25. 1 Acute pancreatitis
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Pigment stones
Pigment gallstones are formed of calcium bilirubinate and contain less than 25 per cent cholesterol (Fig. 23) 1246. They are usually small and multiple, and about half are radio-opaque. As might be expected they are more prevalent in patients with haemolytic disorders such as hereditary spherocytosis or sickle-cell disease, and in patients with cirrhosis, who commonly have a mild degree of haemolysis. They are frequently found in oriental countries, where they are associated with parasitic infections. Bilirubin in bile is normally conjugated with glucuronide. The enzyme &bgr;-glucuronidase, which may be produced by bacteria such as Escherichia coli, splits the molecule and the unconjugated bilirubin precipitates as the calcium salt. Hydrolytic enzymes from gallbladder mucosa may act in the same way.
Clinical presentation of stones in the gallbladder
Since the sixteenth century it has been realized that most people who have gallstones remain asymptomatic throughout their lives. In a few patients stones are discovered by accident during the investigation of some other problem. In general these stones should be left alone. In a study of patients in whom gallbladder stones were discovered on screening, only 15 per cent developed biliary pain in the subsequent 15 years.
There may be a case for removing asymptomatic stones in diabetics because of their greater susceptibility to infection, and an incidental cholecystectomy for gallstones during a laparotomy for an unrelated condition may sometimes be appropriate because such patients are at greater risk of developing subsequent symptoms. There is no justification for removing the gallbladder with stones to prevent the later development of cancer.
Disease in the gallbladder affects only a small minority of people with gallstones. It presents with a variety of clinical syndromes, of which the most common are chronic cholecystitis, which appears slowly over time, biliary colic, and acute cholecystitis, both of which develop rapidly. Patients occasionally present with the complications of one of these three, either locally in the gallbladder or from stones in the bile duct, and very occasionally from a stone that has ulcerated through into the bowel.
Chronic cholecystitis
Pathology
About two-thirds of patients present with chronic cholecystitis. The pathological changes, which often do not correlate well with symptoms, vary from those of an apparently normal gallbladder with minor chronic inflammation in the mucosa to a shrunken organ with gross transmural fibrosis and organized adhesions (Fig. 25) 1248. The mucosa is initially hypertrophied but later becomes atrophied; the epithelium protrudes into the muscle coat, leading to the formation of Rokitansky-Aschoff sinuses. The most severe form is represented by cholecystitis glandularis proliferans in which there are buried areas of hyperproliferative epithelium within the wall of the gallbladder (see Fig. 28 1251 below). Rarely, dystrophic calcification may occur, resulting in the formation of a porcelain gallbladder (Fig. 26) 1249.
Diagnosis
The typical patient complains of recurrent attacks of right hypochondrial or epigastric pain, usually after meals, and particularly after consumption of fatty foods. The pain, which often occurs at night, varies from mild indigestion after eating to persistent, moderately severe, right upper quadrant pain which may radiate round to the back and sometimes to the right shoulder or between the shoulder blades. The pain is often described as a tight band all the way round the upper abdomen; very occasionally the pain on the right hand side of the abdomen is suppressed and the patient presents only with left-sided pain.
Nausea usually accompanies the pain, sometimes associated with vomiting. There may be additional minor symptoms such as flatulence and abdominal distension, but these are equally common in patients who do not have gallstones. There may be mild right upper quadrant abdominal tenderness, but examination is usually unremarkable.
It is often possible to make a confident clinical diagnosis of chronic cholecystitis in a patient with classical symptoms, but the presence of gallstones should be confirmed by ultrasonography (Fig. 9) 1232. Occasionally an oral cholecystogram is also needed. When it is difficult to distinguish chronic cholecystitis from peptic ulceration, a hiatus hernia, or diverticular disease, further radiology and endoscopy may be required. The last two conditions often occur together with gallstones, a condition known as Saint's triad.
It is easy to ascribe the patient's symptoms to stones which are found on investigation when this is not the case: many patients with other conditions have gallstones. On the other hand patients with symptoms that show enough features related to proven gallstones are likely to improve on treatment.
Treatment
Once the diagnosis is established some form of active treatment is indicated since the symptoms will almost always continue. Some patients can control their symptoms by taking care over their diet. Others are only occasionally troubled and simply require mild analgesia. More commonly, some form of surgical treatment is needed to remove the stones, with or without the gallbladder. The risks of surgery must be balanced against the potential benefits, and the views of the informed patient are just as important as the opinion of the doctor. Most surgeons prefer the patient to request the operation.
