learndrugs
Nervous

Guillain-Barré Syndrome

GBS Verified · Oct 2026

Guillain-Barré syndrome (GBS) is an acute, immune-mediated, monophasic polyradiculoneuropathy — usually post-infectious — in which cross-reactive antibodies damage peripheral nerve roots and nerves, producing rapidly progressive, symmetric, ascending flaccid weakness with absent reflexes; it is the most common cause of acute neuromuscular paralysis worldwide.

The disorder behind molecular mimicry, the ascending areflexic weakness, the 20/30/40 rule and single-breath counting, albuminocytologic dissociation, "IVIG or plasma exchange — never both," and the fully aware patient who cannot move.

What’s going wrong in the body

The normal physiology, where it fails, and why the body’s compensation backfires.

01 Molecular mimicry — an infection teaches the immune system the wrong target

About 70% of GBS cases follow an infection, most within the previous 6 weeks, and symptoms typically begin about 10 days after the trigger. The most common identified culprit is Campylobacter jejuni, the diarrheal pathogen — roughly 1 in 1,000 infections is followed by GBS, and an antecedent Campylobacter infection, especially with diarrhea, predicts a poorer outcome. Other triggers include cytomegalovirus, Epstein-Barr virus, hepatitis E, HIV, Mycoplasma pneumoniae, influenza A, Zika and other arboviruses, surgery, and drugs such as immune checkpoint inhibitors. Vaccines are a real but tiny association: the 1976 swine-flu vaccine carried about one additional case per 100,000 vaccinated, today’s seasonal flu vaccine at most 1–2 additional cases per million doses, and the CDC’s own framing is that a person is more likely to get GBS after the flu than after the flu vaccine.

The mechanism is molecular mimicry. Peripheral nerve fibers carry gangliosides — sialic-acid-containing glycosphingolipids — on their surface. The lipooligosaccharides on the Campylobacter membrane contain ganglioside-like moieties, so the antibodies raised against the bacterium cross-react with gangliosides such as GM1, GD1a and GQ1b on the patient’s own nerves. The antibodies fix complement, and complement plus recruited macrophages do the damage. Which ganglioside is targeted shapes the syndrome: anti-GM1 and anti-GD1a antibodies mark the axonal motor form, and anti-GQ1b is found in up to 90% of Miller Fisher syndrome, whose target nerves supply the eyes.

Two caveats keep this honest. At least 40% of patients have no identifiable antibody, so antibodies explain the mechanism but are not a diagnostic requirement — and the diagnosis never waits for them. And the attack is monophasic: one immune assault that peaks and then stops, which is why the illness climbs, plateaus, and recovers rather than relapsing like multiple sclerosis.

Molecular mimicry: antibodies made against a microbe cross-react with peripheral nerve gangliosides, and complement-driven injury to myelin or axons produces the ascending weakness — including the nerves that drive breathing, swallowing, and heart rate.

02 Two ways to break a nerve — demyelination versus axonal injury

In AIDP (acute inflammatory demyelinating polyradiculoneuropathy) the target is the myelin sheath. The membrane attack complex forms on the Schwann cell, myelin undergoes vesicular degeneration, and macrophages insinuate themselves between the myelin wraps, stripping and digesting the sheath. A demyelinated fiber conducts slowly or not at all — conduction block — which is why nerve conduction studies in AIDP show slowed velocities, temporal dispersion, and partial motor conduction blocks. AIDP is about 90% of cases in North America and Europe.

In AMAN (acute motor axonal neuropathy) and AMSAN (acute motor-sensory axonal neuropathy) the antibodies bind nodal structures, ventral roots, and nerve terminals, complement activates, and intra-axonal calcium accumulates — the axon itself degenerates, so the electrical signal is not slowed but lost in amplitude. The axonal forms are only about 3–5% of cases in North America and Europe but 30–50% in Asia and Latin America, and they recover more slowly because a degenerated axon must regrow rather than simply remyelinate. Two variants deserve their own names: Miller Fisher syndrome (ophthalmoplegia, ataxia, areflexia — anti-GQ1b) is 5–10% of Western cases and up to 25% in Japan, and Bickerstaff brainstem encephalitis is its CNS-involving relative.

One modern nuance: the 2023 EAN/PNS guideline, as carried by the recent reviews, no longer uses the AIDP-versus-AMAN distinction for diagnosis — electrodiagnosis now supports the diagnosis of GBS rather than sorting subtypes. Learn the subtypes as pathophysiologic patterns that explain the prognosis, not as gates the patient must pass through before treatment.

The demyelinating and axonal forks: AIDP blocks conduction by stripping myelin, while AMAN/AMSAN degrade the axon itself — same bedside picture, different recovery.

03 Why a "peripheral" nerve disease stops the breathing and swings the heart

Weakness begins with distal paresthesias, then symmetric weakness of the legs that spreads to the arms and the cranial nerves — the ascending pattern. Reflexes are reduced or absent in most patients at presentation and in almost all at nadir, because the peripheral nerve and root that carry the reflex arc are the tissue under attack. The speed is the first danger: in some patients the course is fulminant — up to 22% need mechanical ventilation within the first week of admission — and weakness can worsen over hours or days. Progressive weakness is an emergency, not a watch-and-wait finding. The nadir arrives within 2 weeks in most and by 4 weeks in nearly all — a nadir inside 24 hours or progression beyond 4 weeks should prompt a search for another diagnosis.

The diaphragm and intercostals are driven by peripheral nerves, so roughly 20–30% — up to one in three — need mechanical ventilation. The trap is that this failure is silent until late. Not every patient with respiratory insufficiency feels dyspneic, and blood oxygen and carbon dioxide change only late: as the pump weakens, vital capacity and cough strength fall first, secretions pool, atelectasis and hypoventilation build — and the pulse oximeter stays reassuring until the reserve is gone. Early detection therefore rests on pressure and volume measurements, not on SpO₂. The bedside heralds are tachypnea, accessory-muscle use, inability to count to 15 in one breath, and a weak cough; neck-flexor weakness, bulbar weakness, bilateral facial weakness, and dysautonomia are the strongest predictors that ventilation is coming, and 84% of those ventilated need it within 7 days of admission.

