|A 45-year-old female presents with a complaint of abdominal pain for the past 3 days. She localizes the pain to her epigastric area and states that it radiates to her right upper quadrant. She notes that it became markedly worse after eating dinner last night. She recalls a past history of similar pain, but has never had any diagnostic workup.
Her past medical history is significant for hypertension and hypercholesterolemia. She is status post a total abdominal hysterectomy 1 year ago.
She does not smoke, drink alcohol, or use drugs.
Her ROS is positive for abdominal pain, nausea, one episode of vomiting, and a subjective fever.
Her VS are BP 155/90, HR 110, RR 14, T 100.6, SpO2 98% on RA.
Her physical exam reveals an overweight woman in no acute distress. Her chest and cardiovascular exams are normal except for mild tachycardia. Her abdominal exam is significant for tenderness to palpation to her epigastric and right upper quadrants without rebound tenderness. Bowel sounds are normal.
You order basic blood work, fluids, and an anti-pyretic. You are contemplating ordering a CT and decide to attempt to visualize her right upper quadrant via ultrasound at the bedside. You see the following on initiation of your exam:
What is the diagnosis?
Which of the following is correct in describing the presentation and diagnosis of biliary colic versus acute cholecystitis?
Biliary colic typically presents with pain to the epigastric or right upper quadrant that reaches a crescendo and then abates completely over a period of time.
The presence of gallstones on ultrasound in a patient with right upper quadrant pain is virtually diagnostic for acute cholecystitis.
Laboratory testing is not helpful is distinguishing acute cholecystitis from biliary colic.
Patients with simple biliary colic commonly have constitutional symptoms such as anorexia and fever.
Which of the following is correct in regards to the ultrasound diagnosis of acute cholecystitis?
It is uncommon for patients with acute cholecystitis to have co-existing gallstones on ultrasound.
The finding of pain or inspiratory pause upon pressure applied directly over the gallbladder as visualized on ultrasound (sonographic Murphy’s sign) is more accurate than a Murphy’s sign that is elicited on physical exam.
Ultrasound is more sensitive in the diagnosis of cholecystitis than cholescintigraphy.
When visualized by ultrasonography, a thickened gallbladder wall always indicates a diagnosis of acute cholecystitis.
Which of the following is correct?
Acalculous cholecystitis typically occurs in young otherwise healthy patients and is associated with a better outcome than cholecystitis in the presence of gallstones.
Chronic cholecystitis is a diagnosis based on CT findings.
Gallstone ileus occurs when a gallstone passes through a cholecystoenteric fistula to cause mechanical bowel obstruction
Emphysematous cholecystitis is caused by the same organisms that cause acute cholecystitis
When performing and interpreting a right upper quadrant ultrasound, which of the following is correct?
The portal venous anatomy is distinguished from other vessels and ducts by the absence of a thick wall surrounding it.
The portal triad contains the hepatic artery, portal vein, and cystic duct.
The location of the gallbladder is identical from patient to patient and can be easily be found with one standard imaging plane.
The diameter of the common bile duct is usually one tenth of a patient’s age, with a maximum normal diameter of 7mm.
When performing and interpreting a right upper quadrant ultrasound, which of the following is correct?
There is no reliable way to distinguish between a polyp in the gallbladder and a gallstone.
Its ready movement can reliably identify gallbladder sludge with change in body position and by the acoustic shadow it produces.
Edge artifacts at the edges of the gallbladder may produce shadowing and lead to the misdiagnosis of gallstones.
Identification of gallstones is made more straightforward when the gallbladder is contracted.
Answer: Acute cholecystitis with cholelithiasis.
Acute cholecystitis is typically related to gallstone disease or cholelithiasis and is characterized by the presence of right upper quadrant pain, fever, and leukocytosis. Chronic cholecystitis does occur and refers to chronic inflammation of the gallbladder wall. It is a histopathologic diagnosis and is not clinically relevant.
Cholecystitis occurs most commonly in patients with a history of gallstones, although acalculous (without gallstones) cholecystitis does occur. Acalculous cholecystitis typically occurs in critically ill patients and is associated with a high morbidity and mortality. Obstruction of the cystic duct does appear to contribute to the initiation of gallbladder inflammation, with subsequent secondary bacterial infection. Common organisms include Escherichia coli, Enterococcus, Klebsiella, and Enterobacter.
The most common presentation of acute cholecystitis is that of abdominal pain, typically located to the right upper quadrant or epigastric area. Radiation to the right shoulder or back may also occur. Acute cholecystitis is characterized by steady and severe pain that is prolonged without improvement. This is in contrast to the typical history of pain associated with acute cholelithiasis (or biliary colic) that is colicky (intermittent) in nature with highest severity at onset and gradual improvement over hours. Associated symptoms of nausea, vomiting, anorexia, or fever often occur with acute cholecystitis. Onset of symptoms may be associated with fatty food ingestion an hour or so before.
