What is a quiet abdomen called?

Ileus: Understanding the Quiet Abdomen

A quiet abdomen refers to ileus, which is a functional obstruction of intestinal transit without mechanical blockage, characterized by absent or diminished bowel sounds due to uncoordinated or attenuated intestinal muscle contractions. 1

Definition and Classification

• Ileus (from the Greek word for "twisted") historically referred to various forms of intestinal obstruction, but in modern medicine specifically denotes a non-mechanical functional obstruction 2
• It represents a diffuse gastrointestinal dysmotility that can affect both small and large intestines, resulting in decreased or absent bowel sounds on auscultation 1
• Also known as "adynamic" or "paralytic" ileus to distinguish it from mechanical bowel obstruction 3

Clinical Presentation

• Characterized by abdominal distension, absent or diminished bowel sounds, nausea, vomiting, and constipation 1
• Radiological findings include dilated intestinal loops with fluid levels similar to mechanical obstruction, but without a transition point 4
• Ultrasound examination may show edema of intestinal walls, absence of peristalsis, and sedimentation of intestinal contents 4

Pathophysiology

• Results from inhibition of normal coordinated propulsive intestinal motility 3
• May lead to intestinal dilatation, increased luminal pressure, and potentially gut wall ischemia 1
• Can promote abdominal fluid sequestration, bacterial overgrowth, and systemic inflammatory response syndrome 1

Common Causes

• Post-surgical (especially abdominal surgery) - most common cause 3
• Metabolic disorders (electrolyte abnormalities, particularly hypokalemia) 3
• Medications (opioids, anticholinergics, calcium channel blockers) 5
• Severe systemic illness or infection 3
• Neurological disorders affecting intestinal innervation 5
• Prolonged immobility 1

Diagnostic Approach

• Clinical examination revealing absent or diminished bowel sounds on auscultation 4
• Plain abdominal radiographs showing dilated intestinal loops without a transition point 4
• Ultrasound can help differentiate between mechanical obstruction and paralytic ileus through assessment of peristalsis 4
• CT imaging may be required to exclude mechanical obstruction 5

Management

• Supportive care including intravenous rehydration and correction of electrolyte abnormalities 3
• Discontinuation of medications that inhibit intestinal motility, particularly opioids 5
• Treatment of underlying causes 3
• Bowel rest and nasogastric decompression if significant distension or vomiting 1
• Prokinetic agents may be considered in select cases 3
• Monitoring for complications, including abdominal compartment syndrome 1

Complications

• Bacterial translocation and systemic infection 1
• Increased intra-abdominal pressure potentially leading to abdominal compartment syndrome 1
• Fluid and electrolyte imbalances 3
• Malnutrition if prolonged 5

Special Considerations

• Differentiation from mechanical bowel obstruction is crucial as management differs significantly 4
• Early ultrasound examination is valuable when X-ray findings are not yet conclusive 4
• Prolonged ileus may require nutritional support strategies 5
• Monitoring intra-abdominal pressure is important in critically ill patients with ileus 1