Matters of the Heart: Aortitis

An obese 61-year-old man who hadchronic obstructive pulmonary diseaseand sleep apnea heard a "pop"in his stomach while lifting a heavyweight; severe abdominal pain followed.He was short of breath thenext morning, and his physician empiricallyprescribed cephalexin.The patient became confusedabout 7 hours later and was taken tothe emergency department; at thistime he was lethargic and had a temperatureof 38.3C (101F). Examinationdisclosed bilateral wheezes, ralesat the lung bases, and paraumbilicaland left upper quadrant abdominal tenderness. His whiteblood cell count was elevated to 12,400/μL, with 50% segmentedneutrophils 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), arrowspoint to inflammation in the aortic wall (A) and the paraaorticretroperitoneal fat. (I, inferior vena cava; K, kidney.)Calcified atherosclerotic plaques were visible, but theaorta was not dilated. There was neither retroperitonealhematoma nor contrast extravasation to suggest rupture.At 24 hours, blood cultures grew Salmonella organisms.The patient was given intravenous antibiotics for9 days, by which time his abdominal pain had increased.A follow-up CT scan (bottom) revealed contrast mediumprotruding into the abnormal aortic wall, penetrating theinfiltrated wall of the aorta and retroperitoneum, as well asdevelopment of an aortocaval fistula. Emergency aortectomyand bypass were performed.Pathologic studies of the resected aortic wall demonstratedexcessive quantities of histiocytes and neutrophils;the numbers increased progressively from the tunicamedia vasorum to the tunica adventitia to the para-aortictissue. The aortic wall itself was disorganized and atheromatous.No organisms could be identified, possibly becauseof the antibiotic therapy.Aortitis is rare, but it should be considered when apatient has fever, leukocytosis, sepsis, and abdominal painwith or without a pulsatile mass. More than 80% of cases ofaortitis occur in men, and most patients are older than 50years. Vascular tissue is normally resistant to infection, butatheromatous, diseased vessels are predisposed to bacterialseeding and growth.Infection can occur in eitheraneurysmal or nonaneurysmal aortas.Salmonella species account forabout one third of the infections,which usually develop following bacteremia.The infection destroys thetunica intima vasorum and tunicamedia vasorum, leading to formationof an aneurysm and eventual eruption.High clinical suspicion, aggressiveantibiotic therapy, and aortectomywith bypass are necessary toprevent a fatal outcome.