A 58-year-old man presents to the emergency department with a 2-hour history of sudden-ons… — USMLE Step 3

A $58$ -year-old man presents to the emergency department with a $2$ -hour history of sudden-onset, severe, diffuse abdominal pain. His medical history is significant for a mechanical mitral valve replacement performed $3$ years ago, for which he takes daily warfarin.

On physical examination, his temperature is $38.4^\circ\text{C}$ ( $101.1^\circ\text{F}$ ), blood pressure is $92/58\text{ mmHg}$ , heart rate is $115/\text{min}$ , and respiratory rate is $22/\text{min}$ . The patient lies completely still on the stretcher. His abdomen is rigid with diffuse rebound tenderness and involuntary guarding.

Laboratory studies show:
- Hemoglobin: $13.2\text{ g/dL}$
- Leukocyte count: $16,500/\text{mm}^3$
- Platelet count: $210,000/\text{mm}^3$
- International normalized ratio (INR): $3.2$

An upright chest radiograph demonstrates free air under the right hemidiaphragm.

Which of the following are the most appropriate immediate steps in management? (Select all that apply)

Emergent exploratory laparotomyAnswer
Administration of 4-factor prothrombin complex concentrateAnswer
Administration of intravenous broad-spectrum antibioticsAnswer
D
Computed tomography of the abdomen and pelvis with water-soluble oral contrast
E
Initiation of a continuous intravenous unfractionated heparin infusion

Answer

The most appropriate immediate steps in management are emergent exploratory laparotomy, administration of 4-factor prothrombin complex concentrate, and administration of intravenous broad-spectrum antibiotics.

This patient presents with a classic acute abdomen, evidenced by a rigid abdomen, involuntary guarding, and diffuse rebound tenderness. The presence of free air under the diaphragm on an upright chest radiograph confirms the diagnosis of a perforated hollow viscus. This is a life-threatening surgical emergency, and the definitive treatment is an emergent exploratory laparotomy. Concurrently, the patient is exhibiting signs of septic shock (hypotension, tachycardia, fever) secondary to peritonitis, necessitating the immediate administration of intravenous broad-spectrum antibiotics to control the systemic infection. Furthermore, the patient is actively taking warfarin for a mechanical mitral valve and has a therapeutic international normalized ratio (INR) of 3.2. Operating on a patient with this level of anticoagulation is extremely dangerous. Therefore, rapid reversal of warfarin using 4-factor prothrombin complex concentrate (PCC) alongside vitamin K is critical to correct the coagulopathy immediately prior to the surgical incision.

Step-by-Step Solution

Identify the primary diagnosis and its severity based on clinical and radiographic findings.

The patient's rigid abdomen, rebound tenderness, and free air on the upright chest radiograph indicate a perforated hollow viscus with secondary peritonitis.

Recognizing a perforated viscus is essential because it is a surgical emergency that requires immediate operative intervention.

Evaluate the patient's hemodynamic status and systemic response.

The patient is hypotensive, tachycardic, and febrile, indicating early septic shock from the intra-abdominal catastrophe.

Hemodynamic instability and signs of sepsis dictate the need for immediate resuscitative measures, including intravenous fluids and broad-spectrum antibiotics.

Assess medication history and specific preoperative risks.

The patient is therapeutically anticoagulated on warfarin (INR 3.2) for a mechanical mitral valve.

Performing major surgery in a therapeutically anticoagulated patient carries a high risk of life-threatening hemorrhage; therefore, immediate pharmacological reversal of anticoagulation is required before entering the operating room.

Synthesize findings to select the concurrent immediate interventions.

The patient requires simultaneous preoperative optimization (antibiotics, PCC for warfarin reversal) and emergent surgical exploration (laparotomy).

Delaying surgery for further imaging or natural INR normalization increases mortality, while proceeding without reversing anticoagulation or treating sepsis leads to profound complications.

Key Concept

Management of a perforated viscus in an anticoagulated patient requires concurrent emergent surgical exploration, rapid reversal of anticoagulation, and aggressive medical resuscitation for sepsis.

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