myasthenia gravis

myasthenia gravis and management

1. MYASTHENIA GRAVIS
ASHWINI SOMAYAJI
1
ST
M.PHARMA
PHARMACOLOGY

2. INTRODUCTION
Myasthenia gravis is an autoimmune disorder
affecting the myoneural junction, is characterized by
varying degrees of weakness of the voluntary
muscles.
Causes problems with the nerves that communicate
with muscles.
Affects the voluntary muscles of the body, especially
the eyes, mouth, throat, and limbs.

3. Characterized by weakness and rapid fatigue of any
of the muscles under the voluntary control.
The cause of myasthenia gravis is a breakdown in
the normal communication between nerves and
muscles.
No cure for myasthenia gravis, but treatment can
help relieve signs and symptoms – such as
weakness of arm or leg muscles, double vision,
drooping eyelids, and difficulties with speech,
chewing, swallowing and breathing.
While myasthenia gravis can affect people of any
age from neonatal to above 60 and more common in
women younger than 40 and in men older than 60.

5. TYPES OF MYASTHENIA GRAVIS
Three types of MG in children:
Congenital MG - Very rare non-immune form of MG that is
inherited as an autosomal recessive disease. This means that
both males and females are equally affected and that two
copies of the gene, one inherited from each parent, are
necessary to have the condition. Symptoms of congenital MG
usually begin in the baby's first year and are life-long.
Transient neonatal MG - Between 10 and 20 percent of babies
born to mothers with MG may have a temporary form of MG.
This occurs when antibodies common in MG cross the
placenta to the developing fetus. Neonatal MG usually lasts
only a few weeks, and babies are not at greater risk for
developing MG later in life.
Juvenile MG - This auto-immune disorder develops typically in
female adolescents - especially Caucasian females. It is a life-
long condition that may go in and out of remission. About 10
percent of MG cases are juvenile-onset.

6. SYMPTOMS
Babies with neonatal MG may be weak, with a poor suck, and
may have respiratory difficulty. A few babies may need the
help of a mechanical breathing machine if their respiratory
muscles are too weak to breathe on their own. Symptoms go
away as the maternal antibodies disappear over time.
Congenital MG symptoms may begin in the first year, with
generalized weakness in the arms and legs, and delays in
motor skills such as crawling, sitting, and walking. Babies may
have difficulty feeding and may have weak eyelids and poor
head control.
Juvenile MG symptoms may begin gradually over weeks or
months. The child may become excessively tired after very
little activity, and begin to have problems chewing and
swallowing. Drooping eyelids may be so severe that the child
cannot see.

9. EYE MUSCLES
In more than half the people who develop MG, their
first signs and symptoms involve eye problems:
Drooping of one or both eyelids (ptosis)
Double vision (diplopia), which may be horizontal or
vertical
Blurred vision, which may come and go

10. FACE AND THROAT MUSCLES
In about 15 percent of people with myasthenia gravis, the first
symptoms involve face and throat muscles, which can cause
difficulties with:
Speaking. The speech may be very
soft or sound nasal, depending upon
which muscles have been affected.
Swallowing. May choke very easily,
which makes it difficult to eat, drink
or take pills. In some cases, liquids may
come out of the nose.

11. Chewing. The muscles
used for chewing may
wear out halfway through
a meal, particularly if
eating something hard to
chew, such as sugarcane.
Facial expressions.
Family members may
note "lost smile" if the
muscles that control
facial expressions are
affected.

12. ARM AND LEG MUSCLES
Myasthenia gravis can cause weakness in arms and
legs, but this usually happens in conjunction with
muscle weakness in other parts of the body – such
as eyes,face or throat.
Normal dumbbell
Weakness dumbbell

13. The disorder usually
affects arms more often
than legs.
If it affects legs, may
waddle when walking.

14. WHEN TO SEE A DOCTOR
If having trouble with:
Breathing
Seeing
Swallowing
Chewing
Walking

15. CAUSES
•In MG, the receptors at the muscle surface
are destroyed or deformed by antibodies that
prevent a normal muscular reaction from
occurring.
•The causative factor is unknown, but the
disorder may have a genetic link.
Risk factors for myasthenia gravis include:
•Female gender and age under 40 years
•Male gender and age over 60 years
•Other autoimmune disorders

16. Myasthenia gravis may be inherited as a rare,
genetic disease, acquired by babies born to mothers
with MG, or the disorder may develop spontaneously
later in childhood.
Nerves communicate with the muscles by releasing
chemicals, called neurotransmitters, which fit
precisely into receptor sites on the muscle cells.
In myasthenia gravis, immune system produces
antibodies that block or destroy many of the muscles'
receptor sites for a neurotransmitter called
acetylcholine.
With fewer receptor sites available, muscles receive
fewer nerve signals, resulting in weakness.

