A 44-year-old woman presents to the emergency department with fluctuating right upper quadrant abdominal pain. The pain was initially a 4/10 in severity but has increased recently to a 6/10 prompting her to come in. The patient has a medical history of type 2 diabetes mellitus, depression, anxiety, and irritable bowel syndrome. Her current medications include metformin, glyburide, escitalopram, and psyllium husks. Her temperature is 99.2°F (37.3°C), pulse of 95/min, blood pressure of 135/90 mmHg, respirations of 15/min with 98% oxygen saturation on room air. On exam, the patient is an obese woman with pain upon palpation of the right upper quadrant. Initial labs are are below:

Na+: 140 mEq/L
K+: 4.0 mEq/L
Cl-: 100 mEq/L
HCO3-: 24 mEq/L
AST: 100 U/L
ALT: 110 U/L
Amylase: 30 U/L
Alkaline phosphatase: 125 U/L

Bilirubin
Total: 2.5 mg/dL
Direct: 1.8 mg/dL

The patient is sent for a right upper quadrant ultrasound demonstrating an absence of stones, no pericholecystic fluid, a normal gallbladder contour and no abnormalities noted in the common bile duct. MRCP with secretin infusion is performed demonstrating patent biliary and pancreatic ductal systems. Her lab values and clinical presentation remain unchanged 24 hours later. Which of the following is the most appropriate next step in management?
Laparoscopy
ERCP with manometry
Analgesics and await resolution of symptoms
MRI of the abdomen
ERCP with manometry
This patient is presenting with classic symptoms of acute cholecystitis or choledocholithiasis such as right upper quadrant pain and direct hyperbilirubinemia with ultrasound findings demonstrating the absence of gallstones. In this setting, sphincter of Oddi dysfunction should be suspected, and ERCP with manometry should be performed to confirm the diagnosis.

Cholecystitis is inflammation of the gallbladder caused by irritation due to an intraluminal stone and possible bacterial translocation. The classic risk factors for this disease can be remembered as "fat, female, fertile and forty". Symptoms of acute cholecystitis are right upper quadrant pain that relapses and remits over time. Lab values will show elevated AST, ALT, alkaline phosphatase, and bilirubin which are also seen in patients where a stone is impacted in the common bile duct. A right upper quadrant ultrasound and MRCP can be used to confirm the diagnosis. Dysfunction of the Sphincter of Oddi should be suspected in patients with classic findings but negative imaging studies. In these cases, the most appropriate test is ERCP with manometry of the sphincter of Oddi. Ultimately, a sphincterotomy will be needed once the diagnosis is confirmed.

Coucke et al. present the current evidence for the diagnosis and treatment of biliary obstruction. They discuss how the most common etiology of biliary obstruction is choledocholithiasis or gallstones. They recommend having a high index of suspicion for cholangitis as this condition can be rapidly fatal if untreated.

Incorrect Answers:
Answer A: Analgesics and await resolution of symptoms (in addition to NPO and IV fluids) would be appropriate management for pancreatitis. The diagnosis in this patient has not yet been confirmed (given the absence of findings on ultrasound) thus prompting another diagnostic test.

Answer B: An elective cholecystectomy would be the most appropriate next step in management if the patient had cholecystitis.

Answer D: Laparoscopy is an inappropriate and invasive method of diagnosing and treating disease of the biliary tree as there are better alternatives such as MRCP or ERCP. Laparoscopy would be effective in the treatment of intestinal tract disorders such as appendicitis.

Answer E: An MRI of the abdomen would not confirm the diagnosis of sphincter of Oddi dysfunction. Though a CT scan could be performed as a more cost-effective alternative, given the absence of stones on ultrasound it is likely that a CT scan will not give more information.

Bullet Summary:
Sphincter of Oddi dysfunction can be diagnosed with ERCP and manometry.