Criteria
Assessment of current diagnostic criteria for Guillain-Barre syndrome[87][148]
Required features
Progressive weakness in both arms and legs
Areflexia (or hyporeflexia).
Features supportive of diagnosis
Progression of symptoms over days to 4 weeks
Relative symmetry
Mild sensory signs or symptoms
Cranial nerve involvement, especially bilateral facial weakness
Recovery beginning 2 to 4 weeks after progression ceases
Autonomic dysfunction
Absence of fever at onset
Typical cerebrospinal fluid (CSF) and electromyogram/nerve conduction studies features.
Features casting doubt on the diagnosis
Asymmetric weakness
Persistent bladder and bowel dysfunction
Bladder or bowel dysfunction at onset
>50 mononuclear leukocytes/mm³ or presence of polymorphonuclear leukocytes in CSF
Distinct sensory level.
Features that rule out the diagnosis
Hexacarbon abuse
Abnormal porphyrin metabolism
Recent diphtheria infection
Lead intoxication
Other similar conditions: poliomyelitis, botulism, hysterical paralysis, toxic neuropathy.
Electrophysiologic classification of Guillain-Barre syndrome[108][112]
Neurophysiologic criteria for acute inflammatory demyelinating polyradiculoneuropathy (AIDP), acute motor-sensory axonal neuropathy (AMSAN), and acute motor axonal neuropathy (AMAN).
At least 3 sensory nerves and 3 motor nerves with multisite stimulation F waves, and bilateral tibial H reflexes, need to be evaluated.
AIDP
At least 1 of the following in each of at least 2 nerves, or at least 2 of the following in 1 nerve if all others inexcitable and distal compound muscle action potential (dCMAP) >10% lower limit of normal (LLN):
Motor conduction velocity <90% LLN (85% if dCMAP <50% LLN)
Distal motor latency >110% upper limit of normal (ULN) (>120% if dCMAP <100% LLN)
Proximal compound muscle action potential (pCMAP)/dCMAP ratio <0.5 and dCMAP >20% LLN
F-response latency >120% ULN.
Newer criteria have been proposed for AIDP, which increase the sensitivity of diagnosis, and include:[114]
At least 1 of the following in at least 2 nerves: mean corpuscular volume <70% LLN; distal motor latency >150% ULN; F-response latency >120% ULN, or >150% ULN (if distal CMAP <50% of LLN); or
F-wave absence in 2 nerves with dCMAP ≥20% LLN or greater, with an additional parameter, in 1 other nerve; or
pCMAP/dCMAP ratio <0.7 (excluding the tibial nerve) in 2 nerves, with an additional parameter in 1 other nerve.
AMSAN
Diminution of muscle and sensory action potentials[64]
None of the features of AIDP except 1 demyelinating feature allowed in 1 nerve if dCMAP <10% LLN
Sensory action potential amplitudes less than LLN.
AMAN
Reduction in distally evoked motor action potential amplitudes, early signs of denervation on needle, normal action potential on sensory nerves, and relatively preserved motor nerve conduction velocity.[51][67][68]
None of the features of AIDP except 1 demyelinating feature allowed in 1 nerve if dCMAP <10% LLN
Sensory action potential amplitudes normal.
Inexcitable
dCMAP absent in all nerves or present in only 1 nerve with dCMAP <10%.
Miller-Fisher syndrome
Reduced or absent sensory action potential response without slowing of sensory conduction velocity.[149]
Electrodiagnostic criteria for acute inflammatory demyelinating polyradiculoneuropathy[113]
Different sets of criteria have been published, including the following (sensitivity 64% to 72%):
150% prolongation of motor distal latency above ULN
70% slowing of motor conduction velocity below LLN
125% (150% if the distal negative-peak CMAP amplitude was 80% of LLN) prolongation of F wave latency above ULN
Abnormal temporal dispersion (peak CMAP duration increase) in ≥2 nerves.
Hughes Scale[150]
0 - healthy
1 - minor symptoms or signs of neuropathy but capable of manual work
2 - able to walk without support of a stick but incapable of manual work
3 - able to walk with a stick, appliance, or support
4 - confined to bed or chairbound
5 - requiring assisted ventilation
6 - dead
Identification of patients with GBS at risk of respiratory failure using the 20/30/40 rule[125]
In patients with no bulbar dysfunction, or with mild bulbar dysfunction without aspiration risk, the 20/30/40 rule should be used.
Intensive care unit monitoring and elective intubation should be considered if any of the following is present:
Vital capacity <20 mL/kg (odds ratio 15.0)
Maximal inspiratory pressure worse than -30 cmH₂O
Maximal expiratory pressure <40 cmH₂O
Reduction of 30% or more of vital capacity, maximal inspiratory pressure, or maximal expiratory pressure.
How to insert a tracheal tube in an adult using a laryngoscope.
How to use bag-valve-mask apparatus to deliver ventilatory support to adults. Video demonstrates the two-person technique.
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