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Child with acute weakness: don’t forget the salts
  1. Kathryn Boyle1,
  2. Ben McNaughten2,
  3. Andrew Thompson2,
  4. Stephen Mullen1
  1. 1 Paediatric ED, Royal Belfast Hospital for Sick Children, Belfast, UK
  2. 2 Paediatrics, Royal Belfast Hospital for Sick Children, Belfast, UK
  1. Correspondence to Dr Ben McNaughten, ST7 Paediatrics, Royal Belfast Hospital for Sick Children, Belfast BT12 6BA, UK; bmcnaughten095{at}


Case summary A 10-year-old boy presented with severe progressive generalised weakness on a background of 3 days of diarrhoea and vomiting. Vital signs were normal. Peripheral neurological examination revealed grade 1–2 power in all limbs, hypotonia and hyporeflexia. Sensation was fully intact. Cranial nerve examination and speech were normal. The ECG (figure 1) and initial venous blood gas (figure 2) are shown.

Question 1 What abnormalities are present on the ECG?

  1. Peaked T waves, prolonged PR segment and loss of P waves?

  2. Shortening of the QT interval and Osborn waves (J waves)?

  3. T wave flattening/inversion, prominent U waves and long QU interval?

  4. Prolonged QT interval with multiple atrial and ventricular ectopics?

Question 2 How would you manage this patient’s hypokalaemia?

Question 3 What is the likely diagnosis?

  1. Conversion disorder.

  2. Myasthenia gravis.

  3. Periodic paralysis.

  4. Guillain-Barré syndrome.

  5. Botulism.

Question 4 What interventions can be considered for long-term treatment of this condition?

Answers can be found on page 2.

  • paediatric practice
  • paralysis
  • hypokalaemia
  • hypokalaemic periodic paralyis

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  • Contributors BMcN and KB wrote the first draft of the manuscript. SM and AT reviewed the manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.