A case of neuralgic amyotrophy with extension disturbance of fingers after Cushing's syndrome remission

Abstract

We describe a 57-year-old female patient who experienced hypercortisolemia caused by adrenal Cushing's syndrome. Two months post-adrenalectomy, she developed acute severe bilateral pain starting in her fingers and spreading up her arms. In the subsequent two weeks, the patient presented upper extremity patchy paralysis with extension disturbance of fingers. In the following two months, she experienced atrophy of the muscles in the hands and joint contracture. Consequently, we diagnosed her with neuralgic amyotrophy. Nerve conduction studies showed low compound muscle action potential of all the peripheral nerves in the forearms, suggesting motor neuron axonopathy. Gadolinium-enhanced MRI and ultrasound studies did not reveal any abnormalities in the brachial plexus and peripheral nerves of the forearms. The patient tested positive for anti-GalNAc-GD1a-IgM antibodies and received intravenous immunoglobulin 6 months after the onset of symptoms, which resulted in reduction of pain, muscle weakness, and contractures. This rare case of potentially immune-mediated bilateral patchy paralysis may have important implications in the understanding of clinical and pathological heterogenicity of neuralgic amyotrophy.