Guillain-Barre Syndrome

The answer first

Guillain-Barre syndrome (GBS) is an acute, immune-mediated polyradiculoneuropathy. The clinical signature is progressive, symmetric, ascending weakness with areflexia that reaches its nadir within 4 weeks. It is the most common cause of acute generalized paralysis since polio was eradicated, and it is a medical emergency: around one in four patients needs mechanical ventilation, and autonomic failure causes a substantial share of deaths. [1]

Three facts organise everything else: [1]

It is treatable. Both intravenous immunoglobulin (IVIG) and plasma exchange speed recovery if given within 2-4 weeks of onset. Corticosteroids do not work and may worsen the disease.
The threat to life is respiratory and autonomic, not the weakness itself. Bedside lung function monitoring (FVC, MIP, MEP), not the strength of the grip, decides who goes to ICU and who is intubated.
The diagnosis is clinical and supported by CSF and nerve conduction studies. A normal CSF in the first week does not exclude GBS — albuminocytologic dissociation appears after 1-2 weeks. [1]

The organising principle on the ward is: diagnose early, monitor lung function relentlessly, treat with IVIG or plasma exchange (not both), never give steroids, and watch the clock for the 8-week boundary that converts the diagnosis to CIDP. [1]

Classification and the spectrum

Classification for guillain barre syndrome

Ascending symmetric weakness progressing from legs to arms to cranial nerves and respiration, with the GBS disability scale and time-to-nadir curve

GBS is a syndrome with several subtypes defined by the site of immune attack and the electrophysiology. The variant determines the antibody, the trigger, and sometimes the prognosis. [1]

The major variants

Variant	Frequency	Mechanism	Typical antibody	Notes
AIDP (acute inflammatory demyelinating polyradiculoneuropathy)	around 85-90% in Western countries	Demyelination	Variable	Most common; the prototype
AMAN (acute motor axonal neuropathy)	Common in Asia, Latin America	Axonal motor	Anti-GM1, anti-GD1a	Pure motor; post-Campylobacter; faster nadir
AMSAN (acute motor-sensory axonal neuropathy)	Less common	Axonal motor and sensory	Anti-GM1	Severe; slow, incomplete recovery
Miller Fisher syndrome	around 5%	Cranial nerve and muscle spindle	Anti-GQ1b	Ophthalmoplegia, ataxia, areflexia
Bickerstaff brainstem encephalitis	Rare	Brainstem overlap	Anti-GQ1b	Miller-Fisher plus altered consciousness (coma)
Pharyngeal-cervical-brachial variant	Rare	Upper-body predominant	Anti-GT1a	Isolated bulbar and arm weakness

DWE high-yield: The most tested association is anti-GQ1b with Miller Fisher syndrome (ophthalmoplegia, ataxia, areflexia). The second is anti-GM1 with AMAN after Campylobacter jejuni. Know both. The ataxia in Miller Fisher is sensory (proprioceptive, from muscle spindle involvement), not cerebellar. [1]

The GBS disability scale

This 0-6 scale (the Hughes scale) is the universal outcome measure and the decision tool for treatment. [1]

Grade	Function
0	Healthy
1	Minor symptoms, able to run
2	Able to walk 10 m without assistance
3	Able to walk 10 m with assistance
4	Chairbound/bedbound
5	Requiring assisted ventilation for some of the day
6	Dead

Treatment threshold is grade 3 or worse (unable to walk unaided), or any sign of respiratory, bulbar, or autonomic decline. [1]

Pathophysiology

Molecular mimicry — the mechanism that links the trigger to the nerve

GBS is a post-infectious, immune-mediated disease. About two-thirds of patients report an infection in the preceding 1-3 weeks. The mechanism is molecular mimicry: the infecting organism expresses surface molecules that resemble gangliosides on human peripheral nerves. The resulting antibody response cross-reacts with nerve tissue. [1]

The best-characterised example is Campylobacter jejuni. Its lipo-oligosaccharide coat carries ganglioside-like structures (GM1, GD1a, GT1a). Antibodies raised against the bacterium bind to gangliosides at the nodes of Ranvier and on myelin. This was proven experimentally: immunising rabbits with C. jejuni LPS from GBS-associated strains induces anti-GM1 and anti-GQ1b antibodies and a flaccid paralysis resembling the human disease (Ang 2001, PMID 11254608). [1]

