SAA is the most common form of visceral artery aneurysm. SAA usually affects women, with a female-to-male ratio of 4:1. More than 80% of the aneurysms are located in the mid or distal splenic artery. The size of splenic aneurysms rarely exceeds 3 cm. Symptomatic aneurysms must be treated
rapidly before rupture. About 22% of reported visceral artery aneurysms present with rupture has 8,5% mortality rate.
Essential hypertension and portal hypertension appear to be significant risk factors for development of splenic artery aneurysm.
Symptomatic splenic artery aneurysms require immediate surgical intervention. Conservation of the spleen is preferable if it is possible.
A 47-year-old woman was admitted to the emergency service because of epigastric and left upper quadrant pain, and
vomiting. The complaints started the previous day following physical strain during washing.
The history revealed rheumatic fever 20 years earlier for which she received aspirin (500 mg/daily) and prophylactic penicillin until one year before admission. Routine blood screening showed white blood cell of 11,100, Hct of 38%, Hgb of 12,2 gr, thrombocytes of 312,000/mm3, liver enzymes with aspartate aminotransaminase of 16 IU/L and amylase of 112 U/L, lipase of 510,7 U/L, the elevated alkaline
phosphatase level was 578 U/L. At physical examination vital signs were stable with a blood pressure of 120/80 mm Hg and a pulse of 76 beats/min.
Ultrasonography showed a cystic lesion measuring
7x6x7 cm in the body of the pancreas. A CT scan of the abdomen demonstrated a cystic lesion measuring 79 x 72 mm with calcification of the cystic wall, located posterior to the body and tail of the pancreas and with anterior displacement of the pancreas and the spleen (fig. 1-2). Colour Doppler ultrasonography showed turbulent movement.
On the second day, while waiting for an arteriogram the patient had a sudden onset of moderate epigastric pain with mild hypotension. The blood pressure was 90/60 mm Hg with a pulse rate of 104 beats/min. Peritoneal lavage revealed intraabominal haemorrhage. The blood pressure further deteriorated to 60/30 mm Hg with a heart rate of 124 beats/min. A preliminary diagnosis of splenic artery aneurysm rupture was made and the patient underwent an emergency laparotomy. At exploration a splenic artery aneurysm measuring approximately 12 cm in diameter with rupture of the superior-posterior wall was found. The aneurysm was opened and the distal and proximal parts of the splenic artery were ligated. The aneurysm was resected with preservation of the spleen.
Postoperatively the patient was evaluated for collagen diseases but all tests were normal and she discharged on the fourth postoperative day. Follow up evaluation by CT scan and ultrasonography showed an intact splenic vein and a normal spleen. The histological examination confirmed a ruptured aneurysm (fig. 3).
In 1770, Beaussier was the first to describe a splenic artery aneurysm (SAA). (1) Visceral artery aneurysms are
relatively uncommon. It is important to recognize and treat them because about 25% present as emergencies and 8.5% result in death. (2) SAA is the most common form of
visceral artery aneurysm (60% of visceral aneurysms),
followed by aneurysms of the superior mesenteric artery (5.5%), the celiac artery (4%), the gastric and gasroepiploic arteries (4%), the jejunal, ileal and colic (3%), the
pancreatico-duodenal and pancreatic arteries (2%), the
gastroduodenal artery (1,5%), and the inferior mesenteric artery (<1%). (2)
SAA usually affects women, with a female-to-male ratio of 4:1. This unusual sex predilection is most likely related to acquired derangements of the arterial wall influenced by a number of processes, including medial fibrodysplasia,
portal hypertension, repeated pregnancy, penetrating or blunt abdominal trauma, pancreatitis, and infection. (3) The mean age of presentation is 52 years (range 2 to 93). (4) Most splenic artery aneurysms are small (less than 2,0 cm), saccular aneurysms. (5) Occasionally, a systolic bruit may be heard. More than 80% of the aneurysms are located in the mid or distal splenic artery. Giant aneurysms of the splenic artery larger than 10 cm are rare. The size of splenic aneurysms rarely exceeds 3 cm. Aneurysms that are often symptomatic because of their size, must be treated rapidly before rupture. (6)
Splenic artery aneurysms are most commonly asymptomatic. Symptomatic patients exhibit vague left upper
