Overlapping symptoms hide a pair of rare autoimmune diseases
Case of woman, 70, suggests dual diagnoses are overlooked, per report
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An older woman with Sjögren’s disease who developed problems walking was ultimately also diagnosed with Lambert-Eaton myasthenic syndrome (LEMS), revealing a rare coexistence between two autoimmune diseases that can share overlapping symptoms, according to a case report.
The researchers noted that the second diagnosis, made after nerve studies, likely took longer because the woman’s LEMS symptoms were “initially attributed solely to Sjögren’s,” leading to a “primary working diagnosis” that did not suggest other autoimmune diseases.
This “case represents only the third reported association between LEMS and Sjögren’s,” and the first “in a Caucasian individual,” the researchers noted.
But it raises the suspicion, the team suggests, that there are other cases like this woman’s in which people with LEMS may have other autoimmune diseases, including Sjögren’s. According to the researchers, the co-occurrence of the two conditions may be underdiagnosed.
A report detailing the woman’s diagnosis, titled “Lambert-Eaton myasthenic syndrome in association with Sjögren’s syndrome: a case report,” was published in the journal Acta Neurologica Belgica.
LEMS is an autoimmune neuromuscular disease in which self-reactive antibodies target proteins called voltage-gated calcium channels (VGCC), preventing nerve cells from properly sending signals to muscle cells.
This leads to the disease symptoms, such as muscle weakness, reduced reflexes, and autonomic dysfunction, or symptoms related to involuntary bodily processes such as the production of saliva and tears. Dry mouth and dry eyes, also known as sicca symptoms, affect about 90% of LEMS cases.
These are also the most common symptoms of Sjögren’s, an autoimmune disease that mainly affects moisture-producing glands.
Woman’s LEMS symptoms first attributed to Sjögren’s
Now, a team of researchers in Czech Republic described the case of a 70-year-old woman with Sjögren’s who developed LEMS.
The woman started experiencing trouble climbing stairs in May 2023, which eased with oral corticosteroids — anti-inflammatory and immunosuppressive medications. However, the problems returned after she discontinued the medications in January 2024.
A few months later, her motor problems started to worsen progressively, resulting in walking problems that required the use of a low walker, as well as arm weakness that prevented her from performing certain movements such as throwing. The woman also experienced general weakness and urinary infections, the report noted.
A clinical examination indicated that the woman had muscle weakness mainly affecting muscles closer to the trunk, particularly in the hips and pelvic region. This contributed to a waddling walking pattern, characterized by side-to-side hip movements, and difficulty standing up from a chair without assistance, the researchers noted.
She also had reduced or absent deep tendon reflexes, although some reflex responses temporarily improved after muscle activation. This is a characteristic feature of LEMS known as facilitation. An MRI of the thighs showed widespread muscle shrinkage.
Nerve conduction studies, which evaluate the ability and speed at which nerve cells send signals to muscles, showed low-amplitude compound muscle action potentials, or CMAP, indicating reduced muscle responses to nerve stimulation. After the woman exercised the muscle, CMAP amplitude increased, which is highly suggestive of LEMS.
Electromyography, which records electrical signals coming from muscles in response to nerve signals, and repetitive nerve stimulation testing confirmed a problem with nerve-muscle communication, also supporting a LEMS diagnosis.
That diagnosis was finally confirmed with the detection of elevated levels of anti-VGCC antibodies in the blood, according to the team.
The researchers reported that the woman also had symptoms that included dry mouth, which, the team noted, “are present in approximately 90% of LEMS cases.” However, these symptoms were first attributed only to the woman having Sjögren’s, according to the researchers.
The woman was also found to have self-reactive antibodies consistent with Sjögren’s.
Woman’s case is third reported with these 2 rare autoimmune diseases
Treatment in this case involved a combination of pyridostigmine and prednisone, a corticosteroid, alongside cyclic administration of intravenous immunoglobulin (IVIG) every 4-5 weeks, per the case report.
Pyridostigmine is approved under the brand name Mestinon (with generic versions available) to treat myasthenia gravis, another neuromuscular disease, and is sometimes used off-label to treat muscle weakness in LEMS. IVIG involves the administration of healthy antibodies to suppress antibody-induced autoimmune responses.
Following treatment, the woman experienced “significant clinical improvement,” regaining “the ability to walk independently,” the researchers wrote. Still, she continued to have a mildly waddling gait.
While LEMS is commonly associated with cancer, “repeated PET/CT scans of the trunk (the last one in 2026) showed no evidence of malignancy,” the researchers wrote, adding that “although most LEMS cases have a paraneoplastic [cancer] etiology [cause], there are instances of non-paraneoplastic LEMS associated with other autoimmune diseases.”
[This woman’s case] raises the hypothesis of whether Sjögren’s … in the context of LEMS might be underdiagnosed, as both conditions share overlapping autonomic symptoms.