Trigger	Approximate frequency	Typical antibody	Variant association
Campylobacter jejuni (gastroenteritis)	around 30%	Anti-GM1, anti-GD1a	AMAN, AMSAN, AIDP
Cytomegalovirus (CMV)	around 10%	Anti-GM2	AIDP, prominent sensory and cranial nerve
Epstein-Barr virus	around 5%	Variable	AIDP
Mycoplasma pneumoniae	less common	Anti-GalNAc-GD1a	Often in children
Haemophilus influenzae	less common	Variable	AIDP
Zika virus	Outbreak-related	Variable	AIDP (French Polynesia, Latin America)
Influenza	less common	Variable	AIDP
Surgery, trauma, immunisation	around 5%	Variable	AIDP

DCE viva trap: When asked "is GBS caused by vaccines?", the honest answer is: the influenza vaccine carries a tiny excess risk (around one extra case per million doses), far smaller than the risk of GBS after influenza itself. The 1976 swine-flu vaccine is the historical outlier. Modern vaccines are safe. The Cao-Lormeau 2016 case-control study (PMID 26948433) established Zika as a robust outbreak trigger. [1]

Demyelinating versus axonal — why electrophysiology matters

In AIDP, antibodies and complement activate macrophages that strip myelin from the Schwann-cell unit, particularly at the nerve roots and proximal segments. Demyelination causes conduction block and slowing — the signal cannot traverse the demyelinated segment. Because the axon is intact, remyelination can restore function, which is why AIDP generally recovers well. [1]

In AMAN/AMSAN, the attack is at the node of Ranvier: macrophages insert between the myelin and the axon and there is direct axonal injury (Wallerian-like degeneration). Conduction velocities are relatively preserved, but compound muscle action potential (CMAP) amplitudes fall because axons are lost. Axonal variants have a less predictable and often slower recovery, because recovery depends on axonal regrowth (around 1 mm/day, or about 1 inch/month). [1]

The antibody target explains the regional pattern of injury. GQ1b is densely expressed on oculomotor, trochlear, and abducens nerves and on muscle spindles — hence ophthalmoplegia and areflexia (loss of the stretch reflex) in Miller Fisher syndrome (Chiba 1993, PMID 8413947; Kusunoki 2008, PMID 17976386). [1]

DWE high-yield: The reflex loss in GBS is not a sensory problem alone — it is the loss of the afferent limb (muscle spindle Ia afferent) due to ganglioside-targeted attack. This is why areflexia can be disproportionate to the weakness. [1]

Clinical features

The classic presentation — ascending weakness

The patient develops bilateral, symmetric weakness that begins in the legs and ascends to the arms, trunk, and cranial nerves over days. The weakness is flaccid with absent or depressed reflexes. Key features: [1]

Time course — progression over days to a maximum of 4 weeks to nadir (the defining criterion). Median time to nadir is around 9-12 days.
Symmetry — usually striking, though minor asymmetry occurs.
Ascending pattern — legs first, then arms. Cranial nerves and respiration may follow.
Areflexia — the reflexes disappear early, often before weakness is severe. Preserved reflexes in a weak limb should prompt reconsideration of the diagnosis.
Sensory involvement — less prominent than motor, but paraesthesia and numbness in the hands and feet are common early features. Sensory loss is usually minor.
Pain — up to two-thirds have pain (back, thigh, calf, paraesthesia), which may precede weakness and mislead toward mechanical back pain or radiculopathy. [1]

Cranial nerve involvement

Bilateral facial (VII) palsy — occurs in around half of severe cases. Bilateral lower motor neuron facial weakness is a red flag for GBS and should never be dismissed as bilateral Bell palsy.
Bulbar weakness — dysphagia, dysarthria, weak cough — signals imminent aspiration and ventilatory risk.
Ophthalmoplegia — in Miller Fisher syndrome and in severe AIDP. [1]

Autonomic dysfunction — a leading killer

Autonomic involvement is common and may be life-threatening. It is driven by involvement of the autonomic fibres and is most dangerous in ventilated patients: [1]

