[Eaton-Lambert syndrome manifested by respiratory failure associated with small cell carcinoma of the lung]

A 63-year-old man with Eaton-Lambert syndrome manifested by marked respiratory failure was reported. He began to notice blepharoptosis and diplopia in September, 1987, followed by weakness and easy fatigability in bulbar, neck and limb muscles in association with impotence by February, 1988. On admission in August, 1988, Gowers' sign, decreased tendon reflexes and muscle weakness improved by the injection of edrophonium were found. Anti-acetylcholine receptor antibody was negative. Single muscle action potential evoked in the thenar muscle was abnormally low in amplitude with the stimulation of the median nerve: repetitive nerve stimulation study revealed the waning at the low rates, but the waxing at the high rate (30 Hz), suggesting the diagnosis of Eaton-Lambert syndrome. Early gastric cancer (adenocarcinoma) was diagnosed from needle biopsy specimens in August, 1988, but no other neoplasm including thymoma or lung cancer was found. After subtotal gastric resection in September, 1988, he failed into respiratory failure, requiring artificial ventilation for seven months. Plasmapheresis and drugs such as anticholinesterase, guanidine hydrochloride, and corticosteroid were ineffective for the recovery from weakness in respiratory muscle. Lung cancer was suspected, based on a chest X-ray in March, 1989, and one month later he died of pneumonia. At autopsy, small cell carcinoma of the lung was observed, but there was neither recurrence nor metastasis of the gastric cancer. Emphasis was placed on the respiratory failure in Eaton-Lambert syndrome which has rarely been reported.