The autonomic fibers are peripheral nerves too, so about two-thirds of patients develop dysautonomia: sinus tachycardia most commonly, but also labile blood pressure (paroxysmal hypertension alternating with orthostatic hypotension), other cardiac arrhythmias, including bradycardia severe enough to risk asystole, abnormal sweating, pupillary changes, gastrointestinal dysmotility with ileus, and urinary retention. Dysautonomia tracks respiratory failure — every ventilated patient in one series had cardiovascular instability — and it turns ordinary care into hazard: arrhythmias and marked swings in blood pressure can appear at any point, emergency intubation and succinylcholine can precipitate arrhythmias and hyperkalemia, and plasma exchange itself can drop the pressure (hypotension is one of its common complications). Through all of it, consciousness, vision and hearing stay intact — the patient with complete paralysis hears everything said at the bedside.

Respiratory failure in GBS is silent until late: volume and pressure measurements fall long before the pulse oximeter moves, so the 20/30/40 rule and the single-breath count — not SpO₂ — decide when the ICU is called.

04 The monophasic course — nadir, plateau, recovery — and where the deaths hide

GBS runs in three phases: a progressive phase of up to 4 weeks (peak illness usually in 1–2 weeks), a plateau of weeks to months, then recovery. Immunotherapy shortens the road: there is no cure, but IVIG and plasma exchange "can reduce its severity and shorten recovery time" (NINDS), and trial benefit is shown only when they are started early — IVIG within 2 weeks and plasma exchange within 4 weeks of weakness onset. Plasma exchange physically removes the antineural antibodies and soluble immune mediators; IVIG works through pleiotropic immune-modulatory effects. Expect a plateau rather than a cure: about 40% of treated patients show no improvement in the first 4 weeks, and that does not mean the treatment failed — the course might have been worse without it.

The outcome numbers are mostly reassuring: about 80% walk independently at 6 months, more than half recover fully within a year, and even patients tetraplegic at nadir or ventilated for weeks show extensive recovery, especially in the first year. Mortality is about 3–7% overall (roughly 5%) and about 20% among the ventilated; roughly 10–20% are left with significant disability, and fatigue affects 60–80% long term, with at least one-third still in pain a year after onset. Advanced age, rapid onset, severe weakness at admission, ventilation, preceding diarrhea, and the axonal subtype predict a worse course.

The nursing point that decides who survives: up to two-thirds of GBS deaths occur during the recovery phase, mostly from cardiovascular and respiratory dysfunction — arrhythmias, blood-pressure shifts, and respiratory distress from mucus plugs in a patient whose cough is still weak. The step-down bed after the ICU is not the safe zone; it is where the vigilance most often lapses.

Causes & risk factors

Modifiable factors are teaching targets — the patient can act on them.

Antecedent infection within ~6 weeks (≈ 70% of cases; two-thirds report a gastrointestinal or respiratory prodrome) Campylobacter jejuni gastroenteritis — the most common identified trigger (≈ 1 in 1,000 infections); exposure via raw/undercooked poultry, contaminated food or water, animal contact modifiable Cytomegalovirus, Epstein-Barr virus, hepatitis E, HIV, Mycoplasma pneumoniae, Haemophilus influenzae, influenza A Arboviruses — Zika, dengue, chikungunya, Japanese encephalitis (COVID-19 association remains controversial) Vaccination — rare and quantified: ≈ 1 per 100,000 after the 1976 swine-flu vaccine; at most 1–2 per million seasonal flu doses; adenovirus-vector COVID-19 vaccines, not mRNA (CDC) Recent surgery Immune checkpoint inhibitors, TNF-α inhibitors, type I interferons Autoimmune disorders such as systemic lupus erythematosus · malignancy such as lymphoma Male sex (≈ 1.5:1) Any age — incidence rises with age, peaking at 50–70 years Sporadic, not inherited — immune-gene variants may raise susceptibility Prior GBS — recurrence is rare (2–5%) but far above the general population’s 0.1% lifetime risk

Signs & symptoms

Each finding tied to the mechanism that produces it — and the triage it calls for.

