GB Flashcards
The majority (≈75%) of gallstones in the USA and Europe are cholesterol stones, which consist mainly of cholesterol monohydrate crystals and precipitates of amorphous calcium bilirubinate, often with calcium carbonate or phosphatein one of the crystalline polymorphs.
These stones are usually
subclassified as either pure cholesterol or mixed stones that contain at least 50% cholesterol by weight
The remaining gallstones are pigment stones that contain mostly calcium bilirubinate and are subclassified into 2 groups: black pigment stones (≈20%) and brown pigment stones (≈4.5%).
Rare gallstones (≈0.5%) include calcium carbonate stones and fatty acid–calcium stones
Gallstones also are classified by their location as intrahepatic, gallbladder, and bile duct (choledocholithiasis) stones.
Intrahepatic stones are predominantly brown pigment stones.
Gallbladder gallstones are mainly cholesterol stones, with a small group of black pigment stones.
Bile duct stones are composed mostly of mixed cholesterol stones
Most relevant studies have found that the prevalence of gallstones in women ranges from 5% to 20% between the ages of 20 and 55 years
25% to 30% after the age of 50 years
The prevalence in men is approximately half that of women of the same age
cholesterol gallstones occur infrequently in childhood and adolescence, and the prevalence of cholesterol gallstones increases linearly with age in both genders and approaches 50% at age 70 years in women
all ages, women are twice as likely as men to form cholesterol gallstones
estrogen increases the risk of cholesterol gallstones by augmenting hepatic secretion of biliary cholesterol, thereby leading to an increase in cholesterol saturation of bile
Pregnancy is a risk factor for the development of biliary sludge and gallstones
During pregnancy, bile becomes more lithogenic
because of a significant increase in estrogen levels, which result in increased hepatic cholesterol secretion and supersaturated bile.
gallbladder motility is impaired, with a
resulting increase in gallbladder volume and bile stasis. These alterations promote the formation of sludge and stones in the gallbladder
Increased progestogen concentrations also reduce
gallbladder motility. Because plasma concentrations of sex hormones, especially estrogen, increase linearly with duration of gestation, the risk of gallstone formation is high in the third trimester
of pregnancy
Increasing parity is probably a risk factor
for gallstones, especially in younger women
Rapid weight loss is a well-known risk factor for the formation of cholesterol gallstones.
As many as 50% of obese patients who undergo gastric bypass surgery form biliary sludge and eventually gallstones within 6 months after surgery
Gallstones also
develop in 25% of patients who undergo strict dietary restriction.
Gallstones may be prevented in this high-risk population by prophylactic administration of UDCA, which, in a dose of 600 mg/day, has been
TPN is associated with the development of cholelithiasis and acalculous cholecystitis.
As early as 3 weeks after initiation of TPN, biliary sludge often forms in the gallbladder because of
prolonged fasting In addition, the sphincter of Oddi may fail to relax, leading to preferential flow of bile into the gallbladder
Approximately 45% of adults and 43% of children form gallstones
after 3 to 4 months of TPN
prophylactic treatment to prevent gallstones should be prescribed if no contraindication exists
CCK octapeptide administered twice daily via an IV line to patients on long-term TPN has proved to be safe and cost effective and should be used routinely in TPN-treated patients
Biliary sludge is a crucial intermediate stage in the pathogenesis of both cholesterol and pigment gallstones because it facilitates crystallization and agglomeration of solid plate-like cholesterol monohydrate crystals, as well as precipitation of calcium bilirubinate, and ultimately develops into macroscopic stones
biliary sludge can induce acute cholecystitis, cholangitis, and acute pancreatitis.
associated with many conditions that predispose to gallstone formation, including pregnancy, rapid weight loss, spinal cord injury, longterm TPN, and treatment with octreotide
UDCA treatment of patients with persistent biliary
sludge decreases the frequency of clinical complications of biliary sludge
oral contraceptive steroids and conjugated estrogens in premenopausal women doubles the prevalence of cholesterol gallstones
Administration of estrogen to postmenopausal women and estrogen therapy to men with prostatic carcinoma have similar lithogenic effects
High levels of estrogen may induce gallbladder
hypomotility and consequently bile stasis
estrogen induces a decrease in plasma LDL cholesterol levels and an increase in plasma HDL cholesterol
concentrations.
Clofibrate is a lipid-lowering drug associated with
gallstone formation.
