Question

“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 to China in 1986. Dozens of paralyzed children---some attached to respirators to assist their breathing--filled the ward to overflowing. The chinese doctors thought the children had Guillain-Barre syndrome (GBS), a rare paralytic condition, but Dr. McKhann wasn’t convinced. There were simply too many stricken children for the illness to be the rate Guillain-Barre syndrome. Was it polio--as some of the Beijing staff feared? Or was it another illness, perhaps one that had not yet been discovered?

Guillain-Barre syndrome is a relatively rare paralytic condition that strikes after a viral infection or an immunization. There is no cure, but usually the paralysis slowly disappears, and lost sensation slowly returns as the body repairs itself. In classic Guillain-Barre, patients can neither feel sensations nor move their muscles.

Which division(s) of the nervous system may be involved in Guillain-Barre Syndrome?

Do you think the paralysis found in the chinese children affected both sensory (afferent) and somatic motor neurons? Why or why not?

In classic GBS, what would you expect the results of a nerve conduction test to be?

Dr. McKhann decided to perform nerve conduction tests on some of the paralyzed children in Beijing Hospital. He found that although the rate of conduction along the children’s nerves was normal, the strength of the summed action potentials traveling down the nerve was greatly diminished.

Is the paralytic illness that affected the chinese children a demyelinating condition? Why or why not?

Dr. McKhann then asked to see autopsy reports on some of the children who had died of their paralysis at Beijing Hospital. In the reports, pathologists noted that the patients had normal myelin but damaged axons. In some cases, the axon had been completely destroyed, leaving only a hollow shell of myelin.

Do the results of Dr. McKhann’s investigation suggests that the Chinese children had classic GBS? Why or why not?

Dr. McKhann suspected that the disease afflicting the chinese children-- which he named acute motor axonal polyneuropathy (AMAN)--might be triggered by a bacterial infection. He also thought that the disease initiated its damage of axons at neuromuscular junctions, the synapses between somatic motor neurons and skeletal muscles.  

Based on information provided in this chapter, name other diseases involving altered synaptic transmission.

Answer 1

GBS is a rapid onset muscle weakness is caused by the immune system damaging the peripheral nervous system. The initial symptoms are typically change in the sensation or pain along with muscle weakness beginning in the feet and hands open spreading to the arms and upper body with both side being involved.During the acute phase the disorder can be life threatening with about 15% of people developing weakness of the breathing muscles and therefore requiring mechanical ventilator. Some affected by changes in the function of the autonomic nervous system which can lead to dangerous abnormality in the heart rate and blood pressure.

Basically mechanism involved in this disease is autoimmune disorder in which body immune system attacks the peripheral nerves and damages their myeline insulation. Symptoms include numbness tingling and pain. The muscles of the neck may be also affected and that experience involvement of cranial nerves which interns supplies the head and face which effects weakness of the muscle of the face swallowing difficulties and weakness of the eye muscles. It also includes weakness of breathing muscles leading to respiratory failure. Since it is auto immune disorder, affects the functions like the Heartbeat sometime Heartbeat stops also required pacemaker based. GBS can happen to anyone but its most common in people 50 years old or older. No one is sure if a firm or virus Zika virus causes GBs that some illnesses your Nerve cells so your immune system start to view them as other things your immune system forget which cells it shouldn't attack. Usually shows up a few days or weeks after a cold stomach virus for the flu in rear cases surgery or vaccination can triggered here to mention compiler bacteria battery associated with GBS when you it immune system begins attacking your nerve cell that weakens the ability to send signals to your brain and your muscles that can't respond to nerve signals as a result of brain gets fever message to your body.

Most of the cases a provoked by compyloBacter bacteria which causes diarrhoea. The Nerve cells have their body so much in the spinal cord and along projection that carries electrical nerve impulse to the neuromuscular junction where the impulse is transferred to the muscle. Axons are wrapped in the sheet of schwan cell that contain Myelin. At the nodes of Ranvier the axons are exposed. Different types of GBs features different types of immune attack the demyelinating variant features damage to myelin sheath buy white blood cells. This process is preceded buy activation of a group of blood proteins known as complement.

