Suspect that a patient has a subphrenic abscess if he deteriorates, or recovers and then deteriorates, between the 14th and the 21st day after a laparotomy, with a low, slowly increasing, swinging fever, sweating, and a tachycardia. This, and a leucocytosis, show that he has ''pus somewhere', which is making him anorexic, wasted, and ultimately cachectic. If he has no sign of a wound infection, a rectal examination is negative, and his abdomen is soft and relaxed, the pus is probably under his diaphragm.
The pus might be between his diaphragm and his liver, in (1) his right or (2) his left subphrenic space, or under his liver in (3) his right or (4) his left subhepatic space in his lesser sac. He may have pus in more than one of these spaces.
Explore him on the suspicion that he might have a subphrenic abscess. Exploration is not a major operation; the difficulty is knowing where to explore, so refer him if you can. If you cannot refer him, explore him yourself. If you fail to find pus, you have done him no harm; missing a subphrenic abscess is far worse. If it is anterior, you can drain it by going under his costal margin anteriorly. If it is posterior, you can go through the bed of his 12th rib posteriorly.