Tingling and numbness in the feet, then the hands (distal paresthesias) early Hold & notify
Why: The earliest sensory fibers to fail are the longest — a distal, symmetric "stocking" start. Sensory signs stay mild relative to the motor deficit; prominent sensory findings with little weakness argue against GBS.
Symmetric weakness climbing from the legs to the arms — cannot climb stairs, then cannot rise from a chair early Report immediately
Why: Demyelination or axonal injury of motor nerves and roots produces flaccid weakness that ascends over hours to days, and some courses are fulminant. Progressive weakness is an emergency, because the next muscles in line are the neck flexors and the diaphragm.
Reflexes reduced, then absent (areflexia) early
Why: The reflex arc runs through the peripheral nerve and root on both its afferent and efferent limbs — the exact tissue under attack. Hyporeflexia is present in most at presentation and areflexia in almost all at nadir; hyperreflexia or clonus points to a spinal-cord or brain problem instead.
Pain — low back, between the shoulder blades, or radicular; common, and may precede the weakness Expected
Why: Inflamed nerve roots hurt, and immobile joints and muscles add nociceptive pain. It is expected but under-detected — a patient with limited movement or a tube will not volunteer it, so the nurse must ask.
Facial weakness, often bilateral (facial diplegia) — up to 70% Hold & notify
Why: The facial nerve is the cranial nerve most often involved. It costs the patient lid closure (exposure keratitis risk), adds an EGRIS point, and is a predictor of mechanical ventilation.
Dysphagia, choking on liquids, weak cough, weak or nasal voice (bulbar weakness, ~40%) Report immediately
Why: Oropharyngeal cranial nerves fail after the facial nerve. Bulbar weakness means aspiration and airway risk and is an ICU-admission criterion: hold oral intake, notify, anticipate speech-language evaluation and a feeding tube.
Neck-flexor weakness — cannot lift the head off the pillow; rapidly weakening hip flexors Report immediately
Why: The neck flexors share innervation levels with the diaphragm, so neck-flexor weakness is the strongest bedside predictor of mechanical ventilation. Severe or rapidly worsening weakness of the neck and hip flexors is an ICU criterion.
Tachypnea, accessory-muscle use, breathlessness while talking, cannot count to 15 in one breath, weak cough late Report immediately
Why: The failing diaphragm and intercostals recruit accessory muscles and shorten each breath; the single-breath count is a bedside vital capacity. A count of ≤ 19 predicts a need for ventilation. Call the provider or rapid response — do not wait for the saturation to fall.
SpO₂ still normal on room air while VC, NIF and single-breath count are falling Hold & notify
Why: The trap of the whole disorder. Oxygen and carbon dioxide levels change only late — the oximeter and blood gas move only when reserve is exhausted. A normal saturation never cancels a falling volume or pressure measurement.
Sinus tachycardia, labile blood pressure (paroxysmal hypertension ↔ orthostatic hypotension), cardiac arrhythmias, abnormal sweating Report immediately
Why: Autonomic fibers are peripheral nerves; about two-thirds of patients develop dysautonomia, and it worsens as respiratory failure deepens. Cardiac arrhythmias are part of why GBS carries significant mortality — severe bradycardia can put the patient at risk of asystole and may need a pacemaker — so heart rate and blood pressure are monitored continuously.
Abdominal distension, absent bowel sounds (ileus) · unable to void (urinary retention) late Hold & notify
Why: Autonomic denervation of the gut and bladder: paralytic ileus and urinary retention are both recognized autonomic features. Opioids and immobility make both worse. Note the red flag: bladder or bowel dysfunction at onset points to a spinal-cord lesion, not GBS.
Ophthalmoplegia + ataxia + areflexia — the Miller Fisher triad
Why: Anti-GQ1b antibodies target the oculomotor, trochlear and abducens nerves (difficulty with eye-muscle movement and vision) and the proprioceptive fibers that steady gait. Pure Miller Fisher usually spares limb strength and recovers on its own — but a subgroup progresses to limb, bulbar or respiratory weakness, so it is monitored, not dismissed.
Awake, alert and fully aware — even when completely paralyzed Expected
Why: GBS spares the brain: consciousness, vision and hearing stay intact. Altered consciousness (outside Bickerstaff encephalitis) argues against the diagnosis. Everything said at the bedside is heard; every unexplained procedure is frightening.
What GBS does not do: marked asymmetry, a sharp sensory level, hyperreflexia or clonus, fever at onset, nadir within 24 h, progression beyond 4 weeks Hold & notify
Why: Each is a documented red flag for an alternative diagnosis — spinal-cord compression or myelitis, myasthenia gravis, botulism, tick paralysis, hypokalemia. Report them; they change the work-up.

Diagnostics

Test In this disorder Normal
Clinical criteria (NINDS / Brighton Collaboration) The diagnosis is clinical — CSF and nerve conduction studies support it but are not required, and treatment is never delayed for them. Brighton criteria grade certainty in 4 levels Required: progressive bilateral weakness of arms and legs plus absent or decreased tendon reflexes in the affected limbs, with progression not beyond 4 weeks NINDS / Brighton Collaboration (per Leonhard et al. 2019) —
Cerebrospinal fluid — albuminocytologic dissociation The timing trap: protein is normal in about half of patients in the first week and rises in 70–90% by the end of the second — a normal early LP does not exclude GBS. Cells 5–50/µL are compatible but should prompt thought; > 50/µL means look for another diagnosis. After the tap, the provider may have the patient lie flat for 1–2 h to prevent headache Elevated protein with a normal cell count — WBC typically ≤ 5/µL; protein can climb into the hundreds (reported up to 1,800 mg/dL) EAN/PNS 2023 cell-count thresholds (via Freiha 2026 / Wiegers 2025) —
Nerve conduction studies / EMG Absent H-reflexes are 95–100% sensitive and sural sparing 91–98% specific — but early studies may be normal within the first week (sensitivity as low as 22% in early AIDP, 87% by week 5); repeat at 2–3 weeks. Used to support the diagnosis, no longer to gate treatment by subtype Reduced conduction velocities, temporal dispersion, partial motor conduction block, prolonged or absent F-waves and H-reflexes; the sural-sparing pattern (sural sensory response normal while median/ulnar are abnormal) —
Bedside respiratory measurements — VC/FVC, MIP (NIF), MEP, single-breath count These are the nurse’s serial tests — frequency is individualized to the rate of deterioration, autonomic status and phase of illness, not a fixed schedule. Sign convention: a NIF of −25 is worse than −35 (the patient cannot pull as negative). Never substitute SpO₂ — it falls last. Meeting 20/30/40 = ICU-level risk; intubate on trend plus clinical signs, electively At risk — the 20/30/40 rule: VC < 20 mL/kg, MIP weaker than −30 cmH₂O, or MEP < 40 cmH₂O. VC < 15 mL/kg (or < 1 L) → elective intubation. Single-breath count ≤ 19 predicts ventilation; cannot reach 15 = impending failure —
EGRIS (Erasmus GBS Respiratory Insufficiency Score) Points: days from onset to admission > 7 = 0, 4–7 = 1, ≤ 3 = 2 · facial and/or bulbar weakness absent = 0, present = 1 · MRC sum score 60–51 = 0, 50–41 = 1, 40–31 = 2, 30–21 = 3, ≤ 20 = 4. Derived in a Dutch population and not yet validated internationally — a triage aid, not a gate Probability of ventilation within 1 week: 0–2 low (4%) · 3–4 intermediate (24%) · ≥ 5 high (65%) Erasmus GBS Respiratory Insufficiency Score (per Leonhard et al. 2019) —
MRC sum score & GBS disability scale Serial strength grading of neck, arms and legs plus reflexes is the neuro assessment — the trend, not one value, drives escalation. Inability to lift the arms 1 week after intubation or to flex the foot predicts prolonged ventilation Lower = weaker: sum of 0–5 grades for bilateral shoulder abduction, elbow flexion, wrist extension, hip flexion, knee extension, ankle dorsiflexion (max 60 = normal). Immunotherapy is indicated when the patient cannot walk 10 m independently (GBS disability score ≥ 3) MRC sum 60
Arterial blood gas / SpO₂ A late indicator only. Continuous cardiac telemetry and blood-pressure monitoring run alongside because dysautonomia deepens with respiratory failure Normal until late. PaCO₂ > 48 mm Hg or PaO₂ < 56 mm Hg are ICU/intubation criteria — by then the pump has already failed —
Anti-ganglioside antibodies & pre-treatment labs Do not wait for antibody results to start treatment. Before IVIG: check IgA (anaphylaxis risk in IgA deficiency). All patients: watch sodium (hyponatremia is a listed complication). Spinal MRI is used mainly to exclude cord compression or myelitis Not recommended routinely — a negative result does not rule out GBS. Exception: anti-GQ1b is positive in up to 90% of Miller Fisher syndrome —

