Paraneoplastic Inverse Myasthenic Syndrome as a Presentation of Bronchogenic Carcinoma

Tumours may produce growth factors and cytokines responsible for signs and symptoms distant to the primary or metastatic site. This may be the first sign of a malignancy and its recognition may be critical for early cancer detection. Moreover, proper diagnosis spares the patient of extensive and expensive search for an alternate cause of the neurological dysfunction. In neurological paraneoplastic syndromes like Lambert Eaton Myasthenic syndrome associated with small cell lung cancer, evidence of autoimmunity against presynaptic neuro-muscular junction by anti voltage gated calcium channel anti bodies is well documented. 60% of patients with LEMS are associated with an underlying cancer, usually SCLC. We report a 49 year old male, with over thirty pack years of smoking, who presented with dysautonomia, constitutional symptoms and weakness of all four limbs. Investigations confirmed axonal motor neuropathy with limited stage SCLC with fibro nodular lesions right upper lobe and mediastinal lymphadenopathy. He improved dramatically following chemotherapy and radiotherapy.