Leaking Mycotic Aneurysm of Abdominal Aorta in a 14-Year-Old Boy with Infective Endocarditis and Severe Mitral Regurgitation—A Rare Case Report

We present a case of leaking mycotic aneurysm of abdominal aorta complicated by infective endocarditis in a young boy of 14 years age. This boy with history of rheumatic heart disease with vegetations on mitral valve and severe mitral regurgitation landed up in complications of infective endocarditis like femoral artery thrombo embolism followed by an abdominal aortic aneurysm with contained rupture. This case was successfully managed addressing two problems i.e. valve and aneurysm repair in single sitting.


Introduction
Abdominal aortic aneurysms are rare in children, causes include Mycotic Aneurysm, vasculitides (e.g.: Takayasu's arteritis) connective tissue diseases (e.g.: Marfan's syndrome, Ehler-Danlos syndrome and tuberous sclerosis) and traumatic false aneurysms [1]. The overall incidence of mycotic aneurysms in patients with infective endocarditis is in between 2 to 10 percent; in 1 to 5 percent the aneurysms involve cerebral vessels [2]. The exact incidence of extra cranial vessels involvement is not known. In 1885, Osler described a case of mycotic aneurysm that originated from infective endocarditis [3]. With the advent of antibiotic era and aggressive management of infective endocarditis, the development of mycotic aneurysms is uncommon.
Mycotic aneurysms may resolve during antimicrobial therapy [4], however, when anatomically feasible, aneurysms that have ruptured should be repaired surgically [5]. Aneurysms that have not leaked should be monitored angiographically during antimicrobial therapy. Anticoagulant therapy should be avoided in patients with persisting mycotic aneurysms. On rare occasions, persistant stable aneurysms may rupture after completion of standard antimicrobial therapy: however, there is no accurate estimation of risk for late rupture, and recommendations for surgical intervention are arbitrary.
In native valve infective endocarditis with heart failure, the mortality rates are around 55 to 85 percent with medical treatment alone and 10 to 35 percent in operated patients [6]. Not only does heart failure increase the mortality rate if there is no surgery, but it also increases the perioperative mortality rate from 5 to 10 percent in patients without heart failure to 15 to 35 percent in patients with heart failure [7].
The objective is to highlight the serious and rare complications associated with neglected/untreated squeals of endocarditis and to share the successful management of two major complications in single setting.

Case Report
This 14 year old boy has come to our hospital with complaints of abdominal distension and vague abdominal discomfort for one day. He also gives history of breathlessness which was worsening over six months, and presented with NYHA grade III. His past history revealed that he is a known case of Rheumatic heart disease with moderate mitral regurgitation managed medically with Tab.Digoxin 0.25 mg per oral o.d, Tab.Fruselac (Frusemide 20 mg + Spironolactone 50 mg 1 tab per oral o.d, Tab.Enalapril 2.5 mg per oral o.d. He also gave history of high grade continuous fever which was managed with antipyretics and antibiotics in a private clinic. This boy was previously admitted in our hospital one month before with claudicating pain in right lower limb, Doppler examination showed a thrombus in right femoral artery and subsequently he has undergone trans femoral embolectomy. He was put on oral anticoagulants with Tab.Acitrom (Nicoumalone) 1 mg o.d. Two weeks after embolectomy he developed high grade fever with chills, blood cultures revealed the growth of Klebsiella and was treated with antibiotics according to culture sensitivity. Repeat blood cultures after one week of antibiotics showed no growth. Echocardiogram revealed dilated Left Atrium (size 38 mm), vegetations over anterior Mitral leaflet (0.9 × 0.7 cm), severe mitral regurgitation, mild tricuspid regurgitation with mild pulmonary artery hypertension with systolic Pulmonary artery pressure around 46 mmhg, Left ventricular ejection fraction 76%, no clot, minimal pericardial effusion. In view of embolic event, severity of mitral regurgitation and vegetations over mitral valve he was advised surgery to repair mitral valve and removal of vegetations World Journal of Cardiovascular Surgery but his parents deferred for surgery in view of financial constrains and went home.
After one month of discharge from the hospital he came with complaints of abdominal distension and discomfort. On clinical examination the boy was poorly built and nourished weighing 25 kilograms. He was not pale, not cyanosed and no lymphadenopathy. There was grade II clubbing, JVP was raised and no pedal edema. General examination showed a swollen left knee joint which was warm and tender to touch with limitation of extension of joint. His vitals were: pulse rate-128/minute, regular, peripheral pulses and femoral pulses were not felt. B.P-90/46 mmhg in left upper limb in supine position, he was afebrile and respiratory rate was 22/minute. Sytemic examination revealed hyperdynamic apical impulse in left 5th intercostal space lateral to nipple and grade IV pansystolic murmur over mitral area radiating to axilla. Respiratory system was normal. No focal neurological deficits. Abdomen was distended and a swelling was palpable in left iliac region which was pulsatile, tender to touch. Bowel sounds were heard. His blood investigations revealed hemoglobin of 9.1 grams/dl, total white cell count of 15,330/cumm, platelet count of 2.29 lakhs/cumm, renal and liver function tests were within normal limits. Coagulation profile also normal. C-reactive protein 1. into the hematoma. Aortic bifurcation was not visualized, common, external and internal iliac arteries were reformed from infrarenal aorta anteriorly. Hematoma seemed to displace left kidney superiorly and laterally. Inferior vena cava is compressed by hematoma and displaced anteriorly. Hematoma appeared to sealed off with thickest wall at sides (pseudo aneurysm formation). Echocardiogram was consistent with previous findings (Figure 3). In view of patient's condition and leaking aneurysm emergency surgery was planned under general anesthesia and cardio pulmonary bypass to repair mitral valve and aneurysm of abdominal aorta. Patient was shifted to the operating theatre, an 18 gauge IV line secured in left cubital fossa, under local anesthesia left radial artery was cannulated for continuous blood pressure monitoring (IBP). Pre-induction monitoring included ECG, Pulse oximetry, Bispectral index (BIS), invasive blood pressure, Central venous pressure. A 7 french triple lumen catheter (Biosensors international PTE LTD) introduced in right internal juglar vein and pre induction hemodynamic parameters were heart rate 120/minute, IBP-88/56 mmhg,

