Spontaneous intestinal intramural hematoma is a rare complication under anticoagulant therapy. Better et al. reported an incidence of 1 in 2,500 patients receiving warfarin . The incidence is higher in males and the average age at presentation is 57.6 years .
Because of the rarity of spontaneous intramural small-bowel hematoma, there are only case reports dealing with this clinical entity. The largest series included 13 patients, of whom 8 received oral anticoagulation .
Intramural small-bowel hematoma may arise spontaneously or after trauma. Blunt abdominal trauma is by far the most common etiologic factor for duodenal hematoma.
The relatively fixed retroperitoneal position of the duodenum and its close anterior relationship to the lumbar spine renders it susceptible to blunt trauma of a crushing type and accounts for the higher incidence of duodenal involvement in this situation .
This condition involves mainly children, and the trauma is frequently insignificant and forgotten by the patient. The weak abdominal muscles and the high costal margin contribute to the susceptibility of children to intramural duodenal hematoma .
Over-anticoagulation with warfarin is the most common cause of spontaneous intramural small-bowel hematoma in adults. In addition to excessive anticoagulation, this condition has also been described as a complication of bleeding disorders, malignancies, and vasculitis .
Excessive anticoagulation with an INR greater than 6 was associated with developing this rare complication in our 3 patients, who all received phenprocoumon because of chronic atrial fibrillation.
Although spontaneous intramural small-bowel hematoma might be expected to occur with over-anticoagulation by heparin, we found only one case report describing this complication in a child who received therapeutic doses of low-molecular-weight heparin because of deep venous thrombosis .
The small bowel is affected in up to 85% of cases of spontaneous intramural gastrointestinal tract hematoma in patients under anticoagulation. Nevertheless, it remains unclear why the jejunum is the site of predilection for spontaneous hematoma.
Bleeding originates in the submucosa from small vessels. Some authors speculate that the progression of the symptoms is due to an intramural osmotic gradient caused by the hematoma, leading to expansion of the intestinal wall .
Small-bowel hematomas can extend into the colon; however, isolated cases are very rare. It has been hypothesized that the taeniae coli may play a protective role against the initiation or expansion of the hemorrhage .
The spectrum of presentation is wide and can vary from mild, vague abdominal pain to intestinal obstruction and an acute abdomen. Nausea and vomiting are found in half of the cases and are related to high intestinal obstruction involving the duodenum and proximal jejunum.
Patients may also present with gastrointestinal hemorrhage as a result of ruptured hematoma. However, obvious bleeding is present in less than half of the cases and cannot be relied upon as a diagnostic criterion . Signs of peritoneal irritation may be present in some cases and usually indicate the development of complications, such as necrosis, perforation, or hemoperitoneum.
The average time from the appearance of symptoms until medical attendance is 2.5 days. The duration of anticoagulation therapy is 25.4 months on average .
In the largest reported series of spontaneous small-bowel hematoma involving13 patients, the mean age of presentation was 64 years. Small-bowel obstruction was present in 85% of the patients, and the jejunum was the most common site of the hematoma, followed by the ileum and duodenum. All patients presented with abdominal pain. The mean INR at presentation was 11.6 .
In our patients, the mean age of presentation was 79 years and the average time from the beginning of symptoms until seeking medical help at the emergency department was 2.5 days. The jejunum was affected in two cases and the duodenum in one case. Abdominal pain was the leading symptom at presentation in all patients. All patients were under long-term anticoagulant therapy because of chronic atrial fibrillation with an INR greater than 6.
CT is the key for diagnosis of this condition. Some authors have suggested that noncontrast CT should be performed before oral and intravenous contrast medium application, as contrast-enhanced CT alone may mask the presence of intramural hemorrhage . Characteristic findings on CT include circumferential wall thickening, intramural hyperdensity, luminal narrowing, and intestinal obstruction [7, 15].
The sonographic appearance of acute intramural small-bowel hematoma consists of a thickened intestinal wall involving mainly the submucosal layer. However, this abnormality is not specific for intestinal tract hematomas and can be seen in a wide spectrum of disorders [1, 16].
The involved bowel segments appear longer in spontaneous hematomas than in traumatic hematomas with an average length of 23 cm [7, 8].
The combination of CT and US can show the exact pathology in all patients, as demonstrated by some authors .
Wall thickening on CT may be also found in other conditions, including malignancy and inflammatory and ischemic bowel disease. However, in contrast to the latter, complete normalization of the imaging findings usually occurs within 2 months after the onset of symptoms.
In all three cases described in this paper, CT (contrast-enhanced CT in two cases and noncontrast CT in one case due to renal impairment) demonstrated circumferential wall thickening and luminal narrowing. The estimated length of the affected jejunal segment was 25 cm in one case and 20 cm in the other.
Sonography was performed in two cases and showed heterogeneous thickening of the intestinal wall.
The MRI characteristics of duodenal hematoma include a well-defined concentric ring of high signal intensity (ring sign) in the subacute bleeding. The unique MRI tissue characteristics (ring with short T1 and long T2 relaxation time) are attributable to the paramagnetic properties of iron in the hemoglobin degradation products within the hematoma .
However, no data are available on the imaging characteristics of small-bowel hematomas other than those that occur in the duodenum.
In case one described in this paper, the “ring sign” was detected on MRI, a finding which helped established the diagnosis of duodenal hematoma.
With the help of pull and push enteroscopy, deep small-bowel lesions can be visualized . However, the role of endoscopy in the diagnosis of intramural hematoma is not well established, as almost all cases are diagnosed “noninvasively” with CT and US. Nevertheless, endoscopy may play a therapeutic role, as shown by Kwon et al. , who have successfully treated a duodenal hematoma with a needle-knife incision relieving obstructive symptoms.
Owing to the rarity of this entity, there are no studies that contain sufficient evidence to standardize treatment.
The first step in the treatment of acute intramural small-bowel hematoma is discontinuation of the anticoagulant medication and correction of coagulation parameters with vitamin K.
Conservative treatment usually leads to improvement of symptoms within 4–6 days. Complete resolution usually occurs within 2 months after the onset, because the hemorrhagic bowel is not necrotic and complete restitution occurs in almost all cases under conservative management [14, 21, 22].
It appears safe to resume anticoagulant therapy in patients after resolution of the hematoma as long as it is administered within the therapeutic range. Neither recurrence of intestinal obstruction or hematoma nor long-term sequelae were observed in this group .
Laparotomy is not indicated in uncomplicated intramural hematoma of the small bowel. Surgical exploration is reserved for cases with uncertain diagnosis or late complications, which include intra-abdominal hemorrhage, suspected ischemia, perforation, peritonitis, and intestinal obstruction not responding to conservative strategies [9, 10, 14, 22].
Two of our three patients were successfully treated conservatively. In the third case, laparotomy was performed owing to worsening of symptoms and signs of peritoneal irritation. In this case, complicating intestinal necrosis indicated resection of the affected hemorrhagic segment.