bubble_chart Overview

Hemorrhage in the retroperitoneal space is one of the severe complications of abdominal injury. Due to its frequent masking by injuries to intra-abdominal organs or other areas (such as the brain, chest, spine, limbs, and pelvis), it is prone to misdiagnosis, making diagnosis challenging. Severe cases can be life-threatening, with reported mortality rates as high as 42%.

bubble_chart Etiology

Retroperitoneal hemorrhage can occur suddenly, such as arterial bleeding, which can form a hematoma that compresses retroperitoneal tissues, diffuses between the mesentery, enters the retroperitoneal space of the pelvis, or enters the peritoneal cavity. If the bleeding occurs slowly, it may stop spontaneously and be absorbed. However, if blood remains in the retroperitoneum for an extended period, it may organize into fibrous masses or even calcify. Since blood contains nutrients, the risk of infection is high.

Retroperitoneal hemorrhage is commonly seen in complex abdominal injuries, accounting for two-thirds of retroperitoneal hemorrhages. The main causes include:

1. Blunt trauma: Retroperitoneal space injuries accompanied by rupture of the liver, spleen, kidneys, adrenal glands, pancreas, duodenum, or their blood vessels; pelvic fractures with injuries to the rectum, bladder, or ureters; abdominal blunt contusions, pelvic fractures, and direct or indirect injuries to retroperitoneal blood vessels and their branches.

2. Penetrating trauma: Gunshot or shrapnel wounds; stab wounds from knives or sharp objects; puncture wounds from fractured bone fragments. Retroperitoneal hemorrhage can also result from pathological damage and bleeding of retroperitoneal organs, including: a. Hemorrhagic necrotizing pancreatitis; b. Hemorrhagic disorders, such as hemophilia, leukemia, or hypersplenism, where impaired coagulation due to various causes may lead to retroperitoneal bleeding; c. Impaired coagulation due to anticoagulant therapy; d. Surgical procedures in the retroperitoneal region; e. Others: Retroperitoneal tumors, hemangiomas, nodular polyarteritis, and spontaneous retroperitoneal vascular rupture (abdominal apoplexy).

bubble_chart Pathological Changes

Since the retroperitoneal space consists of loose connective tissue, bleeding episodes are often sudden, with hematomas rapidly and extensively infiltrating to form massive hematomas. Systemic reactions may include a drop in blood pressure or even shock. The retroperitoneal tissue is compressed, and the hematoma can spread along the posterior abdominal wall and between the mesenteries, or it may rupture into the abdominal cavity. If the bleeding occurs slowly or stops spontaneously, it may form an encapsulated or localized hematoma. Eventually, the center may liquefy or undergo fibrosis and organization, while smaller hematomas can be absorbed.

bubble_chart Clinical Manifestations

The clinical manifestations depend on the speed and volume of bleeding, the underlying cause, the location of occurrence, and the organs involved. If the bleeding is minimal and localized, it is difficult to have fixed typical manifestations, especially when complicated by combined injuries, where the symptoms are more easily masked.

Most patients with this condition progress rapidly, developing symptoms within hours or days, while a few have a clinically occult course, presenting with anemia and masses only later.

The main symptom is abdominal pain, which is the earliest and most common symptom, varying in severity and possibly localized or diffuse. The pain may occur in the abdomen, flank, lumbar region, or even the back or sacroiliac area, sometimes relieved by squatting. Other common symptoms include nausea, vomiting, constipation or grade I diarrhea, decreased borborygmi, abdominal distension and fullness, and paralytic ileus. Severe cases may be accompanied by hemorrhagic shock and severe anemia. Blood loss and stimulation of the retroperitoneal nerves can cause sweating, palpitations, hypotension, syncope, or even shock. Some patients may experience transient fever. As the condition progresses, paralytic ileus may develop. Compression of the mesenteric vessels by a hematoma can lead to necrosis of localized intestinal loops. Compression of nerves by the hematoma may cause lower limb neuropathic pain, numbness, or even functional impairment. The hematoma may affect the celiac plexus, leading to autonomic dysfunction, resulting in impaired gastrointestinal and urinary tract motility and excretory functions.