Biliary colic
Biliary colic is due to impaction of a stone in the neck of the gallbladder. The severe pain starts abruptly in the epigastrium, often at night after a heavy meal, and lasts for several hours. It is usually continuous and is associated with restlessness, vomiting, and sweating. The pain may radiate through to the back but does not radiate to the shoulder, as in acute cholecystitis. General examination may disclose a patient in obvious severe pain with a mild tachycardia and normal temperature. Abdominal examination shows only mild tenderness in the epigastrium. In contrast to acute cholecystitis, tenderness over the gallbladder is absent. The gallbladder in patients with biliary colic is often normal in external appearance and shows only mild inflammatory changes on histological examination. Most patients need a strong analgesic given by injection, and after two attacks of severe biliary colic will want some form of definitive treatment.
Acute cholecystitis
Pathology
About one-fifth of patients first present with acute cholecystitis; in about one-third there is clinical or pathological evidence of previous chronic cholecystitis. It is usually due to persistent impaction of a stone in the neck of the gallbladder. The result is initially a chemical inflammation of the gallbladder wall perhaps due to the mucosal toxin lysolecithin, produced by the action of phospholipase on biliary lecithin. This is soon followed by bacterial infection. Because the cystic duct is occluded the inflammatory process is particularly aggressive and the gallbladder becomes acutely distended, with accompanying lymphatic and venous obstruction. The serosa may be covered by a fibrinous exudate and subserosal haemorrhage gives the appearance of patchy gangrene. The gallbladder wall itself is grossly thickened and oedematous and the underlying mucosa may show hyperaemia or patchy necrosis (Fig. 27) 1250. Histologically, three grades of inflammation are recognized: acute cholecystitis, acute suppurative cholecystitis, and acute gangrenous cholecystitis. Rarely an abscess or empyema develops within the gallbladder, while perforation of an ischaemic area leads to a pericholecystic abscess, bile peritonitis, or a cholecystoenteric fistula.
Diagnosis
Patients present with acute upper abdominal pain that has often been present for 2 or 3 days. Because the inflammation extends to the parietal peritoneum the pain is well localized and it hurts the patient to move or to breathe. Patients feel generally unwell, may have been febrile, and are anorexic. Physical signs vary with the severity of the inflammation but there is usually some degree of fever and tachycardia. Mild jaundice is present in 10 to 15 per cent of patients. Right hypochondrial tenderness is invariable and there may also be guarding, rigidity, and rebound tenderness. If the latter physical signs are subdued it may be possible to feel the gallbladder itself. Murphy's sign (inspiratory arrest during subcostal palpation) is widely regarded as pathognomonic of cholecystitis. It is certainly present in patients with established acute cholecystitis, but it only reflects peritoneal inflammation in the right upper quadrant, other causes of which include chronic cholecystitis, acute hepatitis, and a localized abscess around a perforated duodenal ulcer. There is usually a clear distinction between acute cholecystitis and biliary colic: this is important since the management is different.
In elderly patients acute cholecystitis may present more insidiously and the frequent absence of typical physical signs results in a delay in diagnosis. In addition, the incidence of complications is higher and the prevalence of intercurrent illness combine to increase the mortality rate 10-fold. Acute cholecystitis is uncommon in children, most of whom have gallstones, sometimes as a complication of haemolytic disease. Acalculous cholecystitis occurs in children with severe sepsis.
Differential diagnosis
Clinically it can be difficult to distinguish acute cholecystitis from acute pancreatitis, acute appendicitis, acute pyelonephritis, perforation of a peptic ulcer, and, occasionally, biliary colic. A raised white cell count and serum amylase level may occur in several of these conditions, although patients with biliary colic rarely have a leucocytosis. Urine should always be examined under the microscope for pus cells and sent for culture if appropriate. One-quarter of patients have disturbed liver function tests, but not all will have stones in the bile duct. There are rarely any specific features of acute cholecystitis on plain radiology, but ultrasound may localize the tenderness to the gallbladder and may demonstrate stones. Free air under the diaphragm on a chest radiograph implies perforation of a viscus, usually a peptic ulcer. A normal HIDA scan excludes acute cholecystitis (Fig. 15) 1238.
Young women who present acutely with severe right upper quadrant pain and signs of peritonitis may have the Curtis– Fitz–Hugh syndrome. Clinically these patients appear to have acute cholecystitis but ultrasound examination fails to show gallstones or any signs of acute cholecystitis. At laparoscopy or laparotomy the gallbladder is normal but there are string-like adhesions between the liver and the peritoneum. This perihepatitis is caused by infection with Chlamydia trachomatis. There may also be evidence of genital tract infection with the same organism. The diagnosis can be confirmed by isolation of the organism from peritoneal fluid or by rising titres of chlamydial antibodies in serum. Treatment is with oxytetracycline 2 g daily for 10 days.
