Abdominal Injury Assessment: Internal Bleeding Signs

The Challenge of Abdominal Injury

The abdomen contains highly vascularized organs that can bleed massively from blunt impact without any visible wound. Unlike extremity hemorrhage — where you can see the blood and apply a tourniquet — intra-abdominal hemorrhage is hidden. The body can compensate and maintain near-normal vital signs for a period, then decompensate rapidly.

The primary goal of field abdominal assessment is not to diagnose which organ is injured — that requires CT scan or surgery. The goal is to identify:

1. Is there significant injury to the abdomen?
2. Are there signs of hemorrhagic shock developing?
3. Is the patient's condition stable, improving, or deteriorating?

High-Risk Mechanisms

These mechanisms cause significant abdominal injury frequently enough that a detailed abdominal assessment is always indicated:

• Direct high-energy blow to the abdomen (steering wheel, handlebar, punch, kick)
• Fall from height landing on the abdomen
• Seatbelt injury (the strap compresses abdominal contents against the spine)
• Crush injury to the torso
• Any penetrating wound to the abdomen (knife, projectile, impaled object)

Lower rib fractures — specifically ribs 9-12 — are closely associated with underlying spleen (left side) and liver (right side) injuries. A patient with lower rib fractures requires abdominal assessment.

Pelvic fractures can cause massive hemorrhage from pelvic vascular injury without any intraabdominal injury. If the mechanism suggests significant pelvic force, assess for pelvic instability (gentle side-to-side compression of iliac crests — if this is painful and reveals movement, stabilize the pelvis and evacuate).

Physical Examination

Inspection

Position the patient supine, abdomen exposed from nipples to groin.

Look for:

• Abrasions, bruises, or deformity over the abdomen
• Seatbelt sign: diagonal bruise from seatbelt — associated with intestinal injury and abdominal aorta injury
• Grey-Turner sign: bruising along the flanks (sides) — indicates retroperitoneal hemorrhage; may take hours to days to appear
• Cullen's sign: bruising around the umbilicus — indicates retroperitoneal hemorrhage; delayed sign
• Distension: an unusually full or tense abdomen
• Impaled object: if present, do not remove — stabilize in place (see below)
• Any open wounds communicating with the abdominal cavity

Auscultation

Listen for bowel sounds before palpating (palpation alters bowel sound patterns).

Normal: intermittent gurgling sounds in all four quadrants. Absent: complete absence of bowel sounds suggests peritoneal irritation or ileus from injury.

Note: absent bowel sounds alone are not specific to serious injury; the combination with tenderness and mechanism is more meaningful.

Palpation

Technique: Begin palpation away from the area of maximum tenderness. Use gentle pressure first, progressing to deeper palpation. Assess all four quadrants.

Findings and their significance:

Tenderness: Pain with palpation. Any abdominal tenderness after trauma is significant. Grade severity: mild (discomfort), moderate (wincing), severe (patient guards or cries out).

Guarding: Involuntary contraction of abdominal muscles when you palpate over an area. The patient cannot voluntarily relax it. This indicates peritoneal irritation — blood or bowel contents in the peritoneal cavity irritating the abdominal lining.

Rigidity: Board-like hardness of the entire abdomen. This is advanced peritoneal irritation. A rigidly hard abdomen means significant intraperitoneal injury.

Rebound tenderness: Press on the abdomen, hold pressure for 2 seconds, then rapidly release. Pain that increases with release (rebound pain) indicates peritoneal irritation. This is a sign of peritonitis.

Right upper quadrant tenderness: Liver injury Left upper quadrant tenderness: Spleen injury Diffuse tenderness with rigidity: Ruptured hollow organ (bowel, stomach) or massive hemorrhage

Percussion

Gentle percussion can detect:

• Tympany (drum-like sound): air — normal in bowel areas, abnormal in solid organ areas
• Dullness: fluid (blood) — dullness in the flanks that shifts with position change suggests free fluid in the peritoneum

Organ-Specific Injury Patterns

Spleen

The most commonly injured solid organ in blunt abdominal trauma.

