USMLE Step 2 CK general surgery & trauma questions

This patient has a Glasgow Coma Scale score of 8 (E2V2M4), which is a standard indication for definitive airway placement in trauma because patients with GCS ≤8 cannot reliably protect their airway and are at high risk for aspiration and hypoventilation. Endotracheal intubation secures the airway, allows controlled ventilation, and protects against aspiration while further workup proceeds. Imaging and other diagnostic steps must wait until the airway is secured per ATLS principles of airway before diagnostics. There is no indication of opioid overdose or isolated facial trauma requiring a surgical airway.

• B. Blood gas analysis does not take priority over securing the airway in this unresponsive patient.
• C. A nasopharyngeal airway is inadequate for a patient with GCS ≤8 who needs definitive airway protection.
• D. There is no history or exam finding suggesting opioid toxicity.
• E. Imaging should not precede airway management in an unstable, obtunded trauma patient.

Severe facial trauma with massive bleeding and distorted anatomy that prevents successful orotracheal intubation is a classic indication for a surgical airway. Cricothyroidotomy bypasses the disrupted upper airway anatomy and ongoing hemorrhage, providing a rapid, reliable airway below the level of injury. Repeated laryngoscopy attempts waste time and risk further hypoxia when the airway cannot be visualized. Nasotracheal intubation is contraindicated with suspected midface or basilar skull fractures because of the risk of intracranial tube placement.

• A. Nasotracheal intubation is contraindicated with possible midface/skull base fracture.
• C. A supraglottic device does not protect against aspiration of blood and is unreliable with distorted facial anatomy.
• D. Continued bag-mask ventilation is inadequate when the airway is obstructed by blood and distorted anatomy.
• E. Repeating a failed technique in a desaturating patient delays definitive airway control.

Tracheal deviation away from the affected side, absent breath sounds, hyperresonance, jugular venous distention, and hypotension are classic findings of tension pneumothorax, caused by a one-way air leak that increases intrapleural pressure, collapses the ipsilateral lung, and shifts the mediastinum, impairing venous return to the heart. Cardiac tamponade also causes jugular venous distention and hypotension but presents with muffled heart sounds and no tracheal deviation or hyperresonance. Massive hemothorax causes dullness to percussion rather than hyperresonance.

• A. Tamponade causes muffled heart sounds and jugular venous distention but not tracheal deviation or unilateral hyperresonance.
• B. Diaphragmatic rupture typically shows bowel sounds in the chest, not hyperresonance with tracheal shift.
• D. Hemothorax produces dullness, not hyperresonance, on percussion.
• E. Flail chest presents with paradoxical chest wall movement, not tracheal deviation or absent breath sounds.

This patient has clinical findings of tension pneumothorax with hemodynamic instability, which requires immediate needle decompression rather than waiting for imaging or confirmatory tests. Needle decompression (large-bore needle in the second intercostal space, midclavicular line, or the fifth intercostal space, anterior axillary line) rapidly relieves the intrapleural pressure and is followed by formal tube thoracostomy. Diagnostic imaging or echocardiography would delay life-saving treatment in a decompensating patient. A sterile chest tube in the operating room introduces unacceptable delay.

• B. Taking the patient to the operating room for sterile tube placement delays urgent decompression.
• C. Fluids alone do not address the underlying mechanical cause of shock and delay definitive treatment.
• D. Echocardiography is used to evaluate tamponade, not tension pneumothorax, and would delay treatment.
• E. Imaging delays treatment in a patient who is hemodynamically unstable with a clinical diagnosis already evident.

An open ('sucking') chest wound should be covered with a dressing taped on three sides, leaving one side open to act as a flutter valve. This allows air to escape during expiration while preventing air entry during inspiration, reducing the risk of converting the injury into a tension pneumothorax. A fully occlusive (four-sided) dressing can trap air inside the pleural space and precipitate tension pneumothorax. Packing the wound tightly similarly risks trapping air and worsening the physiology.

• A. Needle decompression is not indicated unless tension pneumothorax physiology develops; the open wound itself needs dressing first.
• B. Leaving the wound open without any dressing allows continued air movement and does not address the defect.
• D. A fully sealed dressing traps air in the pleural space and can cause tension pneumothorax.
• E. Packing and tight pressure can trap air and precipitate tension pneumothorax.

Flail chest occurs when three or more adjacent ribs are fractured in two or more places, creating a free-floating segment that moves paradoxically with respiration, inward on inspiration and outward on expiration, due to loss of continuity with the bony thorax. The underlying pulmonary contusion, not the paradoxical motion itself, is the primary cause of hypoxemia, as seen here with a PaO2 of 62 mmHg. Management focuses on pain control, pulmonary hygiene, and judicious fluid management, with intubation reserved for respiratory failure. Tension pneumothorax would show tracheal deviation and absent breath sounds, not a paradoxically moving segment.

• A. Diaphragmatic rupture presents with bowel sounds in the chest or respiratory distress without paradoxical wall motion.
• B. A simple rib fracture does not cause paradoxical chest wall movement.
• C. Tension pneumothorax presents with tracheal deviation, absent breath sounds, and jugular venous distention, not paradoxical chest wall motion.
• D. Pericardial tamponade presents with muffled heart sounds, jugular venous distention, and pulsus paradoxus, not chest wall paradox.

Patients in hemorrhagic shock requiring massive transfusion benefit from early balanced resuscitation with packed red blood cells, fresh frozen plasma, and platelets in a 1:1:1 ratio, which approximates whole blood and reduces dilutional coagulopathy. The PROPPR trial demonstrated improved hemostasis and fewer deaths from exsanguination with this ratio compared with a 2:1:1 ratio. Crystalloid-predominant resuscitation worsens coagulopathy, acidosis, and hypothermia (the lethal triad). Waiting for a hemoglobin threshold or treating coagulopathy in isolation delays correction of the global oxygen debt and clotting factor depletion.

• A. A plasma-poor ratio increases dilutional coagulopathy compared with balanced 1:1:1 resuscitation.
• B. Plasma alone does not restore oxygen-carrying capacity or platelet function needed in hemorrhagic shock.
• C. Crystalloid-heavy resuscitation dilutes clotting factors and worsens the lethal triad of acidosis, hypothermia, and coagulopathy.
• D. Delaying transfusion until a hemoglobin threshold ignores ongoing hemorrhage and risks worsening coagulopathy.

