Cervical spondylosis and disc prolapse.
• Cervical rib.
• Brachial neuritis: a mononeuritis multiplex of acute
onset due to infection or post-vaccine.
• Referred pain from the heart (angina, myocardial
infarction), or gallbladder.

D.Brachial Neuralgia
Clinical picture:
• Sensory manifestations: Pain and paraesthesias
along the course of the brachial plexus.
• Motor: Slight L.M.N. weakness in the muscles
supplied by the the brachial plexus.
Investigations:
• M.R.I. cervical spine and EMG and NC study.
Treatment: Treatment of the cause.

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5. The muscle.
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III. Diorders of the peripheral nerves
Peripheral Neuropathy
Definition:
• It is inflammation or degeneration of the
peripheral nerves and/or the cranial nerves
resulting in impairment of the conductivity of
these nerves leading to motor, sensory and
autonomic manifestations.

Classification of peripheral nerves
• There are three types of peripheral nerves:
Motor
Sensory
Autonomic.

Classification of peripheral neuropathies
1. Mononeuropathy: affecting a single nerve
trunk in one limb.
2. Mononeuropathy multiplex: affecting more
than one nerve trunk in one limb.
3. Polyneuropathy: systemic affection of the
peripheral nerves of all limbs.

Classification of peripheral neuropathies
Acute , Chronic ,
Subacute,
intermittent
Axonal vs
demyelinating
Sensory vs motor
Inherited vs
acquired
Peripheral neuropathy

Causes of Mononeuropathy (DVTI):
• Diabetes mellitus.
• Vascular: polyarteritis nodosa.
• Trauma: wrong injection into a nerve, callus
compression.
• Infective: leprosy, herpes zoster.

Causes of polyneuropathy:
• Amyloidosis
• Paraneoplastic syndromes: bronchial carcinoma, lymphoma, myeloma
• Collagen vascular disorders: e.g. rheumatoid arthritis, polyarteritis nodosa, scleroderma and
systemic lupus erythematosis.
• Drugs and toxins: e.g. I.N.H, cycloserine, sulphonamides, corticoids, phenytoin, vincristine.
• Diabetes mellitus.
• Deficiency disorders: e.g. beri beri, pellagra, S.C.D.
• Endocrinal causes: acromegaly, myxoedema
• Organ Failure: liver and renal failure
• Granulomatous e.g. sarcoidosis.
• Heridofamilial:
• Infection:
– Viral: acute post-infective poiyneuritis, mumps, measles.
– Bacterial: diphtheria, typhus, typhoid, tetanus.
– Mycobacterial: leprosy.
• Immune mediated: Landry-Guillain-Barre syndrome (acute post-infective polyneuropathy).
• Idiopathic.

Clinical picture of polyneuropathy:
A. Motor:
• Weakness or paralysis of L.M.N. nature (wasting, hypotonia,
hyporeflexia . . .).
• The weakness and wasting are:
• Bilateral and symmetrical.
• Affecting L.L. > U.L.
• Affecting distal muscles > proximal muscles.
• Affecting extensors > flexors, so weakness in the extensors of
the distal group of muscles leads to bilateral foot drop and
wrist drop.

Clinical picture of polyneuropathy:
Sensory:
• Irritative lesion: distal pain and paraesthesia in the limbs.
• Destructive lesion:
• Superficial sensory impairment of the stock and glove
distribution.
• Deep sensory loss specially distally with absence of
deep reflexes sensory ataxia.
Autonomic:
• Vasomotor: coldness and cyanosis of the limbs.
• Cutaneous: loss of hair, brittle nails, trophic ulcers.

Positive
Symptoms
Negative
Symptoms
Somatic Nerves
Sensory Pain Numbness
Tingling Lack of feeling
Motor Cramps Weakness
Fasciculations Atrophy
Autonomic Nerves
Hyperhydrosis Orthostatic hypotension
Diarrhea Impotence
Anhydrosis
Constipation

Diabetic Polyneuropathy
Diabetes mellitus is the most
common cause of
neuropathy worldwide.
• Length-dependent Diabetic
Polyneuropathy
More than 80% of patients
with clinical diabetic
neuropathy have a distal
symmetrical form of the
disorder.

