Review on Mycotic Aneurysm

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


Saccular aneurysm




Peri-aneurysmal gas




Vertebral osteomyelitis

CTA: irregularity and abrupt truncation of distal SMA arteritis and thromboembolism

Fat stranding around SMA arteritis

Periaortic fat stranding


Saccular aneurysm




Peri-aneurysmal gas





Gas forming inflammation

Hazy aortic wall and gas formation


Saccular aneurysm




Peri-aneurysmal gas





Hazy aortic wall, para-aortic fluid collection, bilateral pleural effusions, intimal calcification

Periaortic edema and inflammatory soft tissue


Saccular aneurysm




Peri-aneurysmal gas





Prominent periaortic inflammation with destruction of the L3



Diagnosis



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

Documents

Review on Mycotic Aneurysm