LEMS often presents as a triad of signs and symptoms, including1:
Proximal muscle weakness
Autonomic dysfunction
Hyporeflexia or areflexia
Autonomic symptoms in particular can provide a vital clue in distinguishing LEMS from other conditions, such as myasthenia gravis (MG).1
For 30% of patients, oculobulbar symptoms may be their chief complaint or the presenting feature of the disease. Patients with LEMS typically present with a triad of symptoms that include proximal muscle weakness, autonomic dysfunction, and hypoflexia/areflexia.1-3
If you suspect your patient may have LEMS, arrange an urgent referral to a neurologist highlighting the patient’s symptoms, such as pupillary dysfunction and autonomic features, and consider ordering tests for anti-voltage-gated calcium channel (VGCC) antibodies and/or an electrodiagnostic test.4
Differentiate LEMS and MG
LEMS is frequently misdiagnosed given its nonspecific and fluctuating symptoms.5 The symptoms of LEMS can overlap with those of MG, increasing the risk of misdiagnosis or delayed diagnosis.1,5 LEMS and MG can be distinguished by differences in their clinical manifestation and by anti-VGCC antibody testing and/or electrodiagnostic testing.5
The symptoms of LEMS and MG can often be confused.5 In fact, 58% of patients with LEMS receive at least 1 misdiagnosis, most often MG.6 If your patient’s symptoms are atypical for MG, such as dry mouth, constipation, and orthostatic hypotension, or they are not having adequate response to their therapy, consider LEMS. An anti-VGCC antibody test and/or electrodiagnostic test can help confirm a diagnosis.1,5,7
An anti-VGCC antibody test is not automatically included in an MG panel and may need to be requested separately. If your patient displays symptoms of LEMS, request a comprehensive autonomic neuromuscular/paraneoplastic panel, including anti-VGCC antibody testing (P/Q and N type). You may want to consider an electrodiagnostic test for your patient as well.1,8-10
Confirm a LEMS diagnosis
When you suspect LEMS or MG, order a comprehensive autoimmune neuromuscular/paraneoplastic panel, including testing for anti-VGCC antibodies (P/Q and N type) and/or electrodiagnostic testing. No-cost anti-VGCC antibody testing is available through a Catalyst-sponsored program. You can get this test here.1,10
No-cost anti-VGCC antibody testing is available through a Catalyst-sponsored program to support the clinical evaluation of patients with suspected LEMS.
The testing is conducted by Quest Diagnostics and includes 2 anti-VGCC antibody assays that may aid in differentiating LEMS from other neuromuscular conditions. You can get this test here.11
Up to 60% of LEMS cases are associated with an underlying malignancy, most commonly small cell lung cancer (SCLC).1,10,12,13 Neuromuscular symptoms may precede cancer diagnosis by months or years.10
Early detection of LEMS plays a pivotal role in ensuring timely oncology care. Patients with LEMS should be screened immediately for cancer with a computerized axial tomography (CAT) and/or positron emission tomography (PET) scan.1,14,15
If cancer is found: Refer to an oncologist to discuss treatment
If no cancer is found: Symptomatic treatment should be initiated and follow-up cancer screenings should be performed every 6 months for 2 years
According to the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines®), consultation with a neurologist for a neurologic workup is recommended in those with a suspected paraneoplastic neurologic syndrome (PNS).16
