To the Editor: Low-molecular-weight heparin (LMWH) has numerous indications in inpatient and outpatient settings. These medications can cause bleeding complications, including abdominal wall hematomas, which occur in 5% of individuals receiving prophylactic doses and in 10% receiving therapeutic doses. The risk of bleeding increases in the elderly population, can range from minor hematomas to major hemorrhage, and can cause serious complications. This review of the literature retrieved 30 case reports of rectus sheath hematomas secondary to LMWH injections. Two more cases seen within the past year are also reported. A 70-year-old woman was admitted for “urinary retention,” tachycardia, and abdominal pain. Her home medications included enoxaparin and warfarin. She was diagnosed with abdominal wall hematoma complicated with abdominal compartment syndrome. She required surgical intervention and was eventually discharged. An 88-year-old woman was admitted for treatment of an exacerbation of chronic obstructive pulmonary disease and a possible pulmonary embolism. She was placed on full-dose enoxaparin and developed an abdominal wall hematoma complicated with shock and acute kidney injury. She was treated conservatively and discharged but was readmitted 3 months later for surgical removal of the hematoma. Articles that had been published from inception of Medline to June 2010 were reviewed. The search included the Medical Subject Headings terms “abdominal wall” or “abdomen rectus muscles” AND “hematomas” AND “enoxaparin” or “heparin, low molecular weight.” Text words included “abdominal wall hematomas” and “rectus sheath hematomas.” Language was initially restricted to English, but eventually one article in French and one in German were included. Other limiters included aged 19 and older and humans only. Thirty-two cases were found; 86% were female (Table 1). The mean age was 72, and 78% of the participants were aged 65 and older. Therapeutic doses were given to 21 participants, prophylactic doses to four, and uncertain doses to seven. The indications for LMWH were atrial fibrillation, pulmonary embolus, acute coronary syndrome, deep venous thrombosis, myocardial infarction, cardiac catheterization, unstable angina pectoris, and subclavian thrombosis. All 32 participants had comorbid conditions. The most common diagnostic imaging study used was computed tomography. Complications included shock, acute kidney injury, respiratory failure, abdominal compartment syndrome, peritoneal bleeding, and arrhythmia. Eleven participants were treated with conservative medical care, four with epigastric artery embolization and ligation, and 11 with surgery. Only four participants died, and 11 had no outcome reported. Damage to the superior or inferior epigastric arteries and their branches or direct damage to abdominal wall muscles cause most hematomas associated with LMWH injections.1 Precipitating factors include poor injection technique, trauma, and abdominal wall straining. Risk is also greater with older age, after surgical procedures, in individuals taking other antiplatelet or anticoagulants, and in pregnancy.1,2 Women are more prone to hematoma formation because they have less muscle mass and more-flaccid abdominal walls from prior pregnancy.3–5 People with renal insufficiency have greater therapeutic effect from impaired clearance and are at a higher risk of bleeding.1,6 Clinical manifestations include abdominal wall ecchymosis, abdominal pain, Fothergill sign (a tender mass that does not cross the midline and remains palpable when the individual tenses the rectus muscle), positive Carnett's test (tenderness persists with head elevation, whereas pain from intraperitoneal disease decreases), and decrease in hemoglobin.1,2,3,6,7 The diagnosis is made by ultrasound or computed tomography.2,3,8 A combination of poor abdominal wall compliance, greater abdominal content, multiple transfusions, and large volume fluid resuscitation puts people at risk for intra-abdominal hypertension and abdominal compartment syndrome.9 Other complications include obstructive uropathy, compression of urinary bladder, hydronephrosis, hemorrhagic shock, myocardial infarction, muscle necrosis, and death.5,9 The treatment of choice is conservative,1,3,8 with fluid resuscitation, reversal of anticoagulation, administration of vitamin K and factor replacement, and pain control.2,3 Spontaneous resolution of hematomas can take up to several months and carries the risk of infection of the hematoma. Surgical intervention is recommended in individuals with hemodynamic compromise.7 Endovascular embolization of the bleeding vessels is an alternative to surgical management if the individual is too unstable.3,10 The risk of hematoma formation is greater in older women, in those using concomitant anticoagulation or antiplatelet medications, and in people with renal insufficiency or abdominal straining (cough). Older adults should be monitored closely if LMWH is indicated, with attention to early signs of abdominal wall hematoma. The overall mortality rate is low, but the complications are potentially serious in high-risk individuals. Conflict of Interest: The editor in chief has reviewed the conflict of interest checklist provided by the authors and has determined that the authors have no financial or any other kind of personal conflicts with this paper. Author Contributions: Nourbakhsh: project design, literature review, manuscript preparation, final approval of manuscript. Anvari: literature review, manuscript preparation, final approval of manuscript. Nugent: project design, manuscript preparation, final approval of manuscript. Sponsor's Role: None.
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Open Access
Jan 1, 2013
Mohammadali Amirzargar + 8
