Guillain-Barré syndrome and acute flaccid paralysis: Viva

Branch 1: Making the diagnosis

A strong candidate recognises this as Guillain-Barré syndrome and applies the Brighton criteria. The diagnosis turns on the tempo, the symmetry, and the reflex pattern rather than on a single test. The child has a rapid onset of progressive, symmetrical, ascending flaccid weakness over days, with early areflexia and no sensory level, which is the classic clinical picture. The antecedent diarrhoeal illness points to Campylobacter jejuni and supports the diagnosis. A lumbar puncture for albuminocytological dissociation and neurophysiology to distinguish the demyelinating from the axonal subtypes are sent, but a normal early cerebrospinal fluid does not exclude the diagnosis, and treatment is started on the clinical picture. [2]

Branch 2: Respiratory monitoring and the intensive care decision

When the examiner asks how the candidate monitors the respiratory status, the answer is bedside spirometry every two to six hours in any child with progressive weakness, measuring the forced vital capacity, the maximum inspiratory pressure, and the maximum expiratory pressure. The intensive care triggers are a forced vital capacity under 20 mL per kilogram, a fall of greater than 30 percent from baseline, a maximum inspiratory pressure under negative 60 centimetres of water, or bulbar weakness with a weak cough and aspiration risk. The candidate stresses that the decision to intubate is driven by the numbers, not by how the child looks, because a child who is still talking in full sentences can have a falling vital capacity. [12]

Branch 3: The treatment ladder

When asked how the candidate runs the ladder, the answer is to secure the airway and breathing first, send the workup, and start first-line therapy with intravenous immunoglobulin 2 g per kg over two to five days as soon as the diagnosis is made, without waiting for confirmatory results. The van der Meche 1992 trial showed that immunoglobulin is as effective as plasma exchange and is easier and safer to give, and the Cochrane review confirmed it speeds recovery. Plasma exchange, five sessions over one to two weeks, is the alternative when immunoglobulin is contraindicated. Corticosteroids are not recommended, because the systematic review showed no benefit and possible harm, and the candidate must be crisp on this point because examiners ask it directly. [4][7]

Branch 4: Excluding the mimics

The examiner then offers a child with asymmetric flaccid weakness confined to one limb after a viral illness, with a spinal MRI showing anterior horn cell T2 change. The strong candidate recognises acute flaccid myelitis, the polio-like grey-matter lesion, and distinguishes it from Guillain-Barré syndrome by the focal asymmetric pattern and the MRI change. The candidate names the other acute flaccid paralysis mimics: transverse myelitis with a sensory level and bladder dysfunction, spinal cord compression with back pain and a surgical emergency, tick paralysis with an embedded tick and resolution on removal, and botulism with descending paralysis and dilated pupils. The rule that protects the child is that any sensory level, bladder or bowel dysfunction, or asymmetric weakness triggers an urgent MRI. [1]

Branch 5: The Miller Fisher variant

If the examiner changes the picture to double vision, ataxia, and areflexia, the candidate recognises the Miller Fisher syndrome and its anti-GQ1b ganglioside antibody, concentrated in the oculomotor nerves and the muscle spindles, which explains the triad. The candidate notes the overlap with Bickerstaff brainstem encephalitis, which adds drowsiness, and confirms that both are treated with intravenous immunoglobulin 2 g per kg. [1]

Branch 6: Prognosis and the family

Asked what to tell the family, the candidate quotes that children recover faster and more completely than adults, with a substantial majority walking independently by six months and near-complete recovery by one year, and that around 10 to 15 percent of children need mechanical ventilation. The candidate is honest that recovery is prolonged, that residual fatigue and proximal weakness can persist, and that the intensive care course is dominated by weaning ventilation and managing autonomic instability and pain. The Erasmus Respiratory Insufficiency Score predicts ventilation from the admission features, and the modified Erasmus Outcome Score predicts the six-month outcome. The candidate gives the family a safety-net and arranges paediatric neurology follow-up and structured rehabilitation. [8][10]

The examiner rewards a candidate who measures the forced vital capacity, who treats early with intravenous immunoglobulin, who refuses corticosteroids, who excludes the acute flaccid paralysis mimics, and who quotes the paediatric recovery data honestly. [1]