Cardiac arrhythmia — bradycardia, asystole, atrial and ventricular arrhythmias. Sudden death from dysautonomia is a recognised cause of mortality.
Blood pressure swings — severe labile hypertension and hypotension, sometimes orthostatic.
Ileus, urinary retention, sweating disturbances, SIADH. [1]

DCE trap: Every GBS inpatient needs continuous cardiac monitoring until stable. Avoid drugs that destabilise the autonomic system; use short-acting vasoactive agents. A sudden bradycardic arrest in a ventilated GBS patient is usually dysautonomia, not a primary cardiac event. [1]

Miller Fisher syndrome — the triad to know

The Miller Fisher triad is ophthalmoplegia, ataxia, and areflexia. The ataxia is sensory (cerebellar testing — finger-to-nose, heel-to-shin — is normal; the problem is proprioceptive input from muscle spindles). Anti-GQ1b antibody is present in over 90% of cases and is essentially diagnostic. Miller Fisher overlaps on a spectrum with Bickerstaff brainstem encephalitis, which adds altered consciousness (drowsiness, coma) and sometimes extensor plantar responses. [1]

What to find on examination

Domain	Typical finding
Tone	Flaccid, reduced
Power	Symmetric weakness, legs worse than arms, distal often worse early
Reflexes	Areflexia or hyporeflexia (early, disproportionate)
Plantars	Down (flexor) — UMN signs are absent
Sensation	Minor glove-and-stocking sensory loss; marked proprioceptive loss in Miller Fisher
Coordination	Limited by weakness; ataxia is sensory in Miller Fisher
Cranial nerves	Bilateral facial palsy, bulbar weakness, ophthalmoplegia in variants
Autonomic	Labile BP, arrhythmia, ileus, urinary retention

Differential diagnosis

Rapidly progressive ascending weakness with areflexia has a focused differential. The dangerous mimics are the spinal cord and electrolyte disorders. [1]

Diagnosis	Distinguishing features
Transverse myelitis / acute cord lesion	A clear sensory level, sphincter (bladder/bowel) involvement, UMN signs below the lesion (hyperreflexia, extensor plantar). MRI of the spine is urgent.
Spinal cord compression	Back pain, UMN signs below lesion, often asymmetric. Imaging is an emergency.
Hypokalaemia / hypokalaemic periodic paralysis	Check potassium urgently. Treatable. Periodic paralysis is episodic and recurrent.
Tick paralysis	Ascending paralysis with areflexia; a tick is attached. Removal reverses it.
Botulism	Descending paralysis, cranial nerve onset, dilated pupils, anticholinergic features, food/wound/IV-drug history.
Diphtheritic neuropathy	Pharyngitis then palatal paralysis weeks later; bull neck; unimmunised.
Acute porphyria	Abdominal pain, psychiatric features, motor neuropathy; check urine porphobilinogen.
Critical illness polyneuropathy/myopathy	Arises in the context of severe critical illness and multi-organ failure, not at presentation.
Myasthenia gravis	Fatigable weakness, fluctuating, ocular onset, reflexes preserved, worsens through the day.
West Nile / polio	Asymmetric weakness, fever, meningitic features; polio is rare in immunised populations.

DWE high-yield: The single most tested discriminator is the reflex pattern and the presence of a sensory level / sphincter involvement. Areflexia with a downgoing plantar and no sensory level points to GBS; hyperreflexia with extensor plantars and a sensory level points to a cord lesion and demands urgent MRI. Never attribute bilateral facial palsy to two separate Bell palsies. [1]

Investigations

CSF albuminocytologic dissociation (high protein, normal cell count, delayed appearance) and nerve conduction study patterns — AIDP demyelinating versus AMAN axonal

Cerebrospinal fluid — albuminocytologic dissociation

The CSF hallmark is albuminocytologic dissociation: a raised protein with a normal cell count. This reflects inflammation of the nerve roots (where the blood-nerve barrier is permeable) with sparing of the meninges. [1]

Protein — elevated, often 0.55-2.0 g/L. But it is frequently normal in the first week. A normal early CSF does not exclude GBS.
White cells — normal (under 5 cells/microL). A cell count above 50 cells/microL should prompt a search for an alternative — HIV-seroconversion GBS, leptospirosis, malignant infiltration, or infection.
Timing — CSF protein rises over 1-2 weeks. If the first LP is normal and suspicion persists, repeat after 1-2 weeks. [1]

