A 78-year-old man with history of chronic constipation is brought to the A&E with a sudden onset of abdominal pain and distension. Examination reveals a distended tympanic abdomen with a 'mass' arising from the pelvis. What is the diagnosis for this patient?

A 9-month-old baby boy has been admitted to the paediatric unit with intermittent colicky abdominal with blood-stained stools and mucus in his nappy. On examination he looks unwell. Abdominal examination shows an empty right iliac fossa with a lump in the epigastrium. What is the diagnosis for this patient?

A 68-year-old man has been admitted as an emergency with colicky abdominal pain with constipation for 3 days. In between the colics he is left with a dull ache. On abdominal examination he is in some discomfort with tenderness and distension particularly in the peripheral part. Over the past 4 months he has been increasingly constipated having to take large amounts of laxatives to open his bowels. What is the diagnosis for this patient?

An 84-year-old woman has been admitted with a 12-hour history of colicky abdominal pain, distension, vomiting and constipation; the vomitus, bilious to start with, became faeculent. Clinical examination shows a small erythematous tender lump below the inguinal ligament and lateral to the pubic tubercle. What is the diagnosis for this patient?