Neuro: GBS

Question 1

Typical presentation of GBS?

Answer 1

Ascending motor and sensory disturbance following recent gastric symptoms

Question 2

Most common cause of peripheral neuropathy in western world?

Answer 2

Guillain-Barre Syndrome
Guillan-Barré syndrome is an “acute paralytic polyneuropathy” that affects the peripheral nervous system. It causes acute, symmetrical, ascending weakness and can also cause sensory symptoms. It is usually triggered by an infection and is particularly associated with to campylobacter jejuni, cytomegalovirus and Epstein-Barr virus.

Question 3

Subtypes of GBS?

Answer 3

95% - acut inflammatory demyelinating polyradiculopathy -AIDP (sensory motor neuropathy +/- autonomic features
AMAN - acute axonal neuropathy - much worse prognosis -
AMSAN - acute motor and sensory axonal neuropathy
Acute pandysautonomia

Overlap- Miller Fisher syndrome (sensory ataxia, arreflexia, opthalmoplegia)

Question 4

PATHOPHYSIOLOGY OF GBS

Answer 4

Guillain-Barré is thought to occur due to a process called molecular mimicry.

The B cells of the immune system create antibodies against the antigens on the pathogen that causes the preceding infection.

These antibodies also match proteins on the nerve cells. (Cross reaction with schwann cell/ (axolemma) antigens

They may target proteins on the myelin sheath of the motor nerve cell or the nerve axon.

This impairs neurotransmission to the periphary

May be damage to sensory and motor nerves in the somatic division of the PNS, but also the autonomic division (causing symptoms such as labile heart rate and blood pressure)

Occurs 1-3 weeks after immunesystem stimulation (or other inflammatory event - trauma, surgery, vaccination, pregnancy)

Question 5

Triggers of GBS?

Answer 5

campylobacter jejuni,
cytomegalovirus
Epstein-Barr virus

Question 6

GBS symptoms?

Answer 6

Symmetrical ascending weakness (starting at the feet and moving up the body)
Reduced reflexes
There may be peripheral loss of sensation or neuropathic pain
It may progress to the cranial nerves and cause facial nerve weakness

Question 7

How long after inflammatory event (usually infection such as GI or URTI) does GBS begin?

Answer 7

1-3 weeks after immune system stimulation

Question 8

Clinical course of Guillain-Barre syndrome?

Answer 8

The symptoms typically start in the feet and progresses upward. (rapidly ascending weakness over hours to days)
FEVER IS ABSENT AT ONSET
Relatively synettric with mild sensory signs or symptom
Lower motor neuron signs develop

Symptoms peak within 2-4 weeks, then there is a recovery period that can last months to years.
Usually monophasic, self limiting
If surpasses 8 weeks without improvement or plataue prognosis is poorer

Question 9

What is CIDP (chronic inflammatory demyelinating polyradiculoneuropathy)

Answer 9

GBS symptoms which reach 8 weeks without plateau or improvement
Relapsing course requiring repeated treatment over long periods of time

Radiculoneuropathy - condition starts in nerve roots - pts often complain of midback pain preceeding weakness and sensory symptoms occur

Question 10

How is GBS diagnosed?

Answer 10

A diagnosis of Guillain-Barré syndrome is made clinically. The Brighton criteria can be used for diagnosis.

Diagnosis can be supported by investigations:

Nerve conduction studies (reduced signal through the nerves)
Lumbar puncture for CSF (raised protein with a normal cell count and glucose)

Question 11

Nerve conduction studies in GBS?

Answer 11

Reduced signals through nerves
May only show very subtle abnormalities in the first week: prolonged F waves - indicating nerve root involvement

Question 12

CSF in GBS?

Answer 12

May be normal in first 1-2 weeks (should still be done early, r/o other differentials)

Increase protein
Normal or mildly raised lymphocytes

Question 13

How might you investigate GBS?

Answer 13

Lumbar puncture
Nerve conduction studies
Consider serology: camplyobacter if GI upset, CMV, EBV, HSV, HIV, mycoplasma
Stool coltures
Throat swab

(Not first line, if suspecting known GBS syndromes of MF syndrome)
Anti-ganglioside antibodies - AMAN - anti GM1, C Jejuni, MF - antiGQ1B

Question 14

What autonomic symptoms may occur in GBS?

Answer 14

Labile pulse and blood pressure
Urinary retention
Illeus

Question 15

Complications of GBS?

Answer 15

Autonomic dysfunction
Type II respiratory failure
Although prognosis usually good, 25% may need ventilatory support - monitor FVC in these patients to consider ITU involvement
DVT/PE - immobile or reduced mobility
Pain
SIADH
Renal failure secondary to IVIG treatment
Hypercalcemia (long term immobility)

Question 16

GBS prognosis

Answer 16

70-80% will fully recover
15-35% will be left with some neurological disability
25% will req ventilattory support at some point
5% will die

Question 17

Management of GBS?

Answer 17

Milder cases do not need treating and are self limiting

IV immunoglobulins
Plasma exchange (alternative to IV IG)
Steroids if above not effective
Supportive care: Nutritional support/NG tube, urinary catheter, laxiatives and bowel care, pain control
Bedside spiromtry to monitor for resp. failure
ECG +/- cardiac monitoring
VTE prophylaxis (pulmonary embolism is a leading cause of death)
In severe cases with respiratory failure patients may need intubation, ventilation and admission to the intensive care unit.

Question 18

Progressive peripheral polyneuropathy with hyporeflexia suggests what?

Answer 18

Guillain-Barre syndrome