Guillain-Barré Syndrome

INTRODUCTION:

-Acute inflammatory demyolinating 

polyneuropathy, AIDP

- Acute inflammatory demyelinating Polyradiculoneuropathy

Acute inflammatory polyneuropathy

-acute inflammatory demyelinating polyneuropathy characterized by acute onset of peripheral and cranial never dysfunction 

-progressive symmetric weakness and areflexia, facial diplegia, oropharyngeal and respiratory paresis, and impaired sensation in hands and feet

INCIDENCE

-annual incidence of 0.6 to 1.9 cases per   100,000 population and occurs at all ages  and  in both sexes

-It increases in patients with Hodgkin   diseases, as well: as with pregnancy or   general surgery

-It is now the most common cause of acute    flaccid paralysis in healthy people 

ETIOLOGY:unknown

-Peripheral nerve demyelination  is believed   to be immune mediated

-Humoral factors and cell-mediated immune    phenomena have been implicated in the damage  of myelin and/or the myelin-producing   Schwann cells

-GBS has been reported to follow: 

 vaccinations 

 epidural anesthesia

 thrombolytic agents 

-It is also associated with some systemic  processes, e.g. 

 Hodgkin's disease 

 SLE 

 Sarcoidosis 

 infection with Campylobacter, Lyme disease,   EBV, CMV, HSV, mycoplasma, and  acquired HIV  infection

-More than half patients describe an   antecedent viral infection

-Campylobacter infection is the most commonly  identified precipitant of GBS

PATHOGENESIS:

-It may be caused by cross-reacting   antibodies to GM1 ganglioside (present in   high concentrations in peripheral nerve   myelin) formed in response to similar   epitopes expressed by the infecting   Campylobacter strain

PATHOLOGY:

-focal segmental demyelination  with   perivascular and endoneurial infiltrates of   lymphocytes and monocytes or macrophages

-These lesions are scattered throughout the   nerve, nerve roots, and cranial nerves

-In severe lesions, both axonal degeneration   and segmental demyelination can  be found

-During recovery, re-myelination occurs, but   lymphocytic infiltrates may persist.

                                          focal segmental demyelination and myelin destruction   

CLINICAL FEATURES:

-It often appears days to weeks after   symptoms of a viral upper respiratory or  gastrointestinal infection

-Progressive symmetric limb weakness involve   more than one limb, often with paresthesia,   proximal muscles are more often than distal   muscle.

-The weakness may be ascending or descending

-Occasionally, facial, ocular, oropharyngeal  muscles may be affected, ＞50% have facial  diplgia, and dysphagia and dysarthria. Some  require mechanical ventilation

-Areflexia

-The degree of sensory impairment varies:  sensory modalities are preserved; or marked  diminution in perception of joint position,  vibration, pain, and temperature in  stocking-and-glove distribution

-Occasionally  exhibits papilledema, sensory  ataxia, and transient extensor plantar  response

-Autonomic dysfunction is commonly  associated, e.g. orthostatic hypotension,  labile BP, tachyarrhythmia, bradyarrhythmia,  resting tachycardia,disturbed sweating is  frequent in severe cases, and easy to die

-There are no signs of minigeal irritation  such as nuchal rigidity

-50% of patients will reach a nadir by 2  weeks

-Recovery of function usually begin 2-4 weeks  after progression stops

LABORATORY TEST:

-CSF（cerebrospinal fluid): cell count is  usually normal. Protein content is elevated  in most patients but may be normal in the  first few days after onset. it may increase  from 2 weeks after onset. Protein(0.8-8g/L). 

 This is called “phenomenon of protein-cell  dissociation”

ELECTROPHYSIOLOGY:

-Electromyography (EMG): As a result of   demyelination of never roots, F-wave or H-  reflex are often slowed or response absent

-Nerve conduction velocities (NCV) are  reduced, but values may be normal early in  the course

-Digital sensory and motor latency are  prolonged

-Amplitudes of compound  motor action  potential (CMAP) may be normal or reduced

VARIANTS:

Miller-Fisher Syndrome:

-characterized by  gait ataxia, arefexia, and  ophthalmoparesis,  papillary abnormalities  are sometimes  present

-It is often preceded by respiratory  infection, it progresses for weeks and then  improve, CSF protein content is increased

