A 48-year-old male arrives at the emergency department reporting an abrupt onset of severe… — USMLE Step 2 CK

A $48$ -year-old male arrives at the emergency department reporting an abrupt onset of severe, constant epigastric pain that radiates to his back. The pain began $4$ hours ago after he consumed a heavy meal. He has experienced two episodes of nonbilious emesis since symptom onset. He has a history of hyperlipidemia and takes rosuvastatin. His temperature is $37.9^\circ\text{C}$ ( $100.2^\circ\text{F}$ ), heart rate is $115/\text{min}$ , blood pressure is $128/82\text{ mmHg}$ , and respiratory rate is $18/\text{min}$ . Cardiopulmonary examination is unremarkable. Abdominal examination reveals decreased bowel sounds and significant epigastric tenderness without rebound or guarding.

Laboratory studies show:

Test	Value
Leukocyte count	$14,500/\text{mm}^3$
Total bilirubin	$1.0\text{ mg/dL}$
Alkaline phosphatase	$95\text{ U/L}$
Aspartate aminotransferase (AST)	$150\text{ U/L}$
Alanine aminotransferase (ALT)	$180\text{ U/L}$
Lipase	$4,500\text{ U/L}$

A right upper quadrant ultrasound reveals multiple mobile gallstones within the gallbladder. The common bile duct measures $4\text{ mm}$ in diameter, and there is no intrahepatic biliary dilation.

Which of the following is the most appropriate next step in the management of this patient?

A
Endoscopic retrograde cholangiopancreatography
Initiation of aggressive intravenous crystalloid hydrationAnswer
C
Insertion of a nasogastric tube for bowel decompression
D
Intravenous meropenem therapy
E
Immediate laparoscopic cholecystectomy

Answer

Initiation of aggressive intravenous crystalloid hydration

The correct answer is the initiation of aggressive intravenous crystalloid hydration. This patient has acute gallstone pancreatitis, diagnosed by characteristic epigastric pain and a markedly elevated serum lipase level (greater than three times the upper limit of normal). The pathogenesis involves severe retroperitoneal inflammation that leads to massive third-spacing of fluids, causing intravascular volume depletion and pancreatic microcirculatory hypoperfusion. Early, aggressive intravenous volume expansion (typically with isotonic crystalloids like lactated Ringer solution) within the first

12

24

hours is the cornerstone of management to prevent progression to pancreatic necrosis and multiorgan failure.

Step-by-Step Solution

Analyze the clinical presentation and laboratory results.

The patient has severe epigastric pain radiating to the back, elevated lipase (

4,500\text{ U/L}

), and evidence of gallstones on ultrasound, confirming the diagnosis of acute gallstone pancreatitis.

Establishing the correct diagnosis and etiology is the first step in determining appropriate management.

Evaluate for complications or indications for urgent invasive procedures.

The patient's total bilirubin and alkaline phosphatase are normal, and the common bile duct is not dilated. There is no evidence of ascending cholangitis or severe biliary obstruction.

This rules out the need for urgent endoscopic retrograde cholangiopancreatography (ERCP).

Determine the optimal supportive care strategy.

Aggressive intravenous fluid resuscitation, along with pain control, is the standard of care to prevent third-spacing hypovolemia and pancreatic necrosis.

Acute pancreatitis causes significant retroperitoneal fluid shifts, leading to microvascular hypoperfusion that worsens the inflammatory cascade.

Key Concept

The primary initial management for acute gallstone pancreatitis without evidence of cholangitis is supportive care, centered on aggressive intravenous fluid resuscitation. Prophylactic antibiotics and urgent ERCP are not indicated in the absence of infected necrosis or biliary obstruction.

Estimated Time:1m 15s

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