Subphrenic abscess

Pus under a patient's diaphragm has usually spread there from somewhere else in his abdomen. A subphrenic abscess may be secondary to: (1) Peritonitis, either local or general, following a perforated peptic (11.2) or a typhoid ulcer (31.8), or appendicitis (12.1), or PID (6.6) or infection following Caesarean section (18.11). (2) An injury which has ruptured a hollow viscus and contaminated his peritoneal cavity (66.2). (3) A laparotomy during which his peritoneal cavity was contaminated (9.2). (4) A ruptured amoebic liver abscess (31.12).

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.

KIMANI (15 years) was admitted with abdominal pain and vomiting of sudden onset, about 4 hours previously. He had shoulder-tip pain, but he also said he had pain when he put his tongue out, so it was first thought that he might be hysterical. He had no abdominal signs, so he was admitted for observation. The following day his abdomen started to distend, and aspiration of his peritoneal cavity withdrew greenish fluid. A laparotomy was done, and an ulcer on the greater curve of his stomach was found and repaired. Initially he recovered well, but as he was about to go home 10 days later, he was not well, he ran a fever, he looked toxic, and there was tenderness and induration on the right side of his upper abdomen. He was suspected of having a subphrenic abscess, his abdomen was reopened through his paramedian incision, and a large quantity of foul-smelling pus was evacuated from under the right side of his liver. Several drains were inserted. The drug vote was almost finished and the hospital could not afford intravenous metronidazole, so he was given intravenous chloramphenicol, and metronidazole by mouth, after which he eventually recovered. LESSONS (1) If you are not certain that a patient is hysterical it always pays to observe him. (2) Beware of the ''latent interval' 3 to 6 hours after a perforation, when there may be few abdominal signs. (3) You may be able to drain a subphrenic abscess through the original laparotomy incision, but the incisions described below may be better. (4) When a peptic ulcer causes general peritonitis, a thorough lavage of the peritoneal cavity is as important as the repair. Fig 6-5 SUBPHRENIC ABSCESSES. A, the spaces where pus can collect under a patient's diaphragm. B, make a subcostal incision when you approach a subphrenic abscess anteriorly. C, exploring the right posterior subphrenic abscess. D, exploring the left posterior space. E, exploring the posterior spaces through the ribs.

1, the right anterior subphrenic space. 2, the left anterior subphrenic space, 3, the right subhepatic space. 4, the left subhepatic space (the lesser sac). 5, the right posterior subphrenic space. 6, the left posterior subphrenic space.

SUBPHRENIC ABSCESS This follows from Section 6.3 on abdominal abscesses.

SIGNS AND SYMPTOMS. Thoracic signs are more useful than abdominal ones. Ask or look for: (1) Cough. (2) Shoulder-tip pain on the affected side. (3) An increased respiratory rate, with shallow or grunting respiration. (4) Diminished or absent breath sounds. (5) Dullness to percussion. (6) Dull pain. (7) Hiccup (rare). (8) Tenderness over the 8th to 11th ribs. A subhepatic abscess may cause tenderness under the costal margin anteriorly. A subphrenic abscess, pyelonephritis, a pyonephros or a perinephric abscess can all cause similar tenderness posteriorly. (9) If the patient is thin and the pus is superficial, you may feel a tender indurated mass under his costal margin in front (right subphrenic space), in his right flank (right subhepatic space), or posteriorly.

X-RAYS are essential. Screening is the most important investigation and the cheapest. Look for: (1) The failure of one side of his diaphragm to move. This is a sign of infection, but not necessarily of an abscess. (2) Give him a little contrast medium, and look for downward and forward displacement of his stomach and spleen.

Also take a PA and a lateral view. Look for: (1) a raised diaphragm, (2) a fuzzy upper border to his diaphragm, (3) fluid in his costophrenic angle, (4) collapse or consolidation at one lung base, (5) a fluid level (rare). (6) You may also see gas in his subphrenic space. This can be the residue from a laparotomy, or it can be due to a perforation of his gut, or to an anaerobic infection.

If his first X-ray examination is negative or equivocal, repeat it a few days later.

CAUTION ! (1) His white count is usually raised but may be normal. (2) 10% of patients have no fever. (2) Don't try to diagnose subphrenic abscesses by aspiration[md]this is dangerous and misleading.

THE DIFFERENTIAL DIAGNOSIS includes a liver abscess (31.12), an empyema (6.1), and pulmonary collapse (9.11).

THE MANAGEMENT [s7]OF SUBPHRENIC ABSCESSES WHICH APPROACH? If you suspect a subphrenic abscess, and a patient's general state does not improve, and his fever does not settle, he needs exploring. Avoid antibiotics which may mask his symptoms.

If he has a swelling, or oedema, or redness or tenderness just below his ribs or in his loin, make the incision there.

If his abscess follows appendicitis, a perforated duodenal ulcer, or cholecystitis, it will probably be on the right. If a high gastric ulcer has perforated, it is more likely to be on the left. If an ulcer in the posterior wall of his stomach has perforated, there will be pus in his lesser sac.