In contrast with axonal variant is mediated by igG antibodies and complement against the cell membrane covering the axon without direct lymphocytes involvement. In axonal subtype these antibodies have been shown to bind to gangliosides. With different anti ganglioside antibodies be associated with particular features. For instance GQ 1B antibodies have been linked with Miller fisher variant GBs and related to forms including Bickerstaff encephalitis.

After compilobacter infection the body produces antibodies of IgA class. Only a small proportion of people also produces igG antibodies against bacterial substances cell wall substances. That cross react with human nerve cell gangliosides it is not currently known how this process is caves Central tolerance to gangliosides which is meant to suppress the production of antibodies against the body own substances.

The diagnosis of GBs depends on the findings such as Rapid development of muscle paralysis ,absent reflexes a,of fever and a likely cause. Cerebrospinal fluid analysis and nerve conduction studies are supportive investigation commonly performed in the diagnosis of GBS. If an MRI scan shows enhancement of the nerve roots this maybe indicator of GBs in children this feature is present in 95% of scans but it is not specific to GBs so other confirmation is also needed. Cerebrospinal fluid envelopes the brain and spine ,a puncture for spinal tap is the removal of a small amount of fluid using a needle inserted between the lumbar vertebrae. Characteristic findings in GBs are an elevated protein level usually greater than 0.55 gram per litre and fewer then 10 white blood cells per cubic millimeter of fluid.

Directly assessing nerve conduction of electrical impulses can exclude other causes of acute muscle weakness as well as distinguish the different types of GBS. Needle electromyography and nerve conduction studies may be performed. In the first two weeks these investigations may not show any abnormality. Neurophysiology studies are not required for the diagnosis. Formal criteria exist for each of the main subtype of GBS n AIDP AND AMAN/AMSAN.

But these Ne mis classify some cases and therefore changes to these Criterias have been proposed. Sometime repeated testing may be helpful.

Types	symptoms	nerve conduction studies
AIDP(ACUTE INFLAMMATORY DEMYELINATING POLYNEUROPATHY)	SENSORY SYMPTOMS AND MUSCLES WEAKNESS WITH CRANIAL NERVE WEAKNESS AND AUTONOMIC INVOLVEMENT.	DEMYELINATING POLYNEUROPATHY
AMAN (ACUTE MOTOR AXONAL NEUROPATHY)	ISOLATED MUSCLE WEAKNESS WITHOUT SENSORY SYMPTOMS IN LESS THAN 10% CRANIAL NERVE INVOLVEMENT UNCOMMON.	AXONAL POLYNEUROPATHY, NORMAL SENSORY ACTION POTENTIAL
AMSAN(ACUTE MOTOR AND SENSORY AXONAL NEUROPATHY).	SEVERE MUSCLE WEAKNESS SIMILAR TO AMAN BUT WITH SENSORY LOSS.	EXONERATE POLYNEUROPATHY, REDUCED OR ABSENT SENSORY ACTION POTENTIAL.
PHARYNGEAL CERVICAL BRANCHIAL VARIANT.	WEAKNESS PARTICULARLY OF THE THROAT MUSCLE AND FACE, NECK AND SHOULDER MUSCLE.	GENERALLY NORMAL SUN-TIMES AXONAL NEUROPATHY IN ARMS.
MILLER FISHER SYNDROME	ATAXIA, EYE MUSCLE WEAKNESS BUT USUALLY NO LIMB WEAKNESS.	GENERALLY NORMAL SOMETIMES DISCRETE CHANGES IN SENSORY CONDUCTION OR H REFLEX DETECTED.

Treatment involves plasmapheresis and intravenous immunoglobulin. These are the two main immunotherapy treatments for GBS. Plasmapheresis attempts to reduce the body is attack on the nervous system by filtering antibodies out of the bloodstream.

Administration of intravenous immunoglobulin neutralizes harmful antibodies and inflammation.

Respiratory failure may require intubation of the trachea and breathing support to mechanical ventilator generally on an Intensive Care Unit.

Intensive rehabilitation with the help of multi disciplinary team to focus on improving activities of daily living.

Teams may include physical therapist, occupational therapist, Speech Language pathologist, social workers , psychologist ,other allied health professionals and nurses. Victim usually works under the supervision of a Neurologist or rehabilitation physician directing treatment goals.