Prepared by:
Dr. Sarwer Jamal Bajalan
M.B.Ch.B, F.I.B.M.S(Neurology)
2014
Essentials of diagnosis

Weakness

No sensory loss or sphincter disturbance

Progressive course.

No identifiable underlying cause other than
genetic basis in familial cases.
General Considerations

Characterized clinically by weakness and variable wasting of
affected muscles, without accompanying sensory changes.

MND generally commences between 30 and 60 years of age.

There is degeneration of:
○
Anterior horn cells in the spinal cord, the motor nucle of the lower cranial
nerves, and
○ Corticospinal and corticobulbar pathways.

The disorder is usually sporadic, but familial cases may occur

Cigarette smoking may be one risk factor.
Classification
Five varieties have been distinguished on clinical grounds.

A. Progressive Bulbar Palsy

B. Pseudobulbar Palsy

C. Progressive Spinal Muscular Atrophy

D. Primary Lateral Sclerosis

E. Amyotrophic Lateral Sclerosis (ALS)
A mixed UMN and LMN deficit is found in the limbs.

ALS (Prof
Stephen Hawking(
Infantile spinal muscular atropy SMA1
Symptoms and Signs

In Bulbar type
○ Dysphagia , dyspea , and dysarthria.
○ Drooping of the palate; a depressed gag reflex; pooling of saliva in the pharynx; a
weak cough; and a wasted, fasciculating tongue.

In pseudobulbar palsy, the tongue is contracted and spastic and cannot
be moved rapidly from side to side.

Weakness , stiffness, wasting & fasciculations (UMN &/or LMN)



No objective changes on sensory examination.
The sphincters are generally spared.
Cognitive changes or pseudobulbar affect may be present.


The disorder is progressive, and ALS is usually fatal within 3–5 years.
Death usually results from pulmonary infections.


Patients with bulbar involvement generally have the poorest prognosis,
Primary lateral sclerosis often have a longer survival.
Ix

EMG:
chronic partial denervation, with abnormal spontaneous
activity in the resting muscle and a reduction in the
number of motor units under voluntary control.

Confident Diagnosis of ALS needs changes to
be found in at least:
o Three spinal regions (cervical, thoracic,
lumbosacral) or
o Two spinal regions and the bulbar musculature.

The serum creatine kinase may be slightly
elevated.

Genitics:
D Dx

Monoclonal gammopathies.
Multifocal nmotor neuropathies with conduction
block.
 Hodgkin disease.


Infective anterior horn cell diseases (polio virus
or West Nile virus infection).
Treatment

Riluzole, 50 mg orally twice daily, which reduces the
presynaptic release of glutamate, may slow progression of
amyotrophic lateral sclerosis. There is otherwise no
specific treatment

Symptomatic and supportive measures may include:
○ Anticholinergic drugs (such as trihexyphenidyl, amitriptyline, or
atropine).
○ Portable suction machine .
○ Physical therapy to prevent contractures.
○ Spasticity may be helped by baclofen or diazepam.
○ A semiliquid diet or nasogastric tube feeding
MYOPATHIC DISORDERS
DISORDERS
Muscular Dystrophies
Essentials of diagnosis
○ Muscle weakness, often in a characteristic
distribution.
○ Age at onset and inheritance pattern depend on the
specific dystrophy
General Considerations

These inherited myopathic disorders are characterized by
progressive muscle weakness and wasting.

They are subdivided by mode of inheritance, age at onset, and
clinical features.

In Duchenne Muscular Dystrophy:
○
○
○
○
○
○
○
○
Pseudohypertrophy of muscles frequently occurs at some stage;
Intellectual retardation is common; and there may be
Skeletal deformities,
Muscle contractures, and
Cardiac involvement.
X-linked recessive
Age at Onset 1-5 year
Pelvic, then shoulder girdle; later, limb and respiratory muscles are
affected.
○ Rapid progression (death within about 15 years after onset).
Ix

The serum creatine kinase(CK) level is increased.

EMG & histopathology may help confirm that weakness is
myopathic rather than neurogenic.

A genetic defect on the short arm of the X-chromosome has
been identified in Duchenne dystrophy. The affected gene
codes for the protein dystrophin, which is markedly
reduced or absent from the muscle of patients with the
disease.

