How should a markedly enlarged abdomen be described on physical examination?

Describing a Markedly Enlarged Abdomen on Physical Examination

A markedly enlarged abdomen should be systematically described by documenting its contour (distended, protuberant, or grossly distended), the presence or absence of visible peristalsis, percussion findings (tympanic suggesting bowel distension versus dull suggesting fluid or mass), and associated features such as tenderness, guarding, or organomegaly.

Systematic Approach to Documentation

Visual Inspection

• Document the overall contour: Use terms such as "distended," "protuberant," or "grossly distended" to characterize the degree of enlargement 1
• Note visible peristalsis: In thin patients with mechanical bowel obstruction, visible peristaltic waves may be observed and represent a strong diagnostic clue 2, 3
• Assess symmetry: Document whether the distension is symmetric or asymmetric, as localized bulging may suggest mass effect or organomegaly 1
• Look for surgical scars: Previous abdominal surgeries have 85% sensitivity for adhesive small bowel obstruction when combined with appropriate clinical context 2

Percussion Findings

• Tympany versus dullness: Tympanic percussion suggests gas-filled bowel distension (as in obstruction), while dullness suggests fluid (ascites), blood, or solid mass 4, 5
• Assess for shifting dullness: This maneuver detects free fluid in the peritoneal cavity and is essential when ascites is suspected 4
• Document hepatic and splenic size: Percussion can identify organomegaly, though imaging confirmation is typically required 4, 5

Palpation Characteristics

• Tenderness location and severity: Document whether tenderness is localized or diffuse, and whether guarding or rebound is present 6, 1
• Assess for masses: Palpate systematically for bladder distention, fecal impaction, or other masses 6, 1
• Evaluate for peritoneal signs: Guarding and rebound tenderness suggest peritonitis or bowel perforation 6

Auscultation Patterns

• Bowel sound character: Hyperactive or "rushes" suggest mechanical obstruction, while absent sounds indicate ileus or advanced ischemia 6, 2, 3
• Duration of auscultation: Listen for at least 2 minutes before declaring bowel sounds absent 1

Common Clinical Scenarios

Bowel Obstruction

• Abdominal distension occurs in 65.3% of cases and carries a positive likelihood ratio of 16.8 for mechanical obstruction 2
• Describe as "distended abdomen with visible peristaltic waves, tympanic to percussion, with hyperactive bowel sounds and rushes" 6, 2
• Warning: Transition from hyperactive to absent bowel sounds indicates progression to ischemia with mortality up to 25% if untreated 2, 3

Ascites

• Describe as "protuberant abdomen with flank dullness and shifting dullness on percussion" 7, 4
• Diagnostic paracentesis is mandatory for all new-onset ascites to determine etiology 7
• Cirrhosis accounts for 75-85% of ascites cases, with the remainder from malignancy, heart failure, tuberculosis, or nephrotic syndrome 7

Organomegaly or Mass

• Document specific organ enlargement: "distended abdomen with palpable hepatomegaly extending 6 cm below the right costal margin" 6, 1
• Percussion combined with palpation remains a useful bedside technique for detecting splenic enlargement 5

Critical Pitfalls to Avoid

• Never rely solely on inspection: Percussion and palpation provide essential diagnostic information that visual assessment alone cannot reveal 1, 8
• Do not mistake incomplete obstruction for gastroenteritis: Patients with partial obstruction may have watery diarrhea, leading to misdiagnosis 2, 3
• Recognize that elderly patients may have minimal pain: Overlooking obstruction in older patients where pain is less prominent can have severe consequences 2
• Absent bowel sounds demand immediate concern: This finding should raise suspicion for bowel ischemia or strangulation requiring urgent surgical evaluation 2, 3

Documentation Template

A complete description should follow this structure:

1. General appearance: "The abdomen is grossly distended/protuberant"
2. Inspection findings: "with/without visible peristalsis, symmetric/asymmetric"
3. Percussion: "tympanic throughout/dull in dependent areas with shifting dullness"
4. Palpation: "soft/firm, tender/non-tender in [location], with/without guarding, no/palpable masses or organomegaly"
5. Auscultation: "bowel sounds are hyperactive with rushes/hypoactive/absent" 6, 2, 1