LEMS May Coexist with Other Autoimmune Disorders in Cancer Patients, Case Study Finds

Patricia Inácio, PhD avatar

by Patricia Inácio, PhD |

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Lambert-Eaton myasthenic syndrome (LEMS) can occur along with other autoimmune diseases affecting the nervous system, namely limbic encephalitis, in patients with lung cancer, a case study found.

The study, “Coexistence of Lambert–Eaton myasthenic syndrome and autoimmune encephalitis with anti-CRMP5/CV2 and anti-GABAB receptor antibodies in small cell lung cancer: A case report,” was published in the journal Medicine.

The nervous system is divided into two components: the central and the peripheral nervous systems. The first comprises the brain and the spinal cord, while the second contains all the nerves and nerve cells outside the brain and spinal cord.

LEMS is a rare autoimmune disease that affects the peripheral nervous system and is characterized by muscle weakness due to problems with signals sent from nerves to muscles. About half of all LEMS cases occur in patients with small cell lung cancer.

In case report, authors described a patient diagnosed with LEMS and autoimmune encephalitis who later was also diagnosed with small cell lung cancer. In the central nervous system, deregulation of the immune system is the cause of autoimmune encephalitis.

The patient, a 56-year-old man, complained of tiredness after walking a short distance. He had several episodes of memory loss a day, lasting five to 10 minutes each, and was unable to find his home. Family members reported changes in character, irritability, and paranoia. He suffered a grand mal seizure – a type of seizure that can cause convulsions – one month later. Weakness in his legs continued to worsen.

After examination, he was diagnosed with limbic encephalitis and LEMS. Limbic encephalitisis is an autoimmune condition affecting the part of the brain involved in behavioral and emotional responses.

His symptoms improved after treatment with immune-suppressing therapies. He was able to climb stairs to the third floor and suffered no more seizures, although the changes in character and short-term memory loss remained.

Nine months after the beginning of symptoms, the patient — a 30-year, pack-a-day smoker — was found to have small cell lung cancer, and was treated with six courses of cisplatin-based chemotherapy combined with sequential chemoradiation therapy.

Therapy was successful and the patient recovered well.

The case report illustrated how “autoimmune diseases of the peripheral and central nervous systems can be observed at the same time in patients with small cell lung cancer.”