Selected polyneuropathies
Diabetic Neuropathy
Pathogenesis
Diabetic microangiopathy of the vasa nervosa
 ischaemia of the nerves, 2ry to
atherosclerosis of the vasa nervosa.

Diabetic Neuropathy
Clinical picture:
Sensory manifestations:
• The polyneuropathy is mainly sensory.
• In early diabetes or in the pre-diabetic stage,
the neuropathy is of the mononeuritic type
which may affect the sciatic, femoral, lateral
popliteal, ulnar or median nerves or Cr. III, VI
or VII nerves  Then the neuropathy is of the
polyneuritic type.

Diabetic Neuropathy
Autonomic manifestations: e.g. impotence, sensory, motor or
autonomic bladder, postural hypotension, gastroparesis,
,hyperhydrosis or anhydrosis, trophic skin changes(ulcers, loss
of hair, brittle nails) and Charcot's neuropathic joint.
Motor manifestations:weakness may occur late in the disease.
Treatment:
1. Proper management of diabetes: diet, oral hypoglycaemic
drugs or insulin.
2. Drugs for treatment of neuropathic pain.

Acute Infective Polyneuritis
Landry-Guillain-Barre Syndrome
Aetiology:
It is due to an allergic or auto-immune reaction
secondary to a previous non-specific virus
infection.

Clinical Picture:
• Febrile stage: it starts with an influenza-like
attack with fever, headache, malaise, pains all
over the body with no nervous symptoms.
• Latent stage: the above symptoms disappear
and the patient is free for 1-4 weeks.

Paralytic stage:
• There is acute severe weakness or paralysis starting in the L.L.
and ascending to involve the trunk and respiratory muscles,
followed by the U.L. muscles.
• Weakness is proximal more than distal.
• Sensory impairment may occur.
• Early in the disease there is tenderness of the calves.
• The cranial nerves are usually involved specially Cr. VII and X
resulting in bilateral facial paralysis and bulbar symptoms.

Chronic Immune Demyelinating
Polyneuropathy (CIDP)
Epidemiology: Male > Female: 2:1
Clinical picture: Motor affection > Sensory affection
– Onset: Slowly progressive, relapsing-remitting course
– Motor system:
– Weakness: Proximal > Distal ,Symmetric.
– Tendon reflexes: Reduced or absent.
– Sensory system:
• All modalities are affected.
– Cranial nerves:
• Ocasional, mild, symmetric weakness of VII, X, XII.

Chronic Immune Demyelinating
Polyneuropathy (CIDP)
Investigations:
– Electrophysiology: Conduction block and
demyelinating neuropathy.
– Nerve biopsy: Onion bulbs in peripheral nerve.
Treatment: Steroids, I.V. immune globulin,
plasma exchange and immunosuppressant
drugs.

Hereditary motor sensory
neuropathy (Charcot Marie Tooth)
• Charcot–Marie–Tooth neuropathy is a
genetically and clinically heterogeneous group
of inherited disorders of the peripheral
nervous system

• It has a gradual onset and a very slow, progressive course.
• The wasting and weakness start in the lower limbs in the
peronii muscles then the anterior tibial group, then ascend to
involve the muscles of the lower 1/3 of the thigh resulting in
the inverted champagne - bottle appearance.
• In spite of the marked degree of wasting there is mild
disturbance of motor power (i.e. discrepancy between the
degree of wasting and the degree of motor weakness).
• Sensations are impaired specially the vibration sense
which is markedly diminished.
• Skeletal deformities are usually present e.g., pes cavus,
scoliosis.
• It was classified from groups I to VII:

Type Other names
HMSN1 Charcot–Marie–Tooth disease type 1
HMSN2 Charcot–Marie–Tooth disease type 2
HMSN3 Dejerine–Sottas disease
HMSN4 Refsum disease
HMSN5 Charcot–Marie–Tooth disease with pyramidal features
HMSN6 Charcot–Marie–Tooth disease with optic atrophy
HMSN7 HMSN + retinitis pigmentosa

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5. The muscle.
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II. Disorders of The Neuromuscular
Junction
Myasthenia Gravis
Definition
An autoimmune disorder that affects
acetylcholine receptors interfering with
neuromuscular transmission causing easy
fatigability of skeletal muscles.