Jugular venous distention, muffled heart sounds, and hypotension (Beck triad) together with pulsus paradoxus greater than 10 mmHg after penetrating chest trauma indicate cardiac tamponade from pericardial blood accumulation restricting diastolic filling. Equal, bilateral breath sounds argue against tension pneumothorax, which would also cause tracheal deviation and hyperresonance. Massive hemothorax causes hypotension with jugular venous flattening (from hypovolemia) and decreased breath sounds on the affected side, not distention. Myocardial infarction and flail chest do not produce this triad after a penetrating wound.

• B. Flail chest presents with paradoxical chest wall movement and respiratory distress, not Beck triad.
• C. Tension pneumothorax would show absent or decreased breath sounds on the affected side and tracheal deviation, not equal breath sounds.
• D. Massive hemothorax causes flat neck veins from hypovolemia and diminished breath sounds, not distention with muffled heart sounds.
• E. Myocardial infarction does not explain the penetrating wound mechanism, jugular distention, or muffled heart sounds.

In a hemodynamically unstable blunt trauma patient, FAST is the best initial test because it is rapid, portable, repeatable, and can be performed in the trauma bay without interrupting resuscitation, identifying free intraperitoneal or pericardial fluid within minutes. CT is more sensitive and specific for grading solid organ injury but requires transport to the scanner and hemodynamic stability, making it unsafe here. Diagnostic peritoneal lavage is invasive, time-consuming, and has been largely replaced by FAST. Plain radiographs do not reliably detect intraperitoneal hemorrhage. Proceeding directly to laparotomy without any imaging risks a nontherapeutic operation if the hypotension has another source.

• A. Diagnostic peritoneal lavage is invasive and slower than FAST and is rarely used in current practice.
• B. CT requires transport out of the resuscitation area and hemodynamic stability, which this unstable patient does not have.
• C. Plain radiographs cannot reliably detect intraperitoneal free fluid or guide the need for immediate laparotomy.
• E. Some initial bedside assessment should confirm a source of hemorrhage before committing to laparotomy.

In a hemodynamically unstable trauma patient with clinical signs of pelvic fracture, a pelvic binder should be applied immediately at the level of the greater trochanters to reduce pelvic volume, stabilize the fracture, and tamponade venous and bony bleeding. This is a rapid, low-risk intervention that can be performed in the trauma bay before any imaging. Definitive imaging such as CT, as well as angiography or external fixation, should follow once the patient is temporized and transport to those resources is safe. Delaying binder placement for imaging risks ongoing exsanguination from pelvic fracture.

• A. A plain radiograph can confirm the fracture but does not address ongoing hemorrhage and should not delay binder placement.
• B. CT imaging requires transport to the scanner and should not precede temporizing stabilization in an unstable patient.
• C. Angioembolization is used for ongoing arterial hemorrhage after initial stabilization, not as the first maneuver.
• D. Operative external fixation is a definitive measure that follows initial temporizing stabilization, not the first step.

Blood at the urethral meatus and a high-riding prostate after pelvic trauma are classic signs of urethral injury, and attempting urethral catheterization in this setting risks converting a partial tear into a complete transection or introducing infection. A retrograde urethrogram should be performed before any attempt at catheterization to define the location and extent of urethral injury. If the urethrogram shows no extravasation, a Foley catheter can then be placed safely; if injury is confirmed, urology should place a suprapubic catheter. This stepwise approach avoids iatrogenic worsening of the injury.

• A. Suprapubic catheter placement may ultimately be needed but should follow confirmation of urethral injury by urethrogram, not precede it.
• C. CT cystogram evaluates bladder injury, not urethral injury, and is not the appropriate first test for suspected urethral trauma.
• D. Attempting catheterization before imaging risks converting a partial urethral tear into a complete disruption.
• E. CT with intravenous contrast does not reliably delineate urethral injury and is not the test of choice for this presentation.

A lucid interval followed by rapid neurologic deterioration after head trauma, combined with a lens-shaped (biconvex) hyperdensity on CT that does not cross suture lines, is characteristic of an epidural hematoma. This injury typically results from a temporal bone fracture lacerating the middle meningeal artery, causing arterial blood to accumulate between the dura and skull, a space limited by the dural attachments at suture lines, producing the biconvex shape. The ipsilateral blown pupil indicates uncinate herniation compressing the oculomotor nerve, a neurosurgical emergency requiring urgent evacuation. Rapid recognition and operative decompression are critical to prevent death from brainstem compression.

• A. Diffuse axonal injury typically shows punctate hemorrhages at gray-white junctions on CT or MRI, not a focal lens-shaped collection.
• B. Subdural hematoma produces a crescent-shaped collection that can cross suture lines, not a lens-shaped one confined by sutures.
• C. Cerebral contusion appears as a mixed-density area within the brain parenchyma, often at sites of direct impact, not an extra-axial lens-shaped collection.
• D. Subarachnoid hemorrhage appears as hyperdensity within the sulci and basal cisterns, not as a focal biconvex extra-axial collection.

A crescent-shaped (concave) extra-axial collection that crosses suture lines on CT, occurring in an elderly or anticoagulated patient after even minor head trauma with a delayed onset of symptoms, is characteristic of a subdural hematoma. Bridging veins between the dura and arachnoid are stretched with brain atrophy in elderly patients, making them prone to tearing with minor trauma, and anticoagulation promotes continued bleeding and hematoma expansion over days to weeks. Because the collection is not confined by dural attachments at sutures, it spreads diffusely over the convexity, producing the crescent shape. Management includes reversal of anticoagulation and neurosurgical evaluation for possible evacuation depending on size and mass effect.

• A. Subarachnoid hemorrhage appears as hyperdensity in the sulci and cisterns, not as a crescent-shaped extra-axial collection over the convexity.
• C. Intraparenchymal hemorrhage appears as a hyperdense focus within the brain tissue itself, not an extra-axial crescent-shaped collection.
• D. Ischemic stroke would show a hypodense area in a vascular territory on CT, not an extra-axial crescent-shaped collection.
• E. Epidural hematoma produces a biconvex, lens-shaped collection confined by suture lines, with rapid onset after trauma, not a crescent shape evolving over weeks.

