Lambert Eaton Myasthenic Syndrome (LEMS) - Overview.docx

**Lambert Eaton Myasthenic Syndrome (LEMS): Overview** **Introduction to Lambert-Eaton Myasthenic Syndrome (LEMS)** - Rare - Autoimmune disorder affecting the neuromuscular junction. - Associated with specific cancers, predominantly small cell lung cancer and lymphomas. - Recognitio...

**Lambert Eaton Myasthenic Syndrome (LEMS): Overview** **Introduction to Lambert-Eaton Myasthenic Syndrome (LEMS)** - Rare - Autoimmune disorder affecting the neuromuscular junction. - Associated with specific cancers, predominantly small cell lung cancer and lymphomas. - Recognition of its clinical features, including proximal weakness, bulbar symptoms, and autonomic manifestations. - Understanding its unique reflex findings and rare sensory involvement aids in distinguishing LEMS from other neuromuscular junction disorders. **Pathophysiology** - **Autoimmune Basis:** Associated with paraneoplastic conditions, often triggered by small cell lung cancer or lymphomas. - **Autoantibodies:** Target presynaptic voltage-gated calcium channels at neuromuscular junctions. - These channels are crucial for nerve action potential propagation and acetylcholine release. **Clinical Presentation** A close-up of a person\'s eye Description automatically generated - **Muscle Weakness:** - Typically starts proximally and may progress distally. - **Bulbar Symptoms:** - Indicative of neuromuscular junction involvement. - Includes ptosis (drooping eyelids), diplopia (double vision), dysarthria (difficulty speaking), dysphagia (difficulty swallowing). **Neurological Examination Findings** - **Sensory Symptoms:** Rarely includes numbness or tingling (paucity of sensory findings). - **Reflexes:** Often normal to reduced; however, LEMS can present with areflexia, which is unusual for neuromuscular junction disorders. - **Autonomic Symptoms:** Common and prominent. - Dry mouth and constipation are notable examples. - Reflects autonomic nervous system involvement in LEMS. **\_\_\_\_\_\_** Which of the following is **not** a characteristic of Lambert-Eaton myasthenic syndrome? - Worsening of symptoms with muscle use