Autoimmune diseases (I)

Introduction

Thyroiditis: Graves disease, Hashimotos thyroiditis

Myasthenia gravis Myasthenia gravis

Rheumatoid arthritis

Introduction

The immune system functions to protect the

host from invasion by foreign organism

However, this protective response can cause

damage to the host of it is directed against damage to the host of it is directed against

the individuals own antigen.

These antigens are often referred as self-

antigens, or autoantigens.

The immune system has developed a series of

checks and balances that enable it to

distinguish between dangerous and harmless

signals.

Therefore, it allow it to respond to foreign

antigens but not self antigens. antigens but not self antigens.

Self-responsiveness: a state of

unresponsiveness to self-antigen.

Autoimmune diseases occurred as a result of

loss of self-tolerance.

Thyroiditis: Graves disease

What is Graves disease?

- It is named for Robert Graves, an Irish physician, who was the first to describe this physician, who was the first to describe this form of hyperthyroidism about 150 years ago.

- Graves disease is an autoimmune disease that affects the thyroid.

- The thyroid is a small gland in the front of the neck.

- It makes hormones called T3 and T4 that

regulate how the body uses energy

- The thyroid is a small gland in the front of

the neck.

- It makes hormones called T3 and T4 that

regulate how the body uses energy.regulate how the body uses energy.

- With Graves disease, the immune system

makes antibodies that cause the thyroid to

make more thyroid hormone than your

body needs.

- Hence, Graves disease is a type of

hyperthyroidism.

- An overactive thyroid causes every function

of the body to speed up, such as heart rate

and the rate your body turns food into

energy. energy.

What causes Graves disease?

- Many factors are thought to play a role in

getting Graves disease. These might include:

i. Genesi. Genes

Many people inherit an immune system

that can cause problems. In Graves

disease, antibodies bind to the surface of

thyroid cells and stimulate those cells to

overproducce thyroid hormones.

ii. Gender

Sex hormones might play a role, and

might explain why Graves disease affects

more women than men.

iii. Stressiii. Stress

Severe emotional stress or trauma might

trigger the onset of Graves disease in

people who are prone to getting it.

iv. Pregnancy

Pregnancy affects the thyroid. As many as 30 percent of young women who get Graves disease have been pregnant in the 12 months prior to the onset of symptoms. This suggests that pregnancy might trigger Graves disease in some women..Graves disease in some women..

iii. Infection

Infection might play a role in the onset of Graves disease, but no studies have shown infection to directly cause Graves disease.

What are the symptoms of Graves

disease?

- Most people with Graves disease have

symptoms of an overactive thyroid, such as:symptoms of an overactive thyroid, such as:

a) Goiter (enlarged thyroid)

b) Trouble sleeping

c) Irritability or nervousness

d) Heat sensitivity, increased sweating

e) Hand tremors

f) Rapid heartbeat

g) Frequent bowel movements

h) Weight loss without dieting

i) Fatigue or muscle weaknessi) Fatigue or muscle weakness

j) Lighter menstrual flow and less

frequent periods

- Unlike other causes of an overactive thyroid,

Graves disease also can cause:

Eye changes.

For some people with Graves disease, the

tissue behind the eyes becomes inflamed tissue behind the eyes becomes inflamed

and swells. This can cause bulging or

discomfort in one or both eyes. Sometimes

it affects vision.

Reddening and thickening of the skin, often

on the shins and tops of the feet.

(pretibial myxedema)

This rare skin problem is not serious and is

usually painless. Most people with this skin

problem also have eye problems from

Graves disease.

How to diagnose Graves disease?

- Symptoms of Graves as mentioned above (bothersome).

- Laboratory tests:

a) Thyroid function testsa) Thyroid function tests

- Determine the right amount of thyroid hormone (T4) and TSH.

- A high level of thyroid hormone in the blood plus a low level of TSH is a sign of overactive thyroid.

b) Radioactive iodine uptake (RAIU)

- An RAIU tells how much iodine the

thyroid takes up.

- A high uptake suggests Graves disease

(thyroid uses it to make thyroid

hormone)hormone)

c) Antibody tests

- Look for antibodies that suggest Graves

disease.

