Diagnosis of Guillain Barre Syndrome

PBL 29 Tattered Nerve

Differential Diagnosis

• Diphtheria

• Lyme disease

• Neuromuscular transmission disorder

• Botulism

• Snake venom

• Brainstem infarction

• Acute myelopathies

• Transverse myelitis

• Take note of the preconditions particularly early in the course

• Ask the patient whether he travelled to any regions (tropical regions, poisonous to be considered, underdeveloped countries)

• Ask the patient regarding their detailed daily activities (recently)

Detailed history and careful examination can come up with correct initial diagnosis GBS

Evaluation of GBS

Electrodiagnostic testing

• Testing of nerves and muscles

• Can provide an estimate of prognosis

• Can be done in emergency room or even ICU and the results can be obtained after completing the test

• May be painful but relatively non-invasive

• Involving electromyography (EMG) and nerve conduction study

Nerve Conduction Studies

• Most important

• Electric shock (given using small, hand held device) through skin at different sites along the course of the nerves (2 sites) to activate the nerves

• Responses are recorded with small needles/small disc inserted

• The electrical impulse travels along the nerve can be recorded from the muscles it supply

Size of response reflects the number of functioning nerves connected to muscle fibers, speed of conduction reflects the integrity of myelin sheath . (Normal electrical impulses travel at 40 to 45 m/s)

Motor conduction study on the hand of 37 years old man who has been weak for GBS for 8 days

Electromyography

• Plays a negligible role but is an important supplementary tool to assess degree of axonal damage

• A needle is inserted into the muscle to sense the electrical activity

• Needle is inserted onto a relaxed muscle initially and ask the patient to contract the muscle, the muscle activity will be transform into visual and aural signal

• Abnormal if electrical activity in relaxed muscle (fibrillation)• Not shown onset, people suspected of having GBS will be

asked to return for second study a few weeks after initial study

• Degree of prognosis is depending on degree of fibrillation

Cerebrospinal fluid testing

• Done by lumbar puncture, where a fine needle is inserted between L4/L5 spinal cord segment and withdrawn the cerebrospinal fluid

• Increase in level of protein concentration with normal numbers of cells (albuminocytologicdissociation), normal level of glucose, lymphocyte cell count <50cells/ml

• Second tap is needed after a week or so if patient is suspected of having GBS

Blood test

• White blood cell count usually normal, no antibodies against nerve components can be reliably detected in blood

• Is done to exclude other conditions/establish nature of any antecedent infection that has lead to GBS

• Antibodies against the microorganisms can be detected

• Monitor level of sodium concentration

X-Ray/MRI Scans

• Not typically necessary

• May be useful if there are unusual feature that makes the diagnosis uncertain

• Eg. Inflammation of spinal cord in transverse myelitis mimics GBS

• MRI of brain will be done if there is prominent involvement of cranial nerves (in Miller Fisher Syndrome)