Post on 31-Mar-2015
transcript
Review on Mycotic Aneurysm
Joint Hospital Surgical Grand RoundLi Hoi Man
Princess Margaret Hospital26/4/2014
History Definition Pathogenesis Disease characteristics Diagnosis Treatment
Content
1844: Rokitansky1 described abscess in the walls of arteries
1851: Koch2 reported the sudden death of a 22/M from a ruptured SMA aneurysm while treating I.E.
1885: Sir William Osler3 proposed a causal relationship between infection of the aortic wall and subsequent aneurysm formation
History of Mycotic Aneurysm
Initially signified an infected aneurysm found in association with bacterial endocarditis
Nowadays denote an infected aneurysm of any type
Mycotic aneurysm: both true and false aneurysms that are associated with infection of the arterial wall
Definition
1. Oslerian mycotic aneurysms Embolization of infected cardiac vegetations
2. Haematogenous seeding Bacteremia microbial seeding of arteries
arteritis aneurysm formation3. Infected aneurysms
Bacteremia lodge within the intramural thrombus and arteriosclerotic intima
4. Others Mechanical arterial injury with contamination Contiguous spread
Pathogenesis
Era of bacterial endocarditis: 2nd -4th decades Now: elderly 6th-8th decades Male predominance (> 2/3) Higher prevalence in drug addicts and
patients with AIDS
Epidemiology
S/S from infection / bacteremia: S/S secondary to local arterial involvement /
aneurysm formation: Localized tenderness, bruits, neurologic
defects, pulsatile masses Thrombosis / thromboembolization Rupture
pseudoaneurysm hypotensive shock, life-threatening haemorrhage
Clinical presentation
Salmonella choleraesuis, S. typhimurium
Staphylococcus aureus Streptococcus spp. Escherichia coli Immunocompromised:
Campylobacter spp., Listeria spp., Mycobacterium tuberculosis
Bacteriology
Depends on pathology type: Oslerian: abdominal
aorta, femoral artery, SMA
Haematogenous seeding: distal aorta, femoral, iliac and popliteal
Mechanical injury: femoral, brachial
Anatomic distribution
Blood: WCC, ESR Blood cultures: only ~ 60% Arterial Gram stains,
cultures, PCR CT and / or MRI Angiography PET-CT
Diagnosis
CT findings of infected aneurysms
Saccular aneurysm
Irregular aneurysmal lumen
Absence of calcification
Gas within aortic wall
Peri-aneurysmal gas
Peri-aneurysmal fluid
Encasing or contiguous mass
Associated para-aortic / psoas abscess
Vertebral osteomyelitisSaccular aneurysms
CT findings of infected aneurysms
Saccular aneurysm
Irregular aneurysmal lumen
Absence of calcification
Gas within aortic wall
Peri-aneurysmal gas
Peri-aneurysmal fluid
Encasing or contiguous mass
Associated para-aortic / psoas abscess
Vertebral osteomyelitis
CTA: irregularity and abrupt truncation of distal SMA arteritis and thromboembolism
Fat stranding around SMA arteritis
Periaortic fat stranding
CT findings of infected aneurysms
Saccular aneurysm
Irregular aneurysmal lumen
Absence of calcification
Gas within aortic wall
Peri-aneurysmal gas
Peri-aneurysmal fluid
Encasing or contiguous mass
Associated para-aortic / psoas abscess
Vertebral osteomyelitis
Gas forming inflammation
Hazy aortic wall and gas formation
CT findings of infected aneurysms
Saccular aneurysm
Irregular aneurysmal lumen
Absence of calcification
Gas within aortic wall
Peri-aneurysmal gas
Peri-aneurysmal fluid
Encasing or contiguous mass
Associated para-aortic / psoas abscess
Vertebral osteomyelitis
Hazy aortic wall, para-aortic fluid collection, bilateral pleural effusions, intimal calcification
Periaortic edema and inflammatory soft tissue
CT findings of infected aneurysms
Saccular aneurysm
Irregular aneurysmal lumen
Absence of calcification
Gas within aortic wall
Peri-aneurysmal gas
Peri-aneurysmal fluid
Encasing or contiguous mass
Associated para-aortic / psoas abscess
Vertebral osteomyelitis
Prominent periaortic inflammation with destruction of the L3
Blood: WCC, ESR Blood cultures: only ~ 60% Arterial Gram stains,
cultures, PCR CT and / or MRI Angiography PET-CT
Diagnosis
Blood: WCC, ESR Blood cultures: only ~ 60% Arterial Gram stains,
cultures, PCR CT and / or MRI Angiography PET-CT
Diagnosis
Control of sepsis Arterial reconstruction
Principles of Management
Antibiotic therapy Broad-spectrum, high dose, according to c/st Extend for at least 6 weeks post-op Lifelong if prosthetic reconstructions involved