Immunopathogenesis
• Normally thymus gland is the site where T
lymphocytes mature.
• Thymic dysfunction  abnormal auto-reactive
T cells  activation of B cells production of
autoantibodies directed to the acetylcholine
receptors on the postsynaptic side of the
neuromuscular junction in skeletal muscles 
impairment of the neuromuscular
transmission.

Clinical features
• Diurnal variation
• Descending order ↓
• Easy fatigability
• More common in Females

Clinical features
Cranial nerve affection
• Ocular muscles are affected first in 40% of
patients and eventually in 85%.
• Ptosis and diplopia are common
presentations.
• Bilateral LMN facial weakness.
• True bulbar palsy  dysarthria, dysphagia,
nasal tone of voice and nasal regurgitation of
fluids.

Clinical features
Respiratory muscle weakness:
may cause respiratory failure in severe cases
Motor system:
The disease gradually progress to involve more
skeletal muscles, usually in a descending order
 limb weakness proximal > distal.
Sensory system:
Sensations are normal (MG is a neuro
MUSCULAR disorder).

Diagnosis
Clinical testing :
• Neostigmine test: mix 0.6mg of atropine
sulfate with 1.5 -2.5mg of neostigmine in a 3
cc syringe , change is usually apparent within
15 min. and is most obvious 30 min following
injection.
• Fatigability tests: repetition of a given action,
such as maintaining upward deviation of the
eyes for testing for the eyelidsappearance
of ptosis

Diagnosis
Acetylcholine receptors antibodies: 85-90% of
generalized cases and 50% of ocular cases.
Electromyography:
• Neuromuscular transmission studies may show a
decremental response in the amplitude of the
muscle action potential with repetitive nerve
stimulation at 3 Hz. A decrement of more than 10%
when comparing the fifth to the first response is
positive.
• Single-fiber electromyography.
CT chest with contrast: to exclude thymoma.

Treatment
• Anticholinesterases
• Corticosteroids.
• Plasmapheresis.
• IVIG.
• Thymectomy.

Prognosis
• If untreated may end in respiratory failure and
death.
• Spontaneous remission may occur, usually after
several years.

The myasthenic crisis
• Myasthenic crisis occurs when weakness from
acquired myasthenia gravis becomes severe
enough to necessitate intubation for
ventilatory support or airway protection.
Triggers:
• Infections e.g. upper respiratory tract
infection.
• Physical stress (such as trauma or a surgical
procedure, including thymectomy).
• Changes in medications e.g. recent initiation

The myasthenic crisis
Triggers:
• Infections e.g. upper respiratory tract infection.
• Physical stress (such as trauma or a surgical procedure,
including thymectomy).
• Changes in medications e.g. recent initiation or tapering of
corticosteroid dosage.
• In 30% to 40% of crises, no obvious trigger can be identified.
Management:
• ICU admission and supportive care.
• Removing triggers.
• Plasma exchange.

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1. The anterior (ventral) horn cell .
4. The muscle.

V. Disorders of The Muscles
Mypopathy
• Causes of myopathy
• Primary Myopathies:
– Muscular dystrophies (MD):

X-linked AD AR
 Duchenne
(DMD)
 Becker
(BMD)
 Limb girdle MD;
 Facioscapulohum
eral (FSH)
 Myotonia
dystrophica
 Oculophayngeal
MD.
 Distal MD.

Mypopathy
• Congenital myopathies: Myotubular
(Centronuclear) Myopathy; Nemaline
Myopathy; Central Core Disease.
• Metabolic/Enzyme deficiency:Phosphorylase
deficiency (MCardle), Acid maltase deficiency
(Pompe), Phosphofructokinase deficiency
(Tarui), Debrancher enzyme deficiency (Cori
Forbes) and mitochondrial myopathy.