DWE trap: The two classic CSF errors are (1) excluding GBS because the first-week CSF is normal, and (2) attributing a high white-cell CSF to "atypical GBS" without testing HIV. Always send an HIV test in any GBS with CSF pleocytosis. [1]

Nerve conduction studies (NCS)

NCS confirm the diagnosis, define the variant (demyelinating versus axonal), and inform prognosis. Early studies may be normal; the abnormalities evolve. [1]

Parameter	AIDP (demyelinating)	AMAN (axonal)
Distal motor latency	Prolonged	Normal or mildly prolonged
Conduction velocity	Slowed (below 70% lower limit)	Normal or near-normal
Conduction block / temporal dispersion	Present (key finding)	Absent
F-waves	Prolonged or absent (early sign — root involvement)	May be absent
CMAP amplitude	May be reduced	Markedly reduced (axon loss)
Sensory action potentials	Often reduced	Normal in pure AMAN

Prolonged or absent F-waves are an early sign because the nerve roots are involved early. Conduction block (the signal fails to traverse a segment) is the electrophysiological signature of demyelination. [1]

Anti-ganglioside antibodies

These support specific variants but are not required for acute management: [1]

Anti-GQ1b — Miller Fisher syndrome (over 90% sensitive), and a marker of ophthalmoplegia in any GBS variant.
Anti-GM1, anti-GD1a — AMAN, post-Campylobacter.
Anti-GalNAc-GD1a — pharyngeal-cervical-brachial variant. [1]

MRI

MRI is mainly used to exclude cord compression and transverse myelitis. Post-contrast MRI of the nerve roots may show enhancement of the cauda equina and nerve roots, which supports the diagnosis when NCS is equivocal. The brain is typically normal. [1]

Bedside respiratory and autonomic monitoring

This is the single most important inpatient monitoring. Measure at least every 4-6 hours, more often if deteriorating: [1]

Forced vital capacity (FVC) — the key parameter.
Maximum inspiratory pressure (MIP, or negative inspiratory force NIF) and maximum expiratory pressure (MEP) — more sensitive than FVC for early diaphragm failure.
Single breath count (count aloud in one breath) — a practical surrogate.
Bulbar assessment — cough, swallow, gag. [1]

Brighton Collaboration criteria

For diagnostic certainty in research and surveillance, the Brighton Collaboration case definition assigns levels 1-3 based on the combination of bilateral and progressive weakness, areflexia, monophasic course, CSF findings, and NCS. The Fokke 2014 validation (PMID 24163275) confirmed that most clinically diagnosed GBS meet level 1 or 2. [1]

Acute management

Decision tree from suspected GBS to respiratory monitoring thresholds, IVIG versus plasma exchange, steroid avoidance, and the supportive care bundle

The three pillars

Disease-modifying therapy — IVIG or plasma exchange (equally effective; not combined).
Supportive care — respiratory, autonomic, DVT, nutrition, pain, skin, psychological.
No corticosteroids — they do not work and may be harmful. [1]

Disease-modifying therapy

Therapy	Regimen	Onset of effect	Role
IVIG	0.4 g/kg/day for 5 days (total 2 g/kg)	Within 2 weeks	First-line in most centres — easier, no central access, fewer haemodynamic risks
Plasma exchange	5 sessions over 1-2 weeks, total 250-300 mL/kg	Within 2 weeks	Equivalent; preferred if IVIG contraindicated (IgA deficiency, prior severe reaction)

Both speed recovery by around 40-50% compared with supportive care alone. The evidence base: [1]

Plasma exchange — the 1985 GBS Study Group RCT (PMID 4022342) first showed plasmapheresis reduced time to recover walking versus supportive care.
IVIG — the 1992 Dutch trial (PMID 1552913) showed IVIG was at least as effective as plasma exchange.
Equivalence — the 1997 Plasma Exchange/Sandoglobulin Trial (PMID 9014908, 383 patients) showed PE, IVIG, and the combination were equivalent; combination added no benefit. This is why we give one, not both. [1]

