Aortitis

An obese 61-year-old man who had chronic obstructive pulmonary disease and sleep apnea heard a “pop” in his stomach while lifting a heavy weight; severe abdominal pain followed. He was short of breath the next morning, and his physician empirically prescribed cephalexin.

The patient became confused about 7 hours later and was taken to the emergency department; at this time he was lethargic and had a temperature of 38.3°C (101°F). Examination disclosed bilateral wheezes, rales at the lung bases, and paraumbilical and left upper quadrant abdominal tenderness. His white blood cell count was elevated to 12,400/µL with 50% segmented neutrophils and a marked shift to the left with 47% band neutrophils. His hemoglobin level was 12.7 g/dL, and his hematocrit was 37.8%.

In a CT scan of the abdomen and pelvis (top), arrows point to inflammation in the aortic wall (A) and the para-aortic retroperitoneal fat. (I, inferior vena cava; K, kidney.) Calcified atherosclerotic plaques were visible, but the aorta was not dilated. There was neither retroperitoneal hematoma nor contrast extravasation to suggest rupture.

At 24 hours, blood cultures grew Salmonella organisms. The patient was given intravenous antibiotics for 9 days, by which time his abdominal pain had increased. A follow-up CT scan (bottom) revealed contrast medium protruding into the abnormal aortic wall, penetrating the infiltrated wall of the aorta and retroperitoneum, as well as development of an aortocaval fistula. Emergency aortectomy and bypass were performed.

Pathologic studies of the resected aortic wall demonstrated excessive quantities of histiocytes and neutrophils; the numbers increased progressively from the tunica media vasorum to the tunica adventitia to the para-aortic tissue. The aortic wall itself was disorganized and atheromatous. No organisms could be identified, possibly because of the antibiotic therapy.

Aortitis is rare, writes Dr Joel M. Schwartz of Irvington, NY, but it should be considered when a patient has fever, leukocytosis, sepsis, and abdominal pain with or without a pulsatile mass. More than 80% of cases of aortitis occur in men, and most patients are over age 50. Vascular tissue is normally resistant to infection, but atheromatous, diseased vessels are predisposed to bacterial seeding and growth.

Infection can occur in either aneurysmal or nonaneurysmal aortas. Salmonella species account for about one third of the infections, which usually develop following bacteremia. The infection destroys the tunica intima vasorum and tunica media vasorum, leading to formation of an aneurysm and eventual eruption. High clinical suspicion, aggressive antibiotic therapy, and aortectomy with bypass are necessary to prevent a fatal outcome.