7th February 2024

A 45-year-old male presents with generalised weakness in his lower limbs.

A 45-year-old male presents with generalised weakness in his lower limbs. This is accompanied by loss of sensation in both lower limbs. He states that he had a diarrhoeal illness nine days before. Examination reveals a power of 2/5 in both lower limbs and 3/5 power in his upper limbs. Paraesthesia of both lower limbs was noted. Global areflexia with hypotonia was noted in all four limbs. 

Following two days of admission, he developed worsening symptoms with a new hypertensive crisis with BP measuring 200/120mmHg. He also developed a new tachypnoea with 30 breaths per minute with little breath sounds heard on auscultation.

Given the likely diagnosis and new respiratory symptoms, which of the following spirometry findings is expected?