17. Chemicals messengers, called neurotransmitters, fit
precisely into receptor sites on your muscle cells. In
myasthenia gravis, certain receptor sites are blocked
or destroyed, causing muscle weakness.

18. It's believed that the thymus gland, a part of the
immune system located in the upper chest beneath
the breastbone, may trigger or maintain the
production of these antibodies.
Large in infancy, the thymus is small in healthy
adults. But, in some adults with myasthenia gravis,
the thymus is abnormally large.
Some people also have tumors of the thymus.
Usually, thymus gland tumors are noncancerous.

19. Thymus gland, a part of your immune system located
in the upper chest beneath the breastbone, may
trigger or maintain the production of antibodies that
result in the muscle weakness common in MG.

20. FACTORS WORSENING MG
Fatigue
Illness
Stress
Extreme heat
Medications – such as beta blockers, calcium
channel blockers, quinine and some antibiotics

21. COMPLICATIONS
Myasthenic crisis:
A life-threatening condition, which occurs when the
muscles that control breathing become too weak to
do their jobs. Emergency treatment is needed to
provide mechanical assistance with breathing.
Medications and blood-filtering therapies help people
recover from myasthenic crisis, so they can again
breathe on their own.
Thymus tumors:
About 15 percent of the people who have myasthenia
gravis have a tumor in their thymus, a gland under
the breastbone that is involved with the immune
system. Most of these tumors are noncancerous.

23. OTHER DISORDERS
Underactive or overactive thyroid. The thyroid gland,
located in the neck, secretes hormones that regulate
metabolism. If thyroid is underactive, body uses
energy more slowly. An overactive thyroid makes
body use energy too quickly.
Lupus. Disease of immune system. Common
symptoms include painful or swollen joints, hair loss,
extreme fatigue and a red rash on the face.
Rheumatoid arthritis. Caused by problems with
immune system. It is most conspicuous in the wrists
and fingers, and can result in joint deformities that
make it difficult to use hands.

24. TESTS AND DIAGNOSIS
Diagnosis is made after the sudden or gradual onset
of specific symptoms and after diagnostic testing.
It is confirmed with a Tensilon test. With this test, a
small amount of medicine (Tensilon) is injected into
the child, if the child has MG, an immediate, but brief,
increase in muscle tone is noted.

25. OTHER DIAGNOSTIC TESTS
Blood tests
Genetic tests - diagnostic tests that evaluate for
conditions that have a tendency to run in families.
Electromyogram (EMG) - a test that measures the
electrical activity of a muscle or a group of muscles.
An EMG can detect abnormal electrical muscle
activity due to diseases and neuromuscular
conditions.
Muscle biopsy - a small sample of the muscle is
removed and examined to determine and confirm a
diagnosis or condition.

26. Reflexes
Muscle strength
Muscle tone
Senses of touch and sight
Coordination
Balance

27. Edrophonium test: Injection of the chemical
edrophonium (Tensilon) may result in a sudden,
although temporary, improvement in muscle strength
— an indication that you may have myasthenia
gravis. Edrophonium acts to block an enzyme that
breaks down acetylcholine, the chemical that
transmits signals from nerve endings to muscle
receptor sites.
Blood analysis: A blood test may reveal the presence
of abnormal antibodies that disrupt the receptor sites
where nerve impulses signal muscles to move.

28. Repetitive nerve stimulation: Is a type of nerve
conduction study, in which electrodes are attached to
skin over the muscles to be tested. Small pulses of
electricity are sent through the electrodes to measure
the nerve's ability to send a signal to muscle. To
diagnose MG, the nerve will be tested many times to
see if its ability to send signals worsens with fatigue.
Single-fiber electromyography (EMG): EMG
measures the electrical activity traveling between
brain and muscle. It involves inserting a very fine
wire electrode through skin and into a muscle. In
single-fiber EMGs, a single muscle fiber is tested.
Imaging scans: CT scan or an MRI to confirm a tumor
or other abnormality in thymus.