Complications

Warning: Respiratory failure — 20–30%, silent until late Report immediately
Falling VC/NIF trend, single-breath count ≤ 19, weak cough, accessory-muscle use, tachypnea or tachycardia, new dysphagia, neck-flexor weakness — with a normal SpO₂.
Rapid response and ICU: 84% of those who need ventilation need it within 7 days of admission. The goal is elective intubation on trend (VC < 15 mL/kg, or 20/30/40 plus clinical signs) — an emergency airway in a dysautonomic patient risks labile pressure, arrhythmia, and hyperkalemia with succinylcholine. Noninvasive ventilation is not recommended: these patients need full support for days and their dysautonomia worsens as failure deepens. Many of the intubated go on to tracheostomy.
Warning: Dysautonomia → arrhythmias, severe bradycardia, blood-pressure instability Report immediately
Blood pressure swinging more than 20% or heart rate more than 10% between checks, paroxysmal hypertension, orthostatic collapse, or any new arrhythmia.
About two-thirds of patients, and every ventilated patient in one series. Heart rate and blood pressure are monitored continuously, and severe autonomic cardiovascular dysfunction — arrhythmias or marked variation in blood pressure — is an ICU criterion. Treat paroxysmal hypertension only with short-acting, quickly titratable agents to avoid rebound hypotension, and expect plasma exchange to be withheld when the hemodynamics are unstable.
Warning: Death in the recovery phase — up to two-thirds of GBS deaths Report immediately
Arrhythmias, blood-pressure shifts, and respiratory distress from mucus plugs in a patient recently out of the ICU whose cough is still weak.
The improvement curve lulls everyone. Monitoring for arrhythmia, pressure swings and secretion retention is especially important in patients who have recently left the ICU and in those with cardiovascular risk factors — the step-down unit inherits the ICU’s vigilance, not its relief.
Caution: Aspiration pneumonia, VAP, VTE and the immobility cascade Hold & notify
Bulbar weakness → choking and aspiration; ventilator-associated pneumonia in about half of the ventilated; DVT/PE; pressure injuries, compression neuropathies, contractures; corneal ulceration from lid weakness.
Infections, ARDS and pulmonary embolism are the most common causes of death. Every item has a nursing owner: swallow screening and speech-language pathology, head-of-bed and oral care, pharmacologic VTE prophylaxis plus compression until ambulation returns, turning and padding, passive range of motion from day one, and eye lubrication or lid taping. Hyponatremia is a listed complication in all patients.
Caution: Treatment-related fluctuation & acute-onset CIDP Hold & notify
Renewed progression within 2 months after an initial treatment-induced improvement or stabilization — 6–10% of patients.
Repeating a full course is common practice despite thin evidence. But three or more fluctuations, or deterioration 8 weeks or more after onset, redefines the illness as acute-onset chronic inflammatory demyelinating polyneuropathy (~5% of "GBS"), which needs a different plan. Recurrence of true GBS is rare (2–5%).

Medications for this condition

Why each class is prescribed here — every card links to its full pharmacology page.

Anticoagulants First-line High-alert
Cardiovascular · heparin

Not a treatment for GBS itself — a shield against the disorder’s most common preventable killer. The paralyzed patient is immobile and hypercatabolic, and pulmonary embolism is among the leading causes of GBS death. Every minimally ambulant or non-ambulant patient receives prophylactic unfractionated or low-molecular-weight heparin (ACCP guidance as reported by Harms 2011), layered with compression stockings or sequential compression devices; some centers hold the heparin on plasma-exchange days and rely on the mechanical devices. Prophylaxis continues into rehabilitation until the patient walks again — not until discharge.
Opioid Analgesics High-alert
Nervous · morphine

An adjunct for the pain that is common in GBS and can precede the weakness — reliable analgesia, but with two disorder-specific costs. Sedation blurs the serial neuro and respiratory assessment that the whole admission depends on, and ileus lands on a gut already dysmotile from dysautonomia (ileus management explicitly includes reducing opioids). Gabapentin or carbamazepine lower pain scores and cut opioid requirements, which is why they are the usual first move for the neuropathic component; constipation is measured and expected.