Indication: any patient who cannot walk unaided (grade 3 or worse), or who has respiratory decline, bulbar weakness, or significant autonomic dysfunction, within 4 weeks of onset. Mild, ambulatory patients (grade 2 or better) who are stable may be observed without treatment, but most physicians treat if there is any progression. [1]

DWE high-yield trap: The most common treatment error is giving both IVIG and plasma exchange, or giving corticosteroids. The evidence is unambiguous: combination is not better (PS GBS Trial Group 1997), and steroids alone or added to IVIG are ineffective (Hughes Cochrane 2016, PMID 27775812; van Koningsveld 2004, PMID 14738791). The methylprednisolone-plus-IVIG trial showed only a non-significant trend toward benefit and is not enough to change practice. [1]

Why steroids fail — and the CIDP contrast

Corticosteroids are ineffective in GBS and may slow recovery. The mechanism is debated (steroids may impair the macrophage-mediated clearance that follows the antibody attack). This is the key contrast with chronic inflammatory demyelinating polyneuropathy (CIDP), in which corticosteroids are first-line. The difference is sometimes summarised: CIDP is steroid-responsive; GBS is not. If you are tempted to give steroids, re-check the diagnosis and the time course. [1]

IVIG practical points

Dose — 0.4 g/kg/day for 5 days. Total 2 g/kg.
Adverse effects — thrombosis (stroke, MI, DVT), acute kidney injury (especially with sucrose-stabilised products and pre-existing renal impairment), aseptic meningitis, haemolytic anaemia (non-O blood group), transfusion reactions. Check IgA level if there is a history of anaphylaxis to blood products (IgA deficiency).
Precautions — slow the infusion in older patients, those with cardiac or renal disease, and those with hyperviscosity. Ensure hydration. Thromboprophylaxis. [1]

Plasma exchange practical points

Regimen — 5 exchanges, usually every other day, 1-1.5 plasma volumes per session, replacement with albumin or fresh-frozen plasma.
Access — large-bore central or peripheral access.
Contraindications — haemodynamic instability, severe sepsis, bleeding diathesis, difficult vascular access.
Adverse effects — hypotension, bleeding (from citrate and clotting-factor removal), line infection, hypocalcaemia. [1]

Respiratory care and intubation thresholds

Around 20-30% of patients require mechanical ventilation. Intubate electively before respiratory arrest, never after desaturation (desaturation is a late, pre-terminal sign). [1]

Parameter	Threshold for ICU review	Threshold favouring intubation
FVC	Below 30 mL/kg, or falling greater than 30%	Below 20 mL/kg
MEP	Below 50 cmH2O	Below 40 cmH2O
Bulbar / cough	Weak cough, poor swallow	Bulbar weakness with aspiration risk
Other	Rapidly progressive course	Autonomic instability, single breath count below 20

DCE viva answer pattern: "I would intubate this patient electively. Her FVC has fallen from 30 to 19 mL/kg, she has a weak cough and bulbar weakness, and she is tiring. Waiting for desaturation is dangerous — desaturation is a late sign in young, fit patients, and by then the arrest is imminent. I would transfer her to ICU, ventilate, and continue IVIG and supportive care." [1]

The Walgaard 2010 model (PMID 20517939) identified predictors of respiratory insufficiency: short interval from onset to admission, low FVC and MIP, weak neck flexion, and bulbar weakness. Use these to triage early ICU involvement. [1]

Autonomic monitoring

Continuous ECG until stable — treat bradycardia (atropine, pacing if severe) and tachyarrhythmia.
Blood pressure — use short-acting agents for both hypertension and hypotension. Avoid sudden position changes. A labile BP often resolves as the disease plateaus.
Urinary catheter if retention; treat ileus and SIADH if present. [1]

The supportive care bundle

Domain	Intervention
DVT prophylaxis	LMWH (e.g. enoxaparin 40 mg SC daily, dose-adjusted in renal impairment) plus intermittent pneumatic compression — risk of DVT/PE is around 30% without prophylaxis
Pain	Gabapentin or pregabalin first-line for neuropathic pain; amitriptyline, carbamazepine; opioids for severe pain; avoid pure opioid monotherapy
Skin / pressure care	Regular turning, pressure-relieving mattress
Physiotherapy	Passive range of motion to prevent contractures; early mobilisation as strength returns
Tracheostomy	Consider if ventilation beyond 2-3 weeks is anticipated; aids weaning and pulmonary toilet
Psychological	Screen for depression, anxiety, PTSD; the awake, paralysed, ventilated patient is at high risk

