When myasthenia gravis affects only the muscles that move the eyes and control the eyelids, it’s called ocular myasthenia gravis. When muscles beyond the eyes are involved, it’s called generalized myasthenia gravis. The muscle weakness associated with myasthenia gravis worsens during periods of activity and improves after resting, per Mayo Clinic. For instance, drooping eyelids or double vision may get worse after reading for a long period and get better after rest, and many symptoms, such as neck weakness or problems with speech, tend to be worse at the end of the day, according to Conquer Myasthenia Gravis. The disease can vary greatly from one person to another — both in the severity of muscle weakness and in the particular muscles that are affected. The onset of the disease is usually gradual over weeks or months, but myasthenia gravis can also arise suddenly. Symptoms tend to get worse over time, usually reaching their worst within a few years after the onset of the disease, says the Muscular Dystrophy Association. While there is no cure for myasthenia gravis, symptoms can be managed with treatment. Because muscle weakness and other common symptoms of myasthenia gravis are common in other conditions, the disease can be hard to diagnose, according to MedlinePlus. In fact, the condition is often missed or delayed for as long as two years in people who experience mild weakness or weakness in a few muscles, per the National Institutes of Neurological Disorders and Stroke. The most common early signs of myasthenia gravis include:
Drooping of one or both eyelids (called ptosis)Blurred or double visionSlurred speechDifficulty chewing and swallowingChanges in facial expression (such as difficulty smiling)
In some cases, the muscles that control breathing and neck and limb movements may also be affected. This can lead to:
Weakness in the arms, hands, fingers, and legsTrouble moving the neck or holding up the headChronic muscle fatigueDifficulty breathing
People with ocular MG may experience vision problems if their eyelids cover enough of their eyes to block vision or if their eye muscles don’t keep their eyes aligned, leading to double vision, or diplopia. Some nonpharmacological treatments for ocular myasthenia gravis include:
Wearing dark glasses in bright lightUsing eyelid tape to hold the eyelids upWearing a patch on one eye (alternating between the two eyes) to eliminate double vision
The drug pyridostigmine (Mestinon), which can improve communication between nerves and muscles, may also help with ptosis. Such sudden worsening of symptoms may be caused by an infection, severe stress, surgery, or a reduction or sudden increase of prednisone, which is used to treat the disease. The primary symptoms of myasthenic crisis include difficulty breathing and swallowing. When the respiratory muscles are affected, respiratory assistance (mechanical ventilation) is required until other therapies can stabilize symptoms. Transient Neonatal MG Babies who are born to mothers with myasthenia gravis can have a temporary form of the disease that usually goes away after a few weeks. Congenital MG In rare cases, a baby can be born with congenital myasthenia gravis, which means that they inherited a mutated gene from each parent to have this disease; congenital myasthenia gravis is a lifelong condition. Juvenile MG The most common form of myasthenia gravis in children is juvenile myasthenia gravis. As with adults, the symptoms can vary from one child to another. Typically, children will experience mild to severe muscle weakness that can impact a few or many muscles. Some children will only have a mild form of the disease, with ocular symptoms that cause drooping of the eyelid. Others can experience more serious symptoms such as trouble walking or talking. In addition to the myasthenia gravis symptoms that commonly occur in adults, such as drooping eyelids, double vision, and difficulty speaking or swallowing, infants and children who have this condition also experience the following:
Trouble breastfeedingDelay in motor skills such as crawling and sittingClumsiness and falling frequentlyTrouble walkingTiring easily when playing or engaging in other activitiesRespiratory problems
Until they receive a proper diagnosis, children with myasthenia gravis may be mistakenly thought to be uncoordinated or even unmotivated.
ReflexesMuscle strengthMuscle toneEye movements, visionSense of touchCoordinationBalance
According to StatPearls, a healthcare professional may also conduct the following tests: Edrophonium Test By injecting the chemical edrophonium chloride, your muscle strength may suddenly, yet temporarily, improve. If this occurs, it’s an indication that you may have myasthenia gravis. Ice Pack Test Instead of the edrophonium test, your doctors may place an ice-filled bag on your droopy eyelid for two minutes. After removing the bag, your doctor will analyze your eyelid for signs of improvement. Blood Analysis A blood test may be taken to look for abnormal antibodies that disrupt the receptor sites where nerve impulses signal your muscles to move. Repetitive Nerve Stimulation By attaching electrodes to your skin over the muscles to be tested, doctors send small pulses of electricity to measure the nerve’s ability to send a signal to your muscle. Your doctor will test the nerve several times to see if its ability to send signals worsens with fatigue. Single-Fiber Electromyography (EMG) By inserting a fine wire electrode through your skin and into a muscle, electromyography measures the electrical activity traveling between your brain and your muscle. This test may be uncomfortable. Imaging Scans To determine if there’s a tumor in your thymus, your doctor may order a computerized tomography (CT) scan or a magnetic resonance imaging (MRI) scan. Pulmonary Function Tests To determine if your condition is affecting your breathing, your doctor may perform pulmonary function tests. Additional reporting by Katherine Lee.
