A Rare but Potentially Lethal Case of Tuberculous Aortic Aneurysm Presenting with Repeated Attacks of Abdominal Pain
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□ CASE REPORT □ A Rare but Potentially Lethal Case of Tuberculous Aortic Aneurysm Presenting with Repeated Attacks of Abdominal Pain Yao-Min Hung 1-3, Yun-Te Chang 1-3, Jyh-Seng Wang 2,4, Paul Yung-Pou Wang 5 and Shue-Ren Wann 1-3 Abstract Tuberculous aortic aneurysm is an extremely rare disease with a high mortality rate. The clinical features of this condition are highly variable, ranging from asymptomatic with or without constitutional symptoms, abdominal pain to frank rupture, bleeding and shock. We herein report the case of a 56-year-old man with a large tuberculous mycotic aneurysm in the abdominal aorta with an initial presentation of repeated attacks of abdominal pain lasting for several months. Due to the vague nature of the initial symptoms, tuberculous aor- tic aneurysms may take several months to diagnose. This case highlights the importance of having a high in- dex of suspicion and providing timely surgery for this rare but potentially lethal disease. Key words: abdominal aortic aneurysm, abdominal pain, aneurysm, aorta, mycotic aneurysm, tuberculosis (Intern Med 54: 1145-1148, 2015) (DOI: 10.2169/internalmedicine.54.3620) a 56-year-old man who presented to the ED with repeated Introduction attacks of abdominal pain. Following a preoperative evalu- ation, including clinical and radiological assessments, he un- Tuberculosis (TB) remains a major global health problem. derwent successful repair of a mycotic aneurysm in the ab- This disease causes ill-health in millions of people each year dominal aorta with excision and replacement of the diseased and ranks as the second leading cause of death from infec- aorta. A postoperative biopsy showed a tuberculous aortic tious disease. The latest estimates from the World Health aneurysm, and he was started on antituberculous chemother- Organization include 8.6 million new TB cases and 1.3 mil- apy based on the histological findings. lion TB deaths worldwide in 2012 (1). TB may have a wide range of clinical presentations due to its disseminative prop- Case Report erties, with both contiguous and hematogenous routes. Aor- tic involvement secondary to TB is exceedingly rare and A 56-year-old man was brought to our ED with abdomi- may occur in the form of arteritis or aneurysm forma- nal pain lasting for 10 days. He had a history of hyperten- tion (2, 3). Whether by direct extension or via the blood sion under medication control. According to his statement, stream, a focus of aortitis becomes established, and the aor- he had no previous tuberculous exposure. He also denied tic wall experiences destruction (2). Symptomatic tubercu- any possibility of relevant household contact, eating habits lous mycotic aneurysm is an extremely rare but uniformly or ownership of unusual pets, such as reptiles. He had vis- fatal lesion if not diagnosed promptly (3, 4). Abdominal ited several clinics and local hospitals for help within the pain is a common chief complaint among patients who visit past two to three months, receiving various diagnoses. He the emergency department (ED).We herein report the case of had also been treated by general practitioners, but never had 1Department of Emergency Medicine, Kaohsiung Veterans General Hospital, Taiwan, 2School of Medicine, National Yang-Ming University, Taiwan, 3Yuhing Junior College of Health Care and Management, Taiwan, 4Department of Pathology, Kaohsiung Veterans General Hospital, Taiwan and 5Division of Nephrology, Kaiser Permanente Baldwin Park Medical Center, U.S.A. Received for publication July 7, 2014; Accepted for publication September 15, 2014 Correspondence to Dr. Shue-Ren Wann, [email protected] 1145 Intern Med 54: 1145-1148, 2015 DOI: 10.2169/internalmedicine.54.3620 Table. Results of the Patient’s Laboratory Data on Admission Variable Patient’s results Normal range WBC (/mm3) 9,590 4,000-9,900 Neutrophils (% ) 88 41-73 Hb (g%) 14.4 12-15 PLT(×1000 /mm3) 275 150- 450 GPT (U/L) 18 0-40 ALP (U/L) 85 42-128 BUN(mg/dL) 14 7- 20 Serum creatnine(mg/dL) 0.7 0.5- 1.5 Sodium (mEq/L) 140 135-147 Potassium(mEq/L) 4.0 3.4- 4.7 Glucose (mg/dL) 193 65- 200 CRP (mg/dL) 11.5 <0.8 WBC: White blood cells, Hb: Hemoglobin, PLT: platelet count, GPT: glutamic pyruvate transaminase, GOT: glutamic oxaloacetic acid transaminase, ALP: alkaline phosphatase, Figure 1. Abdominal computed tomography showing a sac- BUN: blood urea nitrogen, and CRP: C-reactive protein cular mycotic aneurysm involving the abdominal aorta, infra- renal type, with a mural hematoma (sagittal view). Figure 2. Abdominal computed tomography showing a sac- Figure 3. Histopathology of the aortic aneurysm showing cular mycotic aneurysm involving the abdominal aorta, infra- features of granulomatous inflammation and focal caseous ne- renal type, with a mural hematoma (transverse view). crosis (Hematoxylin and Eosin staining, ×200). a complete workup. His vital signs were as follows: blood quent rupture, a potentially lethal complication. Therefore, pressure= 