LEMS deemed respiratory failure cause in woman: Case study
Unusual case highlights need for timely diagnosis, researchers say
Lambert‐Eaton myasthenic syndrome (LEMS) may, in rare cases, manifest with severe respiratory muscle weakness leading to respiratory failure, researchers noted in a case study.
“Establishing the association of LEMS with respiratory disease could lead to timely identification of LEMS, diagnosis of an underlying malignancy (if unknown), and initiation of appropriate symptomatic treatment,” the researchers wrote.
The study, “Acute Respiratory Failure Resulting From Lambert-Eaton Myasthenic Syndrome: A Case Report and Literature Review,” was published in Cureus.
LEMS is an autoimmune neuromuscular disease marked by the presence of self-reactive antibodies targeting voltage-gated calcium channels (VGCCs) found on nerve cell endings that are important for nerve-muscle communication. In up to 60% of cases, LEMS is associated with an underlying cancer, most commonly small cell lung cancer (SCLC).
Typical symptoms of LEMS include proximal muscle weakness, which affects the muscles closest to the core of the body, lack of reflexes, and autonomic dysfunction. The autonomic nervous system is responsible for regulating unconscious bodily processes, such as breathing and digestion. Autonomic dysfunction occurs when these nerves are damaged, causing patients to experience symptoms like constipation and erectile dysfunction.
A rare LEMS symptom as respiratory failure cause
Researchers in the U.S. described a woman with an unusual case of LEMS with respiratory muscle weakness, a rare symptom of the disease.
The 63-year-old patient was admitted to the emergency department in March 2023 with signs of a stroke, including impaired speech. She had experienced progressive shortness of breath in the prior two months.
A neurological examination in which she was asked to bring her finger to the tip of her nose revealed lack of movement coordination. Her blood pressure and oxygen levels dropped below normal, and she lost consciousness. She was intubated and transferred to the neuroscience intensive care unit (ICU) on suspicion of seizures.
Her clinical history included SCLC and colon cancer that had spread, or metastasized, to both ovaries and the peritoneum, the membrane that lines the inside of the abdomen. In 2008, she underwent chemotherapy and had surgery to remove her uterus, ovaries, and fallopian tubes, which connect the connect the ovaries to the uterus. Her colon cancer, despite having spread to other parts of the body, was in remission. She also had Crohn’s disease, a type of inflammatory bowel disease, for which she was being treated with dexamethasone.
In May 2022, during a chest CT surveillance scan, a new mass was detected in the perihilar lymph nodes, which are found in a particular region of the lung, with potential metastasis in the liver. A chest biopsy confirmed the presence of SCLC, which was found to have spread into the liver and bones. She then received additional chemotherapy.
Imaging tests, including brain MRI scans, in the emergency department showed no abnormalities, even though she showed signs of a stroke.
Two weeks after being admitted, she suddenly became unresponsive, and her breathing was severely impaired. She was intubated and readmitted to the ICU. She failed to respond to any command, and a neurological examination showed poor attention.
After two days, her mental status slowly improved, and she was extubated. However, further examination showed fluid accumulation around the lungs and a collapsed left lung, which required her to be reintubated.
Once she was removed from assisted breathing, she developed respiratory failure. She had to be reintubated for another 10 days, but again her oxygen levels dropped, and her left lung collapsed.
LEMS diagnosis confirmed
The woman’s frequent respiratory problems that lacked an obvious respiratory cause along with her cancer history led clinicians to suspect of LEMS. Blood work came back positive for the presence of VGCC antibodies, with further tests confirming the diagnosis of LEMS.
The patient was treated with intravenous immunoglobulin (IVIG) for three days, but her condition continued to worsen. Further tests revealed potential signs of pneumonia and respiratory worsening. She received treatment with two antibiotics for six days, but was unable to wean off oxygen support.
About one month after admission, her oxygen levels severely dropped despite external supplementation. She died four hours later from cardiac arrest.
A literature search turned up 15 additional reports of LEMS associated with respiratory failure.
The case highlights “the importance of considering neuromuscular junction disorders, particularly LEMS, in patients presenting with isolated profound respiratory muscle weakness without focal neurological deficits,” the researchers wrote.
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