Treatment

- There are 3 main treatments for Graves'

disease :

a) Antithyroid medicine

Methimazole

Propylthiouracil

b) RAI (Radioactive Iodine)

- With this treatment, you swallow a pill

that contains RAI, which is a form of

iodine that damages the thyroid by

giving it radiation.

- The RAI destroys thyroid cells so that - The RAI destroys thyroid cells so that

less thyroid hormone is made

c) Surgery

- Most or all the thyroid is removed.

Thyroiditis: Hashimotos thyroiditis

What is Hashimotos thyroiditis?

- Hashimotos thyroiditis is characterized by

the production of immune cells and

autoantibodies, which can damage thyroid

cells and compromise their ability to make

thyroid hormone.

- Hypothyroidism occurs as a result of

insufficient thyroid hormone produced,

which is not enough for the bodys needs

- The thyroid gland may also enlarge in some

patients, forming a goiter.

What is the cause of Hashimotos

thyroiditis?

- The immune system recognizes normal

thyroid cells as foreign tissue, and it thyroid cells as foreign tissue, and it

produces antibodies that may destroy these

cells.

What are the symptoms of Hashimotos thyroiditis?

- The first sign of this disease maybe painless swelling in the lower front of the neck.

- This enlargement may eventually become easily - This enlargement may eventually become easily visible and maybe associated with an uncomfortable pressure sensation in the lower neck.

- Left untreated, a person may begin to have trouble swallowing or even breathing

- Other symptoms include:

a) Sore muscles

b) Weight gain

c) Fatiguec) Fatigue

d) Drowsiness

e) Forgetfulness

f) Puffy face

g) Constipation

How is Hashimotos thyroiditis

diagnosed?

- Performing a physical examination and can

recognize hypothyroidism by identifying recognize hypothyroidism by identifying

characteristic symptoms,finding typical

physical signs.

- Doing appropriate laboratory tests:

a) ANTITHYROID ANTIBODIES

- Increased antithyroid antibodies provide the most specific laboratory evidence of Hashimotos thyroiditis. (but no all cases).cases).

b) TSH (THYROID-STIMULATING HORMONE OR THYROTROPIN) TEST

- Increased TSH level in the blood is the most accurate indicator of hypothyroidism

c) OTHER TEST

- Free T4 (thyroxine)

A low level of free T4 is consistent with

thyroiD hormone deficiency.

- Fine-needle aspiration of the thyroid

A good way to diagnose difficult cases

and a necessary procedure if a thyroid

nodule is also present. (not necessary

for all patients)

How is Hashimotos thyroiditis treated?

Thyroid hormone therapy.

-Treatment consists of taking a single daily

tablet of levothyroxine.tablet of levothyroxine.

-Thyroid hormone acts very slowly in the

body, so it may take several months after

treatment is started to notice improvement

in symptoms or goiter shrinkage.

Myasthenia grevis

What is Myasthenia grevis (MG)?

- MG is an autoimmune disease that

weakens the muscles.

- This muscle weakness usually occurs during

periods of activity and improves after

periods of rest.

- MG is not contagious, or fatal, and does not

affect life expectancy.

- MG is not passed down through the family.

- A group of rare disorders called congenital

myasthenic syndromes (CMS) can produce

symptoms similar to MG. symptoms similar to MG.

- Unlike MG, these disorders are not autoim-

mune disorders but are caused by defec-

tive genes.

What is the cause MG?

- MG occurs when normal communication

between nerves and muscles is interrupted

at the neuromuscular junction.

- The interruption is due to antibodies that

prevent acetylcholine from reaching the

muscles by destroying or blocking the

receptors.

What are the symptoms of MG?

- MG can affect any muscle, but the muscles

that control eye and eyelid movement,

facial expression, and swallowing are most

often affected. often affected.

- In some people, the first symptom is

weakness of the eye muscles.

- Other symptoms include:

a) Drooping of one or both eyelids

b) Blurred or double vision

c) Problems walking

d) Weakness in arms, hands, fingers, legs, and neckneck

e) Change in facial expression

f) Having a hard time swallowing

g) Trouble talking

h) Shortness of breath

(feeling like you cant get enough air)

How is MG diagnosed?

- MG is hard to diagnose because weakness is

a common symptom of many disorders.