Abdominal examination may reveal localized tenderness, and sometimes a mass or fullness may be palpable in the abdomen, flank, or lumbar region, usually with no or only grade I abdominal muscle tension. If the hematoma ruptures into the abdominal cavity or is accompanied by intra-abdominal organ injury, paralytic ileus may occur. In cases of severe pulsatile bleeding, the mass may rapidly enlarge and even exhibit pulsation. Ecchymosis may appear on the skin near the bleeding site, such as the lumbar region, abdominal wall, or scrotum. Rupture of the hematoma into the abdominal cavity often leads to shock and peritoneal irritation signs. There are occasional reports of femoral nerve involvement, presenting with quadriceps weakness and loss of the patellar reflex.

bubble_chart Auxiliary Examination

1. Plain X-ray or double-contrast radiography can reveal some lesions that may cause retroperitoneal hemorrhage, such as fractures, abdominal aortic aneurysms, urinary or gastrointestinal diseases, blurred psoas muscle contours, and partial interruption of the margins.

2. B-mode ultrasound can detect hematomas and abdominal aortic aneurysms, but distinguishing hematomas from abscesses and other abdominal fluid masses (such as urine) is often challenging.

3. CT scans can more clearly show the relationship between hemorrhagic hematomas and other tissues. An increase in attenuation value during contrast-enhanced scanning is evidence of active bleeding.

4. Angiography and isotope scanning can indicate the location of bleeding.

5. Aspiration under B-mode ultrasound or CT guidance can confirm the diagnosis.

6. Laboratory tests: In the initial stage [first stage], white blood cell counts may be slightly elevated or normal, while red blood cells and hemoglobin may decrease. In the late stage [third stage], white blood cell counts are significantly increased, with elevated neutrophils. In cases of pancreatic injury, both serum and urinary amylase levels are elevated. Renal contusions or lacerations may present with hematuria and proteinuria.

bubble_chart Diagnosis

The misdiagnosis rate of retroperitoneal hemorrhage is relatively high, mainly due to insufficient understanding of intra-abdominal organ injuries complicated by retroperitoneal bleeding. Attention is often focused solely on diagnosing splenic rupture or pelvic fractures, while overlooking retroperitoneal injuries. Diagnosis is primarily based on abdominal trauma (location, severity of force, and other medical history) and typical symptoms and signs, combined with B-mode ultrasound, abdominal CT, and X-ray plain films. If necessary, excretory urography or selective angiography can be performed.

bubble_chart Treatment Measures

The treatment principles depend on whether there is combined injury to the intra-abdominal organs, the integrity of the peritoneum in front of the hematoma, and the location of the hematoma. The hematoma may be classified as stable, expanding, or pulsatile.

1. Non-surgical Treatment

Patients with stable conditions, no obvious symptoms, or grade I symptoms, or those whose blood pressure and pulse stabilize after fluid and blood transfusion do not require surgery. Treatment methods and principles include: ① Active and rational use of antibiotics to prevent infection; ② Rational use of hemostatic medications. If caused by anticoagulant therapy, discontinue anticoagulants and administer blockers; ③ For significant blood loss, timely blood transfusion to effectively replenish blood volume and correct shock; ④ For concurrent intestinal paralysis, fasting, gastrointestinal decompression, or the use of Chinese medicinals may be employed, such as the purgative method with Composite Major Purgative Decoction modified and administered via gastric tube.

2. Surgical Therapy

Indications for surgery include: ① Persistent blood loss caused by pelvic fracture or intra-abdominal injury; ② Hematoma with open penetrating wounds around the perineum or anus; ③ Confirmed or suspected injury to major or medium-sized blood vessels; ④ Concurrent severe injury to solid or hollow intra-abdominal organs; ⑤ Penetrating injury with significant blood loss and peritoneal inflammation. Early surgery is warranted in these cases.

1. Retroperitoneal hemorrhage occurring during pregnancy or childbirth is generally severe. In addition to immediate blood transfusion, cesarean section is often required.

2. For retroperitoneal hematoma following penetrating injury, surgical treatment is indicated. For blunt injury, conservative treatment is preferred initially, including close observation, bed rest, blood transfusion, and fluid-electrolyte replacement to maintain balance. If blood pressure remains unstable and organ injury or rupture is present, surgical intervention is advisable.

3. Spontaneous retroperitoneal hemorrhage (often associated with renal or adrenal diseases) usually requires surgical treatment. Encapsulated retroperitoneal hematomas may be treated with simple drainage or surgical excision.

bubble_chart Prognosis

It depends on the speed, amount, cause, and timing of detection. The mortality rate of a ruptured main stirred pulse is very high. Pregnancy combined with posterior membrane hemorrhage poses serious risks to both mother and child. The prognosis is better for bleeding caused by other reasons.

bubble_chart Complications

Complications include hemorrhagic shock, paralytic ileus, thrombophlebitis of the lower extremities, and acute renal failure.