MYASTHENIA GRAVIS MYASTHENIA GRAVIS

Ø Myasthenia gravis is the most important disease affecting the neuromuscular junction .

Ø Main features of M.G is fluctuating weakness of certain voluntary muscles particularly those innervated by motor nuclei of brainstem.

Ø Continuous activity leads to weakness & rest quickly restores the power.

Ø M.G is also characterized by dramatic improvement in muscle strength following the administration of anticholinesterase drugs.

HISTORY

Ø Jolly was the first to use the name myasthenia gravis. It was he who demonstrated that myasthenia weakness could be reproduced by repeated faradic stimulation of the relevant motor nerve & that the fatigued muscle would still respond to galvanic stimulation(jolly’s test).

Ø The therapeutic use of physostigimins was demonstrated by Reman in1932.

Ø The relationship between myasthenia gravis& tumors of the thymus gland was first noted by Laquer & weigert in1901.

Ø In 1960 simpson theorized that an autoimmune mechanism must be operative in myasthenia gravis.

Etiology & Pathogenesis

Ø The basic defect in myasthenia gravis is a marked reduction in the number of ACH receptors on the post synaptic membrane .

Ø Myasthenia gravis is autoantibody mediated disorder

Ø Myasthenia weakness and fatigue are due to the failure of the effective neuromuscular transmission.

Clinical manifestations

Ø Onset is usually insidious.

Ø Weakness may begin months/years after removal of thymoma.

Ø Thymic abnormalities are closely connected with the disease.

Ø Weakness of levator palpebrae / extra ocular muscles is the initial manifestations of the disease in about half the cases and these muscles are involved eventually in more than 90% cases.

Ø Optokinetic stimulus will cause progressive paresis of the extraocular muscles.

Ø Attempts to overcome the ptosis may be seen without opthalmoplegia in myasthenia gravis.

Ø In about 80%cases muscles of facial expression mastication, swallowing and speech are frequently affected.

Ø Flexors and extensors of the neck, muscles of the shoulder girdles and flexors of the hips are the other muscles which can be involved .even erectorspinae muscles are most affected.

Ø In most advanced cases all muscles are weakened, including the diaphragm,abdominal and intercostal muscles,even the external sphincter of the bladder and bowel.

Clinically myasthenia gravis is most accurately conceived as a fluctuating oculofaciobulbarpalsy.

In general proximal muscles are more effected than distal.

Drooping the eyelids &intermittent diplopia are the most important complaints.

Facial mobility &expression are altered. As a result natural smile becomes snarl, jaws may hang, chewing tough food becomes difficult. More difficult to eat after talking, voice fades & becomes nasal after sustained conversation.

Overhead activities become difficult. Women may complain of inability to fix their hair or difficulty in applying lipstick because of inability to purse and roll the lips.

Weakness neck muscles causes fati gue in holding up the head.

PHYSIOTHERAPY MANAGEMENT of MYASTHENIA GRAVIS

PHYSIOTHERAPY MANAGEMENT

Goals of Management

Avoid exhaustion or minimize fatigability.

• Let gravity assist the movement.

• Use adapted equipments or methods to conserve energy.

• Use powered tools and utensils.

• Use biochemical principles of (a)levers(b)application of force (c) friction

Conservation of energy by work simplification or modification of job.

• Energy conservation methods.

• Plan ahead, organize work.

• Eliminate unnecessary task.

• Have all required equipment ready before starting work.

• Combine task to eliminate extra work.

• Rest before fatigue.

Retraining basic activities of daily living.

Improving functional quality of the patient.

Maintaining general condition in later stages.