Keywords
mycotic aneurysm - subarachnoid hemorrhage - endocarditis
Introduction
Mycotic cerebral aneurysm is one of many lesions due to infective endocarditis (IE)
but still rare and potentially fatal complication. Medical treatment is based on antibiotics
and in specific cases surgical treatment is required (craniotomy or endovascular).
The absence of randomized trials generates a lack of consensus regarding the management
of unruptured aneurysms. We present a case report of a patient diagnosed and treated
surgically with improvement on follow-up with the trapping technique of the aneurysm.
Case Report
A 32-year-old man presented with sudden headache, high-grade fever with chills, and
right hemiparesis. Sought medical attention and on the examination of admission, he
was febrile (38°C). The pulse rate was regular (76 beats/min) and blood pressure was
130/70 mm Hg. Cardiac auscultation revealed soft first heart sound, normal aortic
component, and a grade 3/6 mitral murmur. On neurologic examination he presented alert
and conscious, with a right paretic gait and muscular strength grade I right-sided
hemiparesis. After the new diagnosis of a febrile syndrome plus pyramidal syndrome
the initial investigation was performed.
Investigations
Hemogram revealed leucocytosis (11,000/mm3) with predominant neutrophilia (70%) and normal platelet count (190,000). Urine examination,
renal function test, and liver function test were normal. Transthoracic echocardiogram
revealed a mitral thickening with perforation leading to severe mitral regurgitation
with two jets.
Blood cultures (four samples) were positive after for Abiotrophia defectiva after 96 hour by the matrix-assisted laser desorption/ionization (MALDI TOF) MS method.
Computed tomographic (CT) angiogram and angiography revealed an M2 aneurysm with subarachnoid
hemorrhage (SAH) ([Figs. 1] and [2]).
Fig. 1 CT of the head with Fisher IV subarachnoid hemorrhage (SAH).
Fig. 2 MCA M2 segment aneurysm.
Treatment
The patient was treated with antifailure medications along with injectable antibiotics
for IE for 8 weeks.
The patient was submitted to surgery (pterional craniotomy) with trapping of the aneurysm
with success.
Outcome and Follow-up
The patient was treated with antibiotics and close monitoring for eventual neurologic
symptoms worsening. The patient became afebrile and the symptoms leading to heart
failure improved with the medical therapy after 10 days. After 8 weeks we performed
a control magnetic resonance imaging (MRI) angiogram who revealed that the previous
lesion increased ([Fig. 3]). After surgery the patient improved the previous deficit on 3 months follow-up
(from grade I–IV hemiparesis) ([Fig. 4]).
Fig. 3 Angiogram revealing increase of the lesion.
Fig. 4 Post-op CT.
Discussion
The epidemiologic profile of IE has changed substantially over the last few years,
especially in industrialized nations. Newer predisposing factors have emerged—valve
prostheses, degenerative valve sclerosis, intravenous drug abuse—associated with increased
use of invasive procedures at risk for bacteremia, resulting in health care–associated
IE.[1]
In developed countries, the incidence of IE ranges from 3 to 9 cases per 100,000 per
year, and it is twice as common in men.[1]
Staphylococcus aureus is the most common organism. Up to 30% of those having bacteremia with Staphylococcus will develop endocarditis and 75% of patients with IE have structural abnormalities
on their hearts.[1]
[2]
A. defectiva, a nutritionally variant Streptococcus (NVS), represents a rare but clinically important cause of IE initially described
by Frenkel and Hirsch in 1961[3] as fastidious gram-positive bacterium and modified by Bouvet et al in 1989[4] who proposed the names Streptococcus defectivus and Streptococcus adjacens, following the use of DNA—DNA hybridization studies.[1]
[5]
[6]
A. defectiva endocarditis is a rare cause of endocarditis with rates around 5% of all cases of
