Myasthenia gravis (MG) is characterized by fluctuating symptoms. Sometimes these changes are part of everyday life with MG — and sometimes, they’re a cause for concern.
An MG flare and a myasthenic crisis both describe worsening symptoms, but they are very different situations. Recognizing the difference between an MG crisis and an MG flare is essential to ensuring the right treatment.
What is a MG flare?
You may have heard an MG flare referred to as a flare-up, exacerbation or relapse. These terms all mean a temporary increase in the normal impact of symptoms.
MG flares are often caused by specific triggers. Each person will experience MG differently, with different triggers and different symptom severity.
Possible triggers to be aware of include:
- Infections, such as a cold or flu.
- Emotional or physical stress.
- Fatigue due to poor quality sleep or interrupted sleep.
- Certain medications, such as antibiotics and blood pressure medicine.
- Extreme temperatures (both hot and cold).
- Hormonal changes related to pregnancy or menstruation.
- Existing medical conditions, such as another autoimmune disease.
- Immunization, though this is relatively uncommon.
These triggers cause increased muscle weakness, leading to the worsening of existing symptoms. Slurred speech, difficulty chewing and swallowing, drooping eyelids, double vision, physical fatigue in the fingers, hands, arms and legs may all deteriorate further.
However, breathing is not usually severely affected by an MG flare — a differentiating factor from an MG crisis — although some shortness of breath is possible.
What is a myasthenic crisis?
A myasthenic crisis, or MG crisis, is a potentially life-threatening event and it must be treated as a medical emergency. Not all people living with MG will experience an MG crisis in their lives; on average, only one in five patients eventually experience an MG crisis. However, the importance of recognizing the warning signs cannot be underestimated.
The main symptom of a MG crisis is difficulty breathing. The muscles of the respiratory system become severely weakened and a ventilator is often needed to help maintain breathing. In the majority of cases, this involves intubation and mechanical ventilation. In around 20% of MG crisis cases, noninvasive ventilation is used.
Other treatment options for an MG crisis may include intravenous immunoglobulin (IVIG), plasmapheresis or immunosuppressants.
The takeaway: Don’t ignore worsening symptoms
Alert your healthcare team immediately if you feel your symptoms intensifying. Rest, recovery, medication and treating any contributing factors are the most common approaches to treatment. However, it is important to seek medical advice as in some rare cases, an MG flare can develop into an MG crisis.
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