- Performing some laboratory tests:- Performing some laboratory tests:

a) Antibody blood tests

- Most people with MG have abnormally

high levels of acetylcholine receptor

antibodies.

b) Edrophonium test b) Edrophonium test

- When this drug is injected into someone

with MG, his or her normally weak eye

muscles will get stronger for a few

minutes.

c) Nerve conduction test/repetitive stimulation

- With this test, a nerve linked with a specific muscle is stimulated to see if the muscle action is weakened.

d) Single fiber electromyography (EMG)d) Single fiber electromyography (EMG)

- In this test, single muscle fibers are stimulated by electrical impulses.

- Muscle fibers of people with MG do not respond to repeated electrical stimulation as well as muscles that function normally

e) Computed tomography (CT) or magnetic

resonance imaging (MRI)

- This test can show if you have an

abnormal thymus gland or a thymus

gland tumor.gland tumor.

How is MG treated?

Treatment for MG may include:

a) Medications

Cholinesterase inhibitors: pyridostigmine

- These drugs help improve nerve signals to - These drugs help improve nerve signals to muscles and increase muscle strength.

Immunosuppressive drugs

- Frequently used to suppress the production of abnormal antibodies

b) Thymectomy

- This is the surgical removal of the thymus

gland, which is abnormal in most persons

with MG.

c) Plasmapheresis (Acute Weakness)c) Plasmapheresis (Acute Weakness)

- This procedure removes abnormal

antibodies from the blood.

- This provides relief from MG symptoms in

many patients for a few weeks

b) High-dose intravenous immuneglobulin

(Acute Weakness)

- This treatment keeps the immune system

from damaging the nerve-muscle

junction for a short time. junction for a short time.

- This provides relief from MG symptoms in

many patients for weeks to months

Rheumatoid Athritis

What is Rheumatoid Athritis (RA)?

- RA is an inflammatory disease affecting

about 2.1 million people.

- It causes pain, swelling, stiffness, and loss

of function in the joints.

- Several features make it different from other kinds of arthritis

Eg: Generally occurring in a symmetrical pattern.

- The disease often affects the wrist joints and the finger joints closest to the hand.

- It can also affect other parts of the body

besides the joints.

- Like some other forms of arthritis, RA occurs much more frequently in women than in men.

What is the cause RA?

- In RA, white blood cells move into the synovium and release protein.

- Protein released in the synovium cause it to become think and cause damage to the become think and cause damage to the bone, ligaments, and cartilage of the joint.

- This happens over months and years.

- The joint then first loses its correct alignment and its function.

What are the symptoms of RA?

- Symptoms first begin in the small joints of the fingers, wrists and feet.

- Often accompanied with warm, swollen and tender joints that are painful and difficult to tender joints that are painful and difficult to move.

- Joints of both sides of the body (symmetrical) are typically affected.

- People with RA often experience fatigue, loss of appetite and low-grade fever.

- Nodules may form under the skin, often

over the bony areas exposed to pressure

(such as the elbows)

- Over time, damage to the cartilage and bone

of the joints may lead to joint deformities.

How is RA diagnosed?

- A diagnosis of rheumatoid arthritis can

generally be made following a thorough

medical history. (Children of parents who have

RA are more likely to have it)RA are more likely to have it)

- Physical examination, looking for:

i. Distribution of joints affected

ii. Joint swelling,warmth and range of motion

iii. Presence of nodules under the skin :

- Imaging studies used to detect the degree of

joint involvement or joint damage:

i. X-rays

ii. Sonograms

iii. Magnetic Resonance Imaging (MRI)

- A blood test can indicate the presence of an

antibody called rheumatoid factor, which is

found in 80 percent of people with RA.

How is RA treated?

- Currently, there is no cure for RA.

- The goals of treatment of RA are to reduce joint pain and swelling, relieve stiffness and prevent joint damage.prevent joint damage.

- Treatment plans often include a combination of rest, physical activity, joint protection, use of heat or cold to reduce pain, and physical or occupational therapy.

- Many people with RA take nonsteroidal

anti-inflammatory drugs (NSAIDs) to help

reduce joint pain, stiffness and swelling.

- Low doses of corticosteroids such as

prednisone may also be used to relieve

joint pain, stiffness and swelling and to joint pain, stiffness and swelling and to

reduce the risk of joint swelling.