Case Report Highlights Very Late-onset MG in Woman, 93

Myasthenia gravis (MG) can occur in very elderly patients, a recent case report highlights. As such, there is a need for early diagnosis in this population, which can allow for better clinical outcomes.

A case report with that finding, “Very late onset of myasthenia gravis: case report and brief review of the literature,” was published in Acta Neurologica Belgica.

Late-onset MG (LOMG), as its name suggests, is MG that develops later in life. There isn’t an universally agreed-upon age cutoff defining LOMG; ages cited in previous publications have ranged from 50 to 75 years.

The subject of the recent case report was a 93-year-old woman who went to the emergency room several times over the course of two months. The patient’s symptoms included general weakness, double vision, and difficulty speaking, chewing, and swallowing.

Numerous diagnostic tests, including X-rays and computed tomography (CT) scans, didn’t provide any useful findings to diagnose the patient. A  neurological examination found the patient to have weakness in all limbs, as well as abnormal movements in the muscles that control the eyes. Those symptoms can be indicative of MG.

The patient was given Mestinon (pyridostigmine), a medication that increases levels of the neurotransmitter acetylcholine. Receptors of this neurotransmitter often are the target of autoantibodies in MG, leading to problems in the transmission of nerve impulses to muscles.

This treatment led to “marked clinical improvement,” the authors of the case report wrote.

Subsequent tests revealed the patient had high levels of antibodies targeting the acetylcholine receptor, the most common cause of MG. The patient was given a higher dose of Mestinon and also was started on prednisone, an anti-inflammatory medication, which led to further improvement of symptoms.

The authors of the case report conducted a brief review of existing scientific literature concerning LOMG. They found relatively few studies (mostly case reports and case series) and noted there were “a scarce number of cases of MG beginning after age 85 and only anecdotal cases with onset after 90 years.”

As such, the current case may constitute the oldest age of onset for LOMG in the existing scientific literature. Researchers noted that, despite typical presentation, there was a two-month delay in the diagnosis of this patient, which can be explained by “age-associated changes, multimorbidity [other diseases present], and the possibility of an alternate diagnosis,” the authors wrote.

Overall, this case highlights the need for proper diagnosis of MG in the elderly, which can facilitate timely and effective treatment.

“LOMG is a treatable condition requiring a high index of suspicion for early diagnosis and thus more favorable outcomes,” the authors wrote.