On physical exam, the patient may appear ill, with fever and tachycardia. The patient may lie very still as cholecystitis frequently results in localized peritoneal inflammation and any movement may cause severe pain. On palpation of the abdomen, patients typically will have tenderness to the right upper or epigastric areas and guarding is frequently present. The Murphy’s sign is elicited by asking the patient to inspire while applying pressure over the area of the gallbladder fossa. In theory, as the patient inspires, the gallbladder should descend inferiorly towards the examiners hand. If the maneuver elicits increased discomfort and an inspiratory pause it is considered to be positive. It should be noted that this sign is less sensitive in the elderly.
Laboratory analysis of a patient with cholecystitis may reveal an elevated white blood cell count with a left shift, or increase in the number of immature neutraphils (bands). As the obstruction in uncomplicated cholecystitis is usually limited to the gallbladder and cystic duct, total bilirubin and alkaline phosphatase are most often within normal limits. If these values are found to elevated, complicating conditions such as cholangitis or choledocholithiasis should be considered. Serum transaminases and amylase may be mildly elevated or within normal limits.
Although laboratory findings may suggest the diagnosis of cholecystitis, imaging studies are necessary to confirm this suggestion. Ultrasonography remains the most common first study employed to examine the right upper quadrant. Gallstones are readily visualized via ultrasound, but alone do not confirm the diagnosis of cholecystitis. Thickening of the gallbladder wall (greater than 4-5mm) or fluid surrounding the gallbladder are very suggestive of acute cholecystitis. It should be noted that thickening of the gallbladder wall is not pathognomatic for cholecystitis, as it can also be found in cirrhosis, portal hypertension, and other chronic conditions. The presence of a sonographic Murphy’s sign is also highly suggestive and thought to be more sensitive than a traditional Murphy’s sign. A sonographic Murphy’s sign is elicited by applying pressure with the ultrasound transducer directly over the gallbladder as visualized on screen. Overall, ultrasound has a sensitivity and specificity for detecting gallstones of 84% and 99% respectively. When used to make the diagnosis of acute cholecystitis, it has a sensitivity and specificity of 88% and 80%.
Computed tomography can be used to diagnose acute cholecystitis, as consistent findings such as gallbladder wall edema and pericholecystic fluid can be easily visualized. However, it is usually unnecessary to use a CT scan for this purpose, as ultrasonography is usually readily available and reliable in diagnosing acute cholecystitis.
Cholescintigraphy, also known as a HIDA scan, is less commonly performed and usually a second line test for cholecystitis. It is typically used when a preliminary ultrasound fails to make the diagnosis. A HIDA scan is performed by injecting technetium labeled hepatic iminodiacetic acid intravenously, which is taken up by the hepatocytes and excreted into bile. The radiolabeled bile will then enter the gallbladder via the cystic duct, if it is patent. If the cystic duct is not patent due to a gallstone or to inflammation, the gallbladder will not be visualized and the test is considered positive. Secondarily, the radiolabeled bile can be used to demonstrate patency of the common bile duct and ampulla. Cholescintigraphy is the most sensitive and specific test for cholecystitis with a sensitivity of 97% and a specificity of 90%.
If the diagnosis of cholecystitis is missed or delayed, several complications can occur. The most common complication is that of gangrenous cholecystitis. It occurs in older patients, diabetics, and in those patients in whom diagnosis is delayed. These patients exhibit many of the symptoms of acute cholecystitis, but are toxic appearing and frequently septic. A complication of gangrenous cholecystitis is perforation of the gallbladder leading to a pericholecystic abscess or peritonitis. Both complications are associated with a high mortality.
Other complications of acute cholecystitis can occur, such as a fistula between the gallbladder and duodenum or jejunum. Once this occurs, a secondary complication of gallstone ileus can result. This occurs when a gallstone passes through a cholecystoenteric fistula into the small bowel, causing a mechanical obstruction.
Emphysematous cholecystitis is a subset of cholecystitis that should not be missed. It is caused by secondary infection of the gallbladder wall by gas producing organisms (such as Clostridia). Organisms that are typically associated with acute cholecystitis may be isolated as well. The typical patient with this illness is male, age 50-70, frequently diabetic, with a history of gallstones. These patients present similarly to patients with typical cholecystitis, but may have crepitus to the right upper quadrant. This is a rare finding, but when present is a clue to the diagnosis. Another clue is the finding of gas apparently obscuring the gallbladder on ultrasound. This may be misread as bowel gas but in reality is air in the wall of the gallbladder.
Treatment of all types of cholecystitis includes prompt administration of antibiotics, resuscitation, and surgical consultation. The antibiotics chosen should provide coverage for the typical organisms found in cholecystitis, which are primarily Gram negatives. If there is a suspicion of emphysematous cholecystitis, an antibiotic with additional anaerobic coverage should be chosen. Cholecystectomy is essential, but may be delayed to allow a “cooling off” period, especially in uncomplicated cholecystitis.
