Clinical History
A 73-year-old woman was rushed to emergency department because of sudden, severe abdominal pain, with suspicion of rupturing aortic aneurysm. She was dyspnoeic, hypotensive (100/55, 110/min heart rate).
Very limited information was available concerning her medical history and current medications. Left-sided induration and diffuse tenderness were appreciated during abdominal palpation.
Imaging Findings
Urgent biochemistry confirmed blood loss (8.8 g/dL haemoglobin). Some ecchymoses suggested probable recent subcutaneous injections. At further questioning, the lady’s relatives revealed anticoagulation with a low-molecular-weight heparin derivate to prevent thromboembolism following recent immobilisation.
On plain radiographs, bowel gas content appeared predominantly located on the right side, with faintly radio-opaque left hemiabdomen. Resuscitation and blood transfusions were started.
Emergency multidetector CT detected marked enlargement of the left rectus abdominis muscle, with stratified hyperdense appearance and fluid-fluid level (haematocrit sign) suggesting coagulopathic haemorrhage, associated involvement of the ipsilateral oblique muscles and contrast extravasation indicating active arterial bleeding. The entire, huge haematoma and the entity of ongoing bleeding were effectively depicted by multiplanar reformations. CT-angiographic maximum intensity projection (MIP) images identified source of bleeding from the left inferior epigastric artery. Aortic disease, haemoperitoneum, iliopsoas haemorrhage, and parenchymal lesions were excluded.
Unfortunately, she died of haemorrhagic shock during attempt at angiographic embolisation.
Discussion
Widely prescribed to prevent or treat acute and chronic thromboembolic conditions, anticoagulant therapy (AT) is associated with a non-negligible risk of haemorrhagic complications that are increasingly encountered in clinical practice, particularly in elderly individuals with comorbidities [1]. Compared to unfractionated heparin, low-molecular-weight heparins require limited monitoring and are more suitable for treating lower risk conditions and outpatients [2].
Sometimes multicentric, AT-related bleeding may occur in the chest, abdomen, musculoskeletal, or central nervous systems, with a propensity to involve the abdominal wall and iliopsoas muscles. Almost always unilateral, rectus abdominis haematomas may be palpated laterally to the linea alba, and cause variable abdominal pain. Alternatively, they may be identified on urgent imaging studies performed to investigate acute abdomen, shock, or suspected aortic rupture [3-6].
Although the bleeding site is sometimes clinically obvious, physical and laboratory findings are insufficient to assess entity of the haematoma, and presence of ongoing haemorrhage. As this case exemplifies, MDCT represents the mainstay technique to image anti-coagulated patients with suspected iatrogenic bleeding, that can promptly assess presence, site, and extent of haematoma, identify active bleeding, and possible underlying diseases [3-5].
Basically, the CT diagnosis of haematoma relies on the identification of its characteristic unenhanced hyperdensity. Hyperacute blood measures 40-60 Hounsfield Units (HU) attenuation due to high protein content. Hours later, clotted blood becomes even hyperdense (60.80 HU) compared to the normal muscle bellies. The involved muscle may be grossly or moderately enlarged compared to the contralateral one. Meanwhile, haemoglobin lysis leads to a characteristic mixed-density appearance including geographic areas of lower attenuation. The fluid-fluid level ( “haematocrit sign”), corresponding to dependent stratification of denser haematic components, is highly sensitive and specific for coagulopathic haematoma. Multi-planar reformations visualise the haematoma in its entirety and relationship with nearby structures. Contrast extravasation indicating source of active bleeding may be observed [3, 6].
CT directly affects clinical management and duration of hospitalisation in 54% of patients, including detection of additional bleeding sites, and of previously unknown anatomic lesions [4]. Treatment of AT-related haemorrhages is usually conservative, including discontinuation or reduction of medications, blood transfusions, and protamine administration. Interventional embolisation procedures may be performed when MDCT identifies arterial bleeding. Surgical decompression treatment is reserved for compartment syndromes [1, 2, 7].
In conclusion, life-threatening AT-related haemorrhages should not go underestimated. Prompt detection and comprehensive diagnostic assessment with MDCT allows correct therapeutic choice, with the aim to reduce the associated morbidity and mortality [3-5].
Differential Diagnosis List
Spontaneous (iatrogenic) abdominal wall hemorrhage secondary to anticoagulation
Haemoperitoneum
Retroperitoneal / iliopsoas haemorrhage
Rupturing aortic aneurysm
Aortic dissection
Abdominal trauma
Abdominal wall sarcoma
Final Diagnosis
Spontaneous (iatrogenic) abdominal wall hemorrhage secondary to anticoagulation