Acute viral hepatitis can sometimes present as acute cholecystitis. The acutely swollen liver is painful and tender but the systemic symptoms and the onset of jaundice soon make the true diagnosis clear.
Treatment
Acute cholecystitis resolves with conservative treatment in the majority of cases. If admission to hospital is necessary patients require intravenous fluids, analgesia, and suspension of oral intake. Vomiting is unusual, but if present nasogastric aspiration is helpful. If the patient fails to respond intravenous antibiotics are prescribed. Our present choice is cefuroxime 1.5 g three times a day.
Most patients should be offered cholecystectomy, which should normally be undertaken on the next convenient operating list. There is no advantage in letting the acute illness subside and removing the gallbladder 6 weeks later except in a patient who is unfit for surgery and whose condition could be improved by waiting.
Complications
An empyema of the gallbladder may be suspected clinically if the physical signs and symptoms fail to improve on conservative management. In particular, fever and right upper quadrant tenderness fail to abate, and there is a persistent or increasing leucocytosis. With time the gallbladder becomes necrotic and ruptures, resulting either in a localized abscess or in generalized peritonitis. An empyema is really an abscess within the gallbladder and it must therefore be drained. The best method is to insert a pigtail catheter into the gallbladder under ultrasound control, as the gallbladder is usually adherent to the peritoneum of the abdominal wall. If there is any doubt a transhepatic route for the catheter should be chosen. Percutaneous drainage is clearly less disturbing for the patient, who is usually quite ill and toxic. If it fails for any reason a conventional surgical approach must be adopted. Occasionally a safe cholecystectomy can be performed by an experienced surgeon. For everyone else a cholecystostomy is better.
Acute emphysematous cholecystitis
This is a severe and fulminant form of acute cholecystitis which accounts for less than 1 per cent of cases. Stones are absent in 30 to 50 per cent of patients, who are usually elderly men, and 40 per cent have diabetes mellitus. It is caused by a mixture of bacteria which includes gas-forming organisms, and the pathognomonic diagnostic sign is gas within the wall or the lumen of the gallbladder seen on a plain radiograph. The onset of the disease is abrupt and the condition of the patient deteriorates rapidly. There is a high incidence of gangrene and perforation, and emergency cholecystectomy is needed.
Xanthogranulomatous cholecystitis
This is a rare but severe form of chronic cholecystitis in which the gallbladder is thickened and irregular with extensions of yellow xanthogranulomatous inflammation to adjacent organs. Foamy macrophages and giant cells are seen within connective tissue in the wall of the gallbladder. The condition is thought to be due to bile penetrating deeply into the gallbladder wall. The appearances both on investigation and at operation resemble carcinoma of the gallbladder; frozen section histology at operation may be necessary because the two conditions are associated.
Acute acalculous cholecystitis
Acute cholecystitis can develop in the absence of gallbladder stones. It is most often seen in the intensive care unit and is associated with severe illness such as multiple trauma, extensive burns, major surgery, and sepsis, often in an elderly person. The aetiology is unknown, but is thought to be related to gallbladder distension and bile stasis. The normal contraction of the gallbladder is inhibited in patients with sepsis and those on total parenteral nutrition, especially if opiate analgesics are administered. This allows the development of biliary sludge, which may be demonstrated in the gallbladder of many patients with major illness, not all of whom develop acalculous cholecystitis.
Pathology
Pathological examination of the gallbladder reveals oedema of the serosa and muscular layers, with patchy thrombosis of arterioles and venules. Areas of necrosis develop and may affect the underlying mucosa. One possibility is that activation of factor VII by trauma may lead to thrombosis of blood vessels in the seromuscular layer of the gallbladder.
Diagnosis
In a severely ill patient, the development of acute acalculous cholecystitis is usually insidious. The clinical features are similar to those of acute calculous cholecystitis but they are often masked by the underlying condition. Ultrasound is the most useful investigation, and may show biliary sludge in a tender thickened gallbladder, but fails to demonstrate stones. All the indicators of liver function deteriorate, and a HIDA scan will fail to demonstrate the gallbladder.
Treatment
Once the diagnosis is made an immediate cholecystectomy is necessary because of the high incidence of gangrene of the gallbladder. The mortality rate varies with the nature of the underlying condition but is generally higher than that in patients with acute calculous cholecystitis.