29. CT CHEST
Thymom
a
Single-fiber EMG

30. PATHOPHYSIOLOGY

33. TREATMENTS & DRUGS
Specific treatment to age, overall health, and medical
history and extent of the condition
No cure for MG, but the symptoms can be controlled.
MG is a life-long medical condition and the key to
medically managing MG is early detection.
The goal of treatment is to prevent respiratory
problems and provide adequate nutritional care to
the child since the swallowing and breathing muscles
are affected by this condition.

34. MEDICATIONS
Cholinesterase inhibitors. Drugs like pyridostigmine
(Mestinon) enhance communication between nerves
and muscles. These drugs don't cure, but improves
muscle contraction and strength.
Long acting anti-cholinesterases
pyridostigmine bromide
neostigmine bromide

35. •Reversible inhibition of anticholinesterase
by carboxylation of hydroxyl group of serine
bound in the active centre of ACHE.

37. Corticosteroids. These types of drugs inhibit the
immune system, limiting antibody production. Prolonged
use of corticosteroids, can lead to serious side effects, like
bone thinning, weight gain, diabetes, increased risk of
some infections, and increase and redistribution of body
fat.
Immunosuppressants. Doctor may also prescribe other
medications that alter immune system, like azathioprine
(Imuran), cyclosporine (Sandimmune, Neoral) or
mycophenolate (CellCept).

39. THERAPY
Plasmapheresis.
This procedure uses a filtering process similar to dialysis.
Blood is routed through a machine that removes the
antibodies that are blocking transmission of signals from
nerve endings to muscles' receptor sites. However, the
beneficial effects usually last only a few weeks.

40. Intravenous immune globulin.
This therapy provides body with normal antibodies,
which alters immune system response. It has a lower
risk of side effects than do plasmapheresis and
immune-suppressing therapy, but it can take a week or
two to start working and the benefits usually last less
than a month or two.

42. SURGERY
Thymectomy –
surgical removal of the thymus gland. The role of the
thymus gland in MG is not fully understood, and the
thymectomy may or may not improve a child's
symptoms.

43. In severe cases, a breathing machine may be
required to help the child breathe easier.
The healthcare team educates the family after
hospitalization on how to best care for their child at
home and outlines specific clinical problems that
require immediate medical attention by their
physician.
A child with MG requires frequent medical
evaluations throughout his/her life.
It is important to allow the child as much independent
function and self care, especially with juvenile MG,
as possible and to promote age-appropriate activities
to ensure a sense of normalcy.

44. About 15 percent of the people who have MG have a
tumor in their thymus, a gland under the breastbone
that is involved with the immune system, thymus will
be removed.
For people with MG who don't have a tumor in the
thymus, it's unclear whether the potential benefit of
removing the thymus outweighs the risks of surgery.
This is an individualized decision between patient
and the doctor, but most doctors don't recommend
surgery if:
Symptoms are mild
Symptoms involve only the eyes
Patients over 60 years old

45. MYASTHENIA GRAVIS THROUGH
YOGA
Yoga Exercises
Help to stretch the body which increase the flexibility as
well as strengthen the muscles of the body, which become
weak due to MG.
Improve blood circulation and remove carbondioxide from
the body & provide oxygenated blood to every part of the
body.

46. NUTRITION
Simple, nourishing, no stimulating foods, including plenty
of fresh fruits & lightly cooked vegetable, particularly
greens.
Asparagus is considered excellent since it contains certain
natural steroid-like nutritious elements, which help
strengthen the weakened muscles caused by MG.
Whole meal grains, sprouts & pulses in places eggs and
meats.
Food should have a blend of all necessary vitamins.

48. REFERENCES
•McGrogan A, Sneddon S, de Vries CS (2010). "The
incidence of myasthenia gravis: a systematic literature
review". Neuroepidemiology 34 (3): 171–183
•Engel AG (3 April 2012). Myasthenia Gravis and
Myasthenic Disorders (2nd ed.). Oxford University
Press, USA. pp. 109–110
•Sathasivam, Sivakumar (January 1, 2014). "Diagnosis
and management of myasthenia gravis". Progress in
Neurology and Psychiatry 18 (1): 6–14.
•Tripathi K D .Essentials of Medical Pharmacology
.Fifth edition;186-88
•Internet sources