Around 5-10% of patients treated with IVIG have a treatment-related fluctuation (TRF) — improvement followed by recurrence within 2 months. Treat with a second course of IVIG. If weakness progresses or relapses beyond 8 weeks, re-diagnose as acute-onset CIDP (A-CIDP) — management shifts to corticosteroids, repeat IVIG, and long-term immunotherapy. The 8-week clock is a defining boundary. [1]

Prognosis

Outcome	Frequency
Full or near-full recovery	around 80%
Mortality	around 5% (3-10% across series)
Unable to walk unaided at 6 months	around 20%
Persistent severe disability	around 5-10%
Persistent pain	up to 50%

Favourable prognostic factors: younger age, AIDP variant, antecedent upper-respiratory (rather than diarrhoeal/Campylobacter) illness, mild nadir, early treatment, and rapid improvement after IVIG. [1]

Adverse prognostic factors (the EGRIS/EGOS inputs): older age, diarrhoeal/Campylobacter antecedent, axonal variant (AMAN/AMSAN), severe nadir (ventilated, grade 4-5), weak neck and bulbar muscles, low CMAP amplitudes on NCS, and a high Erasmus GBS Outcome Score (EGOS, PMID 17537676). [1]

The EGOS at 2 weeks uses age, antecedent diarrhoea, and GBS disability score to predict the probability of independent walking at 6 months. A modified EGOS (mEGOS) incorporates the Medical Research Council sum score. Use it to set realistic expectations and to flag the patients who will need prolonged rehabilitation. [1]

DCE long-case trap: When presenting a recovering GBS patient, state the variant, the nadir disability grade, whether ventilation was required, the current grade, and the EGOS-predicted 6-month outcome. Examiners want to see that you understand prognosis is determined at nadir, not at presentation. [1]

CIDP — the chronic boundary

Chronic inflammatory demyelinating polyneuropathy (CIDP) is the chronic cousin of GBS. The defining difference is time course: progression continues beyond 8 weeks (GBS reaches nadir within 4 weeks). CIDP may follow a relapsing-remitting or progressive course. [1]

The critical management contrast: [1]

Feature	GBS	CIDP
Time to nadir	Under 4 weeks	Over 8 weeks
Course	Monophasic	Chronic, relapsing or progressive
Corticosteroids	Ineffective	Effective (first-line)
IVIG	Effective	Effective
Plasma exchange	Effective	Effective

DWE high-yield: The most tested contrast is the steroid response: CIDP responds to steroids, GBS does not. A patient who is given steroids and improves may have had CIDP from the start. The diagnosis is made on time course, not on steroid response after the fact. [1]

DCE long-case approach

Opening statement (SASPOP)

"Mr Davies is a 54-year-old mechanic who presents with four days of progressive weakness beginning in his feet and ascending to his legs and hands, with paraesthesia in his fingers and toes, and now difficulty standing. Two weeks ago he had a week of diarrhoea, diagnosed as Campylobacter jejuni enteritis by his GP. He is otherwise well, takes no regular medications, and is a non-smoker. [1]

On examination he is afebrile, alert, and oriented. His FVC is 28 mL/kg and falling, MIP is -45 cmH2O. He has symmetric flaccid weakness, power 3/5 in the legs and 4/5 in the arms, with absent reflexes throughout and downgoing plantars. Sensation is reduced to pinprick in a glove-and-stocking distribution. Cranial nerves are intact except for mild bilateral facial weakness. [1]

CSF shows protein 1.2 g/L with 3 white cells. Nerve conduction studies show prolonged distal latencies, conduction block, and absent F-waves consistent with AIDP. [1]

His main problems are:

Acute Guillain-Barre syndrome, AIDP variant, post-Campylobacter, currently GBS disability grade 4 — disease-modifying therapy indicated
Respiratory function declining — high risk of ventilatory failure, requires ICU-level monitoring
Autonomic risk — requires continuous cardiac monitoring
Pain and immobility — VTE prophylaxis, analgesia, physiotherapy
Psychological impact and prognosis communication" [1]

