Aneurysm and infarction

Aneurysm of the splenic artery

This is an uncommon condition; estimates of its incidence at post-mortem examination vary between 0.04 and 1 per cent. Whereas aneurysms of other arteries are more common in men, in the splenic artery they are about twice as common in women. They are usually single and situated in the main trunk of the splenic artery (Fig. 53.3), but more than one are found in a quarter of cases.

The aneurysm is symptomless unless it ruptures. Occasionally it is palpable in the epigastrium or associated with a bruit over the left hypochondrium. It may be discovered accidentally, on plain radiograph of the upper abdomen, as a calcified ring situated to the left of the first lumbar vertebra. Rupture of the aneurysm is unsuspected in about half of all cases; it bursts into the peritoneal cavity and the symptoms resemble those of splenic rupture. Nearly half of all cases of rupture occur in patients less than 45 years of age, and a quarter of all cases are in pregnant women (usually in the third trimester of pregnancy or actually in labour).

The treatment of choice is splenectomy and removal of the length of artery bearing the aneurysm. If the aneurysm has eroded into the pancreas or is close to the origin of the splenic artery, then proximal and distal ligation of the sac is usually followed by thrombosis in the aneurysm. In younger patients, particularly women, with an asymptomatic splenic artery aneurysm, surgery is indicated after the diagnosis has been confirmed by selective coeliac arteriography. The maternal mortality rate for surgery at the time of rupture, in late pregnancy, is over 70 per cent. In elderly patients, particularly men, where an asymptomatic calcified aneurysm is detected on plain radiograph, there is less risk of rupture and surgery is not indicated.

Infarction of the spleen (Fig. 53.4)

This occurs in patients with massive spleens resulting from myeloproliferative syndrome, or with vascular occlusion produced by sickle cell disease or an embolus from an infected heart valve in bacterial endocarditis. The infarct may be asymptomatic or may cause left upper quadrant abdominal pain radiating to the left shoulder with splinting of the hemidiaphragm and guarding and, at times, a friction rub may he heard over the splenic area. Sedation and bed rest are sufficient except rarely when a septic infarct causes an abscess necessitating splenectomy.