History Taking · Foundation · Neurology

Progressive Weakness Following Infection

Practise this PLAB 2 history taking station on Guillain-Barré Syndrome. 8-minute voice AI simulation with feedback on all 3 marking domains.

Clinical scenario

You are an FY2 doctor in acute assessment unit. Mr Robert Chen, a 45-year-old man, presents with a three-day history of progressive weakness starting in his legs and now affecting his arms. He had a viral illness one week ago. He is anxious about the rapid progression. Please take a detailed history, assess severity, and discuss urgent management and investigations.

Background notes: PMH: Type 2 diabetes, Mild asthma (childhood, now asymptomatic)

What this station tests

  • Recognising the ascending paralysis pattern: weakness starting distally in legs and progressing proximally and to arms over days
  • Identifying the post-infectious trigger: diarrhoeal illness 1 week prior (Campylobacter-associated GBS)
  • Urgent respiratory assessment: counting to 20 in one breath, cough strength, swallowing ability, and breathlessness as indicators of impending respiratory failure
  • Distinguishing GBS from spinal cord compression: ascending pattern without sensory level, areflexia, post-infectious trigger
  • Communicating prognosis honestly: 70% full recovery but weeks to months of rehabilitation, with the possibility of ventilation

How to use your 8 minutes

  • 0-1 min — Introduction: Introduce yourself, confirm identity, open question. 'What's brought you in today?'
  • 1-4 min — Systematic History: Presenting complaint detail (SOCRATES for pain, timeline, severity). Systems review. PMH, medications, allergies.
  • 4-6 min — Context and ICE: Social history (smoking, alcohol, occupation, living situation). Family history. Ideas, Concerns, Expectations.
  • 6-7 min — Summary and Plan: Summarise findings back to patient. Share differential/working diagnosis. Outline investigation and management plan.
  • 7-8 min — Closing: Safety netting with specific red flags. Arrange follow-up. Check for questions.

Consultation approach

The opening

Rapidly progressive ascending weakness is a neurological emergency. The candidate must recognise the pattern (ascending weakness post-infection), assess respiratory function (the life-threatening complication), and arrange urgent admission. Mr Chen is 45, presenting with 3 days of progressive weakness starting in his legs and now affecting his arms. He had a viral gastroenteritis-like illness one week ago. Open with: 'Mr Chen, I can see you're struggling. Tell me how the weakness has progressed.' The speed of progression should set the urgency of your response.

Core approach

Establish the ascending pattern. Weakness started in his feet 3 days ago, progressed to his entire legs by end of day one, worsened so he could barely walk by day two, and now involves his arms and hands (day three). He cannot walk unassisted, cannot lift his arms above his shoulders, and has difficulty gripping. This rapid ascending paralysis over days is the hallmark of Guillain-Barre syndrome.

The preceding illness is critical. One week ago he had 2 to 3 days of fever, diarrhoea, and abdominal cramps, which resolved completely. Campylobacter jejuni is the commonest trigger for GBS, and a preceding diarrhoeal illness fits. Other triggers include viral URTI, CMV, EBV, and Mycoplasma. The 1 to 3-week gap between infection and weakness onset is typical.

Assess respiratory function urgently. This is the life-threatening risk. Ask: 'Are you more breathless than normal? Can you count to 20 in one breath? Can you cough strongly? Can you swallow normally?' If respiratory muscles are affected, he may need mechanical ventilation (15 to 20% of GBS patients). Bulbar symptoms (difficulty swallowing, weak cough, voice changes) are warning signs of impending respiratory failure.

Check for autonomic dysfunction: blood pressure variability, heart rate changes, urinary retention. These indicate more severe disease. Confirm areflexia if possible (hallmark of GBS). No sensory level (which would suggest spinal cord compression instead).

Closing and safety netting

Communicate the diagnosis and urgency. 'Mr Chen, the pattern of weakness starting in your feet and moving upward over three days, following the stomach illness last week, is consistent with a condition called Guillain-Barre syndrome. This is an immune reaction where your body's immune response to the infection has mistakenly attacked the nerves. You need to be admitted to hospital urgently because the weakness can progress, and we need to monitor your breathing closely.'

He will be frightened. Address his specific fears: 'Will I be paralysed?' Most patients (70%) make a full recovery, though it takes weeks to months. 'Will I need a ventilator?' Possibly, which is why monitoring is essential. Treatment: IV immunoglobulin (IVIg) is first-line and can shorten the duration and severity of the illness.

Investigations: nerve conduction studies (will show demyelinating pattern), LP (albumino-cytological dissociation: raised protein, normal cells), bloods including anti-ganglioside antibodies. Safety net: 'If your breathing becomes more difficult before admission, call 999 immediately.' Involve his wife in the discussion as she brought him and will be his primary support.

