Go Back Brain/18. More than one of above/Vascular Disorder/18.7 - Mycotic aneurysm/ Go to Index
57 yr old male
Mycotic aneurysm
Headache
Right upper and lower extremity weakness.
IVDA
Febrile
Infective Endocarditis with mitral valve vegetations
Mycotic aneurysm
Secondary to tumor emboli
Choriocarcinoma
Atrial Myxoma
Trauma
Arteritis
Abnormal flow dynamics:
Moya-moya
AVM.
Septic microemboli to the vasa vasorum ("embolomycotic aneurysms")
usually occur in patients with active IE
source of infection is the cardiac vegetation
arterial emboli lodge in the vasa vasorum
Site: often at points of bifurcation of the affected artery
Hematogenous seeding of the intima
Bacteremia related to a distal infectious source
Normal arterial intima is very resistant to infection.
Contiguous extension
Trauma to the arterial wall with direct contamination.
Location:
Characteristically develop in the peripheral distribution of the middle cerebral artery
< 2% of all intracranial aneurysms
Distribution indicates that the lesions are usually secondary to infection.
At peripheral bifurcation points
Multiple, bilateral aneurysms may be present.
Up to 10% missed on angiography
Ziment 1969 Am J Med 47: 593-607
IE is most common predisposing condition
2 to 4% of IE patients develop intracranial mycotic aneurysms
Clinically difficult to differentiate IE patients with aneurysms/ICH
Neurologic symptoms in infective endocarditis
16 to 23% at presentation
30% develop neurologic manifestations eventually (12 - 52%)
Focal neurologic deficits, headache, confusion, meningismus, seizures, or coma
Sudden focal deficit consistent with embolic event: 23% of patients with IE
Salgado AV, Furlan AJ, Keys TF. Mycotic aneurysm, Subarachnoid hemorrhage, and indications for cerebral angiography in infective endocarditis. Stroke. 1987;18:1057-1060.
Usually clinically silent
Hemorrhage
Majority of intracranial hemorrhages associated with IE are related to septic necrotic arteritis (not ruptured aneurysms)
Selky AK, Roos KL. Neurologic complications of infective endocarditis. Semin Neurol. 1992;12:225.
Symptomatic intracranial hemorrhage was associated with a mortality rate of 60 to 90%
Patients with symptomatic intracranial mycotic aneurysms associated with IE treated in one neurosurgical unit over an 18-month period – 5 of 9 died
Bullock R, Van Dellen JR, Van den Heever CM. Intracranial mycotic aneurysms. A review of 9 cases. S Afr Med J. 1981;60:970
Symptoms typically more like stroke than SAH
Fusiform, eccentric aneurysms, without necks
Treatment goal is to eliminate aneurysmal segment from the circulation
Options:
Medical: Antibiotics
Surgical
Endovascular
No uniformly acceptable approach has been devised for the treatment of mycotic aneurysms
56 aneurysms occurring in 45 patients (review of published literature)
Bingham WF: Treatment of mycotic intracranial aneurysms. J Neurosurg. 1977;46:428.
3 of 20 patients died when treatment was limited to antibiotics alone.
8 of the 17 survivors with mild to moderate neurologic deficits.
6 of 25 patients in whom treatment included both antibiotics and surgery died
9 of 19 survivors with mild-moderate neurological deficits
“Statistically, there does not appear to be a clear-cut advantage to antibiotic plus surgical therapy over antibiotic alone.”
13 intracranial mycotic aneurysms with associated subarachnoid hemorrhage
Frazee JG, Cahan LD, Winter J. Bacterial intracranial aneurysms. J Neurosurg. 1980;53:633.
6 of 8 patients who received treatment with antibiotics alone died
no deaths were observed in the surgical treatment group
“…prompt excision of aneurysms whenever possible.”
85 intracranial mycotic aneurysms between 1954 and 1978
Bohmfalk GL, Story JL, Wissenger JP, et al. Bacterial intracranial aneurysm. J Neurosurg. 1978;48:369
20 of 38 patients managed solely with antibiotics died
8 of 30 undergoing surgery died
mortality rate was 29% after rupture of an intracranial mycotic aneurysm
Recommended surgical excision of “…single superficial aneurysms”
17 patients with 28 cerebral mycotic aneurysms
Brust et al., 1990 The Diagnosis and Treatment of Cerebral Mycotic Aneurysms. Ann Neurol 27: 238-46
Seven ruptured, 10 with other presentations
Outcomes during antibiotic therapy
4 ruptured while on antibiotic therapy
1 ruptured at the conclusion of antibiotic therapy
“…single accessible mycotic aneurysms in medically stable patients be promptly excised, with individualization of multiple or proximal aneurysms”
Serial angiographic studies during medical treatment
21 patients (literature review)
increased in size: 5
did not change: 1
became smaller: 6
completely resolved: 11
new aneurysms developed: 2
Bingham WF: Treatment of mycotic intracranial aneurysms. J Neurosurg. 1977;46:428
19 patients followed angiographically
10 smaller/gone
9 unchanged or enlarged
Brust et al., 1990 The Diagnosis and Treatment of Cerebral Mycotic Aneurysms. Ann Neurol 27: 238-46
Approximately 50% resolve during a course of antibiotic therapy for infective endocarditis
Earliest possible diagnosis of the underlying disorder
Appropriate antibiotic therapy
Early four-vessel cerebral angiography and follow-up studies every 2 to 3 weeks
Definitive operation upon completion of antibiotic therapy if the lesion is larger or the same size
Postoperative angiography to evaluate the effectiveness of treatment and to search for interim lesions
Bingham WF: Treatment of mycotic intracranial aneurysms. J Neurosurg. 1977;46:428
Surgery is indicated for aneurysms increasing in size on serial angiographic studies
Leipzig MJ, Brown FD. Treatment of mycotic aneurysms. Surg Neurol. 1985;23:403-407
Rodesch G, Noterman J, Thys JP, et al. Treatment of intracranial mycotic aneurysm: Surgery or not? Acta Neurochir. 1987;85:63-68.