Periorbital ecchymosis not caused by direct local trauma (raccoon eyes), bruising over the mastoid process (Battle sign), and clear fluid draining from the nose that is positive for glucose, consistent with cerebrospinal fluid rhinorrhea, together form the classic triad of basilar skull fracture. These findings result from fracture lines extending through the anterior or middle cranial fossa, disrupting the dura and allowing CSF leakage along with ecchymosis tracking to the periorbital and mastoid soft tissues. Diagnosis is confirmed with CT of the head and temporal bones, and management is largely supportive, with surgical repair reserved for persistent CSF leak or evidence of meningitis.

• A. A frontal sinus fracture may cause CSF rhinorrhea but does not typically produce Battle sign, which indicates a basilar fracture involving the middle fossa.
• B. Le Fort II fractures involve the midface and nasal bones with malocclusion, not the combination of raccoon eyes, Battle sign, and CSF rhinorrhea.
• C. An orbital blowout fracture causes periorbital swelling and diplopia from direct orbital trauma, not bilateral raccoon eyes with Battle sign and CSF leak.
• D. A nasal bone fracture causes local nasal swelling and epistaxis but does not explain Battle sign or CSF rhinorrhea.

In a patient with elevated intracranial pressure (greater than 20-22 mmHg) without a surgical mass lesion, after head elevation and sedation have been optimized, hyperosmolar therapy with intravenous mannitol or hypertonic saline is the next appropriate step to reduce cerebral edema by osmotically drawing fluid out of brain tissue. Mannitol also transiently improves cerebral blood flow by reducing blood viscosity. Prophylactic or sustained hyperventilation is avoided because it can cause cerebral vasoconstriction and worsen ischemia; it is reserved only as a brief temporizing measure for acute herniation. Corticosteroids are not beneficial for traumatic brain edema, and hypothermia and craniectomy are reserved for intracranial pressure refractory to first-tier medical therapy.

• B. High-dose corticosteroids have not been shown to improve outcomes in traumatic brain injury and are not recommended for traumatic cerebral edema.
• C. Therapeutic hypothermia is not first-line and is reserved for intracranial pressure refractory to standard medical therapy.
• D. Decompressive craniectomy is a surgical option for refractory intracranial hypertension after medical therapy has failed, not the immediate next step here.
• E. Routine or prophylactic hyperventilation to this degree causes cerebral vasoconstriction and risks ischemia; it should be used only briefly for acute herniation, not as a standard step.

This patient meets all NEXUS low-risk criteria: no midline cervical tenderness, no focal neurologic deficit, normal alertness, no intoxication, and no painful distracting injury. He also demonstrates full active range of motion as required by the Canadian C-Spine Rule for low-risk patients. When these criteria are satisfied, the cervical spine can be clinically cleared without any imaging. Imaging is reserved for patients who fail these clinical decision rules, as unnecessary imaging adds cost, radiation exposure, and delays care without added benefit.

• A. Prolonged immobilization is unnecessary and can cause harm (pressure ulcers, discomfort) when clinical criteria allow clearance.
• B. CT imaging is unnecessary when a patient meets all NEXUS or Canadian C-spine low-risk criteria.
• C. MRI is reserved for suspected ligamentous or spinal cord injury, not as an initial step in a low-risk patient.
• D. Plain radiographs are not indicated when clinical decision rules permit clearance without imaging.

Expanding hematoma and bruit are hard signs of vascular injury, along with active pulsatile bleeding, airway compromise, and hemorrhagic shock. In penetrating neck trauma with hard signs, the patient should proceed directly to the operating room for surgical exploration regardless of the anatomic zone, bypassing further imaging. Delaying for diagnostic studies in this unstable setting risks exsanguination or airway loss. Hemodynamic instability here further supports immediate operative intervention rather than observation or imaging.

• A. Laryngoscopy may be useful for suspected airway injury in a stable patient but does not address the vascular emergency here.
• C. Esophagography evaluates for esophageal injury in stable patients and is not appropriate when hard signs mandate immediate exploration.
• D. CT angiography is appropriate for stable patients without hard signs, not when hard signs of vascular injury are present.
• E. Observation is inappropriate given hemodynamic instability and hard signs of vascular injury.

Acute compartment syndrome is a clinical diagnosis suggested by pain out of proportion to the injury that is refractory to opioids, along with pain on passive stretch of the muscles within the affected compartment. Paresthesia and pulselessness are later findings; pulses are frequently preserved early because compartment pressure rises above capillary pressure (impairing perfusion and causing ischemia) well before it exceeds arterial systolic pressure. The cast should be removed or split promptly, and compartment pressures measured if the diagnosis remains uncertain. Early recognition is essential to prevent irreversible muscle and nerve ischemia.

• A. Pulses are preserved here, and arterial occlusion alone does not produce pain with passive stretch this early.
• B. An isolated peroneal nerve injury would not cause this pattern of pain with passive stretch and compartment tenseness.
• C. Fat embolism syndrome presents with respiratory distress, petechiae, and altered mental status, not localized compartment findings.
• E. DVT typically presents with unilateral swelling and tenderness but not severe pain with passive stretch of muscle compartments.

Absent distal pulses with an expanding hematoma and a pulseless, cool, pale limb (hard signs of vascular injury) in a patient with penetrating extremity trauma mandate immediate operative exploration. Imaging, including CT angiography or Doppler ultrasound, is reserved for patients without hard signs and would only delay revascularization, risking limb loss from prolonged ischemia (generally irreversible after 6 hours of warm ischemia). Rapid restoration of perfusion, with temporary vascular shunting if needed before definitive repair, is the priority in this setting.

• A. Ankle-brachial index is a screening tool for patients without hard signs of vascular injury, not for this clearly ischemic limb.
• B. Doppler ultrasound would delay necessary operative intervention in a limb with obvious hard signs of vascular injury.
• D. Serial observation risks progression to irreversible limb ischemia and is inappropriate when hard signs are present.
• E. CT angiography delays definitive treatment and is appropriate only when hard signs are absent.

