LEMS and autoimmune enteropathy co-occur in rare disorder case
Woman previously diagnosed with two other autoimmune diseases
Researchers recently described the case of a young woman diagnosed with Lambert-Eaton Myasthenic syndrome (LEMS) together with another very rare immune disorder called autoimmune enteropathy.
The report, “A Rare Case of Autoimmune Enteropathy Associated With Lambert-Eaton Myasthenic Syndrome and a Literature Review,” was published in Cureus.
Normally, the immune system protects the body from infection. In autoimmune diseases, however, it mistakenly attacks the body’s own healthy cells.
LEMS is a rare autoimmune disease caused by self-reactive antibodies that target voltage-gated calcium channels (VGCCs) — proteins needed for certain nerve cells to signal muscles. The antibody attack on VGCCs disrupts nerve signaling, resulting in LEMS symptoms such as muscle weakness.
Understanding LEMS and the co-occurring disorder
Autoimmune enteropathy is a rare autoimmune disorder typically affecting children. It is driven by self-reactive antibodies that target healthy cells in the gut, which leads to symptoms like diarrhea and malnutrition.
People who already have one autoimmune disease are at heightened risk of developing others, for reasons that aren’t fully understood.
Here, a team of scientists in Greece reported the case of a 24-year-old woman who developed LEMS and autoimmune enteropathy almost simultaneously.
She had previously been diagnosed with two other autoimmune diseases — autoimmune thyroiditis, characterized by thyroid inflammation, and vitiligo, which is marked by white patches on the skin due to an immune attack on pigment-producing skin cells.
The woman sought care at the researchers’ hospital after nearly a year of symptoms, including trouble walking, weakness in her legs, dry mouth, and dry eyes.
Tests of her nerves and muscles showed a pattern typical of LEMS, and bloodwork confirmed antibodies against VGCCs, verifying the LEMS diagnosis. Because LEMS often develops as a complication of an underlying cancer, doctors ran additional tests, but no cancer was detected.
The woman received intravenous immunoglobulin — a treatment meant to normalize a comprised immune system — along with the approved LEMS therapy Firdapse (amifampridine), and the immunosuppressive therapy rituximab. This led to a reduction in LEMS symptoms.
She was also briefly given the muscle-strengthening agent pyridostigmine but stopped it after a few days due to diarrhea. The diarrhea was presumed to be a side effect of the medication.
But even after stopping pyridostigmine, her diarrhea worsened and she also began vomiting. After two months, her digestive problems became so severe she needed to be hospitalized again.
“In retrospect, this gastrointestinal symptom was more likely related to the underlying autoimmune enteropathy rather than a direct adverse effect of pyridostigmine,” the researchers wrote.
Unraveling the diagnostic challenge
During her hospital stay, doctors ran a series of diagnostic tests — including imaging and biopsies of the intestines. After ruling out other causes, they diagnosed her with autoimmune enteropathy.
Following this diagnosis, she was given high-dose corticosteroids, a type of anti-inflammatory and immunosuppressive medication. This helped ease her diarrhea and stop her vomiting.
After tapering corticosteroids, she started the immunosuppressive therapy azathioprine. This has helped keep her disease under control, “without disease recurrence and with normal blood tests,” the researchers wrote. “Combination treatment with corticosteroids and azathioprine proved to be effective in our patient.”
The team also conducted a review of studies published from January 2015 until July 2025 reporting on autoimmune enteropathy cases. They identified 147 patients, but no cases of simultaneous autoimmune enteropathy and LEMS.
“While autoimmune enteropathy is often linked to multiple autoimmune disorders,” its association with LEMS “is an exceptionally rare and dramatic manifestation of autoimmunity,” the scientists wrote. “Their concurrent appearance complicates the diagnostic process, as muscle weakness may result from either the neurological disorder or severe malnutrition.”
The team also noted the simultaneous occurrence of LEMS and autoimmune enteropathy suggests possible shared autoimmune mechanisms. They called for future studies to identify these mechanisms and determine the best treatment approaches for such rare cases.
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