Beyond medications

  • IVIG or plasma exchange — the only proven disease-modifying treatments, and they are equivalent. Head-to-head trials and meta-analysis show no difference in mortality, improvement at 4 weeks, residual disability, or ventilator days; the 2023 EAN/PNS guideline (via its carrier reviews) leaves the choice to local cost and availability. IVIG is usually chosen because it is easier to give. Neither is a cure — they shorten recovery time (NINDS), and about 40% show no improvement in the first 4 weeks even when treated.
  • Who, when, and the rules: treat when the patient cannot walk 10 m independently, and consider it in walking patients with rapid progression, bulbar failure, autonomic dysfunction, or respiratory risk; watchful waiting is valid for mildly affected patients who still walk. Start as early as possible — trial evidence covers IVIG within 2 weeks and plasma exchange within 4 weeks of weakness onset, and the guideline window is 4 weeks. Do not combine (plasma exchange followed by IVIG is no better than either alone) and do not give a second IVIG course routinely — a strong recommendation against, because it adds adverse events without benefit.
  • IVIG at the bedside — dosing concept 0.4 g/kg/day for 5 days (the 5-day schedule carries less relapse risk than 2 days). Check IgA before the first infusion — IgA deficiency means anaphylaxis risk and a switch to IgA-depleted product or plasma exchange. Start slowly and titrate the rate up every 15–30 minutes; infusion-related headache, myalgia, chills or nausea are managed by slowing the rate. Watch urine output and creatinine (kidney injury with sucrose-containing products, elderly and diabetic patients), volume status (cardiac or renal disease), and teach the patient to report headache, chest pain, or shortness of breath immediately (aseptic meningitis, thromboembolism, TRALI, anaphylaxis).
  • Plasma exchange at the bedside — a course of "200–250 ml plasma/kg body weight in five sessions" is as effective as IVIG, and "IVIg and plasma exchange carry comparable risks of adverse events, although early studies showed that plasma exchange was more likely than IVIg to be discontinued"; "As IVIg is also easier to administer and generally more widely available than plasma exchange, it is usually the treatment of choice" (Leonhard 2019). The American Society for Apheresis (ASFA) 2023 guidelines list GBS as a Category I indication, meaning plasma exchange is accepted as a first-line treatment (as reported in a 2026 open-access study; StatPearls gives the same category from the 2016 edition, and a tenth ASFA edition appeared in September 2026). At the bedside it needs central or large-bore access, and it is withheld with hemodynamic instability or septicemia (hypocalcemia and an ACE inhibitor in the last 24 hours are relative contraindications). Watch for the complications: hypotension, citrate-induced hypocalcemia or hypomagnesemia (treated with IV calcium and magnesium), transfusion reactions, and bleeding from low fibrinogen and platelets. So the vital signs are watched throughout, and blood counts, calcium and fibrinogen are drawn before the exchange and calcium and fibrinogen again after it.
  • Corticosteroids are not beneficial — the classic exam point, confirmed by eight randomized trials: no benefit, and oral corticosteroids may worsen outcome or delay recovery; the 2023 EAN/PNS guideline carries a strong recommendation against them. Proposed reasons: harm to denervated muscle and inhibition of the macrophage-dependent repair the nerve needs. The one exception is GBS triggered by immune checkpoint inhibitors.
  • ICU and airway plan — admit for evolving respiratory distress, severe autonomic instability, severe swallowing dysfunction or diminished cough, or rapidly progressive weakness (especially neck and hip flexors). Plan elective intubation when VC falls below 15 mL/kg rather than waiting for an emergency airway; no noninvasive ventilation; no succinylcholine (hyperkalemia in denervated muscle). Early tracheostomy is considered when the patient cannot lift the arms a week after intubation or the nerves are axonal/inexcitable.
  • Rehabilitation, nutrition, and the Miller Fisher exception — physical, occupational and speech-language therapy start early (passive range of motion in the severely affected), with graded intensity because overwork causes fatigue. GBS drives a high metabolic and protein-breakdown load: high-protein feeding starts as soon as possible by mouth, nasogastric tube, or parenterally, tracking weight and nitrogen balance. Pure Miller Fisher syndrome is generally not treated with IVIG or plasma exchange — most recover fully within 6 months, and 96% are symptom-free at one year — but is monitored closely because a subgroup develops limb, bulbar, or respiratory weakness.

Nursing considerations

The RN-specific layer — each action paired with the reason it matters.