In a hemodynamically stable patient with extremity trauma and no hard signs of vascular injury, the ankle-brachial index (ABI) is the appropriate initial screening test. An ABI of 0.9 or greater has high sensitivity and specificity for excluding a clinically significant arterial injury, allowing safe observation. If the ABI is below 0.9, further imaging with CT angiography (or formal arteriography in select cases) is warranted to evaluate for occult vascular injury. This stepwise approach avoids unnecessary invasive imaging or exploration in most patients.

• A. Compartment pressure measurement evaluates for compartment syndrome, not for vascular injury.
• C. Catheter-based arteriography is invasive and reserved for cases with an abnormal ABI or other equivocal findings, not as the initial screening test.
• D. Operative exploration is reserved for hard signs of vascular injury, which are absent here.
• E. Venous duplex evaluates for venous thrombosis, not arterial injury, and is not the screening test of choice here.

The Parkland formula calculates total 24-hour crystalloid requirement as 4 mL x body weight in kg x % total body surface area burned, using lactated Ringer's solution: 4 x 70 x 40 = 11,200 mL. Half of this volume is given over the first 8 hours from the time of injury (not from time of arrival), and the remaining half is given over the next 16 hours. Only second- and third-degree burns are included in the %TBSA calculation; superficial first-degree burns are excluded. Fluid administration is subsequently titrated to a urine output goal of approximately 0.5 mL/kg/hr in adults.

• A. This volume corresponds to using a multiplier of 6 mL/kg/%BSA, overestimating the standard Parkland requirement.
• C. This volume corresponds to using a multiplier of 3 mL/kg/%BSA, which underestimates the standard Parkland requirement.
• D. This volume represents only the first 8-hour requirement, not the total 24-hour volume.
• E. This volume corresponds to using a multiplier of 2 mL/kg/%BSA, not the standard 4 mL/kg/%BSA Parkland formula.

Using the rule of nines, the anterior trunk accounts for 18%, the entire arm (anterior and posterior) accounts for 9%, and the anterior surface of one leg accounts for 9%, giving a total of 18 + 9 + 9 = 36%. The rule of nines divides the adult body into regions that are each 9% or multiples of 9% of total body surface area: head and neck 9%, each arm 9%, anterior trunk 18%, posterior trunk 18%, each leg 18% (9% anterior, 9% posterior), and perineum 1%. Accurate estimation guides fluid resuscitation using formulas such as the Parkland formula.

• A. This overestimates the burned area; it would correspond to involvement of the entire leg or an additional region.
• C. This underestimates the total; it omits the correct contribution of either the arm or the leg.
• D. This underestimates the involved regions; it would correspond to only the trunk and arm or two leg surfaces.
• E. This overestimates the burned area; it would require more body regions to be involved.

Circumferential full-thickness burns create a rigid, inelastic eschar that does not expand as underlying tissue edema develops, leading to a tourniquet-like effect that compromises distal perfusion. Signs of vascular compromise, including absent pulses, pallor or duskiness, and paresthesias, are an indication for emergent escharotomy, a surgical incision through the eschar down to subcutaneous fat to relieve pressure. This is distinct from fasciotomy, which is reserved for compartment syndrome from causes other than the burned eschar itself. Delay in decompression risks irreversible ischemia and limb loss.

• A. Increasing fluids will not relieve the mechanical constriction caused by the rigid eschar.
• B. Anticoagulation does not address the mechanical compression caused by the eschar.
• C. Delaying intervention with elevation risks progression to irreversible ischemia given current pulselessness.
• E. Clinical findings of ischemia already warrant immediate decompression; measurement would only delay necessary treatment.

This presentation is classic for acute appendicitis: periumbilical visceral pain that migrates to the right lower quadrant as localized parietal peritoneal irritation develops, accompanied by anorexia, low-grade fever, and leukocytosis with neutrophil predominance. Tenderness at McBurney point, located one-third of the way from the anterior superior iliac spine to the umbilicus, along with rebound tenderness and guarding, reflects localized peritoneal inflammation over the appendix. The classic migratory pain pattern has a high positive predictive value for appendicitis when present. In a young man without gynecologic organs, this history and examination strongly favor appendicitis over the other listed diagnoses.

• A. Ovarian torsion occurs in women and presents with sudden severe unilateral pelvic pain, not applicable to this male patient.
• B. Diverticulitis classically presents with left lower quadrant pain, not periumbilical pain migrating to the right lower quadrant.
• C. Mesenteric lymphadenitis typically follows a viral illness and lacks the classic migratory pain pattern and peritoneal signs described here.
• E. Meckel diverticulitis is a rare cause of lower abdominal pain, typically presenting with painless bleeding or an appendicitis-like picture in children, and is far less common than appendicitis.

In nonpregnant adults with equivocal clinical findings for appendicitis, contrast-enhanced CT of the abdomen and pelvis is the most accurate imaging study, with sensitivity and specificity both exceeding 95%. CT can identify an enlarged, inflamed appendix, periappendiceal fat stranding, and complications such as abscess or perforation, and it also helps evaluate alternative diagnoses when the appendix is not clearly visualized. Ultrasound is preferred as the initial test in children and pregnant women to avoid ionizing radiation, but it is operator-dependent and less sensitive in adults, particularly in those who are obese. MRI without contrast is reserved for pregnant patients when ultrasound is inconclusive.

• A. Diagnostic laparoscopy is invasive and reserved for cases where imaging is unavailable, inconclusive, or when proceeding directly to surgery is already planned.
• B. Ultrasound is preferred in children and pregnant women but has lower sensitivity than CT in nonpregnant adults.
• C. MRI is reserved mainly for pregnant patients with inconclusive ultrasound, not as a first-line test in this patient.
• E. Plain radiographs have poor sensitivity and specificity for appendicitis and are not used to confirm the diagnosis.

In patients with perforated appendicitis complicated by a well-formed periappendiceal abscess and no diffuse peritonitis, the preferred initial management is image-guided percutaneous drainage combined with intravenous antibiotics, followed by interval appendectomy 6 to 8 weeks later once inflammation has resolved. Immediate surgery in this setting is technically difficult due to dense inflammatory adhesions and carries higher rates of complications such as bowel injury, incomplete resection, and fistula formation. This nonoperative approach controls sepsis while avoiding a hazardous dissection in acutely inflamed tissue. Immediate appendectomy is reserved for simple (nonperforated) appendicitis or when the patient has diffuse peritonitis or clinical deterioration despite drainage.

