MSFinals-4148

MSFinals-4148

A 6-year-old boy is admitted to the paediatric ward with a cough and lethargy. His dad is concerned as his breathing is fast and he has had a high temperature which hasn’t improved with paracetamol. He is normally healthy and up to date with all his vaccinations.

Upon examination, he is tachypnoeic with a temperature of 39.5ºC. He has crackles in the left lower zone on auscultation. Blood tests reveal the following results:

– Hb 132 g/L (Male: 135-180, Female: 115-160)
– Platelets 290* 109/L (150-400)
– WBC 18.5* 109/L (4.0-11.0)
– Na+ 140 mmol/L (135-145)
– K+ 4.2 mmol/L (3.5-5.0)
– Urea 5.5 mmol/L (2.0-7.0)
– Creatinine 90 µmol/L (55-120)
– CRP 85 mg/L (<5) A chest radiograph shows a left lower lobe consolidation. What is the most likely causative agent of his pneumonia?