ORIGINAL ARTICLES zyxw Acute Motor Axonal Neuropathy: A Frequent Cause of Acute Flaccid Paralysis in Chna G. M. McKhann, MD,"? D. R. Cornblath, MD,? J. W. Griffin, MD,? T. W. Ho, MD,"? C. zyx Y. Li, MD,§ zy 2. Jiang, MDj1 H. S. Wu, MD," G. Zhaori, MD," Y. zyxw ku, MD," L. P. Jou, MD," T. C. Liu, MD," C. Y. Gao, MD,§ J. zyxwvu Y. Mao, MD,§ M. J. Blaser, MD,"" B. Mishu, MD,'" and A. K. Asbury, MD$ zy ~~ ~ ~~ In northern China, annual epidemics of acute-onset flaccid paralysis diagnosed clinically as Guillain-Barre syndrome have been recognized for at least 20 years. On the basis of an historical analysis of more than 3,200 patients, distinctive features include most cases occurring during the summer months among children and young adults, most of whom reside in rural areas. Of 90 patients with acute flaccid paralysis, 88 had a distinctive pattern that shares clinical and cerebrospinal fluid findings with demyelinating Guillain-Barre syndrome, but that differs from Guillain-Barre syn- drome physiologically and pathologically. The clinical course is marked by rapidly progressive ascending tetraparesis, often with respiratory failure, but without fever, systemic illness, or sensory involvement. Cerebrospinal fluid is acellular, and elevations of protein content occur in the second or third week of illness. Electrodiagnostic studies show normal motor distal latencies and limb conduction velocities, but reduced compound muscle action potential ampli- tudes. Sensory nerve action potentials and, when elicitable, F waves are within the range of normal. Recovery is usually good. Autopsy studies have shown Wallerian-like degeneration of motor fibers. These studies establish that this is a distinctive syndrome, distinguishable from poliomyelitis and demyelinating Guillain-Barre syndrome. McKhann GM, Cornblath DR, Griffin JW, Ho zyxwv TW, Li CY, Jiang Z, Mu HS, Zhaori G, Liu Y, Jou LP, Liu TC, Gao CY, Mao JY, Blaser MJ, Mishu B, Asbury AK. Acute motor axonal neuropathy: a frequent cause of acute flaccid paralysis in China. Ann Neurol zyx 1993,33:333-342 The near-elimination of poliomyelitis in many areas of the world has focused attention on other causes of acute flaccid paralysis (AFP) in children and adults. In North America and Europe, the most frequent cause of AFP is acute infEammutory demyelinating polyneuropa- thy, a term often used interchangeably with the ep- onym Guillain-Barri. syndrome (GBS) [l]. In these locations, GBS is a sporadic, nonseasonal illness that affects persons of all ages, with the median age in the fifth decade [21. Electrodiagnostic features reflect the primary demyelinating lesion of nerves and roots, with or without associated axonal damage [3-5]. Autopsy studies have emphasized the presence of inflammatory infiltrates {61. Several recent studies have found ele- vated serum titers to Campylobacter jejuni in some pa- tients with GBS 17-91. Reports from China described patients with AFP whose clinical characteristics resemble those of patients with demyelinating GBS, but whose epidemiological features differ from those of patients seen in North America and Europe [lo-131. These Chinese cases occur largely among rural residents of northern China, predominantly during the summer and primarily in children. In a preliminary report, we suggested that there were clinical and electrophysiological differences between the Chinese and demyelinating GBS cases. Specifically, cases from northern China appeared to be an exclusively motor disorder, with involvement of motor axons but with little evidence of demyelination. We suggested the name "Chinese paralytic syndrome" [14]. This name implies that the disease occurs exclu- sively in China. A5 discussed, however, patients with some similar features apparently reside elsewhere. Thus, in this report, we refer to these patients as hav- ing a pattern of "acute motor axonal neuropathy" (AMAN). We present the results of intensive examination and analysis of 90 patients with neuropathic AFP, most of From the *Zanvyl Krieger MindlBrain Institute, The Johns Hopkins University, and the tDepartment of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD; the $Department of Neurology, University of Pennsylvania School of Medicine, Philadel- phia, PA; the §Second Teaching Hospital of the Hebei Medical Col- lege, Shijiazhuang, and "Beijing Children's Hospital, Beijing, China; and the "Department of Medicine, Vanderbilt University, Nash- ville, TN. Received Aug 10, 1992, and in revised form Nov 19. Accepted for publication Nov 23, 1972. Address correspondence tO Dr McKhann, Zanvyl fiieger Mind, Brain Institute, 338 Krieger Hall, 3400 North Charles St, Baltimore, MD 21218-2687, Copyright 0 1993 by the American Neurological Association 333