Clofibrate induces cholesterol supersaturation in bile and diminishes bile salt concentrations by reducing the activity of cholesterol 7α-hydroxylase
The 3-hydroxy-3-methylglutaryl coenzyme A (HMGCoA) reductase inhibitors (statins) reduce the biliary cholesterol saturation index (CSI), but their role in the prevention or therapy of gallstone disease requires further investigation in humans
The somatostatin analog octreotide increases the prevalence of gallstones when administered to patients as treatment for acromegaly,
The third-generation cephalosporin ceftriaxone has a long duration of action, with much of the drug excreted in the urine.
Approximately 40% of the drug, however, is secreted in an unmetabolized form into bile, where its concentration reaches 100 to 200 times that of the concentration in plasma and exceeds its saturation level in bile.
Obesity is a well-known risk factor for cholelithiasis
Gallbladder bile is more lithogenic in obese than in non-obese persons, and a higher ratio of cholesterol to solubilizing lipids (bile acids and phospholipids)
Gallbladder motility is often impaired in obese persons, thereby promoting mucin secretion and accumulation, as well as cholesterol crystallization.
Patients with diabetes mellitus have long been considered to be at increased risk of developing gallstones because hypertriglyceridemia
and obesity are associated with diabetes mellitus and because gallbladder motility is often impaired in patients with diabetes mellitus
Disease or resection of the terminal ileum has been found to be a risk factor for gallstone formation
intestinal bile salt absorption is often impaired in patients with Crohn disease, who are at increased risk of gallstones
The loss of specific bile salt transporters in the terminal ileum may result in excessive bile salt
excretion in feces and a diminished bile salt pool size, presumably with a consequent increase in the risk of cholesterol gallstones
Spinal cord injuries are associated with a high prevalence of gallstones
Both gallstone disease and NAFLD are highly prevalent in the general population and often co-exist in the same populations
The prevalence of NAFLD was significantly higher in the group that underwent cholecystectomy (48.4%) and in the gallstone group (34.4%) than in the gallstone-free group (17.9%).
These findings suggest that both conditions are tightly associated with metabolic disturbances such as obesity, insulin resistance, dyslipidemia, and the metabolic syndrome.
Use of statins has been associated with a decreased risk of gallstone disease in 2 large case-control studies.
The observation that deficiency of ascorbic acid (vitamin C) is associated with the development of gallstones
subjects who consistently drank 2 to 3 cups of regular coffee per day were approximately 40% less likely to develop symptomatic gallstones
Drinking 4 or more cups per day was even more beneficial (relative risk 0.55), but there was no benefit to drinking decaffeinated coffee.
Cholesterol, phospholipids, and bile salts are the 3 major lipid species in bile, and bile pigments are minor solutes.
Celiac disease is a chronic, small intestinal, autoimmune enteropathy caused by an intolerance to dietary gluten in genetically predisposed individuals
Defective CCK release from the proximal small intestine caused by enteropathy in patients with celiac disease before they start a gluten-free diet, gallbladder emptying in response to a fatty meal is impaired.
The primary bile salts are hepatic catabolic products of cholesterol and are composed of cholate (a trihydroxy bile salt) and chenodeoxycholate (a dihydroxy bile salt
The most important of the conversion reactions is 7α-dehydroxylation of primary bile salts to produce deoxycholate from cholate and lithocholate from chenodoxycholate
Approximately 20% of the cholesterol in bile comes from de novo hepatic biosynthesis, and 80% is from pools of preformed cholesterol within the liver
De novo cholesterol synthesis in the liver uses acetate as a substrate and is mainly regulated by the rate-limited enzyme HMG-CoA reductase
5 primary defects that lead to
formation of cholesterol gallstones: (1) certain genetic factors, including LITH genes, (2) hepatic hypersecretion of biliary cholesterol,(3) gallbladder hypomotility, (4) rapid phase transitions of cholesterol, and (5) certain intestinal factors
Precholecystectomy treatment with the hydrophilic bile acid UDCA for 3 months prolongs the crystal detection time of bile in patients with cholesterol gallstones, thereby suggesting that UDCA could be an antinucleating factor.
Between meals, the gallbladder stores hepatic bile (with an average fasting volume of 25 to 30 mL in healthy subjects). Following a meal, depending on the degree of neurohormonal response, the gallbladder discharges a variable amount of bile.