• A. Laparoscopic appendectomy in this inflamed field is also technically difficult and risky; drainage is preferred initially.
• B. Immediate surgery in a densely inflamed, abscessed field carries higher risk of bowel injury and complications compared to drainage first.
• D. Hemicolectomy is an excessive and inappropriate procedure for appendiceal pathology; it is not indicated here.
• E. Observation alone without source control is inadequate given the ongoing abscess and systemic signs of infection.

Acute cholecystitis is distinguished from simple biliary colic by the presence of fever, leukocytosis, and a positive Murphy sign (inspiratory arrest due to pain when the inflamed gallbladder contacts the examining hand), combined with pain lasting longer than the typical few hours seen in uncomplicated biliary colic. Biliary colic results from transient cystic duct obstruction by a gallstone and resolves once the stone passes or dislodges, without systemic inflammatory signs. The persistence of pain beyond 6 hours along with fever and neutrophilic leukocytosis indicates ongoing inflammation of the gallbladder wall rather than a self-limited episode. This patient's prior self-resolving episodes represent earlier biliary colic, while this presentation reflects progression to cholecystitis.

• B. Acute pancreatitis typically presents with epigastric pain radiating to the back and markedly elevated lipase, not isolated right upper quadrant findings with Murphy sign.
• C. Choledocholithiasis classically presents with jaundice and elevated bilirubin from common bile duct obstruction, which is not described here.
• D. Biliary colic is typically self-limited, lasting a few hours, and does not cause fever or significant leukocytosis as seen here.
• E. Ascending cholangitis presents with Charcot triad (fever, jaundice, right upper quadrant pain) or Reynolds pentad, and jaundice is not present in this patient.

Right upper quadrant ultrasound is the best initial imaging test for suspected acute cholecystitis because it is widely available, rapid, inexpensive, and avoids ionizing radiation, with good sensitivity and specificity for detecting gallstones, gallbladder wall thickening greater than 3 mm, pericholecystic fluid, and a sonographic Murphy sign. These findings together support the diagnosis in most patients without need for further testing. HIDA scan has higher sensitivity for acute cholecystitis but is reserved for cases where ultrasound findings are equivocal, since it takes longer and involves radioisotope administration. CT and MRCP are more useful for evaluating complications or common bile duct pathology rather than as first-line tests for cholecystitis.

• A. HIDA scan is more accurate but reserved as a second-line test when ultrasound findings are equivocal, due to longer study time and radiotracer use.
• B. ERCP is a therapeutic procedure for bile duct stones or obstruction, not a first-line diagnostic test for cholecystitis.
• C. MRCP is primarily used to evaluate suspected choledocholithiasis or bile duct abnormalities, not as the initial test for cholecystitis.
• D. CT is less sensitive than ultrasound for gallstones and is not first-line for suspected cholecystitis.

This patient has acute calculous cholecystitis diagnosed by clinical findings (fever, Murphy sign) and ultrasound (wall thickening, pericholecystic fluid, impacted stone). Current guidelines recommend early laparoscopic cholecystectomy, ideally within 72 hours of symptom onset, as this reduces hospital stay and complications compared with delayed surgery, without increasing conversion-to-open rates when performed by experienced surgeons. Percutaneous cholecystostomy is reserved for patients who are poor surgical candidates due to severe comorbidity or septic shock. ERCP is indicated for choledocholithiasis or cholangitis, not isolated cholecystitis without bile duct obstruction.

• A. There is no evidence of choledocholithiasis or cholangitis requiring duct decompression.
• B. Delayed surgery is associated with longer hospital stay and higher conversion rates compared with early surgery.
• C. Reserved for patients who are too unstable or high-risk for surgery, not this stable patient.
• E. Delaying surgery with antibiotics alone increases risk of complications such as gallbladder perforation.

This patient has fever, jaundice, and right upper quadrant pain (Charcot triad) plus hypotension and altered mental status, completing Reynolds pentad, which indicates severe, suppurative acute cholangitis. This occurs when bacterial infection develops proximal to an obstructed common bile duct, most commonly from choledocholithiasis, causing biliary stasis, bacterial overgrowth, and systemic sepsis. Reynolds pentad signifies a surgical emergency requiring urgent resuscitation, antibiotics, and biliary decompression. Cholecystitis typically does not cause significant jaundice or hyperbilirubinemia unless Mirizzi syndrome is present.

• A. Jaundice and markedly elevated bilirubin are not typical of isolated cholecystitis without duct obstruction.
• B. A hepatic abscess may cause fever and right upper quadrant pain but does not classically produce this pentad of findings.
• D. Viral hepatitis does not typically cause this degree of leukocytosis, hypotension, or altered mental status.
• E. Perforated ulcer causes diffuse peritonitis with rebound tenderness and free air, not isolated jaundice with fever.

Once initial resuscitation with IV fluids and antibiotics has stabilized a patient with acute cholangitis, urgent biliary decompression is required to relieve the obstruction and control the source of infection. ERCP with sphincterotomy and stone extraction (or stent placement) is the preferred method because it is minimally invasive and allows simultaneous diagnosis and treatment. Delaying decompression risks recurrent sepsis and progression to multiorgan failure. Cholecystectomy does not address the ductal obstruction and is performed later, after biliary drainage, if the gallbladder remains in situ.

• A. Cholecystectomy addresses gallbladder disease, not the common bile duct obstruction causing cholangitis.
• B. Antibiotics alone do not relieve the biliary obstruction driving the infection; decompression is required.
• C. Diagnostic cholangiography without drainage fails to relieve the obstruction causing ongoing sepsis.
• D. CT angiography does not evaluate or treat biliary obstruction and is not indicated here.

This patient has clinical and laboratory evidence suggestive of choledocholithiasis (elevated bilirubin and alkaline phosphatase, dilated common bile duct) but without signs of cholangitis or hemodynamic compromise, so a noninvasive confirmatory test is preferred before proceeding to an invasive intervention. MRCP is the best noninvasive imaging modality, offering high sensitivity and specificity for common bile duct stones without the risks of ERCP, such as pancreatitis or perforation. ERCP is reserved for therapeutic intervention once choledocholithiasis is confirmed, or used diagnostically when clinical suspicion is very high and intervention is anticipated.