Mypopathy
Secondary Myopathies
– Infectious: e.g. trichinosis; cysticercosis; toxoplasmosis;
Lyme disease; Staph aureus pyomyositis; human
immunodeficiency virus (HIV); coxsackie A and B viruses;
influenza.
– Toxic/Metabolic: e.g. alcohol, several medicines
(corticosteroids; AZT; statins; colchicine; amiodarone;
cocaine).
– Endocrinal: Corticosteroids (Addison or Cushing), hyper or
hypothyroidism, hyperparathyroidism.
– Inflammatory: Polymyositis, dermatomyositis, inclusion
body myositis.

Duchenne Muscular Dystrophy (DMD)
Definition:
• Is a recessive X-linked form of muscular
dystrophy, affecting around 1 in 3,600 boys,
which results in muscle degeneration and
weakness.

• Genetics:
• The disorder is caused by a mutation in the dystrophin gene,
located on the human X chromosome, which codes for the
protein dystrophin, an important structural component within
muscle tissue.
• Since women have two X chromosomes, if one X chromosome
has the non-working gene, the second X chromosome will
have a working copy of the gene to compensate. Because of
this ability to compensate, women rarely develop symptoms.
Males have only one X chromosome, so one copy of the
mutated gene will cause DMD.

Clinical picture:
• Usually appear in male children < 5 years and
may be visible in early infancy.
• Progressive proximal muscle weakness of the
legs and pelvis associated with a loss of
muscle mass is observed first  inability to
climb the stairs then weakness spreads to the
arms, neck, and other areas, low endurance,
and difficulties in standing unaided or inability
to ascend staircases.

Clinical picture:
• The weakness is of L.M.N. nature i.e. it is associated with
wasting, hypotonia, hyporeflexia. The weakness and wasting
are bilateral, symmetrical and proximal more than distal i.e.,
the shoulder and arm are more affected than the forearm and
hand and the hip and thigh are more affected than the leg
and foot.
• Pseudohypertrophy develops as the condition progresses,
muscle tissue experiences wasting and is eventually replaced
by fat and fibrotic tissue (fibrosis). Pseudo hypertrophy affect
mainly the gluteus maximus, quadriceps and calf muscles in
the L.L., and the deltoid, supra and infra spinatus muscles in
the U.L.

Clinical picture:
The weakness and wasting of the shoulder, pelvic girdle and trunk muscles
results in:
• a) Winging of the scapulae due to weakness of the serratus anterior and
trapezius.
• b) Pot-belly abdomen due to weakness of the abdominal muscles.
• c) Exaggerated lumbar lordosis due to weakness of the extensor muscles
of the trunk in an attempt from the patient, to prevent himself from falling
forwards by the effect of gravity.
• d) Waddling gait due to weakness of the gluteus medius & minimus
(abductors of the hip).
• e) Characteristic manner in getting up from the floor (climbing test or
Gower's sign) due to weakness of the gluteus maximus.

Clinical picture:
• There is selectivity of the involved muscles e.g.,
there is atrophy of the sternal head of the pectoralis
major with preservation of its clavicular head.
• Later on there are fibrosis and contractures of the
affected muscles resulting in skeletal deformities
e.g. pes cavus and talipes equinus.
• No mentality changes, sensory changes or
sphincteric disturbances.

Complications:
• Deformities (particularly kyphosis).
• Permanent, progressive disability manifested
as decreased mobility or decreased ability to
care for self.
• Cardiomyopathy.
• Pneumonia or other respiratory infections.
• Respiratory failure.

Investigations:
• Creatine phospho kinase (CPK-MM) levels in the bloodstream
are extremely high.
• An electromyography (EMG): small MUP, polyphasesity, early
recruitement which denote muscle disease.
• DNA testing : DNA testing confirms the diagnosis in most
cases.
• A muscle biopsy confirms the absence of dystrophin, although
improvements in genetic testing often make this unnecessary.
• E.C.G. changes, histological changes in the heart due to
associated cardiomyopathy.
• Prenatal tests: via Chorion villus sampling (CVS)
,Amniocentesis or Fetal blood sampling.

Treatment:
• There is no current cure for DMD.
• Treatment is generally aimed at controlling the onset
of symptoms to maximize the quality of life e.g.
corticosteroids such as prednisolone and deflazacort.
• Physical therapy is helpful to maintain muscle
strength, flexibility, and function.
Orthopedic appliances (such as braces and
wheelchairs) may improve mobility and the ability for
self-care.
• Appropriate respiratory support.