May be deferred for 4 to 6 weeks for aneurysms remaining the same size.
AHA Review
Bayer AS, Bolger AF, Taubert KA, et al. Diagnosis and management of infective endocarditis and its complications. Circulation. 1998; 2936-2948.
Single intracranial mycotic aneurysm distal to the first bifurcation of a major artery (e.g., middle cerebral artery) should be followed with frequent serial angiograms and excised if the aneurysm enlarges or bleeds.
Multiple aneurysms should be similarly monitored, and any enlarging one should be managed surgically.
Aneurysms proximal to the first bifurcation are less amenable to surgical therapy, as they arise from major vessels and their ligation may result in severe neurologic deficits.
These latter lesions should also be serially assessed, and surgery pursued should enlargement or leakage occur.
20 patients with 27 infectious aneurysms were treated during a 10-year period.
Four patients with multiple aneurysms
Cause:
Bacterial endocarditis (65%)
Septic emboli from other sources (35%)
Organism:
Bacterial: Staph and Strep (17)
Fungus: Cocci, Candida (2)
Protozoan (Toxo)
Presentation
Rupture (75%)
Infarct
Sepsis
Sinusitis
Location
Middle cerebral artery (70%)
ACA (15%)
Structure
Typically fusiform, irregular and without a defined neck
Factors that guide management
Aneurysm rupture
Hematoma with increased intracranial pressure
Eloquence of brain tissue supplied by the parent artery.
Patients with unruptured infectious aneurysms are initially treated medically, with antibiotics and serial angiography.
Medically treated patients with enlarging or dynamic unruptured aneurysms require direct surgical or endovascular intervention
Endovascular therapy is the first option for patients in stable condition with ruptured aneurysms
Ruptured aneurysms that are not associated with large parenchymal hematomas causing mass effect or increased ICP
Do not involve an eloquent vascular territory
Surgical therapy is the first option for patients in unstable condition with ruptured aneurysms and the second option for patients in stable condition who experience failure of endovascular therapy.
Large hematoma with mass effect
Increased ICP
Risk of ischemic complications in an eloquent territory.
Treatment
Five patients were treated endovascularly
Direct coiling for three patients
Parent artery occlusion for two patients.
Ten patients (15 aneurysms) were treated surgically
6 aneurysms being trapped/resected
2 trapped/bypassed
4 clipped
3 wrapped
Five patients were treated medically (6 weeks IV antibiotics)
Serial angios (1-2 weeks)
7 initially: 2 enlarged (surgery), two dec, two thrombosed, one nsc
No ruptures during inpatient anitbiotic therapy or in follow-up
Outcome
Treatment-associated neurological morbidity was observed for two patients (10%)
Two patients died (10%)
Good outcomes were observed for 16 patients (80%)
Distal aneurysms more accessible with new microcatheters/wires
Minimal aneurysm manipulation, decrease re-rupture risk
Amytal testing can be incorporated into the procedure
Multiple aneurysms can be treated in one session
Location easy with angiography, may be difficult surgically
No landmarks
Difficult to localize on cross-sectional imaging, limits stereotaxy
Review of literature: all case reports and small series
16 patients with 23 aneurysms
Sites: MCA (15), PCA (6), ACA (1), VBJ (1)
Presentation: Rupture 14/16 patients
Endovascular Treatment: 17/23 aneurysms
Parent Vessel Occlusion: 11 (65%)
Coiling Aneurysm: 6 (35%)
Means of therapy
n-BCA alone: 3
GDC alone: 8
n-BCA and GDC: 2
Other (balloon, ethylene vinyl alcohol, autologous clot): 4
Result
Complete occlusion: 15/17 (88%)
Incomplete occlusion: 2/17 (12%)
No intraprocedural aneurysm perforations
No delayed aneurysmal hemorrhage after treatment
No complications resulting from the introduction of foreign material into aneurysms
Two neurological complications
Stroke after MCA coil embolization
Stroke/Coma after bilateral VA occlusion (after tolerating BVA test occlusion)
Two deaths for reasons unrelated to treatment
Sepsis, ARDS
11/16 patients with “good outcomes”
Endovascular therapy more likely to involve parent vessel sacrifice
Endovascular: 65%
Surgery: 37%
Amytal testing possible to determine eloquence of parent vessel territory
Acute mycotic aneurysms demonstrate diffuse circumferential arterial wall degeneration
Possible clip erosion of vascular wall and catastrophic perioperative rupture