Discussion
Abdominal aortic aneurysms secondary to infectious cause (mycotic aneurysms) is a rare presentation. The pathogenesis of mycotic aneurysms may include five different mechanisms [8], 1) septic embolization lodged in the vasovasorum or vessel lumen, 2) a contiguous inflammatory process outside the vessel wall that extends to the nearby artery, 3) inoculation of bacteria at the time of accidental arterial trauma, 4) Vascular manipulation or iatrogenic causes and 5) an intimal defect such as an atherosclerotic plaque, that is seeded by concurrent bacteremia.
Most of the abdominal aortic aneurysms are asymptomatic but might present as sudden rupture or as secondary complications. Our patient presented with secondary complications apart from pulsatile swelling in the lower abdomen. Less than 5 percent of patients with abdominal aortic aneurysms have evidence of arterial insufficiency to legs [9] (thrombosis of aneurysm or embolization of thrombus to leg arteries). Apart from size, signs of impending rupture like severe abdominal pain, tenderness over swelling or evidence of leak from aneurysms mandates emergency repair of aneurysm [9]. Along with thrombotic complications this patient also had contracture of leg due to psoas spasm and erosion of transverse process of L4 vertebra both due to retroperitoneal extension of hematoma. Since patient is a known case of rheumatic heart disease with heart failure (NYHA CLASS III), severe mitral regurgitation complicated by bacterial endocarditis and history of embolic events it was decided to repair mitral valve and abdominal aortic aneurysm in single setting.
The first indication for cardiac surgery in infective endocarditis is heart failure. It represents more than half of the indications. The embolism rate varies from 10% -50% in different series [10]. Three quarters of embolisms occur before the beginning of antibiotic treatment [11]. The embolic risk decreases greatly and regularly overtime from 15% after one week of treatment to 1% after four weeks of treatment [12]. In mitral infective endocarditis, occurrence of embolism is more frequent if vegetations are located over the anterior mitral leaflet than over the posterior mitral leaflet. In a study 10 embolic events were more frequent when the size of vegetations was more than 10 mm or when vegetations were very mobile.
Rapid surgery must be performed when there has been an embolic event and In view of rarity of mycotic aneurysm in this era of antibiotics we hardly found any similar case like ours in the literature.

Conclusion
Complicated infective endocarditis is rare and is associated with cardiac, neurologic, renal, musculoskeletal, and systemic complications related to infection, such as embolization, metastatic infection, and mycotic aneurysm. Infective endocarditis caused by Staphylococcus aureus is more frequently associated with complications. Because the mortality rate increases when complications develop, aggressive antibiotic therapy and surgery, combined with specific treatments for the complications, are necessary.