Rectus sheath hematoma is accumulation of blood in the sheath of rectus abdominis muscle due to disruption of epigastric vessels or rectus muscle 1. Although the etiology includes trauma, abdominal operations, trocar site injury after laparoscopic operations, subcutaneous drug injections, anticoagulant therapy, hematological diseases, hypertension, coughing, physical exercise, pregnancy, it rarely occurs spontaneously 12345. It usually occurs in the lower quadrants of the abdominal wall and almost never crosses the midline 126. Hematoma below the linea semicircularis causes an indirect irritation on the peritoneum due to weak posterior rectus sheath in this region leading to misdiagnoses as acute abdomen 12.

Three consecutive cases presenting to our Emergency Department in the past 2 months are reported in this paper regarding the accurate diagnosis and management.

Rectus sheath hematoma (RSH) is a rarely seen but important disease causing abdominal pain. There is a female predominance as may be explained by larger rectus muscle mass in man 7. All three of our patients were also female. There are various causes resulting in RSH as abdominal trauma, previous surgery, coughing, streching, hypertension, intraabdominal injections, iatrogenic causes during laparoscopy and anticoagulation therapy 89. In the abdominal wall below the arcuate line there's only transversalis fascia between peritoneum and posterior rectus sheath, therefore rupture of epigastric vessels or muscle within this sheath causes a hematoma mimicking acute abdomen 2. Common presenting signs and syptoms are abdominal pain, abdominal wall mass, decrease in hemoglobin, abdominal wall ecchymosis, nausea, vomiting, tachycardia, peritoneal irritation, fever, abdominal distention and abdominal cramping 7.

Fothergill's sign and Carnett sign are positive in rectus sheath hematoma, and helps to differentiate this condition from intraabdominal pathologies 1246. Fothergill' sign is positive when the haematoma within the rectus sheath produces a mass that does not cross the midline and remains palpable when the patient tenses his rectus muscle by touching his chest using his chin 4. Carnett sign is exacerbation of the pain and tenderness over the hematoma by contraction of rectus muscle by sitting halfway up in a supine position 2. Both of these tests were positive in three of our patients. Echymosis on the abdomen may occur late in the follow up period. The ecchymosis may be seen in the flanks or periumblical region causing Grey Turner's and Cullen's sign 46.

Misdiagnosis may lead to unnecessary negative laparotomies with increase in morbidity and mortality 10. US, CT and magnetic resonance imaging are widely used in the diagnosis. Although US seems to be the procedure of choice due to its high sensitivity rates, time and cost effectivity and low radiation in some series, however sometimes it is difficult to differentiate intraperitoneal lesions from extraperitoneal lesions by US as the technique is subject to error by means of probe induced tenderness and limitations of interpretation of the images 6. This was the case in the first two cases as the ultrasonographers identified the hematomas as "intraperitoneal". CT is superior to US in localisation, extension and evaluation of the size of the hematoma. Moreover CT imaging can give the classification of the hematoma. According to the CT classification, Type I hematomas are mild and the hematoma occurrs within the muscle with an increas in muscle length and do not require hospitalization. Type II hematomas are moderate, the hematoma is within the muscle but bleeding occurs into the space between transversalis fascia and the muscle. Type III hematomas are severe and located between transversalis fascia and the muscle, anterior to the peritoneum and urinary bladder. Type II and III hematomas require hospitalization. In Type I hematomas hospitalisation is not usually required and the hematoma resorbs spontaneously within 30 days. In Type II lesions bed rest, intravenous fluid replacement and analgesia is the appropriate treatment. In Type III lesions additional blood product transfusions are required. These kind of hematomas resorb approximately in 3 months 411. All three of our cases were Type II.

Conservative treatment is the mainstay of management in hemodynamically stable patients with non expanding hematoma 146. In cases with failure of conservative treatment, surgical approach can be chosen but the mortality rates of surgery for rectus sheath hematoma is high. Coil embolisation can be an alternative in high risk patients refractory to conservative therapy 14.

Rectus sheath hematoma is a rarely seen entity often misdiagnosed as acute abdomen. Prompt history taking with careful physical examination and appropriate imaging studies help the correct diagnosis avoiding unnecessary laparotomies. CT seems to be the most appropriate choice of imaging. Management is conservative in most cases including bed rest, analgesia, intravenous fluid replacement and blood transfusions when necessary.

The author(s) declare that they have no competing interests.

SK was involved in the management of the patient as well as writing the case reports. HA and MUK were involved in the management of the patients. ANT and EA has been involved in the correction of the manuscript as well as general supervision. SH and HY were involved in the design of the study and helped to draft the manuscript. All authors read and approved the final manuscript.

Written informed consent was obtained from the patients for publication of this study.