“Like a polio ward from the 1950s†is how Guy McKhann,M.D., a neurology specialist at John Hopkins School of Medicine,describes a ward of Beijing Hospital that he visited on a trip toChina in 1986. Dozens of paralyzed children---some attached torespirators to assist their breathing--filled the ward tooverflowing. The chinese doctors thought the children hadGuillain-Barre syndrome (GBS), a rare paralytic condition, but Dr.McKhann wasn’t convinced. There were simply too many strickenchildren for the illness to be the rate Guillain-Barre syndrome.Was it polio--as some of the Beijing staff feared? Or was itanother illness, perhaps one that had not yet beendiscovered?
Guillain-Barre syndrome is a relatively rare paralyticcondition that strikes after a viral infection or an immunization.There is no cure, but usually the paralysis slowly disappears, andlost sensation slowly returns as the body repairs itself. Inclassic Guillain-Barre, patients can neither feel sensations normove their muscles.
Which division(s) of the nervous system may be involvedin Guillain-Barre Syndrome?
Do you think the paralysis found in the chinese childrenaffected both sensory (afferent) and somatic motor neurons? Why orwhy not?
In classic GBS, what would you expect the results of anerve conduction test to be?
Dr. McKhann decided to perform nerve conduction tests onsome of the paralyzed children in Beijing Hospital. He found thatalthough the rate of conduction along the children’s nerves wasnormal, the strength of the summed action potentials traveling downthe nerve was greatly diminished.
Is the paralytic illness that affected the chinesechildren a demyelinating condition? Why or why not?
Dr. McKhann then asked to see autopsy reports on some ofthe children who had died of their paralysis at Beijing Hospital.In the reports, pathologists noted that the patients had normalmyelin but damaged axons. In some cases, the axon had beencompletely destroyed, leaving only a hollow shell ofmyelin.
Do the results of Dr. McKhann’s investigation suggeststhat the Chinese children had classic GBS? Why or whynot?
Dr. McKhann suspected that the disease afflicting thechinese children-- which he named acute motor axonal polyneuropathy(AMAN)--might be triggered by a bacterial infection. He alsothought that the disease initiated its damage of axons atneuromuscular junctions, the synapses between somatic motor neuronsand skeletal muscles. Â
Based on information provided in this chapter, nameother diseases involving altered synaptictransmission.
