Nonmotor symptoms in people with myasthenia gravis (MG) are often overlooked, but they are common and may have a significant impact on patients’ quality of life, according to a new review of research on the disease published recently in the European Journal of Neurology.
MG is typically known for its hallmark motor symptom of muscle weakness, but patients may also experience sleep problems, anxiety, cognitive difficulties, headaches and sensory loss such as diminished taste or smell.
“[C]urrent research on the non-motor symptoms of MG is relatively limited,” explained the review’s authors. “While we have listed a series of non-motor symptoms, there could be potential symptoms yet to be discovered, necessitating further investigation through large-scale cross-sectional studies.”
Researchers examined evidence for these nonmotor symptoms and outlined potential causes, including immune system activity beyond the neuromuscular junction. For example, the antibodies that attack muscle receptors in MG may also interfere with receptors in the brain and sensory pathways. Patients may lose the ability to detect sweetness or struggle with smell due to disruptions in cholinergic signaling, a critical communication system involving acetylcholine.
Read more about signs and symptoms of MG
Headaches in MG may be caused by posture issues such as “head drop,” inflammation or overlap with other neurological pathways. Cognitive impairment, including difficulty with memory and attention, has been linked to structural changes in the brain and potential damage from MG-related hypoxia or long-term fatigue, the authors noted. In many cases, these problems occur in patients much younger than those typically affected by conditions such as Alzheimer’s disease.
People with MG also commonly experience sleep disturbances and psychological conditions. More than two-thirds report moderate to severe anxiety, and over one-third live with depression. These issues are more prevalent than in many other autoimmune and neurological diseases and may worsen severity of disease by interfering with treatment adherence.
A more complex picture emerges in patients with thymoma-associated MG, a subtype linked to tumors of the thymus. In these cases, additional autoimmune syndromes such as neuromyotonia, limbic encephalitis or hair loss may develop. These effects are likely caused by immune cells and antibodies misfiring due to the tumor’s presence.
Understanding the full range of MG symptoms may help doctors offer more personalized care. While treatments now effectively target muscle weakness, few protocols address nonmotor symptoms directly. The authors called for more research and encouraged clinicians to screen for these underrecognized challenges to help patients live fuller, healthier lives.
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