Gallbladder hypomotility could precede gallstone formation. Gallbladder stasis induced by the hypofunctioning gallbladder could provide the time necessary to accommodate nucleation of cholesterol crystals and growth of gallstones within the mucin gel in the gallbladder
The high prevalence of cholelithiasis in patients receiving long-term TPN (see earlier) highlights the importance of gallbladder stasis in the formation of gallstones
Daily IV administration of CCK can completely prevent
gallbladder dysmotility and eliminate the inevitable risk of biliary sludge and gallstone formation
gallstones in patients with CF are generally black pigment stones (i.e., composed of calcium bilirubinate with an appreciable cholesterol admixture
Black pigment stones are formed in uninfected gallbladders, particularly in patients with chronic hemolytic anemia (e.g.,β-thalassemia, hereditary spherocytosis, sickle cell disease), ineffective erythropoiesis (e.g., pernicious anemia), ileal diseases (e.g., Crohn disease) with spillage of excess bile salts into the large intestine, extended ileal resections, and liver cirrhosis.
alterations promote formation of black pigment stones
because higher colonic bile salt concentrations enhance the solubilization of unconjugated bilirubin, thereby increasing bilirubin concentrations in bile.
The unifying predisposing factor in black
pigment stone formation is hepatic hypersecretion of bilirubin conjugates (especially monoglucuronides) into bile.
In the presence of hemolysis, hepatic secretion of these bilirubin conjugates increases 10-fold
Unconjugated monohydrogenated bilirubin is formed by the action of endogenous β-glucuronidase, which
coprecipitates with calcium as a result of supersaturation
Brown pigment stones are composed mainly of calcium salts of unconjugated bilirubin, with varying amounts of cholesterol, fatty acids, pigment fraction, and mucin glycoproteins, as well as small amounts of bile salts, phospholipids, and bacterial residues.
Brown pigment stones may be easily distinguished
grossly from black pigment stones by their reddish brown to dark brown color and lack of brightness.
Their shape is irregular or molded and occasionally spherical. Most of the stones are muddy in consistency, and some show facet formation
The cut surface is generally a stratified structure
(lamellation) or is amorphous without the radiating crystalline structure seen in cholesterol stones.
Brown pigment stones are formed not only in the gallbladder but also commonly in other portions of the biliary tract, especially in intrahepatic bile ducts.
Formation of brown pigment stones requires the presence of structural or functional stasis of bile associated with biliary infection, especially with Escherichia coli.
These stones are quite prevalent in Asia, where Clonorchis sinensis and roundworm infestations are common, and parasitic elements have been considered to be kernels of brown pigment stone formation
The cardinal symptom of gallstones is biliary pain (“colic”), which is described as pain in the RUQ often radiating to the back, with or without nausea and vomiting.
The pain is usually not true colic and is almost never associated with fever.
prophylactic cholecystectomy is not recommended in
patients with insulin-resistant diabetes mellitus and asymptomatic gallstones
Only 50% of pigment stones and 20% of cholesterol stones contain enough calcium to be visible on a plain abdominal film
Because 80% of gallstones in the Western world are of the cholesterol type, only 25% of stones can be detected by simple radiographs
Plain abdominal films have their greatest usefulness in
evaluating patients with some of the unusual complications of gallstones (e.g., emphysematous cholecystitis, cholecystenteric fistula, gallstone ileus) or in detecting a porcelain gallbladder
US requires only an overnight or 8-hour fast,
involves no ionizing radiation, is simple to perform, and provides accurate anatomic information
The diagnosis of gallstones relies on detection of echogenic objects within the lumen of the gallbladder that produce an acoustic shadow
The stones are mobile and generally congregate in the dependent portion of the gallbladder
Modern US can detect stones as small as 2 mm in diameter routinely
The sensitivity of US for detection of gallstones in the gallbladder is greater than 95% for stones larger than 2 mm.
The specificity is greater than 95% when stones produce acoustic shadows.
