What is the best course of action for an adult patient with abdominal distension and breathlessness, but otherwise normal findings, and an unspecified medical history?

Immediate Diagnostic Workup for Abdominal Distension and Breathlessness

This presentation demands urgent evaluation for life-threatening conditions including bowel obstruction, mesenteric ischemia, abdominal compartment syndrome, and pulmonary hypertension with right heart failure—all of which can present with these symptoms and carry significant mortality if missed.

Critical Initial Assessment

Vital Signs and Physical Examination

• Measure respiratory rate, pulse, blood pressure, temperature, and oxygen saturation immediately 1
• Assess for signs of shock: tachycardia, tachypnea, cool extremities, mottled skin, altered mental status, and oliguria 1
• Examine for peritonitis signs (diffuse tenderness, guarding, rebound, absent bowel sounds)—their presence mandates emergency surgical consultation 1, 2
• Palpate all hernia orifices (umbilical, inguinal, femoral) and examine all surgical scars for incarcerated hernias 1
• Perform digital rectal examination to detect blood or masses 1
• Auscultate for increased bowel sounds with high-pitched rushes (suggests mechanical obstruction) versus absent sounds (suggests peritonitis or ileus) 1

Cardiovascular Examination

• Assess for signs of right heart failure: jugular venous distension, hepatomegaly, peripheral edema, ascites, cool extremities 1
• Listen for left parasternal lift, accentuated pulmonary component of S2, tricuspid regurgitation murmur 1
• Pulmonary hypertension should be suspected when breathlessness occurs with abdominal distension and signs of right ventricular failure 1

Immediate Laboratory Testing

Order the following stat labs 1:

• Complete blood count (marked leukocytosis suggests ischemia or perforation)
• Arterial blood gas with lactate (elevated lactate and low pH indicate bowel ischemia)
• Renal function and electrolytes (assess for prerenal failure)
• Liver function tests
• Coagulation profile

Critical red flags: Low serum bicarbonate, low arterial pH, high lactic acid, and marked leukocytosis strongly suggest intestinal ischemia requiring emergency surgery 1

Initial Stabilization

Immediate Interventions

• Start aggressive IV crystalloid resuscitation (20 mL/kg bolus initially) to restore intravascular volume 3, 4
• Insert nasogastric tube for decompression if significant distension or vomiting present 1, 3, 4
• Insert Foley catheter to monitor urine output (target >0.5 mL/kg/hour) 3, 4
• Initiate supplemental oxygen to maintain SpO2 94-98% 1
• Keep patient NPO 4

Diagnostic Imaging Algorithm

First-Line Imaging

CT abdomen/pelvis with IV contrast is mandatory 1, 3, 2, 4:

• Diagnostic accuracy exceeds 90% for bowel obstruction 3, 4
• Superior to plain radiography (only 50-60% sensitivity) 1, 4
• Do not delay CT even with renal dysfunction—consequences of missed diagnosis far outweigh contrast risks 1

Critical CT Findings Requiring Emergency Surgery

The following findings mandate immediate surgical consultation 1, 2:

• Pneumatosis intestinalis
• Free intraperitoneal air
• Portal or mesenteric venous gas
• Bowel wall thickening with poor enhancement
• Closed-loop obstruction
• Superior mesenteric artery or vein thrombosis

Adjunct Imaging

• Transthoracic echocardiography if pulmonary hypertension suspected (elevated right ventricular systolic pressure, right heart chamber dilation) 1
• Plain abdominal X-ray has limited value but may show bowel distension patterns 1

Differential Diagnosis and Management Pathways

Bowel Obstruction (Most Common)

If CT confirms small bowel obstruction without ischemia 3, 4:

• Continue conservative management with NG decompression, IV fluids, NPO status
• Consider water-soluble contrast (100 mL Gastrografin via NG tube) with follow-up X-rays at 4,8,12,24 hours 3
• If contrast reaches colon within 24 hours, surgery rarely needed 3
• Proceed to surgery if: signs of peritonitis develop, failure of conservative management after 24-48 hours, or clinical deterioration 3, 4

If CT shows large bowel obstruction 2:

• Emergency surgery required for peritonitis, ischemia, or perforation
• Consider endoscopic decompression for sigmoid volvulus if no perforation
• Mortality ranges 11-22% depending on intervention 2

Acute Mesenteric Ischemia

Suspect in critically ill patients, those on vasopressors, or with atrial fibrillation 1:

• Non-occlusive mesenteric ischemia (NOMI) may present with unexplained abdominal distension as the only sign in sedated/ICU patients 1
• Emergency surgery required immediately if diagnosis confirmed 1
• Mortality approaches 25% with delayed diagnosis 3

Abdominal Compartment Syndrome

Suspect if intra-abdominal pressure >20 mmHg with organ dysfunction 5:

• Measure bladder pressure via Foley catheter 5
• Causes hypoventilation, decreased cardiac output, renal dysfunction, oliguria 5
• Surgical decompression required for refractory cases 5

Pulmonary Hypertension with Right Heart Failure

Consider when breathlessness predominates with abdominal distension (ascites) 1:

• ECG may show right ventricular hypertrophy (87% of cases) and right axis deviation (79%) 1
• Chest X-ray shows central pulmonary artery dilatation with peripheral "pruning" 1
• Requires echocardiography and right heart catheterization for definitive diagnosis 1

Critical Pitfalls to Avoid

• Never delay imaging or surgical consultation when ischemia suspected—mortality reaches 25% with bowel ischemia 3
• Do not perform CT without IV contrast unless absolutely contraindicated—venous phase essential for detecting mesenteric venous thrombosis 1
• Avoid excessive fluid administration that worsens bowel edema and impairs perfusion 3
• Do not assume normal vital signs exclude serious pathology—25% of NOMI cases have minimal abdominal findings 1
• Do not delay surgery for "optimization" if peritonitis, ischemia, or perforation present—these require immediate intervention 1, 3, 2, 4

When to Activate Emergency Surgery

Immediate surgical consultation required for 1, 3, 2, 4:

• Signs of peritonitis (diffuse tenderness, guarding, rebound)
• Suspected bowel ischemia (fever, tachycardia, lactic acidosis, leukocytosis)
• Free perforation with pneumoperitoneum
• Closed-loop obstruction on imaging
• Failure of conservative management after 24-48 hours
• Hemodynamic instability despite resuscitation