• A. CT is less sensitive than MRCP for detecting common bile duct stones, which may be isodense with bile.
• B. HIDA scan assesses gallbladder function and cystic duct patency, not common bile duct stones.
• C. ERCP carries procedural risks (pancreatitis, perforation) and is better reserved for confirmed or highly likely stones requiring therapeutic extraction.
• E. This invasive procedure is used for biliary drainage when ERCP is not feasible, not as an initial diagnostic test.

The diagnosis of acute pancreatitis requires at least 2 of 3 criteria: characteristic abdominal pain (epigastric pain radiating to the back), serum lipase or amylase greater than 3 times the upper limit of normal, and/or characteristic findings on imaging. This patient meets 2 criteria (typical pain and lipase elevation greater than 3 times normal), making imaging unnecessary to confirm the diagnosis. Alcohol use is a leading etiology of acute pancreatitis, along with gallstones. Perforated ulcer and mesenteric ischemia typically present with peritoneal signs or more diffuse pain rather than isolated epigastric pain with this degree of lipase elevation.

• A. Perforation typically causes rigid, board-like abdomen with rebound tenderness and free air on imaging, not isolated lipase elevation.
• B. Biliary colic causes right upper quadrant pain without significant lipase elevation and this patient's ultrasound shows no gallstones.
• D. Mesenteric ischemia classically presents with pain out of proportion to exam findings and often in older patients with vascular risk factors, not isolated lipase elevation.
• E. Gastritis does not cause lipase elevation of this magnitude or pain radiating to the back.

Initial management of acute pancreatitis centers on aggressive IV isotonic fluid resuscitation (typically lactated Ringer's) to correct third-space losses and prevent pancreatic hypoperfusion, combined with early initiation of oral or enteral feeding as tolerated, usually within 24-72 hours. Early feeding supports gut mucosal integrity, reduces bacterial translocation, and is associated with lower rates of infectious complications compared with prolonged bowel rest. Enzyme levels do not need to normalize before feeding is resumed. Prophylactic antibiotics are not recommended in the absence of documented infection, and routine nasogastric decompression is not beneficial unless there is significant ileus or intractable vomiting.

• A. Enteral feeding is preferred over parenteral nutrition when the gut can be used, as it reduces infectious complications and cost.
• B. Prophylactic antibiotics are not recommended in acute pancreatitis without evidence of infection.
• C. Routine nasogastric decompression has not been shown to improve outcomes and is reserved for severe ileus or vomiting.
• E. Prolonged fasting until enzymes normalize is unnecessary and delays recovery; feeding should resume as symptoms allow.

Gas within a peripancreatic fluid collection on CT is highly suggestive of infected pancreatic necrosis, and combined with clinical signs of sepsis (fever, leukocytosis, tachycardia), intervention is indicated. Current guidelines recommend a minimally invasive step-up approach, beginning with image-guided (percutaneous or endoscopic) drainage, reserving open surgical necrosectomy for cases that fail to improve with less invasive measures. This approach reduces morbidity and mortality compared with immediate open surgery. Delaying intervention in the setting of infected necrosis with sepsis risks clinical deterioration and multiorgan failure.

• A. Infected necrosis with sepsis requires source control through drainage; antibiotics alone are insufficient.
• B. Immediate open necrosectomy is associated with higher morbidity and mortality compared with a step-up minimally invasive approach and is reserved for cases failing less invasive therapy.
• C. Delaying intervention in the setting of infected necrosis with sepsis risks clinical deterioration.
• E. ERCP addresses ductal pathology, not infected necrotic peripancreatic collections.

A strangulated hernia occurs when incarceration compromises blood supply to the herniated bowel, leading to ischemia and potential necrosis. Features distinguishing strangulation from simple incarceration include systemic toxicity (fever, tachycardia), skin changes overlying the hernia (erythema, dusky or mottled discoloration), and elevated lactate indicating tissue ischemia, all present in this patient. This presentation constitutes a surgical emergency requiring immediate operative exploration, in contrast to simple incarceration, which may sometimes be reduced manually without emergent surgery. Delay in recognizing strangulation risks bowel necrosis, perforation, and sepsis.

• A. Incarceration without strangulation lacks systemic toxicity, skin discoloration, and elevated lactate indicating ischemia.
• B. Testicular torsion presents with scrotal rather than groin bulge and a high-riding, horizontally-lying testis.
• D. Lymphadenitis presents as discrete tender nodes, not an irreducible groin bulge with overlying skin necrosis.
• E. Cellulitis alone would not cause mottled, dusky skin changes with a firm irreducible mass and elevated lactate.

A reducible, asymptomatic or minimally symptomatic inguinal hernia without signs of incarceration or strangulation (no pain at rest, no overlying skin changes, easily reducible) can be managed with elective outpatient repair. Emergent surgery is reserved for incarcerated or strangulated hernias with signs of bowel compromise such as severe pain, tenderness, erythema, or obstructive symptoms. Watchful waiting is an option in minimally symptomatic patients but elective repair is generally preferred to prevent future incarceration and because surgical risk is low. No imaging is needed when the diagnosis is clear on physical exam.

• B. There is no incarceration requiring emergency reduction; this is an elective, not emergent, problem.
• C. A truss does not fix the hernia and delays definitive treatment without benefit in a surgical candidate.
• D. CT is unnecessary when the diagnosis is established by physical examination alone.
• E. Emergent surgery is reserved for incarcerated or strangulated hernias, not an easily reducible one.

Dilated small bowel loops with air-fluid levels in a stepladder pattern, colonic gas paucity, and a history of prior abdominal surgery are classic for small bowel obstruction caused by postoperative adhesions, the most common cause of SBO in adults. The lack of peritoneal signs, normal lactate, and mild leukocytosis suggest a simple, non-strangulated obstruction. Adhesions account for over 50-70% of SBO cases, most often following pelvic or lower abdominal surgery. Plain films showing the stepladder sign support the diagnosis before further imaging confirms the transition point.

