splenic artery aneurysm

Introduction

rare cause of abdominal pain and may be the result of arterial or venous occlusion
often is the presenting complaint of an underlying condition
usually in a person with an underlying hematologic disorder (eg. sickle cell disease (SCD)), hypercoagulable state, blood-borne malignancy causing splenomegaly, blunt abdominal trauma, pancreatitis, compressive pancreatic masses, or embolic illness.
1/3rd have splenomegaly; 1/3rd have a fever; over half have a raised WCC; over 2/3rds have raised LDH;
splenic artery aneurysm with distended thin wall and impending rupture
rare, but a condition to consider in 2nd or 3rd TM of pregnancy, portal hypertension, liver transplant, pancreatitis, hypertension, atherosclerosis, Marfans, trauma, large vessel vasculitis, etc
prevalence of splenic artery aneurysm is 0.04% to 0.10% at arteriography and autopsy
78% are in women ¹⁾
- 50% of those that occur in pregnant women will rupture during pregnancy! Two-thirds of SAA rupture in the third trimester and typically in the last two weeks of pregnancy. ²⁾
accounts for about 60% of visceral arterial aneurysms (remainder are mainly renal artery aneurysms)

may present with episodic LUQ pains often lasting 24hrs +/- radiation to L shoulder
may be detected as a cystic mass near the pancreas on US if not obese, or CTKUB
may present after rupture with hypovolaemic shock, abdo/chest pain and positive FAST USS

early diagnosis with contrast CT is critical to manage prior to rupture
risk of rupture is 2% to 10% (much higher in pregnant patients)
intervention prior to rupture is usually recommended if either:
- aneurysm size larger than 2 or 2.5 cm
- growth of the aneurysm by 3 to 5 mm or more during surveillance regardless of initial size
- symptomatic
- women of childbearing age
- portal hypertension
- planned liver transplant
mortality of intervention options is said to be ~1% ³⁾
- complications of intervention include postembolization syndrome, splenic infarction or abscess, and pancreatitis

ruptured splenic artery aneurysm - this may be rapidly fatal mortality is over 25% (maternal mortality due to SAA rupture increases up to 75%, and fetal mortality increases as high as 95%)
- usually present in hypovolaemic shock with abdominal or chest pain and positive FAST US (DDx ruptured ectopic or spleen), but may also have haematuria
- patients in shock needing massive blood transfusion to keep alive should probably go straight to theatre for surgical intervention rather than radiologic intervention

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