A 42-year-old woman presents to the emergency department with a 12\text{-hour} history of … — USMLE Step 2 CK

A 42-year-old woman presents to the emergency department with a $12\text{-hour}$ history of severe, constant, epigastric pain that radiates to her back. The pain is associated with nausea and multiple episodes of nonbilious vomiting. She has no significant past medical history and does not consume alcohol. Her temperature is $37.3^\circ\text{C}$ ( $99.1^\circ\text{F}$ ), pulse is $112\text{/min}$ , and blood pressure is $132/84\text{ mm Hg}$ . Physical examination reveals marked epigastric tenderness to deep palpation without rebound or guarding. Bowel sounds are decreased.

Laboratory studies show:
Leukocyte count: $11,500/\text{mm}^3$
Alanine aminotransferase (ALT): $185\text{ U/L}$
Aspartate aminotransferase (AST): $150\text{ U/L}$
Alkaline phosphatase: $110\text{ U/L}$
Total bilirubin: $1.0\text{ mg/dL}$
Lipase: $2,400\text{ U/L}$

A right upper quadrant ultrasound shows multiple gallstones in the gallbladder but a normal-caliber common bile duct without sonographic evidence of choledocholithiasis. Which of the following is the most appropriate next step in management?

Administration of intravenous lactated Ringer solutionAnswer
B
Endoscopic retrograde cholangiopancreatography (ERCP)
C
Computed tomography (CT) of the abdomen with intravenous contrast
D
Intravenous ciprofloxacin and metronidazole
E
Urgent laparoscopic cholecystectomy

Answer

Administration of intravenous lactated Ringer solution

The correct answer is the administration of intravenous lactated Ringer solution. This patient meets the diagnostic criteria for acute pancreatitis (typical severe epigastric pain and a serum lipase elevation greater than

3 \times

the upper limit of normal). Acute pancreatitis is characterized by severe inflammation and extensive retroperitoneal third-spacing of fluid, which can quickly lead to hypovolemia, end-organ hypoperfusion, and necrosis. Therefore, the most critical immediate step in management is aggressive intravenous fluid resuscitation using isotonic crystalloids (preferably lactated Ringer solution), along with adequate pain control and antiemetics.

Step-by-Step Solution

Identify the primary diagnosis based on the clinical presentation and laboratory results.

The patient has typical epigastric pain radiating to the back and a serum lipase level significantly greater than

3 \times

the upper limit of normal, confirming the diagnosis of acute pancreatitis.

The diagnosis of acute pancreatitis requires at least

2

3

criteria: characteristic abdominal pain, serum lipase or amylase

>3 \times

upper limit of normal, and characteristic imaging findings.

Determine the etiology of the acute pancreatitis.

The elevated ALT (

>150\text{ U/L}

) and the presence of gallstones on ultrasound indicate gallstone pancreatitis.

Gallstones and alcohol are the most common causes of acute pancreatitis. An ALT

>150\text{ U/L}

has a high positive predictive value for a biliary etiology.

Select the most appropriate immediate intervention.

Aggressive intravenous fluid resuscitation, specifically with an isotonic crystalloid like lactated Ringer solution, is the indicated next step.

Acute pancreatitis induces a profound systemic inflammatory response, leading to severe retroperitoneal third-spacing of fluids, intravascular volume depletion, and potential organ hypoperfusion.

Key Concept

The initial management of acute pancreatitis focuses on aggressive intravenous fluid resuscitation, pain control, and nutritional support. Interventions such as ERCP or antibiotics are reserved for specific complications like cholangitis, biliary obstruction, or infected necrosis.

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