Assessment & monitoring — the respiratory and autonomic watch
Measure vital capacity, MIP/NIF and MEP, and perform a single-breath count serially — at a frequency set by the rate of deterioration, the autonomic picture and the phase of illness — and trend them on the chart.
Why: Not every patient with respiratory insufficiency feels short of breath, and oxygen and carbon dioxide levels change only late. The trend in volume and pressure is the early warning; SpO₂ is the late one.
Escalate immediately for the 20/30/40 breach (VC < 20 mL/kg, NIF weaker than −30, MEP < 40 cmH₂O), a single-breath count ≤ 19 or inability to reach 15, tachypnea, accessory-muscle use, breathlessness while talking, or a weakening cough.
Why: These mark ICU-level risk and predict ventilation; 84% of those ventilated need it within a week of admission. Early escalation buys an elective intubation instead of an emergency one in a dysautonomic patient.
Grade strength serially on the MRC scale (neck flexors, arms, legs), check reflexes, and score disability; flag new neck-flexor, facial, or bulbar weakness at once.
Why: Neck-flexor weakness is the strongest bedside predictor of ventilation, and facial or bulbar weakness adds an EGRIS point. The slope of the MRC sum score tells you where the diaphragm is on the list.
Keep continuous cardiac telemetry and frequent blood-pressure checks running; report BP swings > 20%, HR swings > 10%, or any arrhythmia.
Why: Dysautonomia affects about two-thirds of patients, worsens as respiratory failure deepens, and its arrhythmias — including bradycardia that can progress toward asystole — and blood-pressure swings are a cause of GBS deaths; the monitor is the only early sign.
Screen swallow, cough and voice before every oral intake; assess bowel sounds, abdominal distension, bladder emptying, and serum sodium.
Why: Bulbar weakness (~40%) means aspiration and is an ICU criterion; ileus and urinary retention are autonomic; hyponatremia is a listed complication in all patients.
Ask specifically about pain, anxiety, hallucinations and low mood at every assessment — especially in the ventilated or minimally communicative patient — and screen for delirium in the highest-risk (age ≥ 60, onset ≤ 3 days before admission, dysautonomia, ICU).
Why: Pain, anxiety and hallucinations are often under-recognized and undertreated, especially when the patient cannot communicate or is in the ICU; delirium appears around day 5 and is usually hyperactive.
Interventions & safety — protecting a body that cannot protect itself
Apply aspiration precautions: hold oral intake when swallow or cough is weak, get speech-language pathology early, anticipate a feeding tube, and start high-protein nutrition as soon as possible.
Why: Bulbar weakness plus a weak cough sets up aspiration pneumonia — infections are among the leading causes of death — and GBS breaks down muscle protein quickly, so delay costs muscle.
Handle and reposition the dysautonomic patient with caution and keep continuous cardiac monitoring running during care; use only short-acting, titratable agents for paroxysmal hypertension; move and sit the patient up slowly.
Why: Arrhythmias and blood-pressure instability occur through autonomic involvement, long-acting antihypertensives cause rebound hypotension, and orthostatic drops are part of the syndrome.
Give the ordered VTE prophylaxis to every minimally ambulant or non-ambulant patient, keep compression devices on, and continue both until ambulation returns — noting any center rule to hold heparin on plasma-exchange days.
Why: Immobility plus a hypercatabolic state breeds DVT, and pulmonary embolism is a leading cause of GBS death.
Turn and pad pressure points frequently, position and brace carefully, and run passive range-of-motion exercises from the first day with physical therapy.
Why: A patient with sensory loss, or sedated on a ventilator, cannot report the pressure or the stretch; pressure injuries, compression neuropathies and contractures are the documented immobility complications.
Protect the eyes when the face is weak: artificial tears and lubricant, careful lid taping or protective eye domes.
Why: Incomplete lid closure from facial palsy leads to exposure keratitis and corneal ulceration — a preventable, painful, sight-threatening complication.
Establish a communication method (eye blinks, letter board, yes/no signals), explain every procedure before touching the patient, and mind what is said at the bedside — including in the ICU.
Why: Consciousness, vision and hearing are intact even in complete paralysis. Patients describe terror and the sense that "who you are is being taken away"; explanation reduces anxiety, and unexplained care feeds delirium.
Prefer intermittent catheterization over an indwelling catheter for retention; for ileus, anticipate holding enteral feeds, gastric decompression, promotility agents, and reducing opioids.
Why: Intermittent catheterization limits infection; ileus is autonomic and every opioid dose deepens it while sedation blunts the neuro exam.
Patient & family teaching — through nadir, plateau, and the long recovery
Teach the early warning signs that need immediate care: ascending weakness or trouble walking, facial weakness, difficulty swallowing, or shortness of breath.
Why: Weakness can worsen over hours or days, and some courses are fulminant — the family is the monitor once the patient is home or on a step-down unit.
Explain the trajectory honestly: nadir within 2–4 weeks, a plateau, then recovery that can take weeks to years; treatment shortens the road but may show nothing for the first month; most people recover, and recurrence is rare (2–5%).
Why: Accurate information about the good chance of recovery and the low recurrence risk measurably reduces fear; mental state influences physical recovery and vice versa.
After the ICU, teach the patient and family that the danger has not passed: weak cough → mucus plugs, plus arrhythmias and blood-pressure swings, still need reporting, deep-breathing and coughing exercises continue, and monitoring stays on.
Why: Up to two-thirds of GBS deaths occur in the recovery phase, mostly cardiovascular and respiratory, and especially in those who recently left the ICU.
Teach mobility exercises, pressure-injury prevention, deep-breathing exercises and safe-swallowing practices; enroll in a graded, supervised rehabilitation program and pace activity so it does not cause overwork.
Why: Rehabilitation improves walking and independence, but exercise intensity must be monitored — overwork causes the fatigue that 60–80% already carry.
Prepare the family for the possibility of residual fatigue, neuropathic pain, or weakness after major improvement, and connect them with caregiver support and other people who have had GBS.
Why: Roughly 10–20% keep significant disability, one-third still have pain at a year, and caregiver support is essential because many patients need help with daily activities, mobility, and communication.
Address vaccination questions with the evidence: prior GBS is not a strict contraindication; expert discussion is advised if GBS occurred less than a year before a planned vaccine or shortly after the same vaccine before.
Why: The recurrence risk from vaccination is small and possibly only theoretical, while the flu itself is the more likely GBS trigger — a benefit-versus-risk conversation, not a blanket ban.

How a real nurse thinks

The clinical-judgment loop, worked for a typical presentation — reasoning, not reference.

  1. 1
    Recognize cues

    The cues that matter at day 1: a falling trajectory on every respiratory measure — single-breath count 25 → 18, VC 35 → 24 mL/kg, NIF −45 → −32 — plus new facial weakness, choking on thin liquids, reflexes gone in all four limbs, an MRC sum score dropping 48 → 40, and heart rate and blood pressure swinging more than 20% within hours. The noise: the reassuring SpO₂ of 96%, the "normal" day-0 CSF protein of 48 mg/dL, and the fact that IVIG has already been running for 18 hours. None of those three cancels a single cue in the first list.

  2. 2
    Analyze cues

    This is GBS progressing toward its nadir on a fast course — onset ≤ 3 days before admission after a diarrheal prodrome is the highest-weighted EGRIS item, and preceding diarrhea itself predicts a harder course. The falling volumes and pressures are the respiratory pump failing; the facial droop and choking are cranial-nerve spread with bulbar weakness, both predictors of ventilation. The HR and BP swings are dysautonomia, which tracks respiratory failure and makes any emergency airway dangerous. The normal SpO₂ is exactly what the physiology predicts — hypoxemia is a late sign. The day-0 CSF protein of 48 mg/dL is normal only because it is week one; about half of patients have a normal early LP, and it changes nothing. IVIG "not working yet" is expected — 40% show no improvement in the first 4 weeks. Re-scored with today’s findings (onset ≤ 3 days = 2, facial/bulbar present = 1, MRC 40 = 2), his EGRIS is 5 — the high-risk band.

  3. 3
    Prioritize

    The threat that kills first is airway and breathing without reserve, followed closely by an autonomic arrhythmia. He has not yet breached the 20/30/40 rule (VC 24, NIF −32), but the slope says he will within hours, the single-breath count of 18 is already under the ≤ 19 predictor, and bulbar weakness is an ICU criterion on its own. The priority is therefore escalation now for ICU-level care and an elective airway plan — not waiting for VC < 20, not waiting for the saturation to move. Second: aspiration protection (nothing more by mouth). Third: the dysautonomia (telemetry running, cautious handling, no rapid position changes). Pain, anxiety and the family’s questions are real and next.

  4. 4
    Generate solutions

    Make him NPO and request speech-language pathology; keep the head of bed up; keep telemetry and frequent BP checks running; increase the frequency of VC/NIF/single-breath counts because the rate of deterioration, not a schedule, sets it. Call the provider with an SBAR that leads with the trend and asks for ICU transfer and an elective intubation plan before VC reaches 15 mL/kg — and flag that noninvasive ventilation is not an option and succinylcholine must be avoided. Continue the IVIG; a second course or adding plasma exchange is not on the table. Establish a communication method now, while he can still speak, and explain what is happening — he is fully aware and terrified.

