Mycotic (Infected) Aneurysm Caused by Streptococcus pneumoniae

Khosrow Afsari, MD, Touro University College of Osteopathic Medicine, Vallejo, Calif; Robert Stallone, MD, Doctor's Medical Center, San Pablo, Calif; Glenn D. Wong, Touro University College of Osteopathic Medicine, Vallejo, Calif.

Disclosures

Infect Med. 2001;18(6) 

In This Article

Case Report

A 73-year-old woman was brought to the emergency department (ED) with the chief complaint of substernal chest pain for 7 days, which was not relieved by nitroglycerin. She denied any previous trauma and stated that the pain was not associated with shortness of breath, fever, diaphoresis, or nausea, and it was not radiating. The woman's chest pain was relieved by acetaminophen.

The patient had an extensive medical history: right upper lung and hilar node resection for squamous cell carcinoma, coronary artery bypass graft (18 months before), aortic abdominal aneurysm repair, bilateral carotid endarterectomies, and total hip replacement. There was a long history of smoking and alcohol abuse but no history of illicit drug use.

The initial physical examination showed a 42-kg (92-lb) woman in moderate discomfort. Her temperature was 37.7°C (99.8°F); blood pressure, 124/72 mm Hg; pulse rate, 103 beats per minute and regular; respirations, 20 breaths per minute; and oxygen saturation, 98% on 2 L of oxygen. Findings on examination of head, eyes, ears, nose, and throat were unremarkable. The neck was supple with no palpable masses. The lungs were clear, and the cardiac examination results were normal. Sternal pressure could not reproduce the pain. The abdomen was benign with no guarding, rebound, or flank tenderness.

The patient was able to move all extremities and displayed no edema or skin changes. The ECG showed sinus tachycardia at 103 beats per minute but was otherwise normal. The chest film displayed no acute changes but did show chronic right interstitial changes. Cardiac enzyme levels were normal. The peripheral leukocyte count was 9100/µL; hemoglobin, 12.2 g/dL; hematocrit, 37 mL/dL. Serum electrolyte levels were normal. The patient was discharged with instructions to follow up with her primary care physician the next day and return to the ED if symptoms got worse.

The patient visited the ED 5 days later with increased substernal chest pain with radiations through her back, along with nausea and vomiting. Her temperature was 37.3°C (99.1°F); blood pressure, 145/76 mm Hg; pulse rate, 114 beats per minute and regular; respirations, 20 breaths per minute; and oxygen saturation, 98% on room air. Physical examination showed tenderness along the left and right lower chest wall. The remainder of the physical examination was benign. Repeated radiographic, ECG, and laboratory studies (including cardiac enzyme levels) were normal. The woman was admitted, and a bone scan was done to determine whether any metastasis had occurred from her lung cancer. The bone scan showed activity on the left 9th, 10th, 11th, and 12th ribs, which correlated well with her history of prior rib fractures to that side (Figure 1). She was discharged with instructions to follow up with her primary care doctor.

A bone scan (posterior view) shows increased isotope uptake at ribs 9, 10, 11, and 12.

Four weeks later, the patient returned to the ED with excruciating chest pain radiating toward her back; the pain was unrelieved by nitroglycerin. The pain was debilitating, causing her to become bedridden. Vital signs were temperature, 35.8°C (96.5°F); blood pressure, 115/58 mm Hg; pulse rate, 100 beats per minute and regular; respirations, 20 breaths per minute. The patient was admitted to the hospital, and radiographic, ECG, and laboratory studies (including cardiac enzyme levels) were repeated; the results were normal. A serum carcinoembryonic antigen level was also normal. A repeated bone scan revealed increased isotope uptake at the midthoracic spine (Figure 2).

A bone scan (posterior view) repeated 4 weeks later shows increased uptake in the thoracic spine.

A CT scan was done and compared with one taken 8 weeks earlier; it showed a saccular aneurysm in the thoracic aorta with erosion of vertebral bodies T9 and T10 (Figure 3). The patient, with her extensive medical history, was considered a poor surgical candidate; however, because of her excruciating pain, elective surgery was consented to by the patient and her family. She received 2 g of cefazolin for prophylaxis. The findings on exploration were a ruptured descending thoracic aortic aneurysm confined against the right lung and erosion of the T9 and T10 vertebral bodies. The aneurysm was dissected, and no purulent material was seen. The patient received a number 20 woven graft from the distal descending aorta to the proximal descending aorta. Total cross-clamp time was 28 minutes. The patient endured the surgery well without any complications. Excised tissue from the aorta, right lung, and T9 and T10 vertebral bodies was sent for pathologic examination. The tissue culture from the aorta grew out penicillin-sensitive S pneumoniae. The pathology report revealed chronic inflammation and fibrosis from the left lung and vertebral specimens; no malignancy was identified from any of the specimens.

Initial CT scan of the abdomen shows a right-sided pulmonary infiltrate (A). Eight weeks later, a follow-up scan shows a large saccular aneurysm (B) with effusion.

Initial CT scan of the abdomen shows a right-sided pulmonary infiltrate (A). Eight weeks later, a follow-up scan shows a large saccular aneurysm (B) with effusion.

Immediately after surgery, the patient, who had a history of penicillin allergy, tolerated 2 g of cefazolin IV every 8 hours. Repeated blood, urine, and sputum cultures continued to be negative. The patient's postoperative course was prolonged, and she eventually died of cardiorespiratory arrest 15 days later.

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