The contracted gallbladder filled with stones may give a “double arc shadow” or “wall-echo shadow” sign, with the gallbladder wall, echogenic stones, and acoustic shadowing seen in immediate proximity
Pericholecystic fluid (in the absence of ascites) and gallbladder wall thickening to more than 4 mm (in the absence of hypoalbuminemia) are suggestive of acute cholecystitis
A more specific finding is the so-called sonographic
Murphy sign, in which the ultrasonographer elicits focal gallbladder tenderness under the ultrasound transducer
Biliary pain
Intermittent obstruction of the cystic duct
No acute inflammation of the gallbladder
Severe, poorly localized, epigastric or RUQ visceral
pain growing in intensity over 15 min and remaining
constant for 1-6 h, often with nausea
Frequency of attacks varies from days to months
Gas, bloating, flatulence, and dyspepsia are not related to stones
Mild-to-moderate epigastric/ RUQ tenderness during an attack, with mild residual tenderness lasting days
After the initial attack, 30% of patients have no further
symptoms Symptoms develop in the remainder at a rate of 6% per year, and severe complications at a rate of 1%-2% per year
Acute cholecystitis
Impacted stone in the cystic duct
Acute inflammation of the gallbladder
Secondary bacterial infection in ≈ 50%
75% of cases are preceded by attacks of biliary pain
Visceral epigastric pain gives way to moderately severe localized pain in the RUQ, back, right
shoulder, or, rarely, chest Nausea with some vomiting is frequent
Pain lasting >6 h favors cholecystitis over biliary pain alone
Fever, but usually to <102°F unless complicated by gangrene or perforation
Right subcostal tenderness with inspiratory arrest (Murphy sign)
Leukocytosis with band forms is common
Serum bilirubin level may be 2-4 mg/dL, and aminotransferase and alkaline phosphatase levels may be elevated even in the absence of a BD stone or
hepatic infection
Mild serum amylase and lipase elevations are seen even in the absence of pancreatitis If serum bilirubin is >4 mg/dL or amylase or lipase is markedly elevated, a BD stone should be suspected
50% of cases resolve spontaneously in 7-10 days
without surgery
Left untreated, 10% of cases are
complicated by a localized perforation and 1% by a free perforation and peritonitis
Choledocholithiasis
Stone passed from the gallbladder via the cystic duct or formed in the BD
Intermitted obstruction of the BD
Often asymptomatic
Symptoms (when present) are indistinguishable from biliary pain
Predisposes to cholangitis and acute pancreatitis
Often findings are completely normal if the obstruction is
intermittent Jaundice with pain suggests stones; painless jaundice and a palpable gallbladder favor malignancy
Elevated serum bilirubin and alkaline phosphatase levels
are seen with BD obstruction Serum bilirubin level
>10 mg/dL suggests malignant obstruction or coexisting hemolysis
A transient “spike” in serum aminotransferase or amylase (or lipase) levels suggests the passage of a stone
The natural history is not well defined, but complications are more common and more severe than for asymptomatic stones in the gallbladder
Cholangitis
Charcot triad (pain, jaundice, and fever) is present in 70% of patients
Pain may be mild and transient and is often accompanied by chills
Mental confusion, lethargy, and delirium suggest sepsis
Fever in 95% RUQ tenderness in 90% Jaundice in 80%
Peritoneal signs in 15% Hypotension and mental confusion (forming Reynolds pentad in combination with Charcot triad) coexist in 15% and suggest gram negative sepsis
Leukocytosis in 80%, but the remainder may have a
normal WBC count with or without band forms
Serum bilirubin level is >2 mg/dL in 80%
Serum alkaline phosphatase level is usually elevated
Blood cultures are usually positive, especially during chills or a fever spike; 2 organisms are grown in cultures from half of patients
Acute cholecystitis Sonographic Murphy sign (focal gallbladder tenderness under the transducer) has a positive predictive value of >90% in detecting acute cholecystitis when stones are seen
Pericholecystic fluid (in the absence of ascites) and gallbladder wall thickening to >4 mm (in the absence of hypoalbuminemia) are nonspecific findings but are suggestive of acute cholecystitis
Cholescintigraphy (hepatobiliary scintigraphy; hydroxyiminodiacetic acid or diisopropyl iminodiacetic acid scan)
Acute cholecystitis
Assesses patency of the cystic duct
A normal scan shows radioactivity in the gallbladder, BD, and small bowel within 30-60 min
A positive result is defined as nonvisualization of the gallbladder, with preserved hepatic excretion of radionuclide into the BD or small bowel
A normal scan result virtually excludes acute cholecystitis
EUS is highly accurate for detecting choledocholithiasis.
More invasive and more expensive than standard US, EUS has the advantage of being able to visualize the bile duct from within the GI lumen and is comparable to ERCP in this respect
Cholescintigraphy (hepatobiliary scintigraphy) is a radionuclide imaging test of the gallbladder and biliary tract that is most useful for evaluating patients with suspected acute cholecystitis.