• A. Pancreatitis causes epigastric pain with elevated lipase, not this obstructive pattern.
• B. Mesenteric ischemia typically causes pain out of proportion to exam and elevated lactate, not seen here.
• D. Perforated ulcer presents with free air and peritonitis, not seen on this film or exam.
• E. Sigmoid volvulus shows a coffee bean sign on x-ray, not stepladder small bowel dilation.

In a hemodynamically stable patient with partial SBO and no signs of strangulation (normal lactate, no peritonitis, afebrile, passing flatus), initial management is nonoperative: nasogastric decompression, bowel rest, and IV fluid resuscitation with correction of electrolyte abnormalities. Most partial SBO episodes from adhesions resolve with conservative management, avoiding the risks of repeat surgery. Serial abdominal exams and monitoring for resolution or progression guide the decision to proceed to surgery if the obstruction fails to resolve or signs of ischemia develop.

• A. A contrast enema evaluates the colon, not the small bowel obstruction identified here.
• B. Immediate surgery is not indicated for a stable partial SBO without peritonitis or ischemia; trial of conservative management comes first.
• C. There is no clinical suspicion for mesenteric ischemia; lactate and exam are reassuring.
• D. Bowel prep and colonoscopy are inappropriate and risky in active small bowel obstruction.

New fever, tachycardia, peritoneal signs (guarding, rebound tenderness), rising leukocytosis, and elevated lactate in a patient with SBO indicate bowel strangulation with ischemia or impending perforation. This is a surgical emergency requiring prompt resuscitation and emergent exploratory laparotomy to resect nonviable bowel and relieve the obstruction, since delay increases the risk of perforation, sepsis, and death. Continued nonoperative management is contraindicated once signs of strangulation appear.

• A. Neostigmine treats colonic pseudo-obstruction (Ogilvie syndrome), not strangulated SBO.
• B. Contrast studies are not indicated and delay necessary surgical intervention in this emergency.
• C. Continued observation delays definitive treatment in a patient with signs of bowel ischemia or perforation.
• D. TPN and prolonged observation are inappropriate when strangulation is suspected; surgery should not be delayed.

Severe abdominal pain that is disproportionate to the relatively benign findings on physical examination, in a patient with atrial fibrillation and no anticoagulation (a source of embolus), strongly suggests acute mesenteric ischemia from embolic occlusion of the superior mesenteric artery. Elevated lactate and leukocytosis reflect early bowel ischemia, and occult blood in the stool reflects mucosal sloughing. Early recognition is critical because the exam often underestimates the severity of ischemia, and delayed diagnosis leads to bowel infarction, perforation, and high mortality.

• A. Appendicitis causes localized right lower quadrant pain and tenderness, not diffuse pain out of proportion to exam.
• B. Perforated ulcer causes diffuse peritonitis with rigid abdomen and free air, not this pattern of pain out of proportion with a soft abdomen.
• C. Diverticulitis typically causes localized left lower quadrant pain with tenderness correlating with exam findings.
• E. Volvulus presents with progressive distension and obstructive symptoms, not sudden severe pain with a source of embolism.

CT angiography of the abdomen is the best initial diagnostic test for suspected acute mesenteric ischemia in a hemodynamically stable patient, as it rapidly identifies arterial or venous occlusion, bowel wall changes, and signs of infarction or perforation with high sensitivity and specificity. It allows prompt diagnosis and guides decisions between endovascular intervention and surgical exploration. Catheter-based angiography remains useful for selected cases but CT angiography has become first-line due to its speed and ability to simultaneously evaluate the bowel.

• A. Colonoscopy is not appropriate in suspected acute ischemia and risks perforation in compromised bowel.
• B. Doppler ultrasound is limited by bowel gas and operator dependence and is not the preferred test for mesenteric ischemia.
• D. Plain x-ray may show nonspecific findings like ileus or thumbprinting but cannot reliably diagnose vascular occlusion.
• E. Upper endoscopy evaluates the stomach and duodenum, not the mesenteric vasculature or distal small bowel.

Sudden severe abdominal pain, a rigid board-like abdomen with diffuse peritonitis, hemodynamic instability, and free air under the diaphragm on upright chest x-ray are classic for perforated peptic ulcer, a surgical emergency. Chronic NSAID use is a major risk factor for peptic ulcer disease and perforation. Management requires immediate fluid resuscitation, broad-spectrum antibiotics, and emergent surgical exploration, typically with omental patch repair (Graham patch) of the perforation, as delay increases mortality from peritonitis and sepsis.

• A. PPI alone does not address an active perforation; definitive surgical repair is required emergently.
• B. Endoscopy is contraindicated in a perforated viscus because insufflation worsens peritoneal contamination.
• D. Nonoperative management is inappropriate once perforation with peritonitis and free air is confirmed.
• E. CT angiography evaluates vascular occlusion, not the free air and peritonitis seen here, and would delay necessary surgery.

This patient has a diverticular abscess larger than 4 cm that has failed to respond to antibiotics alone, which is an indication for image-guided percutaneous drainage combined with continued intravenous antibiotics. Abscesses smaller than 3-4 cm often resolve with antibiotics alone, while larger collections typically require drainage to achieve source control. Percutaneous drainage can often allow the acute episode to resolve, with elective sigmoid resection considered afterward if the patient has recurrent or complicated disease. Emergency surgery is reserved for patients with diffuse peritonitis, free perforation, or failure of percutaneous drainage.

• B. Continued observation alone is inappropriate given the large abscess size and failure of antibiotic therapy alone.
• C. Emergent laparotomy is reserved for diffuse peritonitis or failed drainage, not an isolated drainable abscess.
• D. Colonoscopy is contraindicated in the acute setting due to perforation risk and should be deferred 6-8 weeks after resolution.
• E. Laparoscopic lavage without resection is not standard first-line management when a percutaneous route is feasible.

Postoperative fever follows a rough timeline often remembered as the "5 W's": wind (atelectasis, postoperative days 1-2), water (urinary tract infection, days 3-5), walking (DVT, days 4-6), wound (surgical site infection, days 5-7), and wonder drugs/deep abscess (intra-abdominal abscess, typically after day 5-7 or later). This patient's fever on day 6, combined with abdominal pain, distension, and a clean incision, is most consistent with an intra-abdominal abscess, a recognized complication after colonic surgery, especially after a case involving perforation and contamination. Imaging with CT of the abdomen and pelvis would be the appropriate next step to confirm and guide drainage. The absence of leg swelling and a clean wound makes the other causes less likely.

