Differentials
Transverse myelitis
SIGNS / SYMPTOMS
Spinal cord disorders including transverse myelitis present with asymmetrical motor or sensory loss usually involving lower extremities, early bowel or bladder dysfunction with persistent incontinence, and segmental radicular pain.
Physical examination demonstrates upper motor neuron signs (hyper-reflexia, positive Babinski's response) and a sensory level.
INVESTIGATIONS
Cerebrospinal fluid analysis: pleocytosis with modest number of lymphocytes and increase in total protein.
MRI shows focal demyelination with possible enhancement at the appropriate level.
Myasthenia gravis
SIGNS / SYMPTOMS
Early involvement of muscle groups including extra-ocular, levator, pharyngeal jaw, neck, and respiratory muscles. Sometimes presents without limb weakness.
Excessive fatigability and variation of symptoms and signs through the day is common.
Reflexes are preserved, and sensory features, dysautonomia, and bladder dysfunction are absent.
INVESTIGATIONS
Electrophysiological study shows normal nerve conduction and presence of decremental response to repetitive nerve stimulation.
Electromyogram shows abnormal jitter and blocking.
Lambert-Eaton myasthenic syndrome (LEMS)
SIGNS / SYMPTOMS
Can be difficult to differentiate because of similar clinical characteristics.
Characteristics more typical of LEMS include slower development of clinical symptoms, dry mouth, lack of objective sensory loss, rare involvement of respiratory muscle group, and potentiation of reflexes after exercise or contraction.[147]
INVESTIGATIONS
Electrophysiological study: hallmark is a low amplitude compound muscle action potential (CMAP) after single nerve stimulus, increase in CMAP amplitude after voluntary contraction, or repetitive stimulation at high frequencies.[147]
Botulism
SIGNS / SYMPTOMS
History of ingesting food tainted with botulinum toxin.
Descending paralysis begins in the bulbar muscles then the limbs, face, neck, and respiratory muscles.
Respiratory muscles are involved with mild limb weakness, and reflexes are usually preserved.
Ptosis, dilated non-reactive pupils are present. Dilated non-reactive pupils are uncommon in GBS, but more common in botulism.
Constipation is also a characteristic feature of botulism.[147]
INVESTIGATIONS
Electrophysiological study: reduced amplitude of evoked muscle potentials, increase in amplitude with repetitive nerve stimulation, and increased number of myopathic units, which is atypical for GBS.[147]
Polymyositis
SIGNS / SYMPTOMS
Presence of pain and muscle tenderness usually in the shoulder and upper arm, involvement of flexor neck muscle disproportionate to limb weakness, absence of sensory symptoms, preservation of reflexes, absence of dysautonomia, and presence of skin lesions, which are uncommon presentation for GBS.[147]
INVESTIGATIONS
Elevated erythrocyte sedimentation rate and creatine kinase, normal nerve conduction study, and myopathic changes with fibrillation on electromyogram.
Muscle biopsy shows muscle fibre destruction and regeneration, and lymphocyte infiltrates.[147]
Vasculitic neuropathy
SIGNS / SYMPTOMS
Common features include painful asymmetrical presentation of muscle weakness, uncommon involvement of cranial nerves, respiratory paralysis, and sphincter dysfunction.
Usually patients report fever, fatigue, weakness, and arthralgia.[147]
INVESTIGATIONS
May have elevated erythrocyte sedimentation rate.
Cerebrospinal fluid does not show albuminocytological dissociation.
Electrophysiological study shows evidence of denervation.
Nerve biopsy shows signs of inflammation and scarring.[147]
Use of this content is subject to our disclaimer