myasthenia gravis

Limb muscle weakness

When myasthenia gravis becomes generalized, the weakness can reach the arms and legs, not just the eyes. Limb weakness tends to fluctuate like the rest of the disease.

Dysarthria

Dysarthria means slurred or unclear speech, which can happen when the muscles used for speaking weaken in MG.

Abnormal thymus morphology

The thymus gland is often abnormal in MG. These thymus changes, including tumors called thymomas, are more common in generalized MG.

Dyspnea

Dyspnea means shortness of breath. In MG it can occur when the breathing muscles weaken.

Respiratory failure

In its most severe form, called myasthenic crisis, the breathing muscles can fail and a person may need a ventilator. This is a medical emergency.

Thymoma

Some people with MG have a tumor of the thymus gland called a thymoma, and the thymus is often abnormal in MG.

Ptosis

Ptosis means drooping of one or both eyelids. It is one of the most common early signs of MG.

Diplopia

Diplopia means double vision, from weakness of the eye muscles. It is a frequent early symptom of MG.

Anti-neuromuscular Junction acetylcholine receptor antibody positivity

Most people with myasthenia gravis have antibodies against the acetylcholine receptor (AChR), the protein that lets nerves signal muscle to contract. A blood test for these antibodies helps confirm the diagnosis and is positive in the large majority of generalized cases.

Anti-muscle-specific tyrosine kinase antibody

A minority of people with myasthenia gravis instead carry antibodies against muscle-specific kinase (MuSK), another protein at the nerve-muscle junction. Testing for MuSK antibodies helps identify this subtype, which can respond differently to treatment.

Anti-Lrp4 antibody positivity

Some people with MG carry antibodies against a protein called LRP4. This is one of the less common antibody types found in MG.

Dysphagia

Dysphagia means difficulty swallowing. In MG it is common and can raise the risk of food or liquid going into the lungs.

Muscle weakness

Muscle weakness is the core feature of MG. It typically fluctuates, often worsening with activity and improving with rest.

Fatigable weakness of skeletal muscles

The hallmark of myasthenia gravis is fatigable weakness: skeletal and eye muscles grow weaker the more they are used and recover with rest. This is why symptoms are often mildest in the morning and worse after activity.

Single fiber EMG abnormality

Specialized nerve-and-muscle electrical tests, especially single-fiber EMG, are used to confirm MG and tell it apart from similar conditions.

Weakness of facial musculature

Weakness of the facial muscles can flatten expression and weaken eyelid closure. It is part of the muscle weakness pattern seen in myasthenia gravis.

Myasthenia gravis

Diagnosed using: Repetitive nerve stimulation.

Pyridostigmine

Pyridostigmine is a medicine that relieves MG symptoms. In this patient it rapidly improved drooping eyelids, speech, and swallowing.

Used to help with: Ptosis.

Zilucoplan

Zilucoplan is a newer targeted medicine for MG. It blocks part of the immune system called complement; in this patient it led to rapid improvement.

Used to help with: Myasthenia gravis.

Thymectomy

Thymectomy is surgery to remove the thymus gland. It is one of the established treatments for MG and is used to help improve long-term outcomes.

Used to help with: Myasthenia gravis.

Plasma exchange

Plasma exchange (plasmapheresis) is a procedure used for severe MG. In this patient it was part of the treatment that led to resolution of symptoms.

Used to help with: Myasthenia gravis.

Intravenous immunoglobulin (IVIG)

Intravenous immunoglobulin (IVIG) is an infusion used for severe MG. In this patient it was part of the treatment that led to resolution of symptoms.

Used to help with: Myasthenia gravis.

Corticosteroids

Corticosteroids are one of the standard immune-suppressing treatments used in myasthenia gravis.

Used to help with: Myasthenia gravis.

Azathioprine

Azathioprine is a steroid-sparing immunosuppressant used as one of the standard treatments for myasthenia gravis.

Used to help with: Myasthenia gravis.

Acetylcholinesterase inhibitors

Acetylcholinesterase inhibitors are a class of symptomatic treatment that forms part of the multimodal management of myasthenia gravis.

Used to help with: Myasthenia gravis.

Mycophenolate mofetil

Mycophenolate mofetil is a steroid-sparing immunosuppressant used as one of the standard treatments for myasthenia gravis.

Used to help with: Myasthenia gravis.