• A. DVT usually presents around days 4-6 with unilateral leg swelling and tenderness, which this patient does not have.
• B. The incision is described as clean without erythema or drainage, making superficial wound infection unlikely.
• C. Atelectasis typically presents within the first 1-2 postoperative days with fever and often with decreased breath sounds, not matching this later presentation.
• D. Urinary tract infection classically occurs around postoperative days 3-5 and would present with urinary symptoms, which are absent here.

This patient had an initial return of bowel function (flatus on day 2, tolerating diet) followed by a new onset of obstructive symptoms with a transition point and distal decompression on imaging, which is characteristic of early postoperative mechanical small bowel obstruction rather than ileus. Postoperative ileus typically presents immediately after surgery with diffuse bowel distension and no transition point, and does not follow a period of normal bowel function. Early mechanical SBO within 6 weeks of surgery, often from adhesions, is initially managed conservatively with nasogastric decompression, bowel rest, and serial abdominal examinations, since many cases resolve without surgery. Indications for surgery include signs of strangulation, peritonitis, or failure of conservative management after several days.

• A. Ileus is inconsistent with this patient's prior return of bowel function and the presence of a transition point on imaging.
• B. There is no vignette evidence of a leak such as peritonitis, tachycardia, or wound findings, and this was a hysterectomy without bowel anastomosis.
• D. There are no signs of ischemia such as peritonitis, severe pain out of proportion, or lactic acidosis to warrant emergent surgery.
• E. Ileus management with prokinetics is incorrect because this presentation reflects mechanical obstruction, not ileus.

A surgical site infection with purulent drainage and a fluctuant, indurated wound requires opening the incision to allow drainage of infected fluid, which is the most important step in source control. The wound should be opened at the skin and subcutaneous level, irrigated, and packed open to heal by secondary intention or delayed primary closure, while the fascia remains intact. Antibiotics are an adjunct, usually reserved for cases with surrounding cellulitis, systemic signs of infection, or immunocompromise, but opening and draining the wound is the essential first step. Imaging is not necessary when there's an obviously drainable superficial collection on examination.

• A. Continuing the dressing and relying on oral antibiotics alone fails to achieve source control of a purulent collection that needs drainage.
• B. CT imaging is unnecessary when there is an obvious superficial fluctuant collection accessible on bedside examination.
• C. Antibiotics alone without opening the wound will not adequately treat an abscess requiring drainage.
• E. Primary closure over a drain is inappropriate for an actively infected wound; it should be left open to drain.

Salmon-colored or serosanguinous fluid draining from a surgical wound, often after a straining event like coughing, is a classic sign of fascial dehiscence, where the fascial closure has failed while the skin remains intact. Risk factors include obesity, diabetes mellitus, wound infection, advanced age, and increased intra-abdominal pressure, all present in this patient. The wound should be covered with sterile saline-soaked gauze to protect exposed viscera and prevent desiccation, and the patient should be taken urgently to the operating room for fascial repair to prevent evisceration or bowel injury. Fascial dehiscence does not heal spontaneously and requires surgical closure, usually with retention sutures given the high risk of recurrence.

• A. Outpatient discharge is inappropriate given the risk of evisceration; this requires inpatient urgent surgical management.
• B. Bedside reduction and skin closure alone do not address the fascial defect and risk incarceration or evisceration.
• D. Reassurance and routine dressing changes are inadequate for a fascial dehiscence, which requires surgical repair.
• E. Fascial dehiscence does not resolve spontaneously and delaying repair increases the risk of evisceration.

Patients undergoing major cancer surgery, such as this pelvic procedure for endometrial cancer, are classified as very high risk for VTE and benefit from combined mechanical and pharmacologic prophylaxis. Current guidelines recommend low-dose unfractionated heparin or low-molecular-weight heparin started preoperatively (or immediately postoperatively if preoperative dosing is not feasible) and continued through the hospital stay, along with mechanical prophylaxis such as intermittent pneumatic compression. Extended prophylaxis for up to 4 weeks after discharge is also recommended in high-risk cancer surgery patients. Mechanical prophylaxis alone is insufficient in very high-risk patients, and therapeutic anticoagulation or warfarin is not used for routine surgical VTE prophylaxis due to bleeding risk and delayed onset of action.

• A. Mechanical prophylaxis alone is insufficient for a very high-risk patient undergoing major cancer surgery; combined prophylaxis is recommended.
• B. Warfarin is not used for surgical VTE prophylaxis due to its delayed onset and the impracticality of delaying cancer surgery for anticoagulation titration.
• D. Withholding pharmacologic prophylaxis is inappropriate for a very high-risk patient; low-dose prophylactic anticoagulation is recommended in addition to mechanical methods.
• E. Therapeutic-dose heparin is used for treatment of VTE, not prophylaxis, and markedly increases perioperative bleeding risk.

According to the ACC/AHA perioperative guidelines, patients with good functional capacity, defined as being able to perform activities requiring more than 4 metabolic equivalents such as climbing two flights of stairs without symptoms, can proceed to surgery without further cardiac stress testing regardless of their RCRI score. Stress testing before noncardiac surgery is reserved for patients with poor or unknown functional capacity and elevated clinical risk (RCRI greater than or equal to 1 for intermediate-risk or vascular surgery) whose test results would change perioperative management. This patient's excellent functional capacity and lack of active cardiac symptoms mean that additional testing would not change management and would only delay a necessary cancer operation. Noninvasive stress testing should never be pursued purely routinely before elective noncardiac surgery when it will not change the surgical plan.

• A. Stress testing is unnecessary in a patient with good functional capacity (greater than 4 METs) regardless of RCRI, as it would not change management.
• B. A resting echocardiogram is not routinely indicated preoperatively in an asymptomatic patient with good functional capacity and no heart failure symptoms.
• C. An exercise stress test is unnecessary when functional capacity is already clinically established as good without symptoms.
• E. Coronary angiography is invasive and reserved for patients with unstable symptoms or strongly positive noninvasive testing, not indicated here.