By demonstrating patency of the cystic duct, cholescintigraphy can exclude acute cholecystitis rapidly (within 90 minutes) in a patient who presents with abdominal pain
ERCP is one of the most effective modalities for detecting choledocholithiasis
The specificity of ERCP for the detection of bile duct
stones is approximately 95%.
Biliary pain is the most common presenting symptom of cholelithiasis, and about 75% of patients with symptomatic gallstone disease seek medical attention for episodic abdominal pain.
Biliary pain (conventionally referred to as biliary “colic,” a misnomer) is caused by intermittent obstruction of the cystic duct by one or more gallstones. Biliary pain does not require that inflammation of the gallbladder accompany the obstruction.
The term“chronic cholecystitis” to describe biliary pain should be avoided because it implies the presence of a chronic inflammatory infiltrate that may or may not be present in a given patient
The most common histologic changes observed in patients with biliary pain are mild fibrosis of the gallbladder wall with a chronic inflammatory cell infiltrate and intact mucosa
pain can also be associated with a scarred, shrunken gallbladder and Rokitansky-Aschoff sinuses (intramural diverticula).
Ingestion of a meal often precipitates pain,
but more commonly no inciting event is apparent.
The onset of biliary pain is more likely to occur during periods of weight reduction and marked physical inactivity such as prolonged bed rest than at other times.
The term “biliary colic,” used in the past, is a misnomer because the pain is steady rather than intermittent, as would be suggested by the word colic.
The pain increases gradually over a period of 15
minutes to an hour and then remains at a plateau for an hour or more before slowly resolving
one third of patients, the onset of pain may be more sudden, and on rare occasions, the pain may
cease abruptly.
Pain lasting more than 6 hours suggests acute cholecystitis rather than simple biliary pain
In order of decreasing frequency, biliary pain is felt maximally in the epigastrium, RUQ, LUQ, and various parts of the precordium or lower abdomen. Therefore, the notion that pain not located in the RUQ is atypical of gallstone disease is incorrect.
Radiation of the pain to the scapula, right shoulder, or lower abdomen occurs in half of patients
In general, the first, and often the only, imaging study recommended in patients with biliary pain is US of the RUQ
with recurrent uncomplicated biliary pain and documented gallstones are generally treated with elective laparoscopic cholecystectomy
Acute biliary pain improves with administration of meperidine, with or without ketorolac or diclofenac
Aspirin taken prophylactically has been reported to
prevent gallstone formation as well as acute attacks of biliary pain in patients with gallstones, but long-term use of other NSAIDs does not prevent gallstone formation
Acute cholecystitis is the most common complication of gallstone disease.
Inflammation of the gallbladder wall associated with abdominal pain, RUQ tenderness, fever, and leukocytosis is the hallmark of acute cholecystitis
Acute cholecystitis generally occurs when a stone becomes embedded in the cystic duct and causes chronic obstruction, rather than transient obstruction as in biliary pain.
Phospholipase A is believed to be released by gallstone-induced mucosal trauma and converts lecithin to lysolecithin.
Although normally absent from gallbladder
bile, lysolecithin is present in the gallbladder contents
of patients with acute cholecystitis
administration of IV indomethacin and oral ibuprofen to patients with acute cholecystitis has been shown to diminish both luminal pressure in the gallbladder and pain.
gallbladder is usually palpable lateral to its normal
anatomic location.
Mild jaundice is present in 20% of patients with acute cholecystitis and 40% of older adult patients.
Serum bilirubin levels are usually less than 4 mg/dL
The pain of untreated acute cholecystitis generally resolves in 7 to 10 days
acute cholecystitis often causes mild elevations in serum aminotransferase and alkaline phosphatase levels.
As noted earlier, the serum bilirubin level may also be mildly elevated (2 to 4 mg/dL), and even serum amylase and lipase values may be elevated nonspecifically.
A serum bilirubin value above 4 mg/dL or amylase value above 1000 U/L usually indicates co-existing bile duct obstruction or acute pancreatitis
US is the single most useful imaging study in acutely ill patients with RUQ pain and tenderness.
It accurately establishes the presence or absence of gallstones and serves as an extension of the physical examination.
The presence of a sonographic Murphy sign,
defined as focal gallbladder tenderness under the transducer, has a positive predictive value greater than 90% for detecting acute cholecystitis if gallstones are also present
US can detect nonspecific findings suggestive of acute cholecystitis, such as pericholecystic fluid and gallbladder wall thickening greater than 4 mm
Both findings lose specificity for acute cholecystitis if the patient has ascites or hypoalbuminemia.