How examiners mark this station

Examiners will focus on the thoroughness and structure of your history taking for guillain-barré syndrome. Domain 1 (Data Gathering) carries the most weight: expect marks for systematic coverage of presenting complaint, red flags, PMH, medications, social and family history. Domain 2 (Clinical Management) requires a clear differential, appropriate investigations, and a safe management plan with safety netting. Domain 3 (Interpersonal Skills) is assessed throughout: genuine exploration of ICE, active listening, empathic responses, and clear communication without jargon.

Domain 1: Data Gathering, Technical and Assessment Skills (Primary focus)

Scores well: Ascending weakness pattern documented with timeline. Preceding infection identified with appropriate gap. Respiratory function assessed (counting, cough, swallowing). Autonomic features checked. Areflexia noted. Sensory level excluded. Power graded in all limbs.

Costs marks: Not establishing the ascending pattern. Missing the preceding illness. Not assessing respiratory function. Not checking for sensory level (would suggest cord compression).

Domain 2: Clinical Management Skills (Primary focus)

Scores well: Urgent admission arranged. Correct diagnosis of GBS with rationale. Knowledge of IVIg as first-line treatment. Appropriate investigations (NCS, LP, bloods). Respiratory monitoring plan. Safety netting for breathing deterioration before admission.

Costs marks: Not arranging urgent admission. Not knowing GBS treatment. Arranging outpatient referral. No respiratory monitoring plan. No safety netting.

Domain 3: Interpersonal Skills (Throughout)

Scores well: Honest prognosis discussion (70% full recovery, but weeks to months). Addressing his fear of paralysis directly. Explaining the need for admission clearly. Involving his wife. Acknowledging how frightening the rapid progression has been.

Costs marks: Being falsely reassuring ('you'll be fine'). Not addressing his fear of permanent paralysis. Not involving his wife. Underplaying the seriousness while the patient can see his own deterioration.

Common examiner feedback (and how to fix it)

Did not gather sufficient information to make an adequate assessment of the patient's condition

Fix: Use a consistent framework for every history. After covering the presenting complaint, systematically move through PMH, drug history, social history, family history, and ICE. Keep a mental checklist.

Did not identify the patient's problems and/or did not develop a management plan adequately

Fix: Reserve the final 2 minutes to summarise your findings, share your working diagnosis with the patient, and outline your investigation and management plan including safety netting.

Common mistakes in this station

  1. Not assessing respiratory function. GBS can cause respiratory failure requiring mechanical ventilation in 15 to 20% of patients. Candidates who take a detailed weakness history but do not check respiratory function (can you count to 20, can you cough, can you swallow) miss the life-threatening complication.
  2. Not connecting the preceding diarrhoeal illness. The 1 to 3-week gap between infection and weakness onset is the diagnostic clue. Candidates who do not ask about recent illness miss the aetiology and the diagnosis.
  3. Not communicating the need for urgent admission. GBS with rapidly progressive weakness over 3 days is a medical emergency. Candidates who arrange outpatient neurology referral instead of immediate hospital admission risk the patient deteriorating at home.

Resitting PLAB 2?

If you have previously struggled with history taking stations, focus on building a consistent systematic framework that you apply to every case. Practise structuring your history into clear phases (presenting complaint, systems review, PMH, social, ICE) so that even under pressure, you cover all domains. Many resitters lose marks not on knowledge but on organisation and time management.

Example opening

Good morning/afternoon, my name is Dr [Name], I'm one of the doctors here today. Could I confirm your name and date of birth please? Thank you. So, what's brought you in to see me today?

Frequently asked questions

How should I structure the guillain-Barré syndrome history in this PLAB 2 station?

Rapidly progressive ascending weakness is a neurological emergency. The candidate must recognise the pattern (ascending weakness post-infection), assess respiratory function (the life-threatening complication), and arrange urgent admission. Mr Chen is 45, presenting with 3 days of progressive weakness starting in his legs and now affecting his arms.

What are examiners marking in this guillain-Barré syndrome station?

Marks are won for: Ascending weakness pattern documented with timeline. Preceding infection identified with appropriate gap. Respiratory function assessed (counting, cough, swallowing). Marks are lost for: Not establishing the ascending pattern. Missing the preceding illness. Not assessing respiratory function. Not checking for sensory level (would suggest cord compression).

What is the most common mistake candidates make in this guillain-Barré syndrome station?

Not assessing respiratory function. GBS can cause respiratory failure requiring mechanical ventilation in 15 to 20% of patients. Candidates who take a detailed weakness history but do not check respiratory function (can you count to 20, can you cough, can you swallow) miss the life-threatening complication.

How do I prepare for this station if I have not managed guillain-Barré syndrome in clinical practice?

This station rewards process over personal experience. The skill being assessed: Identifying the post-infectious trigger: diarrhoeal illness 1 week prior (Campylobacter-associated GBS). The written guidance on this page covers the full approach, and practising the consultation aloud builds the fluency the examiner is listening for.

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