According to the researchers, just two other cases of LEMS and Sjögren’s have been reported in the literature, and both occurred in Japanese people, indicating that this is the first case to be reported in a Caucasian person.
Overall, however, this woman’s dual diagnosis “raises the hypothesis of whether Sjögren’s … in the context of LEMS might be underdiagnosed, as both conditions share overlapping autonomic symptoms,” the team wrote.
The researchers noted that “further case reports and studies are needed to clarify this association.”
Linda Pyle
My husband was diagnosed with LEMS in 2018 and was diagnosed with sojourns in 2024.
Sonja Bates
Dear Linda, Please let your husband he is not alone! There are more of us out there we just need to find each other. Sonja
Carol Ann Beatts
I was diagnosed with sero negative LEMS in 2024
I was diagnosed on symptomology and response to treatment
The symptoms for borh conditions quite similar
My symptoms have never subsided and are indeed now getting worse.
So its a case of living the best I can
Dorothy Dempsey
Since my LEMS diagnosis, I have been diagnosed with Collagenous Colitis and Lichen Sclerosis.
Sharon Gill
I was diagnosed Dec22 with Fibromyalgia and arthritis ( aged 57). I was diagnosed with LEMS without cancer in Jan 24. Despite 3 4 Diaminopyridine, high steroid and mycophenalate, i have IVIG too. Stkll symptomatic. I thought i had sjorgrens. Dry eyes, ptosis, diplopia. (Also had cysts on my retinas) Dry mouth problems with swallowing. Chocking on nothing, tongue and jaw ache. Slurred unclear speech. Problems with chewing. A funny one Dry nose and when blowing my nose I sound like an elephant and my soft palette vibrates. I was born with Hypermobility, did party tricks and was told I was double jointed. Always had clicky hips and trouble with knees neck back shoulders and elbows. Last year diagnosed with (60yrs)WPW, supraventricular ectopics. After echo gram...tricuspid; aorta , bicuspid and mitral valves regurgitating mildly. Aorta also has acceleration and left ventricle remodelled due to high BP. I had diagnoses of arthritis in thumbs and fingers at around age 45. Along with lumber degenerative disease and spinal stenosis. I now have arthritis in shoulder, hip, knee and neck. I have ligament injuries in shoulders and knees. I fall regular especially right ankle foot, of which just learned us foot drop. There are a plethora and host of symptoms for these conditions going back y
Sonja Bates
Hi, I'm a caucasian woman who just turned 59 on 7/30, and in late March of this year, I discovered LEMS. After reading what felt was my entire experience alongside the Sjorgrens Disease diagnosis I was given a couple years ago, I instantly knew I was a dead ringer for LEMS. With further digging, I was able to determine it was Idiopathic LEMS. I sent a note to my Immunologist and asked him to order 4 tests along with their respective lab codes and on June 15th, the results confirmed LEMS with Small Cell Lung Cancer Antibodies. Then it was a race to meet with my new Neuromuscular Neurologist on 7/30 who specializes in Myasthenia Gravis and LEMS and she also agreed with the same diagnosis.
I also need to report that I had to figure out each of my diagnosis before I met any drs for not only the Sjogrens, Mitochondrial Myopathy, with directly led to development of Secondary Adrenal Insufficiency and Idiopathic LEMS, Mast Cell Activation Syndrome (since childhood), Chronic Fatigue Syndrome and Dupuytrens Contracture. The greatest challenge was finding a doctor that didn't gaslight me because I fell into their blind spot of ignorance. Once I found the right drs, they shared similar speculations with mine based on their experience, education and speciality, respectively listened, ordered my tests I asked for and the results proved everything. Now that I have proved of from the years of researching and justified with diagnosis, I will also speculate that I believe that LEMS is more common and when a woman is tested for LUPUS and Sjogrens that LEMS should be tested at the same time because all 3 share the same SICCA symptoms. And all 3 autoimmune disorders are linked in commonality with Mitochondrial Myopathy.
I frankly am appalled that as the patient, I had to become a medical investigator, researcher and had to play Dr with Drs who were inept at helping me most of the time but also took aim at me for falling into their vulnerable blind spot. The therapeutic nihilism I had to endure caused medical trauma of which I used to fuel my quest to prove them all wrong.
I am sharing my story with health information because it should be public to encourage others to follow their gut instincts especially when their chronic clinical health symptoms and biofeedback is telling you something is very wrong.
Your symptoms are textbook for an AutoImmune Clinical chronic disorder, it just means testing and discovering which one(s). While I'm glad this article exists, here I am another one of the extremely rare duo combo of LEMS with Sjogrens. The first isn't a genetic disorder but the second one is while both are linked with MItochondrial Myopathy and that should become public knowledge.