Integrated management plan

Present in three phases: [1]

Immediate (hours): Confirm diagnosis (CSF, NCS). Transfer to a monitored bed (HDU/ICU if FVC below 30 mL/kg or falling). Start bedside respiratory monitoring every 4 hours. Continuous ECG. Establish IV access. Check IgA and renal function before IVIG. Start IVIG 0.4 g/kg/day for 5 days. Do not give steroids. Insert a urinary catheter if retention. Start DVT prophylaxis.
Subacute (days to weeks): Continue respiratory and cardiac monitoring; intubate electively at the thresholds above. Continue supportive care — early enteral nutrition, pain management, physiotherapy, pressure care. Watch for treatment-related fluctuation (re-treat with IVIG) and for progression beyond 8 weeks (re-diagnose as A-CIDP). If ventilation is prolonged, plan tracheostomy at 2-3 weeks.
Recovery and rehabilitation: As strength returns, mobilise with physiotherapy. Address persistent pain, fatigue, and psychological sequelae. Set functional goals. Plan outpatient follow-up to assess residual disability and return to work and driving. [1]

DCE examiner probing questions you must anticipate:

"Why IVIG and not plasma exchange?" — Both are equivalent; IVIG is easier, avoids central access and haemodynamic instability, and is preferred in most ANZ and UK centres. Choose plasma exchange if IVIG is contraindicated.

"Will steroids help?" — No. Steroids are ineffective in GBS and may be harmful. The van Koningsveld 2004 trial and the Cochrane review are definitive.

"When will you intubate?" — Electively at FVC below 20 mL/kg, MIP more negative than -30 cmH2O, MEP below 40 cmH2O, or with bulbar weakness and aspiration risk. Not after desaturation.

"What is his prognosis?" — Around 80% recover well; he has adverse features (Campylobacter antecedent, grade 4 at nadir). I would quote him a guarded-but-hopeful outlook with a realistic chance of independent walking by 6 months, and intensive rehabilitation to maximise recovery. [1]

DCE short-case approach: neurological examination in suspected GBS

Instruction: "Examine this patient's neurological system. They were admitted three days ago with progressive leg weakness." [1]

Systematic routine

Observe from the end of the bed: posture, work of breathing (use of accessory muscles, paradoxical abdominal movement suggesting diaphragm weakness), ability to speak in full sentences.
Bedside respiratory: FVC, single breath count, cough — state you would do this first in a real exam.
Cranial nerves: facial power (bilateral LMN facial palsy), eye movements (ophthalmoplegia in Miller Fisher), bulbar (cough, gag, swallow), tongue and palate symmetry.
Motor: tone (flaccid), power (symmetric, legs worse than arms, distal worse early), and reflexes (the key finding — areflexia or hyporeflexia).
Sensory: pinprick, light touch, joint position sense, vibration — minor glove-and-stocking loss; marked proprioceptive loss in Miller Fisher.
Coordination: limited by weakness; test for sensory ataxia (positive Romberg) in Miller Fisher.
Gait: if able — stamping, steppage gait. [1]

Presentation template

"I examined Mr Davies's neurological system. He is alert and cooperative but is using accessory muscles to breathe and speaks in short phrases. [1]

On general inspection there is no facial asymmetry at rest. Cranial nerve examination reveals mild bilateral lower motor neuron facial weakness with reduced eye closure and a symmetrical smile. Eye movements are full. The cough is weak. [1]

In the upper limbs, tone is reduced. Power is 4 out of 5 in the arms proximally and distally, symmetric. In the lower limbs, tone is reduced. Power is 2 out of 5 in the legs, symmetric, with the feet and toes most affected. Reflexes are absent in all four limbs. The plantar responses are downgoing. [1]

Sensation is reduced to pinprick and light touch in a glove-and-stocking distribution. Joint position sense is impaired at the toes. Coordination cannot be tested in the legs due to weakness but is intact in the arms. [1]