A normal cholescintigraphy result shows radioactivity in
the gallbladder, bile duct, and small intestine within 30 to 60 minutes of injection of the isotope
sensitivity and specificity of scintigraphy
in the setting of acute cholecystitis are approximately 94%
However, sensitivity and specificity are reduced considerably in patients who have liver disease, are receiving parenteral nutrition, or are fasting. These conditions can lead to a false-positive result, defined as the absence of isotope in the gallbladder in a patient who does not have acute cholecystitis
a false-negative result is defined as filling of the gallbladder with isotope in the setting of acute cholecystitis, a situation that virtually never occurs
abdominal CT is highly sensitive for detecting pneumoperitoneum, acute pancreatitis, pancreatic pseudocysts, hepatic or intra-abdominal abscesses, appendicitis, and obstruction or perforation of a hollow viscus
Oral feeding should be withheld and an
NG tube inserted if the patient has a distended abdomen or persistent vomiting
In uncomplicated cases of acute cholecystitis, antibiotics need not be given. Antibiotics are warranted if the patient appears toxic or is suspected of having a complication such as perforation of the gallbladder or emphysematous cholecystitis
The most commonly used regimens include piperacillin-tazobactam, ceftriaxone plus metronidazole, or levofloxacin plus metronidazole
Definitive therapy of acute cholecystitis consists of cholecystectomy.
Cholesterol stones form only in the gallbladder, and any cholesterol stones found in the bile duct must have migrated there from the gallbladder.
Black pigment stones, which are associated with old age, hemolysis, alcoholism, and cirrhosis, also form in the gallbladder but only rarely migrate into the bile duct
The majority of pigment stones in the bile duct
are the softer brown pigment stones.
These stones form de novo in the bile duct as a result of bacterial action on phospholipid and bilirubin in bile
They are often proximal to a biliary stricture and are frequently associated with cholangitis.
Brown pigment stones are found in patients with hepatolithiasis and recurrent pyogenic cholangitis
The pressure in the bile duct is normally 10 to 15 cm H2O and rises to 25 to 40 cm H2O with complete obstruction.
When the pressure exceeds 15 cm H2O, bile flow decreases, and at 30 cm H2O, bile flow stops
Deep jaundice without pain, particularly with a palpable
gallbladder (Courvoisier sign), suggests neoplastic obstruction of the bile duct, even when the patient has stones in the gallbladder
With longstanding obstruction, secondary biliary cirrhosis may result, leading to physical findings of chronic liver disease
Bilirubin accumulates in serum because
of blocked excretion, whereas alkaline phosphatase levels rise because of increased synthesis of the enzyme by the canalicular epithelium
The rise in the alkaline phosphatase level is more
rapid than and precedes the rise in bilirubin level
The absolute height of the serum bilirubin level is proportional to the extent of obstruction, but the height of the alkaline phosphatase level bears no relation to either the extent of obstruction or its cause.
In cases of choledocholithiasis, the serum bilirubin level is typically in the range of 2 to 5 mg/dL and rarely exceeds 12 mg/dL.
Transient “spikes” in serum aminotransferase or amylase levels suggest passage of a bile duct stone into the duodenum.
In approximately 85% of cases, cholangitis is caused by a stone embedded in the bile duct, with resulting bile stasis. Other causes of bile duct obstruction that may result in cholangitis are neoplasms biliary strictures parasitic infections and congenital abnormalities of the bile ducts
The bacterial species most commonly cultured from the bile are E. coli, Klebsiella, Pseudomonas, Proteus, and enterococci
Anaerobic species such as Bacteroides fragilis and Clostridium perfringens are found in about 15% of appropriately cultured bile specimens.
Anaerobes usually accompany aerobes, especially E. coli. The fever and shaking chills of cholangitis are due to bacteremia from bile duct organisms.
The hallmark of cholangitis is Charcot triad, consisting of RUQ pain, jaundice, and fever
The full triad is present in only 70% of patients
The pain of cholangitis may be surprisingly mild and transient but is often accompanied by chills and rigors
Altered mental status and hypotension in combination with Charcot triad, known commonly as Reynolds pentad, occur in severe suppurative cholangitis.
