Abdominal distention is an increase in abdominal girth due to elevated intra-abdominal pressure, typically manifesting as outward protrusion of the abdominal wall. Distention may be:

• Localized or generalized

• Acute or chronic

• Mild to severe

Etiologies

Classic mnemonic: 5 F’s

• Fat: Obesity

• Flatus: GI gas accumulation

• Fetus: Pregnancy, intra-abdominal mass (e.g., ectopic pregnancy)

• Fluid: Ascites, hemoperitoneum, perforation with pneumoperitoneum

• Feces: Severe constipation or fecal impaction

Pathophysiology

Distention arises from the inability of gas or fluid to transit through the gastrointestinal tract or from accumulation in the peritoneal cavity (e.g., ascitic fluid, blood, or air). Distention may also reflect mass effect or altered neuromuscular bowel function (e.g., ileus).

Initial assessment & emergency Considerations

Red Flags:

• Signs of hypovolemic shock: hypotension, tachycardia, oliguria, altered mental status

• Severe, acute-onset abdominal pain

• Peritoneal signs: rigidity, rebound tenderness, guarding

• History of trauma or recent abdominal surgery

Immediate interventions:

1. Vital signs & rapid ABC assessment

2. Supine positioning, administer high-flow oxygen

3. Establish large-bore IV access; initiate fluid resuscitation

4. Insert nasogastric tube if bowel obstruction is suspected

5. Prepare for imaging (X-ray/CT) and possible surgical consultation

History taking

• Onset: acute vs. insidious

• Pattern: intermittent vs. persistent

• Associated symptoms: pain, nausea, vomiting, altered bowel habits, weight changes

• Surgical history: recent operations (risk of adhesions)

• Trauma: even minor incidents

• Comorbidities: cirrhosis, CHF, IBD

• Reproductive history in females: rule out pregnancy

Physical examination

Inspection

• Abdominal asymmetry (localized vs. generalized)

• Contour: flat, rounded, protuberant

• Skin: tautness, striae, scars, visible veins (caput medusae)

• Umbilicus:

  • Everted: ascites, hernia

  • Inverted: obesity or gas

Auscultation

• Hyperactive, high-pitched bowel sounds: obstruction

• Hypoactive/absent: ileus, peritonitis

• Listen for succussion splash, bruits, or friction rubs

Percussion

• Tympany: gas-filled structures

• Dullness: fluid or mass

• Assess for:

  • Shifting dullness

  • Fluid wave (less reliable in pediatric patients)

  • Puddle sign

Palpation

• Identify tenderness (localized vs. diffuse)

• Check for guarding, rigidity, masses

• Special signs:

  • Rebound tenderness, McBurney’s point

  • Psoas, obturator signs

Additional exams

• Digital rectal exam with FOBT

• Pelvic/genital exam based on sex

• Baseline abdominal girth: mark with skin pen for tracking

Differential Diagnosis

Life-threatening causes

Common medical conditions

Special populations

Pediatrics:

• Normal rounded abdomen may obscure distention

• Causes: GI malformations, hernia, ascites (cardiac/nephrotic origin)

• Use shifting dullness, not fluid wave

• Assess in parent’s lap if uncooperative

• Remove clothing to fully inspect abdomen

Geriatrics:

• Abdominal wall laxity and fat redistribution may mimic distention

• Common causes: obstruction, CHF, malignancy

• Consider atypical presentations and polypharmacy side effects

Diagnostics

• Imaging:

  • Abdominal X-ray: obstruction, air-fluid levels

  • Ultrasound: ascites, masses

  • CT abdomen/pelvis: obstruction, masses, perforation

• Laboratory tests:

  • CBC, CMP, LFTs, lipase

  • Serum amylase/lipase: pancreatitis

  • β-hCG: all reproductive-age females

  • Paracentesis (if ascites): SAAG, cytology, culture

Management

• Treat underlying cause (e.g., obstruction, infection, ascites)

• Symptom relief:

  • Pain management

  • NG decompression for obstruction

  • Diuretics for ascites

• Positioning: left lateral for flatus, head elevated for ascites

• Patient education:

  • Dietary modifications

  • Importance of oral hygiene with vomiting or NG tube use

  • Use of slow, deep breathing for pain/discomfort

References

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