Retroperitoneal Haemorrhage

Retroperitoneal haemorrhage is bleeding into the retroperitoneal space, from trauma or spontaneously, that can accumulate large volumes without early external signs. Delay in recognition raises mortality.

Epidemiology. Spontaneous bleeds mostly occur in anticoagulated or coagulopathic older adults. Iatrogenic bleeds follow femoral arterial puncture and cardiac catheterisation (about 0.1 to 0.5% of procedures).

Causes and associations.

• Trauma: pelvic fracture, renal, adrenal and pancreatic injuries, great vessel and lumbar vessel injury.
• Spontaneous: ruptured aortic aneurysm, renal angiomyolipoma, renal tumour, adrenal haemorrhage, ruptured visceral artery aneurysm, vasculitis (polyarteritis nodosa) and anticoagulant or thrombolytic therapy.
• Iatrogenic: femoral puncture high over the inguinal ligament, nephrostomy, biopsy and surgery.

Pathophysiology. The retroperitoneum is distensible and holds many litres. Bleeding can be tamponaded in a contained space, but pressure effects on organs, nerves (femoral neuropathy) and the abdominal compartment add morbidity.

Presentation is flank, back, groin or lower abdominal pain, shock, falling haemoglobin, flank or groin bruising (Grey Turner or Cullen sign, late), ileus, hip flexion contracture with femoral neuropathy, and haematuria. Anticoagulated patients may have little pain.

Red flags.

• Hypotension or unexplained fall in haemoglobin.
• Anticoagulant therapy or recent femoral puncture.
• Known aortic aneurysm.

CT with arterial and portal venous phases (active extravasation, haematoma, source). Ultrasound may miss the bleed. Check full blood count, coagulation, fibrinogen, group and crossmatch, creatinine and anticoagulant activity.

Differential diagnosis. Intraperitoneal bleeding, psoas abscess, renal colic, aortic dissection and pancreatitis.

Resuscitation. Large bore access, balanced transfusion (1 red cell unit to 1 plasma to 1 platelet pool), permissive hypotension (systolic 80 to 90 mmHg) until control, warming and calcium. Tranexamic acid 1 g IV over 10 minutes then 1 g over 8 hours in trauma.

Reverse anticoagulation.

• Unfractionated heparin: protamine 1 mg for each 100 units given in the last 2 to 3 hours (maximum 50 mg).
• Enoxaparin: protamine 1 mg for each 1 mg of enoxaparin if given within 8 hours (0.5 mg for each 1 mg for 8 to 12 hours), maximum 50 mg.
• Warfarin: prothrombin complex concentrate 25 to 50 units/kg and vitamin K 10 mg IV.
• Dabigatran: idarucizumab 5 g IV. Factor Xa inhibitors: prothrombin complex concentrate 50 units/kg (maximum 5000 units), or the specific reversal agent.

Control of bleeding.

• Angioembolisation for active arterial bleeding in stable and borderline patients.
• Surgery for instability that does not respond, an expanding haematoma with a compartment effect or aortic rupture (open or endovascular repair).
• Pelvic and renal bleeding managed with packing or embolisation.

Femoral neuropathy. Early decompression if progressive.

Monitoring. Haemoglobin every 4 to 6 hours, vital signs, lactate, coagulation, bladder pressure for abdominal compartment syndrome and neurovascular status.

Referral and escalation. Surgery, interventional radiology and intensive care at once.

Special groups. In pregnancy, give the same treatment with obstetric input. Resume anticoagulation only after bleeding is controlled and the benefit is clear.