On physical examination, fever is almost universal, occurring in 95% of patients, and usually greater than 102°F
RUQ tenderness is elicited in about 90% of patients, but jaundice is clinically detectable in only 80%.
Notably, peritoneal signs are found in only 15% of patients
The combination of hypotension and mental confusion indicates gram-negative septicemia. In overlooked cases of severe cholangitis, intrahepatic abscess may manifest as a
late complication
In particular, the serum bilirubin level exceeds 2 mg/dL in 80% of patients.
ERCP is the definitive test for the diagnosis of bile duct
stones and cholangitis.
Moreover, the ability of ERCP to establish drainage of infected bile under pressure can be lifesaving.
If ERCP is unsuccessful, percutaneous THC can be performed
In mild cases, initial therapy with a single drug (e.g., cefoxitin 2.0 g IV every 6 to 8 hours) is usually sufficient.
In severe cases, more intensive therapy (e.g., gentamicin, ampicillin, and metronidazole
or a broad-spectrum agent such as piperacillin-tazobactam 3.375 g IV every 6 hours or, if resistant organisms are suspected, meropenem 1 g IV every 8 hours) is indicated.
The patient’s condition should improve within 6 to 12 hours, and in most cases, the infection comes under control within 2 to 3 days, with defervescence, relief of discomfort, and a decline in WBC count.
emphysematous cholecystitis present with the
same clinical manifestations as patients with uncomplicated acute cholecystitis, but in the former, gas-forming organisms have secondarily infected the gallbladder wall. Pockets of gas are evident in the area of the gallbladder fossa on plain abdominal films, US,
and abdominal CT
Emphysematous cholecystitis often occurs in diabetic persons or older men who do not have gallstones, in whom atherosclerosis of the cystic artery with resulting ischemia may be the initiating event
A cholecystoenteric fistula occurs when a stone erodes through the gallbladder wall (usually the neck) and into a hollow viscus. The most common entry point into the bowel is the duodenum, followed in frequency by the hepatic flexure of the colon, the stomach, and the jejunum
Symptoms are initially similar to those of acute
cholecystitis, although at times the stone may pass into the bowel and may be excreted without causing any symptoms
the terminal ileum is the most common site of obstruction Gastric outlet obstruction (Bouveret syndrome) may occur rarely
An impacted stone in the gallbladder neck or cystic duct, with extrinsic compression of the common hepatic duct from
accompanying inflammation or fistula
Mirizzi syndrome
ERCP demonstrates dilated intrahepatic ducts and extrinsic compression of the common hepatic duct and possible fistula
Preoperative diagnosis is important to guide surgery and minimize the risk of BD injury
Porcelain gallbladder
Intramural calcification of the gallbladder wall, usually in association with stones
If the gallstone exceeds 25 mm in diameter, it may manifest (especially in older adult women) as a small intestinal obstruction (gallstone ileus); the ileocecal area is the most common site of obstruction.
plain abdominal film may show the pathognomonic features of pneumobilia, a dilated small bowel, and a large gallstone in the right lower quadrant
Bouveret syndrome is characterized by gastric outlet obstruction resulting from duodenal impaction of a large gallstone that has migrated through a cholecystoduodenal fistula.
Porcelain gallbladder, defined as intramural calcification of the gallbladder wall, is not a complication of gallstones but is mentioned here because of the remarkable tendency of carcinoma
to develop as a late complication of gallbladder calcification (specifically, a gallbladder with focal rather than diffuse wall calcification)
Prophylactic cholecystectomy, preferably through a laparoscopic approach, is indicated to prevent subsequent development of carcinoma, which may otherwise occur in up to 20% of cases
Laparoscopic cholecystectomy is the standard method for the management of
patients with biliary pain and complications of gallstone disease, such as acute cholecystitis, gallstone pancreatitis, and choledocholithiasis
The mainstay of current nonsurgical treatment of gallstone disease is oral dissolution with UDCA, with or without extracorporeal shock-wave lithotripsy
Nonsurgical treatments are effective only in patients with small, radiolucent cholesterol gallstones. Significant admixtures of pigment or calcium salts make stones indissoluble
The rationale for oral dissolution therapy is the reversal of the condition that led to formation of cholesterol gallstones, namely, the supersaturation of bile with cholesterol
Cholesterol stones dissolve if the surrounding medium can solubilize the cholesterol in the stones.