If you don't know which side it is on, there is about a 75% chance that it will be on the right, probably anterior. Approach it anteriorly, if possible through the old laparotomy wound, unless there are very clear signs that it is posterior. If one route fails try another. You cannot reach the posterior surface of his liver through an anterior incision, or vice versa, but if pus extends all the way from front to back, one incision will be enough.

Alternatively, decide if the pus is on the right or left, and then explore all subphrenic abscesses from in front. If you don't find pus, explore posteriorly.

ANAESTHESIA. Take him to the theatre. If he is a poor anaesthetic risk, block his lower 6 intercostal nerves (A 6.7). If he is a better risk, you can give him a general anaesthetic and intubate him.

ANTERIOR APPROACH. Make an incision which is large enough to take your hand. Depending on the signs, make it a finger's breadth below and parallel to his right (usually) or his left costal margin. Cut from the middle of his rectus muscle laterally, as in B, Fig. 6-5. Cut the muscle fibres in the line of the incision. Often, you can open the abscess cavity without entering his general peritoneal cavity, so try to keep outside it until you have found the abscess. His extraperitoneal tissue will probably be oedematous. Push your index finger upwards through it, peeling the peritoneum off his diaphragm as you do so. Sweep your finger under his liver from one side to the other to explore his subhepatic space. If you don't find pus there, sweep it round the lateral edge of his liver, and explore his subphrenic space between his diaphragm and his liver.

Somewhere you will feel an indurated abscess cavity. If you have opened his general peritoneal cavity pack off his gut, and have a sucker ready before you push your finger through it, in case pus squirts out. Explore it with your hand, break down any loculi, and send pus for culture. Insert a drain as described below.

If his liver is not adherent to his diaphragm, there may still be pus posteriorly, pushing his liver forwards.

CAUTION ! (1) Try not to go above his diaphragm. This is more likely to happen with an anterior approach. If you enter his pleura, suture his diaphragm with ''1' multifilament or monofilament sutures and insert an under water seal drain (9.2D, 65-6) before you approach the abscess. (2) Be sure that he has only one abscess.

Alternatively, cut everything except his parietal peritoneum in the line of the incision. Burrow upwards with your finger between his peritoneum and his diaphragm, until you feel the induration of the abscess. Peel his peritoneum off his diaphragm as you do so.

Fig. 6-6 THE POSTERIOR APPROACH TO A SUBPHRENIC ABSCESS. A, a hectic fever subsided as the patient's abscess was drained. B, his 12th rib has been excised and an incision is about to be made in its bed. C, the bed of his 12th rib has been divided, showing his liver and the fat round his kidney. After Ochsner and Graves.

POSTERIOR APPROACH. Lay him on his sound side with his lumbar region slightly elevated by breaking up the table or placing pillows under his other side. Make an incision which is big enough to take your hand over his 12th rib posteriorly (E, in Fig. 6-5). Remove the distal 2/3 of his 12th rib; divide it at its angle. Cut through the periosteum, reflect this from the whole circumference of the bone with Faraboef's rougine, as you would when you drain an empyema (6.1).

CAUTION ! Take great care not to damage his diaphragm.

Incise the inner aspect of the periosteum horizontally. Push your finger upwards and forwards above his renal fascia to enter the abscess (C, or D, in Fig. 6-5). Occasionally, you may need to tie his intercostal vessels.

POSTOPERATIVELY (both routes). At the most dependent part of the abscess, insert one or even two 1.5 cm plastic or rubber drainage tubes with several side holes, or a sump drain. Bring the drain out through a stab wound in his flank. Stitch it to his skin. Close his wound as usual, but leave his skin unsutured. If you have left a large space under his diaphragm, connect the drain to an underwater seal, to encourage it to close.

As soon as the discharge is reduced to about 20 ml of pus a day, shorten the drain progressively during a few days and then remove it. Sinograms are unlikely to be helpful.

If there is any rise in his pulse or temperature, or localized pain, suspect that his abscess is not settling. Be sure to leave the drain in. Antibiotics are less important than adequate drainage.

DIFFICULTIES [s7]WITH SUBPHRENIC ABSCESSES If the fluid you aspirated from his chest was a STRAW-COLOURED EFFUSION, and he is not very toxic, X-ray him again in a few days to see what has happened. Is it clearing? Is his diaphragm still raised? If you aspirated frank pus, drain it a day or two later by inserting a chest tube connected to an underwater seal (65.2).

If he is so toxic, weak, and wasted from his subphrenic abscess that SURGERY MIGHT SEEM TO BE TOO MUCH FOR HIM, don't hesitate to explore his abscess. If necessary, drain pus from his pleural space also, it is his only hope.

If you DAMAGE HIS PLEURA ACCIDENTALLY, insert an underwater seal drain.

If pus from below the diaphragm RUPTURES INTO A BRONCHUS, he may drown in a spasm of coughing. The pus is more likely to have spread from an amoebic abscess in his liver than from a subphrenic one.