streptococcal endocarditis. There are around 100 cases of A. defectiva endocarditis in the literature. It predominantly occurs in the setting of preexisting
heart disease (90%); prosthetic heart valves are involved in 10% of patients. There
are no published cases on adults without previously documented valvular heart disease
developing.[5]
[6]
The 1-year rate of IE mortality is around 30%. Neurologic complications, most commonly
cerebral embolism, are seen in 20 to 40% of the patients and are associated with high
morbidity and mortality. The reported incidence of mycotic cerebral aneurysms is 2
to 3% of all the patients with IE. This is possibly underestimated, because most patients
remain asymptomatic and the aneurysm may resolve after antibiotic therapy.[2]
[7]
The symptoms usually include headache (83%), fever (67%), vomiting (50%), ocular palsy
(25%), seizures (21%), behavioral changes (21%), hemiparesis (21%), drowsiness (17%),
and loss of consciousness (17%).[1]
[7]
The clinical diagnosis of IE is usually made based on modified Duke criteria and the
neurologic complications with CT and magnetic resonance angiography.[1]
[7]
Authors such as Thuny et al[8] reported that cerebral and thoracoabdominal CT revealed silent emboli in only 8%
of patients. Cooper et al[9] performed MRI of the brain in 40 patients with IE and found acute brain embolization
in 80% of patients.[10]
Several authors have recommended the antimicrobial therapy tailored by culture for
6 to 8 weeks along with close follow-up as the first line of treatment for unruptured
intracranial aneurysms and serial imaging. Invasive procedures (microsurgery/endovascular)
are indicated for very large, enlarging, or ruptured aneurysm.[1]
[10]
Surgical management of mycotic aneurysm (MA) depends on several factors, including
size, location, expertise of the surgeon (on microsurgery or endovascular) ([Table 1]), and if the aneurysm has ruptured. There are no data comparing microsurgery versus
endovascular.[11]
[12] Ruptured MAs are managed by either open or endovascular means, following which a
2- to 3-week delay is recommended prior to cardiac valve replacement. Microsurgery
in this case is technically difficult, as MAs tend to be fusiform with poorly defined
necks and friable walls. Proximal ligation is therefore often necessary. Anastomotic
procedures that can spare distal vessels in eloquent areas are sometimes possible.
Endovascular therapies are less invasive alternatives that may be more appropriate
in patients who are unfit for surgery due to cardiac disease. Detachable coils are
preferred for proximal aneurysms, whereas distal aneurysms that are not accessible
to microcatheters can be managed with acrylic glue or autologous clot injections.[2]
[11]
[12]
Table 1
Presentation of reported patients treated with endovascular versus current patient
(microsurgery)
|
Reference (year)
|
Age (y)
|
Clinical presentation
|
Etiology
|
Pathogen
|
Follow-up
(mo)
|
Modified Rankin Scale score
|
|
Current patient, 2015
|
32
|
Fever, headache, and hemiplegia
|
Bacterial
|
Abiotrophia defectiva
|
3
|
0
|
|
Ding et al, 2014[13]
|
35
|
Diplopia
|
Bacterial endocarditis
|
Streptococcus mitis
|
3
|
0
|
|
Sugg et al, 2006[14]
|
47
|
Hemiplegia, headache
|
Bacterial endocarditis
|
Unknown
|
None
|
3
|
|
Yen et al, 2007[15]
|
46
|
Ophthalmoplegia
|
Meningitis
|
Streptococcus constellatus
|
6
|
1
|
|
Appelboom et al, 2007[16]
|
10
|
Ophthalmoplegia
|
Meningitis
|
Streptococcus pneumoniae
|
3
|
0
|
Conclusion
IE is a serious disorder very often in developing countries that is frequently complicated
when associated with neurologic disease including ischemic and hemorrhagic stroke.
The surgical management of the underlying disease still lacks of randomized trials
and sets a new opportunity for new studies regarding the matter. A multidisciplinary
collaborative approach is critical to optimizing outcomes.
