A 60-year-old man was admitted with a 3-day history of diarrhoea

A 60-year-old man was admitted with a 3-day history of diarrhoea. A diagnosis of lung and peritoneal metastases from an unknown primary carcinoma had been made 4 months previously, and he had been receiving platinum-based combination chemotherapy. He had been discharged from hospital 5 days previously after an episode of neutropenic sepsis following his second cycle of chemotherapy.On examination, he was apyrexial, his pulse was 98 beats per minute and his blood pressure was 110/65 mmHg lying. He looked dehydrated. His abdomen was soft but tender over the left iliac fossa.
Investigations:

haemoglobin 113 g/L (130–180)

white cell count 6.5 × 109/L (4.0–11.0)

neutrophil count 5.4 × 109/L (1.5–7.0)

platelet count170 × 109/L (150–400)

CT scan of abdomen thickened sigmoid colon

What is the most likely diagnosis?

Question 9

A: cryptosporidiosis

B: flare-up of diverticular disease

C: ischaemic colitis

D: pseudomembranous colitis

E: tumour progression