quadrant or epigastric discomfort and occasional radiation of pain to the left shoulder or subscapular area. Visceral artery aneurysm presented with rupture has 8,5% mortality rate. The reported risk of rupture of splenic artery aneurysms varies from 3,0% to 9,6%, and rises during
pregnancy up to ³ 20%. (7) The presence of a splenic artery aneurysm in childbearing age represents a serious and potentially life-threatening condition. Of those that do rupture, more than 95% occur in young women
during pregnancy. (8) In pregnant patients, splenic artery aneurysm rupture can be confused with ectopic pregnancy or placental abruption. (9,10)
Essential hypertension and portal hypertension appear to be significant risk factors for development of splenic artery aneurysm. Rupture of splenic artery aneurysm is
associated with a significant mortality, highest among patients with portal hypertension. Elective ligation remains a safe and effective method of treatment. Splenic artery aneurysms should be recognized and electively treated in patients undergoing liver transplantation, especially if the aneurysm is larger than 1.5 cm. (11) The presence and risk of rupture of splenic artery aneurysms may be greater in patients with serum alpha-1 antitrypsin deficiency. Serum alpha-1 antitrypsin deficiency can induce cirrhosis with portal hypertension, and resulting protease-antiprotease imbalances may exaggerate arterial wall weakness due to proteolysis of arterial structural proteins. A reported splenic artery aneurysm, which ruptured 7 days after liver transplantation, provoked a reassessment of the incidence of this phenomenon in a liver transplant population. (12)
Splenic artery aneurysm is reported as an incidental
findings in 0,78% of arteriograms and can be found in 0,1% to 10,4% of autopsies. They can be discovered on the
abdominal roentgenogram as signet-ring-appearing or egg shelf-appearing calcification in the left upper quadrant. Although calcification of the aneurysm has traditionally been described as a clinical marker for an increased risk of rupture, this has never been shown conclusively. Ultrasonography, CT of the abdomen with IV contrast, and MRI scan can
distinguish aneurysms from other cystic lesions in the left upper quadrant. (13) Splenic arteriography has been the gold standard of diagnosis. In pregnancy, however, ultrasonography and pulsed-wave Doppler ultrasonography are more favourable.
The differential diagnosis in a pregnant patient with a rupture of the splenic artery aneurysm would include a
ruptured ectopic pregnancy (depending on the gestational age), placental abruption, uterine rupture, or even normal labour. (4) Conversely, this diagnosis should be considered in any pregnant patient who presents with acute abdominal pain and fetal compromise. The differential diagnosis for an
elderly person with a ruptured splenic artery aneurysm would encompass an acute myocardial infarction. Abdominal aortic aneurysm, acute pancreatitis, peptic ulcer disease (with
possible perforation), biliary colic, renal colic or mesenteric ischemia are other diagnosis in differentiation. Erosion of the aneurysm into the stomach can present as an upper gastro-intestinal bleed. (8)
Symptomatic splenic artery aneurysms require immediate surgical intervention. Conservation of the spleen is preferable whenever is technically possible, in view of the implications of operative and long-term infectious morbidity. Transcatheter embolization has been successfully performed in some patients and is an alternative to surgery. (14) A splenic artery aneurysm in a woman of childbearing age or a pregnant patient should be treated electively because of the increased risk of rupture during pregnancy and its associated high
mortality rate. The elective operative mortality rate ranges between 0.5% and 1.3%. Symptomatic splenic artery aneurysms require immediate operative intervention, particularly in pregnant women or in women of childbearing age. Maternal mortality from rupture during pregnancy is
approximately 70%. The clinical presentation of abdominal pain, hypotension and anaemia can mimic uterine rupture or abruptio placenta. An emergency caesarean section and splenectomy are necessary. (15)
Laparoscopic approach to splenic artery aneurysm by aneurysmectomy or splenic artery ligation has been applied. (16) A case of splenic artery aneurysm treated with stent-graft has been reported. This method preserves the blood flow to the spleen. (17) Interventional coil and gel foam occlusion are other methods for treatment of aneurysms of the splenic artery. (18)
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