-There is no limb weakness

-Titers of anti-GQ1b antibodies are increased

-NCV are commonly normal, H-reflex may be  affected 

Acute motor axonal neuropathy (AMAN): 

-there is  motor axonal degeneration and  little or no demyelination 

-It may follow infection with campylobacter  jejuni or paraenteral injection of  gangliosides

-Titers of IgG or IgA antibodies to GM1 or  GD1a gangliosides may increase by serologic  studies

DIAGNOSIS:

-Acute or subacute development of symmetric 

 motor or sensorimotor neuropathy after a  viral illness, delivery, or  surgery

-Compatible EMG alterations

-CSF: elevated protein content 

 with normal cell count 

DIFFERENTIAL DIAGNOSIS:

1.Acute poliomyelitis:

-acute, generalized disease caused by  destruction of motor neurons in the spinal  cord

-It is distinguished by asymmetry of flaccid  paralysis, signs of meningeal irritation,  fever, and CSF pleocytosis

-no dysfunction of sense( anaesthesia;  hyperaesthesia

2.Acute myelitis: 

-a transverse myelitis interrupting both  motor and sensory tracts at one level,  usually thoracic. 

-It usually begins with localized back or  radicular pain followed by abrupt onset of  bilateral paresthesia in the legs, an  ascending sensory level

-Urinary bladder and bowel involvement occurs  early and is prominent

-Both cell count and Protein content in CSF  are mildly elevated or normal

3.Myasthenia Gravis

-characterized by fluctuating weakness

 affected muscles involve: ocular, facial,   oropharyngeal muscles. Limb and neck 

-weakness is also common

-Myasthenia weakness is the clinic response  to cholinergic drugs

-CSF are normal

4. Periodic paralysis (hypokalemic):

-characterized by episodic bouts of limb   weakness

-Familial history of transient attack of  weakness

-Low potassium in the serum, and low  potassium changes in the ECG

-CSF are normal

-Weakness can be terminated by administration  of potassium salts

TREATMENT:

-Early plasmapheresis has proved useful

-IVIG (intravenous immune globulin) therapy  is also beneficial

-Glucocorticoid administration does not  shorten the course or affect the prognosis

-Mechanically assisted ventilation is  sometimes necessary

-Precautions against aspiration of food or  stomach contents must be taken if  oropharyngeal muscles are affected

-Exposure keratitis must be prevented in  patients with facial diplegia

-Rehabilitations: sport, acupuncture,  physical therapy, gait training, traditional  medicine, etc

COURSE AND PROGNOSIS:

-Symptoms are usually most severe within 1wk  of onset but may progress for 3 w or more

-In most, recovery is slow and not complete  for many months

-Recovery is accelerated by early plasma  exchange or IVIG

-In untreated series, about 35% have  permanent residual hyporeflexa, atrophy, and  weakness of  distal muscles or facial  paresis

-Recurrent after recovery occurs in about 2%

-Death is uncommon but may follow aspiration  pneumonia, pulmonary embolism, intercurrent  infection, or autonomic dysfunction

CASE STUDY:

-A 20 y female developed flu-like symptoms, severe diarrhoea and abdominal pain 3 d after attending a dinner party at which he had eaten a chicken. These symptoms settled within a few days. Stool cultures taken from her grew Campylobacter jejuni. About 9 d after the onset of diarrhoea, he developed diffuse aching around his body and pins and needles in his hands and feet. Over the next week the sensory spread to involve his arms and legs. His limbs became progressively weaker and 8 d after the onset of neurological symptoms he could not hold a cup or stand unaided. He was  found to have severe symmetrical distal limb weakness and ‘glove and stocking’ sensory loss to the elbows and knees. EMG studies showed evidence of reduced NCV and her CSF showed a very high total protein level at 3g/l but without  increase of cells in the CSF. High titres of IgM and IgG antibodies to Campylobacter jejuni were found in her  blood. 

-She was treated with high-dose intravenous immunoglobulin but his condition deteriorated with respiratory muscle weakness and he required mechanical ventilation. His condition slowly improved and he was able to breathe spontaneously after 2 w. His strength and sensory symptoms slowly improved with  physiotherapy, but 1 y later he still had a little weakness in his hands and feet.