Surgical debridement Aggressive wide debridement Drains
Control of sepsis
Open approach - extra-anatomic reconstruction
In-situ reconstruction - EVAR
Arterial reconstruction
Debridement of infected tissues Stump closure
Conventional open surgery
Extra-anatomic reconstruction
Extra-anatomic reconstruction
Conventional approach Lower reoperation rate for graft infection High mortality rate 20,21(23-39%) Complications:
aortic stump blowout extra-anatomic bypass occlusion recurrent aortoenteric fistula recurrent graft infection9 (up to 13%)
In-situ reconstruction: EVAR
EVAR Rapid control of haemorrhage Reduced surgical morbidity and
mortality Places a graft in direct proximity
to the infection Does not afford the opportunity to
debride infected tissue In combination with prolonged
antibiotics and use of drainage offer resolution of arterial infection
Comparison between open vs EVAR
Kan12 reviewed on efficacy of EVAR in infected AAA, 41cases, EVAR (n=20) vs conventional surgery (n=21)-Early (30 days) post-op mortality similar-Late (2 year) mortality greater in conventional surgery (10% vs 25%)-Aneurysm-related event-free survival similar
References:1.Rokitansky: Handbuch der pathologischen Anatomie, Ed 2, 1844, p552.Koch: Uber Aneurysma der Arteriae mesenterichae superioris, 1851, Erlangen3.Osler: The Buslstonian lectures on malignant endocarditis4.Crane: Primary multilocular mycotic aneurysm of the aorta. Arch Patho 24: 634, 19375.Ponfick: Uber embolische Aneurysmen, nebst Bemerkungen uber das acute Herzaneurysma. Virchows Arch 58: 528, 18736.Eppinger: Pathogenese der Aneurysmen einschliesslich des Aneurysma equiverminosum. Arch Klin Chir 35: 404, 18877.Revell: Primary mycotic aneurysms. Ann Intern Med 22:431, 19438.Hawkins: Primary mycotic aneurysms. Surgery 40:747, 19569.Ewart: Spontaneous abdominal aortic infections: essentials of diagnosis and management. Am Surg 49: 37, 198310.Berchtold: Endovascular treatment and complete regression of an infected AAA. J Endovasc Ther 9: 543, 200211.Koeppel: mycotic aneurysm of the abdominal aorta with retroperitoneal abscess: successful endosvascular repair. J Vasc Surg 40: 164, 200412.Kan: The efficacy of aortic stent grafts in the management of mycotic abdominal aortic aneurysm institute case management with systemic literature comparison. Ann Vasc Surg 24(4): 433-440, 201013.Forbes: Endovascular repair of Salmonella-infected AAAs: a word of caution. J Vasc Surg 44(1): 198-200, 200614.Vallejo: The changing management of primary mycotic aortic aneurysms. J Vasc Surg 201115.Lee: In situ versus extra-anatomic reconstruction for primary infected infrarenal AAA. J vasc Surg 54(1): 64-70,201116.Brown: Arterial reconstruction with cryopreserved human allografts in the setting of infection: a single-center experience with midterm FU. J Vasc Surg 49(3): 660-666, 200917.Gelabert: Primary Arterial infections and antibiotic prophylasix. Vascular and Endovascular Surgery – a comprehesive review 157-17718.Perler: Infected aneurysm. Vascular Surgery Principles and Practice Ed3 669-68619.Semba: Mycotic aneurysms of the thoracic aorta: repair with use of endovascular stent grafts. J Vasc Interv Radiol 1998; 9: 33-4020.Leon: Diagnosis and Management of aortic mycotic aneurysms. Vasc and Endova Surg 44(1) 5-13, 201021.Stone: Comparison of open and endovascular repair of inflammatory aortic aneurysms. J Vasc Surg 10-2012 951-6
~ The End ~
M/65, GPH, walks unaided LLQ pain with radiation to back and subjective fever
for 1/52 Temp 37.7 abd: 5cm expansile mass, tender CT: 5.2cm infra-renal AAA with impending rupture and
para-aortic fat stranding Put on augmentin and flagyl Blood c/st, TB, widal test, Treponema: all –ve EVAR done FU CT showed no endoleak and aortic sac wall
thickening showed interval improvement Lifelong levofloxacin 750mg daily
Our cases
M/65 GPH Abd pain x 1/12 CT: 2.9cm infrarenal AAA with eccentric mural
thrombus EVAR + fem-fem bypass on 5/2010 Blood C/st: salmonella sensitive to ciprofloxacin Subsequent CT: resolution of the inflammatory changes Antibiotic coverage discontinued 1 year later FU CT 2.5 years later: ? Relapse of infection with
increased perigraft soft tissue swelling Treated with a 8-week course of rocephin 2gm daily
then changed to azithromycin 500mg daily po afterwards
Our cases