  5. 5
    Take action

    Act, then call. NPO sign up, head of bed raised, suction set up at the bedside, no independent order needed. Then the SBAR: "Day-1 GBS on IVIG, fast course after Campylobacter-type diarrhea. Overnight the single-breath count fell 25 to 18, VC 35 to 24 mL/kg, NIF −45 to −32, MRC sum 48 to 40; new facial weakness and choking on liquids; HR 52 to 118 and BP 92/50 to 176/98 within two hours. SpO₂ is 96% but that is a late sign. I have made him NPO and raised the frequency of respiratory measurements. Requesting ICU evaluation and an elective airway plan now." The trap to avoid: charting "SpO₂ 96%, no distress, will recheck VC in the morning" — and the second trap, if the family asks, is suggesting steroids or a bigger IVIG dose; neither helps and both can harm.

  6. 6
    Evaluate

    Success in the next hours: ICU transfer accepted, VC/NIF trended on a tighter interval with an intubation threshold written down, no aspiration event, dysautonomia documented and handled without a rebound-hypotension episode, pain and anxiety asked about and treated with an eye on sedation and ileus. Success weeks later is the harder kind: when he steps down from the ICU improving, the vigilance does not step down with him — up to two-thirds of GBS deaths happen in the recovery phase, from arrhythmias, pressure swings, and mucus plugs behind a still-weak cough.

Scenario — you’re the nurse

Work each question before revealing the answer. Rationales explain the wrong options too.

Neurology step-down unit · admission day 0 through day 1

A 58-year-old man admitted with two days of tingling in both feet and hands and trouble climbing stairs, beginning about 10 days after a diarrheal illness. History: hypertension. He is alert and anxious. Provisional diagnosis GBS; IVIG ordered pending IgA level; continuous telemetry and serial bedside respiratory measurements ordered.

Day 0, 0800 admission — HR 96 · BP 138/84 · RR 16 · SpO₂ 97% room air · T 37.0 °C · alert, oriented, anxious
Neuro — symmetric leg weakness, cannot rise from a chair unaided · reflexes 1+ at knees, absent at ankles · MRC sum score 48 · face symmetric, swallow intact, neck flexion strong
Bedside respiratory — single-breath count 25 · VC 35 mL/kg · NIF −45 cmH₂O · strong cough
LP / labs (day 0) — CSF protein 48 mg/dL (within the laboratory reference range) · CSF WBC 3/µL · Na 136 · IgA normal → IVIG started 1400
Day 1, 0800 — reflexes absent in all four limbs · MRC sum 40 · single-breath count 18 · VC 24 mL/kg · NIF −32 cmH₂O · new left-greater-than-right facial droop, coughed on thin liquids at breakfast · HR 52 → 118 over the past 2 h · BP 92/50 → 176/98 · SpO₂ 96% room air
Q1 Select all that apply
Which day-1 findings require immediate follow-up? Select all that apply.
  1. A. Single-breath count fell from 25 to 18
  2. B. New facial droop and coughing on thin liquids
  3. C. Heart rate 52 → 118 and BP 92/50 → 176/98 over two hours
  4. D. SpO₂ 96% on room air
  5. E. Day-0 CSF protein 48 mg/dL
Reveal answer & rationale
Answer: A, B, C
A single-breath count of 18 is under the ≤ 19 cutoff that predicts mechanical ventilation, and the whole respiratory trend is falling (A). New facial and bulbar weakness (B) means aspiration risk, an ICU criterion, and a predictor of ventilation. Blood pressure swinging more than 20% and heart rate more than 10% (C) is dysautonomia: arrhythmias, including severe bradycardia with a risk of asystole, and blood-pressure instability are a cause of GBS deaths. SpO₂ 96% (D) is expected — hypoxemia is a late manifestation and a normal saturation never cancels a falling VC. A CSF protein of 48 mg/dL (E) is within the laboratory reference range, as expected in week one — protein is normal in 30–50% of patients in the first week — so it neither excludes GBS nor requires action.
Q2 Multiple choice
The nurse notes the SpO₂ is 96% on room air. Which interpretation is correct?
  1. A. Respiratory function is adequate; continue routine monitoring
  2. B. Oxygen saturation falls only late in neuromuscular respiratory failure, so the falling VC and NIF drive escalation regardless
  3. C. The pulse oximeter should be replaced with an arterial blood gas every 4 hours
  4. D. Apply supplemental oxygen prophylactically to prevent desaturation
Reveal answer & rationale
Answer: B
In GBS the pump fails before gas exchange does: vital capacity and cough strength fall first, and oxygen and carbon dioxide levels change only late — early detection rests on volume and pressure measurements (B). Treating a normal saturation as adequacy (A) is the disorder’s classic trap. A blood gas (C) is also a late indicator, and no fetched guidance sets a fixed 4-hour schedule for anything — the frequency is individualized to the rate of decline. Oxygen (D) does nothing for hypoventilation and may delay recognition by keeping the number reassuring.
Q3 Multiple choice
At 1400 on day 1, VC is 18 mL/kg and NIF is −24 cmH₂O; the patient is using accessory muscles. The best nursing action is to:
  1. A. Apply noninvasive positive-pressure ventilation and reassess in one hour
  2. B. Notify the provider and rapid response now, anticipating ICU transfer and elective intubation
  3. C. Encourage incentive spirometry and recheck VC at the next scheduled interval
  4. D. Prepare succinylcholine for rapid-sequence intubation at the bedside
Reveal answer & rationale
Answer: B
VC < 20 mL/kg and NIF weaker than −30 cmH₂O meet the 20/30/40 rule, accessory-muscle use is a clinical sign of impending failure, and the goal is an elective airway before VC reaches 15 mL/kg (B). Noninvasive ventilation (A) is not recommended in GBS — patients need full support for days and dysautonomia worsens as failure deepens. Waiting for a scheduled recheck (C) ignores a patient already at ICU-level risk. Succinylcholine (D) must be avoided — it can precipitate hyperkalemia in denervated muscle — and preparing drugs is not the nurse’s first move.
Q4 Put in order
Put the nurse’s first four actions on day 1 in priority order:
  1. A. Notify the provider (SBAR) requesting ICU evaluation and an elective airway plan
  2. B. Make the patient NPO, raise the head of the bed, and place suction at the bedside
  3. C. Explain to the patient what is happening and set up a yes/no communication method
  4. D. Document the respiratory trend and the plan of care
Reveal answer & rationale
Correct order: B → A → C → D
Protect the airway from aspiration and set up suction first — these need no order and take a minute (B). Escalation follows immediately (A): the trend, the bulbar weakness, and the dysautonomia together meet ICU criteria, and the provider needs the picture to arrange elective intubation. Communication and explanation (C) are urgent — he is fully aware and frightened — but come after the two safety actions. Documentation (D) never precedes protecting the patient. Calling first (A before B) leaves a choking patient with a breakfast tray in reach while you are on the phone.
Q5 Multiple choice
Three weeks later the patient is extubated and transferred from the ICU to the step-down unit, improving daily. His wife says, "The worst is over now, right?" The best response is:
  1. A. "Yes — once patients leave the ICU, the dangerous part of GBS is behind them."
  2. B. "He is improving, but up to two-thirds of GBS deaths happen during recovery — we keep watching his heart rhythm, blood pressure, and cough closely."
  3. C. "The risk now is a relapse, so he will receive a second course of IVIG as a precaution."
  4. D. "He is safe as long as his oxygen saturation stays normal."
Reveal answer & rationale
Answer: B
Up to two-thirds of GBS deaths occur in the recovery phase, mostly from arrhythmias, blood-pressure shifts, and respiratory distress from mucus plugs behind a still-weak cough — and monitoring is especially important in patients who have recently left the ICU (B). Declaring the danger over (A) is the lapse that kills. A routine second IVIG course (C) carries a strong recommendation against — no added benefit, more adverse events — and true recurrence is rare (2–5%). Saturation (D) is a late indicator here exactly as it was on day 1.