Location: Left upper quadrant, under the left diaphragm. Injury indicators: Left lower rib fractures, left flank pain, Kehr's sign (referred pain to the left shoulder tip from diaphragmatic irritation by blood), left upper quadrant tenderness.

Splenic injury is dangerous because: The spleen has a rich blood supply and can bleed massively. Some splenic injuries are initially compensated and then rupture hours to days later (delayed splenic rupture).

Implication: A patient with left rib fractures and left upper quadrant tenderness requires evacuation and monitoring even if initially stable — delayed rupture is a real risk.

Liver

The largest solid organ; the most commonly injured organ overall in abdominal trauma.

Location: Right upper quadrant, under the right diaphragm. Injury indicators: Right lower rib fractures, right upper quadrant tenderness, elevated right hemidiaphragm (if visualized on X-ray), hypotension.

Hollow Viscus (Small Bowel, Colon, Stomach)

Mechanism: Seatbelt injuries compress loops of bowel against the spine, causing rupture. Deceleration injuries at the bowel mesentery (connecting tissue) can cause vascular injury.

Signs: Diffuse abdominal tenderness, guarding, increasing pain over hours (as bowel contents leak and peritonitis develops), visible seatbelt mark.

Time course: Initial sign may be subtle. Peritonitis from bowel perforation typically becomes obvious over 3-6 hours as bowel contents spread in the peritoneal cavity.

Retroperitoneal Structures (Kidneys, Great Vessels, Pancreas)

The retroperitoneum is behind the abdominal cavity — injuries here may not produce classic anterior abdominal signs.

Renal injury: Flank pain, hematuria (blood in urine). Check urine after any significant flank trauma. Great vessel injury: Rapid hemodynamic collapse, back pain radiating to abdomen.

Hemorrhagic Shock Assessment

Monitor vital signs sequentially — trending is more important than any single value.

Class I (< 750ml blood loss): Heart rate < 100, normal blood pressure. No obvious signs.

Class II (750-1500ml): Heart rate 100-120, normal systolic BP, diastolic may rise (peripheral vasoconstriction), respiratory rate 20-30, anxiety.

Class III (1500-2000ml): Heart rate 120-140, systolic BP beginning to fall (below 90-100), respiratory rate 30-40, confusion, pale and diaphoretic.

Class IV (> 2000ml): Heart rate > 140, systolic BP < 70, minimal urine output, severely confused or unconscious, pale/ashen, cold/clammy.

The key observation: Blood pressure is maintained until blood loss exceeds approximately 30% of total blood volume (approximately 1500ml in an adult). Earlier signs — rising heart rate, narrowing pulse pressure (systolic-diastolic gap), peripheral vasoconstriction (pale, cool skin, delayed capillary refill), anxiety — are more sensitive.

Capillary refill: Press a fingernail until white, release, count seconds until pink returns. Normal: ≤ 2 seconds. Delayed (> 3 seconds): peripheral vasoconstriction from compensated shock.

Field Management

You cannot treat serious intraabdominal injury in the field. The definitive treatment is surgery. Every intervention is a bridge to the operating room.

Positioning: Supine. Do not give oral fluids (if surgery is needed, an empty stomach is safer; also the patient may not be able to protect their airway). Keep warm — hypothermia worsens coagulopathy and hemorrhage.

Penetrating abdominal wounds: Do not remove impaled objects (stabilize in place with bulky dressings around the object). For evisceration (bowel protruding from wound): cover with moist, clean dressings. Do not attempt to push bowel back in.

IV fluids: Judicious fluid resuscitation for hemorrhagic shock — enough to maintain perfusion pressure (systolic BP 80-90 mmHg for penetrating trauma, 80-90 for blunt trauma), not full restoration of normal BP (which can worsen hemorrhage by increasing pressure against clots that are forming).

Analgesics: Morphine or fentanyl do not "mask" the abdominal exam in a way that changes management decisions in a field setting. Adequate pain control is humane and appropriate. The old teaching that analgesics should be withheld to preserve the exam is obsolete.

Evacuation priority: High priority. Do not delay for secondary assessment or patient stabilization that will not change the evacuation decision. The abdomen that you are monitoring is a bomb — it can detonate rapidly.