Lambert–Eaton myasthenic syndrome has a more progressive course in patients with lung cancer

Abstract

We studied whether a difference exists in the development of symptoms of the Lambert-Eaton myasthenic syndrome (LEMS) between patients with or without small cell lung cancer (SCLC). We assessed symptoms in 38 LEMS patients, 13 with SCLC, by interviewing them using a structured checklist, backed up by a review of their clinical records, and compared the frequency and time scale of symptoms during the course of LEMS. Bulbar (87%) and autonomic (95%) symptoms for the whole group were more common than reported in the literature. Frequencies of symptoms did not differ significantly between patients with and without SCLC, but symptoms in patients with SCLC appeared within a shorter time-frame, indicating a more rapid clinical course. The presence of a particular symptom associated with LEMS did not predict the presence of SCLC, but in patients with rapidly progressive LEMS the possibility of underlying lung cancer should be of particular concern.

Electrophysiological differences in seropositive and seronegative Lambert–Eaton myasthenic syndrome

“…12,13 Our findings clearly support this rationale. In the seronegative group in which electrophysiological testing was needed for a definite diagnosis of LEMS, our study showed that the classic triad of abnormalities on RNS was rare, giving rise to a double difficulty in the diagnosis of LEMS.…”

Managing Paraneoplastic Neurological Disorders

“…Bulbar symptoms may occur more frequently than previously reported [85] but are generally milder than with myasthenia gravis. Respiratory weakness can occur.…”

“…Deep tendon reflexes, especially those in the legs, are diminished or absent but may reappear after exercise. Autonomic features, especially dryness of the mouth, impotence, and mild/moderate ptosis, ultimately develop in 95% of patients [85][86][87]. In some patients, LEMS may develop in association with other PNS, including PCD and encephalomyelitis [50].…”

“…The prevalence of LEMS in patients with SCLC is estimated to be around 3% [87,89]. Clinically and serologically, the 30% without identifiable tumors are indistinguishable from the paraneoplastic LEMS patients, although LEMS may have a more progressive course in patients with SCLC [85]. In patients presenting with LEMS, a smoking history and absence of the HLA-B8 genotype strongly predict underlying SCLC [90].…”

The Lambert-Eaton Myasthenic Syndrome

“…Screening with CT-thorax or PET scans detected SCLC in 91 % of patients within 3 months after the diagnosis of LEMS (Titulaer et al 2008b). Specific symptoms do not distinguish between patients with and without underling SCLC, but LEMS associated with SCLC has a more progressive course (Wirtz et al 2005c). …”