Common questions

What causes guillain-barré syndrome?
Common causes and risk factors include antecedent infection within ~6 weeks (≈ 70% of cases; two-thirds report a gastrointestinal or respiratory prodrome), campylobacter jejuni gastroenteritis — the most common identified trigger (≈ 1 in 1,000 infections); exposure via raw/undercooked poultry, contaminated food or water, animal contact, cytomegalovirus, epstein-barr virus, hepatitis e, hiv, mycoplasma pneumoniae, haemophilus influenzae, influenza a, arboviruses — zika, dengue, chikungunya, japanese encephalitis (covid-19 association remains controversial), vaccination — rare and quantified: ≈ 1 per 100,000 after the 1976 swine-flu vaccine; at most 1–2 per million seasonal flu doses; adenovirus-vector covid-19 vaccines, not mrna (cdc), and others.
What are the early signs of guillain-barré syndrome?
Early findings include Tingling and numbness in the feet, then the hands (distal paresthesias), Symmetric weakness climbing from the legs to the arms — cannot climb stairs, then cannot rise from a chair, Reflexes reduced, then absent (areflexia).
Which findings should a nurse report immediately in guillain-barré syndrome?
Report immediately: Symmetric weakness climbing from the legs to the arms — cannot climb stairs, then cannot rise from a chair, Dysphagia, choking on liquids, weak cough, weak or nasal voice (bulbar weakness, ~40%), Neck-flexor weakness — cannot lift the head off the pillow; rapidly weakening hip flexors, Tachypnea, accessory-muscle use, breathlessness while talking, cannot count to 15 in one breath, weak cough, Sinus tachycardia, labile blood pressure (paroxysmal hypertension ↔ orthostatic hypotension), cardiac arrhythmias, abnormal sweating, and others. These signal deterioration that needs rapid intervention.
What is the 20/30/40 rule in Guillain-Barré syndrome?
It is the bedside threshold for respiratory danger: a vital capacity below 20 mL/kg, a maximal inspiratory pressure (NIF) weaker than −30 cmH₂O, or a maximal expiratory pressure below 40 cmH₂O marks the patient as at risk of respiratory failure and needing ICU-level care. It matters because GBS respiratory failure is silent — oxygen saturation and blood gases change only late — so the nurse measures volumes and pressures serially, along with a single-breath count (≤ 19 predicts ventilation), and escalates on the trend. Once VC falls below 15 mL/kg, elective intubation prevents a far more dangerous emergency airway.
IVIG or plasma exchange — which is better, and why not both or steroids?
They are equally effective; the choice depends on availability, cost, and the patient (IVIG is easier to give and more widely available; plasma exchange is withheld when hemodynamics are unstable). Both work best started early — trial evidence covers IVIG within 2 weeks and plasma exchange within 4 weeks of weakness onset. Combining them adds nothing, and a second IVIG course adds adverse events without benefit, so guidelines recommend against both. Corticosteroids do not help and may worsen outcome — the one exception is GBS caused by immune checkpoint inhibitors.
Do people recover from Guillain-Barré syndrome?
Most do. Weakness peaks within 2 weeks in most patients and by 4 weeks in nearly all, plateaus, and then recovers over weeks to months: about 80% walk independently at 6 months and more than half recover fully within a year, even after weeks on a ventilator. Mortality is roughly 5% overall (about 20% if ventilated), and roughly 10–20% keep significant disability; fatigue affects 60–80% long term and one-third still have pain at a year. Recurrence is rare (2–5%).

Sources

Reviewed by Hae Suk Lee, RN

Educational summary for nursing students. Scenarios are fictional teaching cases. Always verify against current guidelines and your institution's protocols before acting in practice. Not medical advice.

Bookmark LearnDrugs.com?

Your saved pages are kept in this browser. Add LearnDrugs.com to your browser’s bookmarks to get back to them in one click.

Drag this link to your bookmarks bar: LearnDrugs.com

Or press Ctrl + D to bookmark the page you’re on.