SCA3 (Machado-Joseph disease) most common in Chinese. Average onset in China is 34 yo. Gene mutation results in the production of abnormal proteins causing cell degeneration in hindbrain.

Clinical presentation: gaze-evoked nystagmus, slow saccades, upper motor neuron signs, spasticity, difficulty with speech and swallowing, muscle weakness, ataxia, frequent urination, rigidity, memory deficits

Intellectual functions usually remain the same

Characterised by anticipation: increasing severity of disease from generation to generation in a family 

Visual field defect Seizures 

•No usual hobbies, lately difficulty with walking even for short distance (e.g. go down for dim sum)

•Major complaints:

– “eye strain” when reading newspaper, sometimes with double vision

– Weaknesses in all limbs

– Tired easily

•Had a chest infection few weeks prior to development of muscle weakness, otherwise healthy

all ethnic groups and both genders. It most commonly affects young adult women (under 40) and older men (over 60), but it can occur at any age

In myasthenia gravis, antibodies block, alter, or destroy the receptors for acetylcholine at the neuromuscular junction, which prevents the muscle contraction from occurring.

trouble talking.
problems walking up stairs or lifting objects.
facial paralysis.
difficulty breathing because of muscle weakness.
difficulty swallowing or chewing.
fatigue.
hoarse voice.
drooping of eyelids.

Eye strain

special blood test can detect the presence of immune molecules or acetylcholine receptor antibodies.

edrophonium test uses intravenous administration of edrophonium chloride to very briefly relieve weakness in people with myasthenia gravis. The drug blocks the degradation (breakdown) of acetylcholine and temporarily increases the levels of acetylcholine at the neuromuscular junction

nerve conduction study may demonstrate gradual decreases of the muscle action potential due to impaired nerve-to-muscle transmission.

electromyography (EMG) can also detect impaired nerve-to-muscle transmission. EMG measures the electrical potential of muscle cells when single muscle fibers are stimulated by electrical impulses. Muscle fibers in myasthenia gravis, as well as other neuromuscular disorders, do not respond as well to repeated electrical stimulation compared to muscles from normal individuals.

computed tomography (CT) or magnetic resonance imaging (MRI), may be used to identify the presence of a thymoma.

Pharmacological

anticholinesterase agents such as neostigmine and pyridostigmine

Immunosuppressive drugs such as prednisone, azathioprine, cyclosporin, mycophenolate mofetil, and tacrolimus may also be used

Thymectomyi

most individuals with myasthenia can significantly improve their muscle weakness and lead normal or nearly normal lives. Some cases of myasthenia gravis may go into remission—either temporarily or permanently—and muscle weakness may disappear completely so that medications can be discontinued. Stable, long-lasting complete remissions are t

Non pharmacological

Doing exercise during daytime as it may be the best time to do the exercise ( not fatigue)

Mild intensity 

General aerobic exercise is also valuable

At first paitents develop symptoms of extraocular muscle weakness with asymmetric ptosis and diplopia

Then proress to bulbar and limb muscles within the first three years

prognosis

Initial presentations with oropharyngeal and limb weakness are less common, but maximum disease severity is reached within the first year

Early in the course of MG, symptoms may fluctuate and occasionally remit, 

Part 5 of 7
Treatment Options for Myasthenia Gravis
Treatment
There is no cure for MG. The goal of treatment is to manage symptoms and control the activity of your immune system.

Medication

Corticosteroids and immunosuppressants can be used to suppress the immune system. These medications help minimize the abnormal immune response that occurs in MG.

Additionally, cholinesterase inhibitors, such as pyridostigmine (Mestinon), can be used to increase communication between nerves and muscles.

Thymus Gland Removal

Removal of the thymus gland, which is part of the immune system, may be appropriate for many patients with MG. Once the thymus is removed, patients typically show less muscle weakness.

According to the Myasthenia Gravis Foundation of America, between 10 and 15 percent of people with MG will have a tumor in their thymus. Tumors, even those that are benign, are always removed because they may become cancerous.

Plasma Exchange

Plasmapheresis is also known as a plasma exchange. This process removes harmful antibodies from the blood, which may result in an improvement in muscle strength.

Plasmapheresis is a short-term treatment. The body continues to produce the harmful antibodies and weakness may recur. Plasma exchange is helpful before surgery or during times of extreme MG weakness.

Intravenous Immune Globulin  

Intravenous immune globulin (IVIG) is blood product that comes from donors. It’s used to treat autoimmune MG. Although it’s not entirely known how IVIG works, it affects the creation and function of antibodies.

Lifestyle Changes

There are some things you can do at home to help alleviate symptoms of MG:

Get plenty of rest to help minimize muscle weakness.
If you’re bothered by double vision, talk to your doctor about whether you should wear an eye patch.
Avoid stress and heat exposure, as both can worsen symptoms.
These treatments cannot cure MG. However, you’ll typically see improvements in your symptoms. Some individuals may go into remission, during which treatment is not necessary.

Tell your doctor about any medications or supplements you take. Some drugs can make MG symptoms worse. Before taking any new medication, check with your doctor to ensure it’s safe.