In summary, these findings — symmetric flaccid weakness with areflexia and a downgoing plantar, plus bilateral facial palsy and declining respiratory function — are consistent with acute Guillain-Barre syndrome. I would immediately assess his ventilatory capacity with FVC and inspiratory pressures and arrange CSF examination and nerve conduction studies." [1]

Discussion questions

Q: "Why are the plantars downgoing in a patient this weak?" [1]

"Because GBS is a lower motor neuron lesion — the pathology is in the peripheral nerve and nerve root, below the anterior horn cell. Upper motor neuron signs (spasticity, hyperreflexia, extensor plantars) require a lesion of the corticospinal tract. The presence of downgoing plantars in a profoundly weak patient with areflexia is itself a clue that the lesion is in the peripheral nerve, not the spinal cord." [1]

Q: "How would you exclude a spinal cord lesion?" [1]

"The presence of a sensory level, sphincter disturbance (urinary retention can occur in both, but a clear bowel/bladder level is cord-suggestive), and upper motor neuron signs would point to a cord lesion. If any of these were present, or if the weakness were asymmetric or predominantly proximal with sparing of the face, I would arrange urgent MRI of the spine. In a classical symmetric ascending presentation with areflexia and downgoing plantars, MRI is mainly confirmatory or to exclude mimics." [1]

Key DWE MCQ patterns

The treatment choice: a patient who cannot walk unaided within 4 weeks — give IVIG or plasma exchange, not both, not steroids.
The CSF pattern: high protein, normal white cells, appearing after 1-2 weeks. A normal first-week CSF does not exclude GBS.
The variant-antibody match: Miller Fisher and anti-GQ1b; AMAN and anti-GM1 (post-Campylobacter).
The Miller Fisher triad: ophthalmoplegia, ataxia, areflexia — ataxia is sensory.
The steroid trap: steroids are ineffective in GBS but effective in CIDP.
The intubation threshold: FVC below 20 mL/kg or MIP more negative than -30 cmH2O.
The trigger: Campylobacter jejuni is the most common identifiable antecedent infection.
The 8-week boundary: progression beyond 8 weeks is CIDP, not GBS. [1]

References

[1] Willison, Jacobs, van Doorn — Guillain-Barre syndrome. The Lancet 2016 comprehensive review of pathogenesis, clinical spectrum, and treatment. [2] Leonhard et al. 2019 — Diagnosis and management of GBS in ten steps; the practical bedside algorithm. [3] van den Berg et al. 2014 — GBS pathogenesis, diagnosis, treatment and prognosis; the Nat Rev Neurol reference. [4] GBS Study Group 1985 — Plasmapheresis RCT (245 patients); established plasma exchange over supportive care. [5] van der Meche and Schmitz 1992 — IVIG at least as effective as plasma exchange (150 patients); the IVIG landmark. [6] PS GBS Trial Group 1997 — PE, IVIG, and combined (383 patients); equivalence; combination not better. [7] van Koningsveld et al. 2004 — Methylprednisolone added to IVIG showed only a non-significant trend; steroids not added routinely. [8] Hughes Cochrane 2016 — Corticosteroids not effective for GBS (and may slow recovery). [9] van Koningsveld et al. 2007 — The Erasmus GBS Outcome Score (EGOS) prognostic model. [10] Walgaard et al. 2010 — Prediction of respiratory insufficiency in GBS (EGRIS inputs). [11] Fokke et al. 2014 — Diagnosis of GBS and validation of the Brighton Collaboration criteria. [12] Chiba et al. 1993 — Anti-GQ1b IgG associated with ophthalmoplegia in Miller Fisher syndrome and GBS. [13] Kusunoki and Kaida 2008 — Antibodies against gangliosides and ganglioside complexes in GBS. [14] Ang, Jacobs et al. 2001 — Campylobacter jejuni LPS from GBS/MFS strains induce anti-GM1 and anti-GQ1b antibodies in rabbits (molecular mimicry proof). [15] Cao-Lormeau et al. 2016 — GBS outbreak associated with Zika virus infection in French Polynesia.

European Academy of Neurology / Peripheral Nerve Society Guideline on GBS (2021); AAN/AANEM Practice Parameter on Immunotherapy for GBS (2012); NICE Guideline NG127 (2021); Therapeutic Guidelines (eTG) Neurology. [1]