20th February 2025

A 68-year-old woman presents with severe breathlessness, cough and fever.

A 68-year-old woman presents with severe breathlessness, cough and fever. She requires 3 L via nasal cannulae to maintain an oxygen saturation of 97%. Her respiratory rate is 32 breaths a minute and heart rate is 110 beats a minute. Her temperature is 38 °C. She has left-sided crackles and left basal reduced air entry. A chest radiograph shows a left-sided pneumonia and large parapneumonic effusion. “Sepsis 6” management is initiated.

A diagnostic and therapeutic aspirate is taken. Two litres are drained and the patient tolerates the procedure well with significant reduction in breathlessness and oxygen requirement to 1 L via nasal cannulae. An hour later, the nursing staff report her oxygen requirement has substantially increased to 15 L via a non-rebreathe mask and worsening cough. Her respiratory rate is 40 breaths per minute and her heart rate is 125 beats per minute. She has bilateral crackles on lung auscultation. 

What is the likely diagnosis of this worsening respiratory function?

Select the SINGLE most appropriate option from the list below. Select ONE option only.