A case of demyelinating polyneuropathy associated with anti-myelin-associated glycoprotein antibodies with progressive quadriparesis and respiratory failure]

A 79-year-old man was admitted due to progressive weakness of both hands for two and a half years. Neurologically, he presented with weakness of the upper limbs, predominantly in the left distal portion, and hypoactive deep tendon reflexes. Nerve conduction studies were consistent with a motor and sensory demyelinating neuropathy. Sural nerve biopsy revealed a decrease of myelinated fibers with a predominance of larger diameter fibers. Widening of myelin lamellae and uncompacted myelin were detected on electron microscopy. Laboratory examinations showed IgM-kappa-type M-protein and anti-myelin-associated glycoprotein (MAG) antibody. He was diagnosed as having anti-MAG-associated demyelinating neuropathy based on the laboratory, electrophysiological, and pathological findings. While no bulbar symptoms or upper motor neuron signs were shown, the patient developed quadriparesis and respiratory failure after three years. Although anti-MAG-associated demyelinating neuropathy is usually characterized by sensory symptoms, particularly sensory ataxia, the present case indicates that motor symptoms such as quadriparesis and respiratory failure can be among the clinical manifestations of antiMAG-associated demyelinating neuropathy.