## Distinguishing Ruptured from Contained AAA ### Key Clinical Discriminator **High-Yield:** Hemodynamic instability refractory to initial fluid resuscitation is the hallmark of rupture and the single best discriminator between rupture and contained expansion. Ruptured AAA causes massive retroperitoneal or intraperitoneal hemorrhage leading to shock; contained AAA may present with pain and mild hypotension but typically responds to fluid resuscitation. ### Comparison Table | Feature | Ruptured AAA | Contained (Expanding) AAA | |---------|-------------|------------------------| | **Hemodynamics** | Profound shock, refractory to fluids | Mild–moderate hypotension, fluid-responsive | | **Pulsatile mass** | May or may not be palpable | Usually palpable | | **Pain severity** | Sudden, catastrophic | Acute but less explosive | | **Mortality** | 50–80% (untreated >90%) | ~10–20% if managed | | **Imaging findings** | Free blood in peritoneum/retroperitoneum | Contained hematoma, no free fluid | ### Clinical Pearl **Key Point:** A ruptured AAA is a surgical emergency. The patient's response to aggressive fluid resuscitation is more discriminating than the presence of pain or a palpable mass, because both rupture and contained expansion present with severe pain and a palpable pulsatile mass. However, rupture causes hemorrhagic shock that does NOT respond adequately to fluids alone, necessitating immediate operative intervention. ### Pathophysiology Rupture allows uncontrolled bleeding into the peritoneal cavity or retroperitoneum, causing rapid hypovolemic shock. A contained rupture is temporarily sealed by surrounding fascia and hematoma, allowing some hemodynamic stability but still requiring urgent surgery. [cite:Robbins 10e Ch 11]
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