Right Upper Quadrant Ultrasound:
Right upper quadrant ultrasound as performed by the emergency medicine practitioner can reliably identify gallstones as well as signs of gallbladder inflammation. The exam is performed typically with a low frequency transducer, either the phased array or curvilinear transducer (Figure 1, 2).
Figure 1. Phased Array Transducer
Figure 2. Curvilinear Transducer
The exam begins with the patient in the supine position. The transducer is placed in the epigastrum in the sagittal orientation (the indicator pointing towards the patient’s head). The gallbladder is usually visualized from this position (Figure 3). It is a hypoechoic (black) structure with a hyperechoic (white) rim (Figure 4). If there is doubt whether this represents the gallbladder or a vascular structure, color flow can be applied. Occasionally, the gallbladder may not initially be apparent from this view. Its position varies from patient to patient, sometimes slightly, sometimes dramatically. When it is not readily identified, the transducer should be moved to the patient’s right, subcostally, until it comes into view. In thin patients, it may be necessary to view through the rib interspaces. An additional view that may reveal the gallbladder is to place the patient in left lateral decubitus and image from the right flank, much as one would a FAST exam (Figure 5).
Figure 3. Patient position to initiate scan.
Figure 4. Normal gallbladder as seen on right of image. Note also normal portal vein to the left of the gallbladder with its hyperechoic (white) wall.
Figure 5. Imaging of the gallbladder with the patient in the left lateral decubitus position and the transducer placed over the right flank. This view may be used as alternative to the technique in shown in Figure 3.
Once the gallbladder is identified, the examiner should attempt to view it in its full longitudinal position. This is achieved by rotating the transducer clockwise. Once in this orientation, the anterior wall should be measured for signs of edema. The anterior wall is usually measured at its midpoint, with a diameter less than 4-5mm. The area around the wall should be examined for the presence of pericholecystic fluid, which appears as anechoic (black) areas surrounding the wall (Figure 6).
Figure 6. Gallbladder with pericholecystic fluid seen surrounding the body,
primarily along the inferior surface. A gallstone is also noted on the left side of
the gallbladder, with a strong shadow emanating from it.
Gallstones may be seen as well in this view. They typically appear as hyperechoic (white) structures, usually rounded in shape, within the body or neck of the gallbladder. Typically, gallstones will create a shadow, which appear as a strong black line below it (Figure 6). Shadowing is created by the high degree of echogenicity of the stone and is one way to differentiate gallstones from gallbladder polyps, which do not shadow (Figure 7).
Figure 7. Image of a gallbladder demonstrating polyps without posterior shadowing.
Additionally, unless impacted, gallstones are gravity dependent and should move with patient position, in contrast to polyps. At times, it may be difficult to identify a gallstone that is in the neck of the gallbladder or surrounded by a contracted gallbladder. Shadowing may been seen without evidence of a distinct gallstone, but caution should be observed in these situations as a normal gallbladder will also cause shadows at its edges. Gallbladder sludge is occasionally seen on ultrasound, and appears as a grayish material within the gallbladder. It is position dependent, but does not produce an acoustic shadow (Figure 8).
Figure 8. Image of a gallbladder filled with biliary sludge. Note that although the sludge is gravity dependent, it produces no acoustic shadow.
The gallbladder should be examined in its entirety, both in its longitudinal and short axis orientations. At this point, pressure can be applied to the patient’s abdomen over the gallbladder in an attempt to elicit a sonographic Murphy’s sign.
Once the gallbladder has been identified, the portal triad should be located. It is typically more superior and towards the patient’s right upper quadrant. The portal triad consists of the portal vein, hepatic artery, and common bile duct. The portal vein is easiest to identify in its longitudinal orientation, with the indicator pointing towards the patient’s right. The portal vein is seen as a tubular structure with a hyperechoic (white) wall. This is contrast to the hepatic ducts and veins, which appear to be black circles with no wall surrounding them (Figure 9).
Figure 9. Image of the portal triad in long axis. The portal vein is the elongated structure at the inferior of the image. Note its hyperechoic (white) wall. The smaller elongated structure above it is the common bile duct. If there is doubt as to which is the duct, color flow can be applied.
Once the portal vein is found, the hepatic artery and common bile duct usually sit above it and are distinguished by using color flow and noting one structure with flow (the artery) and one without (the duct). If difficulty is encountered in this view, the transducer can be rotated clockwise to reveal the common bile duct in short axis. It should be noted that slight variations in hand position may dramatically alter the image.
Once the common bile duct has been identified in the portal triad, its anterior to posterior wall diameter should be measured. The duct should one tenth of the patient’s age, with a maximum diameter of 7mm.