Prognosis:
• Duchenne muscular dystrophy is a progressive
disease which eventually affects all voluntary
muscles and involves the heart and breathing
muscles in later stages. The life expectancy is
currently estimated to be around 25.

Becker muscular dystrophy (BMD)
Definition:
• Is a recessive X-linked form of muscular dystrophy
affecting around 3 to 6 in 100,000 male births which
results in muscle degeneration and weakness.
Genetics:
• Becker muscular dystrophy is related to Duchenne
muscular dystrophy in that both result from a
mutation in the dystrophin gene, but in Duchenne
muscular dystrophy no functional dystrophin is
produced making DMD much more severe than
BMD.

Becker muscular dystrophy (BMD)
Duchenne MD Becker MD
Age of onset 1st decade 2nd and 3rd decades
Dystrophin Absent Deficient
Severity of the
condition
Severe Less severe
Course Progressive Slowly progressive
Skeletal deformities Present Absent
E.C.G. changes Commonly present Absent

Facioscapulohumeral muscular dystrophy
• AD
• Initially affects the skeletal muscles of the face
(facio), scapula (scapulo) and upper arms
(humeral).
• it is widely stated to be the third most
common genetic disease of skeletal muscle.
• Symptoms may develop in early childhood and
are usually noticeable in the teenage years.

• A progressive skeletal muscle weakness
usually develops in other areas of the body as
well; often the weakness is asymmetrical.
• Life expectancy is normal, but up to 15% of
affected individuals become severely disabled
and eventually must use a wheel chair.

Limb-girdle muscular dystrophy
• This is a heterogeneous group of conditions
that usually appear in adolescence or adult life
with proximal limb weakness. The weakness
usually progresses slowly, but it may arrest
spontaneously.
• There are at least 15 different mutations that
contribute to LGMD
• Some of them are AR,others are AD.

Myotonic Dystrophy
Definition of myotonia: Delayed relaxation of the
skeletal muscles after voluntary, mechanical or
electrical stimulation.
– Voluntary: when the patient voluntarily clenches his fist, he is unable
to open his hand, except after sometime.
– Mechanical:on tapping the thenar eminence, adduction of the
thumb occurs with difficulty & delay in abduction.
– Electrical: 2-3 milliamperes are sufficient to produce contraction of
the muscle due to hyperexcitability.
The myotonic phenomenon: Improves by: repetition of
movement, warmth, calcium, quinine, procamamide
and worsened by: cold, potassium and prostigmine.

Myotonic Dystrophy
• Myotonic dystrophy is an AD condition, usually
begins in childhood or young adult life.
• Myotonic dystrophy, as opposed to most forms of
myopathy, is characterized by distal weakness,
affecting the muscles of the hands before more
proximal musculature.
• In addition, facial (muscles of mastication) and neck
musculature are involved early.
• Numerous non-neurologic problems are found:
frontal balding, testicular atrophy, diabetes, cardiac
arrhythmias, and others. It progresses slowly.

Myositis
Polymyositis
• Definition: It is an acquired autoimmune
disease of the skeletal muscle.
• Clinical Picture:
• Age: usually above 30 years, unless there is an
associated collagen disorder.

Myositis
Polymyositis
• Onset: acute or subacute with general
symptoms of fatigue followed by:
• Pain and tenderness of the muscles (60% of
cases).
• Weakness affecting:
– The proximal muscles of U.L. and L.L.
– The posterior neck muscles (forward lolling of the head).
– The pharyngeal and laryngeal muscles (bulbar symptoms).
• No involvement of the ocular muscles.
• The deep reflexes are intact.

Dermatomyositis
In this disease the clinical picture of polymyositis is
associated with cutaneous manifestations as Gottron
papules on dorsum of hand and heliotropic rash on
upper eyelid.
Investigations:
1. labs: ↑ E.S.R, ↑↑C.P.K. in serum.
2. E.M.G. shows a myopathic pattern with fibrillation
potentials.
Treatment:
1. Steroids.
2. Immunosuppressive drugs.

Lower motor disorders

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