Incarcerated/strangulated hernias

Definitions - When Guts Get Stuck

• Reducible: Hernia contents can be manually pushed back through the fascial defect.
• Irreducible (Incarcerated): "Trapped." Hernia contents are stuck outside the abdominal wall; cannot be manually reduced. Often leads to bowel obstruction (pain, vomiting, constipation).
• Strangulated: "Choked." An incarcerated hernia with compromised blood supply (ischemia → necrosis). Presents with intense, steady pain, fever, and erythema over the lump. A true surgical emergency.

⭐ Femoral hernias have the highest risk of strangulation.

Pathophysiology - The Vascular Squeeze

• Incarceration: Irreducible trapping of hernia contents (e.g., bowel, omentum) at the hernia orifice. Blood flow is initially preserved.
• Strangulation: A surgical emergency where vascular supply is compromised, leading to ischemia.

• Progression from ischemia to necrosis can be rapid, often within 4-6 hours.

⭐ Femoral hernias carry the highest risk of strangulation (~15-20%), making them a high-priority surgical repair candidate. Direct inguinal hernias have the lowest risk.

Clinical Picture - Red Flags Flying

• Incarceration: A previously reducible hernia becomes irreducible. Presents as a painful, tender bulge. May be associated with nausea, vomiting, and constipation, signaling early bowel obstruction.
• Strangulation (Vascular Compromise): A surgical emergency where blood supply is cut off.
  • Local Signs (The "Angry Lump"):
    • Pain becomes severe, constant, and localized.
    • Overlying skin shows erythema, warmth, edema, or ecchymosis.
    • The hernia mass is tense and exquisitely tender.
  • Systemic Signs (Sepsis):
    • Fever (>38°C), tachycardia (>100 bpm), hypotension.
    • Labs: Leukocytosis (↑ WBC), metabolic acidosis (↑ lactate).

⭐ High-Yield: Pain out of proportion to exam findings is a classic sign of intestinal ischemia. Do not attempt forceful reduction if strangulation is suspected, as it can perforate gangrenous bowel.

Dx & Management - The Escape Plan

• Clinical Dx: Tender, erythematous, non-reducible mass. Systemic signs (fever, tachycardia, ↑WBC, acidosis) suggest strangulation.
• Imaging:
  • Ultrasound with Doppler: Initial choice to assess blood flow.
  • CT Scan: Confirms diagnosis, shows bowel wall thickening, edema, or free air.

• Management Steps:
  • Pre-Op: NPO, IV access, fluid resuscitation, analgesia.
  • Antibiotics: Cover gram-negatives & anaerobes (e.g., Cefoxitin, Zosyn).

⭐ Exam Favorite: Never attempt manual reduction if strangulation is suspected. This risks perforating ischemic bowel or causing sepsis by returning non-viable tissue to the abdomen.

High‑Yield Points - ⚡ Biggest Takeaways

• Incarceration is an irreducible hernia; strangulation adds vascular compromise, creating a surgical emergency.
• Suspect strangulation with severe, steady pain, skin erythema, and systemic signs like fever or tachycardia.
• Femoral hernias carry the highest risk of strangulation.
• Diagnosis is mainly clinical; a CT scan can confirm bowel ischemia or obstruction.
• Management requires immediate surgical exploration to prevent bowel necrosis and sepsis.
• Never manually reduce a suspected strangulated hernia in the ED.