168/98 mmHg, pulse rate= 75 beats per minute, the patient underwent surgery, and a biopsy showed features respirations= 16 per minute and body temperature= 37.5°C. of chronic granulomatous inflammation and focal caseous A physical examination of the chest was normal, and the ab- necrosis, consistent with TB infection, which confirmed the domen was soft and mildly tender diffusely with no evi- diagnosis (Fig. 3, 4). He was thus started on a four-drug an- dence of rebound or guarding. A rectal examination revealed tituberculous regimen (isoniazid, rifampin, ethambutol, hard stools, but no masses or hemorrhoids. The laboratory pyrazinamide), and the aneurysm cultures eventually grew data obtained on admission are shown in Table; only in- mycobacterium TB resistant to isoniazid. He has since been creased an C-reactive protein (CRP) level was found. A rou- followed up regularly at our outpatient department. Further tine urinalysis was negative, and an electrocardiogram CT scans showed negative findings. showed a normal sinus rhythm at 87 beats/min. Chest and abdomen roentgenograms showed no abnormalities; how- Discussion ever, abdominal computed tomography (CT) revealed a 6- cm mycotic aneurysm involving the abdominal aorta, infra- Aneurysms are a very rare complication of TB. With re- renal type (Fig. 1, 2). As typical organisms, such as the Sal- spect to extrapulmonary TB, tuberculous aortic aneurysm monella species or Staphylococcus aureus, were suspected at formation is considered a rare form of TB. The largest series the time, the patient received empirical intravenous antibiot- review from 1945 to 1999 found only a total of 39 cases in ics and was admitted to the intensive care unit. the published literature (3), and Kamen first reported this There was evidence of a significant mycotic aneurysm on devastating complication of TB in 1858 (5). Volini et al. a CT scan of the abdomen, with the possibility of subse- later described the pathophysiology of aortic TB, in which a 1146 Intern Med 54: 1145-1148, 2015 DOI: 10.2169/internalmedicine.54.3620 infected mycotic aneurysms, such as invasive infections with Salmonella species or Staphylococcus aureus. Tuberculous aortic aneurysms are diagnosed based on the detection of the growth of organisms in culture or histologi- cal features or both. TB has already been diagnosed at pres- entation in 63% of patients, and disseminated TB is present in 46% of cases (3). Our patient had no history of TB, and CXR findings were negative. The only hint to the presence of an aneurysm was the persistence of abdominal pain last- ing for 10 days. Due to the varied presentation and often nonspecific nature of the signs and symptoms of aortitis, the index of suspicion must be high in order to establish an ac- Figure 4. Histopathology of the aortic aneurysm showing curate diagnosis in a timely fashion. In particular, the differ- positive staining for acid-fast bacilli (Hematoxylin and Eosin ential diagnosis includes various infected mycotic aneurysms staining, ×1,000). that should be ruled out before surgery. In addition, the di- agnosis of tuberculous aortitis is very difficult to establish, as the disorder is exceedingly rare and can mimic Takayasu primary tuberculous focus in the lungs involves periaortic arteritis (11). For these reasons, the diagnosis may be de- structures in the first pathologic stage, subsequently causing layed and the patients may be treated with immunosuppres- lymphadenitis, pericarditis, empyema, spondylitis and/or sive therapy before the diagnosis of TB is established. paravertebral abscesses. Later, tubercle bacilli may invade Therefore, the possibility of tuberculous aortitis should be the aortic wall. The second pathway involves hematogenous considered in patients with aortitis or atypical aortic aneu- dissemination. Whether by direct extension or via the blood rysms who have a history of pulmonary or extrapulmonary stream, a focus of aortitis becomes established and the aortic TB and/or chronic immunosuppression (8). In the current wall exhibits destruction (6). The speed of progression var- case, a definitive diagnosis was not obtained before surgery, ies (2), and treating this condition is challenging due to at and infection with typical organisms, such as Salmonella least two factors. First, great imitators of TB are common, species or Staphylococcus aureus, was favored based on our and second, tuberculous aortic aneurysms are prone to previous experience. In addition, in a past case report, the abrupt rupture and underdiagnosis is possible until post- rapid progression of bacterial aortitis to an ascending aortic mortem pathology findings can be obtained. mycotic aneurysm was documented on transesophageal The syndromic diagnosis in this case may be called echocardiography within six days (12). “chronic periaortitis,” which is characterized by the presence Managing tuberculous aortic aneurysms is challenging, of inflammation and fibrosis surrounding the aorta and typi- and the standard therapeutic strategy has not yet been estab- cally involves the infrarenal portion of the abdominal lished (13).