Both chenodeoxycholic acid and UDCA dissolve gallstones by decreasing biliary cholesterol secretion and desaturating bile
Chenodeoxycholic acid was the first bile acid used for gallstone dissolution but has been abandoned because of side effects, including diarrhea and increased serum aminotransferase and cholesterol levels.
Oral dissolution therapy should be considered for patients with uncomplicated gallstone disease, including those with mild, infrequent biliary pain.
Selection Criteria for Oral Bile Acid Dissolution
Therapy
STAGE OF GALLSTONE DISEASE
Symptomatic (biliary pain) without complications
GALLBLADDER FUNCTION
Opacification of gallbladder on oral cholecystography (patent cystic duct)
Normal result of stimulated cholescintigraphy (normal gallbladder emptying)
Normal result of functional US (normal gallbladder emptying after a test meal)
STONE CHARACTERISTICS
Radiolucent
Isodense or hypodense to bile and absence of calcification on CT Diameter ≤10 mm (<6 mm optimal)
Oral dissolution therapy works only on cholesterol stones. Although verifying the composition of gallstones can be difficult, the appearance of stones on plain films or CT images can be useful.
Cholesterol stones are radiolucent on plain films, and they are hypodense or isodense to bile and lack stone calcification on CT images
The number of stones does not influence the success of oral dissolution therapy; however,
only patients with stones that occupy less than half of the gallbladder volume should be considered for treatment.
Although oral dissolution therapy has been effective in stones up to 10 mm in diameter, results are best in stones less than 5 mm in size.
UDCA (ursodiol) is the preferred drug for oral dissolution treatment.
It is taken in a dose of 10 to 15 mg/kg of body weight per day. Night time dosing is more effective and is associated with better patient adherence than mealtime dosing
Treatment should continue until stone dissolution is documented by 2 consecutive negative ultrasonograms at least 1 month apart.
Treatment should be stopped if the patient does not tolerate the drug or experiences a complication of gallstones during therapy or if the stones fail to dissolve
after 6 months or dissolve only partially after 6 months with lack of progression to complete dissolution by 2 years
The rationale for shock-wave lithotripsy is to diminish the surface- to-volume ratio of a stone, thereby increasing the efficacy of oral dissolution therapy and decreasing stone size to allow small stones and debris to pass directly from the gallbladder into the
intestine without causing symptoms.
The technique involves the delivery of focused high-pressure sound waves to gallstones
Selection Criteria for Extracorporeal Shock-Wave
Lithotripsy
STAGE OF GALLSTONE DISEASE
Symptomatic (biliary pain) without complications
GALLBLADDER FUNCTION
Opacification of gallbladder on oral cholecystography (patent cystic duct)
Normal result of stimulated cholescintigraphy (normal gallbladder emptying)
Normal result of functional US (normal gallbladder emptying after a test meal)
STONE CHARACTERISTICS
Radiolucent
Isodense or hypodense to bile and absence of calcification on CT
Single Diameter <20 mm
Pregnant patients and patients on anticoagulants
should not undergo lithotripsy.
Shock-wave lithotripsy is reserved for patients with a solitary stone, measuring less than 2 cm in size.
Because only cholesterol stones are reliably cleared by
the addition of oral dissolution therapy, stones should have imaging features, such as radiolucency, suggestive of cholesterol stones
The energy of shock waves, number of shock waves per session, and number of sessions also influence the success rate.
UDCA, 10 to 15 mg/kg of body weight per day, is administered orally to dissolve stone fragments, especially when residual stone fragments are larger than 2 mm in size, gallbladder function is poor, or the gallbladder has not cleared small fragments within 3 to 6 months of lithotripsy
Recurrence is most often related to the presence of lithogenic bile and gallbladder dysmotility, rather than patient variables such as gender, age, and weight.
Factors that predict higher rates of treatment failure include stone size larger than 16 mm, multiple stones, and stones with a CT density greater than 84 Hounsfield units
Lithotripsy is more cost-effective in older adults than in the young and less cost-effective in patients with multiple stones than in those with a single stone
When lithotripsy is compared with laparoscopic
cholecystectomy, patients who undergo laparoscopic cholecystectomy experience a greater incremental improvement in quality of life at 6 months,
The triangle of Calot is the space bordered by
the cystic duct, cystic artery, and inferior edge of the gallbladder.
Dissection and identification of these structures permits safe division of the cystic duct and minimizes the chance of bile duct injury. The abdominal incision is then closed. Closed suction drains are rarely indicated after cholecystectomy