Cholesterolosis
This is caused by the deposition of cholesterol in the mucosa and submucosa of the gallbladder wall and produces the classical ‘strawberry gallbladder’. Microscopy shows macrophages loaded with cholesterol. Ultrasound identifies the cholesterol in the wall as bright shiny spots, and there may also be cholesterol stones within the lumen. Cholesterolosis may cause pancreatitis, perhaps as a result of small cholesterol crystals passing down the bile duct and briefly occluding the ampulla, so that symptomatic patients should be advised to undergo cholecystectomy.
Adenomyomatosis
Adenomyomatosis or cholecystitis glandularis proliferans is characterized by hypertrophic smooth muscle bundles and epithelial sinus formation. The gallbladder has a thickened wall which may be divided into two separate sections by a stricture of incomplete septum (Fig. 28) 1251. Granulomatous polyps develop in the lumen at the fundus. Inflammation develops later and gallstones are sometimes present. Symptomatic patients require a cholecystectomy. Others in whom the diagnosis is made but not treated require surveillance since adenomyomatosis may predispose to carcinoma.
Mucocele of the gallbladder
A mucocele of the gallbladder forms when a stone impacts in the cystic duct but bacterial infection does not occur. Bile is reabsorbed but the epithelium continues to secrete mucous, and the gallbladder becomes distended (Figs. 29, 30) 1252,1253. It is easily palpable and may even be visible, but it is not tender. Such patients have somewhat subdued but nevertheless persistent symptoms, often including distressing nausea. If infection does occur an empyema may develop rapidly. In either circumstance a cholecystectomy is required. Rarely a mucocele of the gallbladder may perforate. Although pseudomyxoma peritonei has been reported to follow rupture of a mucocele it probably only follows rupture of a cystadenoma or cystadenocarcinoma of the gallbladder.
Torsion of the gallbladder
Infarction of the gallbladder due to torsion or volvulus is a rare event. Two anatomical anomalies permit torsion. Firstly the gallbladder may have no attachment to the liver, lying free in the peritoneal cavity suspended only by the cystic duct and artery. Secondly, and more commonly, the gallbladder is suspended from the liver by a narrow mesentery. Acute torsion causes right-sided abdominal pain and the tense, infarcted gallbladder may be palpable (Fig. 31) 1254. It is often misdiagnosed as acute appendicitis. Intermittent torsion can occur and produces periodic bouts of pain.
Biliary pain without stones
A small group of patients, usually young women, presents with pain in the right hypochondrium which, in the opinion of everyone who sees them, is typical biliary pain. However, all conventional biliary investigations, which may be repeated on several occasions, are normal. Furthermore a minority benefit from cholecystectomy even though no pathological abnormality is discovered in the gallbladder at operation.
Now that cholesterolosis and adenomyomatosis can be excluded by ultrasound studies before operation interest has centred on the possibility that these patients have a functional disorder of the biliary tract. This idea has received support from the discovery that some develop identical pain following an intravenous injection of cholecystokinin, and it was hoped that this would identify those who would benefit from a cholecystectomy. This test has not turned out to be so specific, but there are a number of other experimental tests of gallbladder and biliary function which may help us to understand these patients better in the future.
In practical terms, it is essential to exclude the irritable bowel syndrome which can produce symptoms very similar to those of biliary pain. After explaining the position very carefully to the patient it is reasonable to proceed to a cholecystectomy. Unfortunately the pain persists after operation in some patients; these form part of a group of patients with postcholecystectomy pain.
Management of gallbladder stones
The first successful cholecystectomy was performed by Langenbuch in 1882, and since then the operation has become the standard treatment for gallbladder stones. It is both safe and effective by modern surgical standards. However, there are deaths and complications following the operation and it takes 6 to 8 weeks to recover following a conventional open operation. An alternative to surgery would clearly be useful. Our understanding of the biochemistry of gallstone formation first led to the development of drugs which dissolve cholesterol gallstones. Further developments have produced a bewildering array of methods for removing or dissolving stones without the disadvantages of surgery.
Alternatives to cholecystectomy
Gallstone dissolution therapy
Cholesterol gallstones can be dissolved by decreasing the cholesterol saturation of bile. The naturally occurring bile salt chenodeoxycholic acid and the synthetic ursodeoxycholic acid when given by mouth achieve this. They probably have their effect by reducing the hepatic synthesis of cholesterol rather than by expanding the bile acid pool. Ursodeoxycholic acid is more efficient at reducing the cholesterol saturation of bile, but both drugs are equally good at dissolving gallstones in vivo. Because they work in slightly different ways there are advantages to giving them together. They are known to be safe, although chenodeoxycholic acid, which is by far the cheaper drug, causes diarrhoea and abnormalities of liver function tests in some patients. One interesting but unexplained benefit is that some patients experience relief of their symptoms whilst taking the drugs even though there is no effect on the size of their stones.