Diagnosing LEMS

Early recognition of LEMS symptoms can lead to quicker diagnosis and initiation of effective treatment12

Anatomical display of neuromuscular and autonomic symptoms of LEMS
Anatomical display of neuromuscular and autonomic symptoms of LEMS

Diagnostic methods

If you suspect that your patient may have LEMS, you can utilize several clinical diagnostic methods to get them on the right treatment path.12

SIGNS AND SYMPTOMS

A diagnosis of LEMS may be suspected based on clinical symptomatology and physical signs, including proximal muscle weakness, autonomic dysfunction, and hyporeflexia or areflexia. However, a definitive diagnosis should be made only after confirmatory testing using the test methods below.12

ANTIBODY AND ELECTRODIAGNOSTIC TESTING MAY CONFIRM A LEMS DIAGNOSIS

Anti-VGCC antibody testing
These antibodies are found in 85%-90% of LEMS patients.12

  • The presence of anti-VGCC antibodies can support a LEMS diagnosis, although it should be noted that a negative antibody test does not rule out a diagnosis of LEMS21
  • Electrodiagnostic testing should be performed as a follow-up21

Electrodiagnostic testing
Increment on high-frequency repetitive nerve stimulation or post-exercise potentiation can also confirm diagnosis.12

  • Consider testing patients who have symptoms of MG, especially with low compound muscle action potential (CMAP) amplitudes on regular nerve conduction studies12

Free LEMS diagnostic test available

Did you know that Catalyst offers a no-cost test that can identify the presence of VGCC antibodies in suspected LEMS patients?

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Uncovering hidden cancer: another benefit of early recognition and diagnosis of LEMS5,12

The sooner LEMS is identified as the disorder behind your patients’ symptoms, the sooner treatment can begin. Treatment for LEMS will be predicated on how the disorder is manifested.16

Manifestations of LEMS

LEMS can manifest in association with an underlying cancer16 or in the absence of an underlying cancer.12,22

50%-60% LEMS ASSOCIATED WITH CANCER

  • Most commonly associated with SCLC; however, it is possible that LEMS may occur with other cancers16,23
  • Predominantly affects males 60 or older, many with a history of smoking22
  • Symptom onset is variable, ranging from 6 years prior to cancer diagnosis to 5 years after cancer diagnosis16*
  • Patients with LEMS associated with SCLC display a more rapidly progressing course of disease vs those with LEMS not associated with SCLC14,15

40%-50% LEMS NOT ASSOCIATED WITH CANCER

  • Increased occurrence with other autoimmune disorders22
  • Typical age of onset is 35-40; gender-neutral12,22
  • Slower progression/fluctuating symptoms12
  • The average life expectancy is similar to that of a healthy individual of the same gender and a similar age24
*Results from a study involving 133 patients with cancer-associated LEMS.
NEXT: Treating LEMS

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