Dystrophin levels are generally normal in the Becker
variety, but the protein is qualitatively altered.
Facioscapulohumeral

Gowers’ sign
showing a patient using
arms to climb up thelegs in
attempting to get up from
the floor

Lordotic posturing
Managemennt

There is no specific treatment for the muscular
dystrophies, but it is important to encourage patients to
lead as normal lives as possible.

Prednisone (0.75 mg/kg orally daily) improves muscle
strength and function in boys with Duchenne dystrophy,
but side effects need to be monitored.

Prolonged bed rest must be avoided, as inactivity often
leads to worsening of the underlying muscle disease.

Physical therapy and orthopedic procedures may help
counteract deformities or contractures.
Myotonic Dystrophy(DM)

A slowly progressive, dominantly inherited disorder,

Usually manifests itself in the 3rd or 4th decade but
occasionally appears early in childhood.

Myotonic dystrophy type 1 results from an expanded
CTG repeat in a protein kinase gene on chromosome 19.

In Myotonic dystrophy type 2, the defect is a CCTG
repeat expansion in the gene for zinc-finger protein-9 on
chromosome 3.

EMG
o Myotonic discharges
o Myopathic changes
DM1
Clinical Features od MD1

Muscle stiffness is evidenced by the marked delay of relaxation
after muscle contraction.

This can often be demonstrated clinically by delayed relaxation of
the hand after sustained grip or by percussion of the belly of a
muscle.

In addition, there is weakness and wasting of the facial,
sternocleidomastoid, and distal limb muscles.

Associated clinical features include:
○
○
○
○
○
○
○
Ptosis
Cataracts ,
Frontal baldness,
Testicular atrophy,
Diabetes mellitus,
Cardiac abnormalities, and
Intellectual changes.
Treatment

When myotonia is disabling, treatment with a
sodium channel blocker—such as:
○ Phenytoin
○ Procainamide
○ Mexiletine

Neither the weakness nor the course of the
disorder is influenced by treatment.

INFLAMMATORY MYOPATHIES:

Inclusion Body Myositis

This disorder, of unknown cause, begins insidiously, usually after
middle age, with progressive proximal weakness of first the lower and
then the upper extremities, and affecting facial and pharyngeal
muscles.

Weakness often begins in the quadriceps femoris in the lower limbs
and the forearm flexors in the upper limbs.

Distal weakness is usually mild( small mm of the hands).

Serum CK levels may be normal or increased.

The diagnosis is confirmed by muscle biopsy.

Corticosteroid and immunosuppressive therapy is usually ineffective,
but IVIG therapy is occasionally of mild benefit.

Polymyositis & Dermatomyositis -----
Myopathies Associated with Other Disorders

Muscle weakness may be caused by a range of
metabolic, endocrine, toxic or inflammatory disorders .

Disorders affecting the muscles’ structural integrity can be
distinguished by EMG from those caused by metabolic
derangement.

In metabolic disorders, weakness is often acute and
generalised, while a proximal myopathy predominantly
affecting the pelvic girdle is a feature of some endocrine
disorders. This may develop without other manifestations
of hormonal disturbance.

A wide variety of drugs and toxins may cause myopathy
Causes of acquired proximal myopathy
PERIODIC PARALYSIS SYNDROMES
(channelopathies)

Periodic paralysis may have a familial (dominant inheritance) basis.

Episodes of flaccid weakness or paralysis, sometimes in association
with abnormalities of the plasma potassium level.

Strength is normal between attacks.

Hypokalemic periodic paralysis characterized by attacks that tend to
occur on awakening, after exercise, or after a heavy meal and may
last for several days. Patients should avoid excessive exertion.

Hyperkalemic periodic paralysis

Normokalemic periodic paralysis
Chanalopathies
Treatment of Hypokalemic PP

A low carbohydrate and low-salt diet may help prevent
attacks, as may acetazolamide, 250–750 mg

An ongoing attack may be aborted by potassium chloride
given orally or by intravenous drip, provided the ECG can
be monitored and kidney function is satisfactory.

In young Asian men, it is commonly associated with
hyperthyroidism.

Treatment of the endocrine disorder prevents recurrences.