Neurology India Medknow Publications on behalf of the Neurological Society of India ISSN: 0028-3886 EISSN: 1998-4022 Vol. 59, Num. 4, 2011, pp. 620-623

Neurology India, Vol. 59, No. 4, July-August, 2011, pp. 620-623

Case Report

Delayed brain abscess after embolization of arterio-venous malformation: Report of two cases and review of literature

Arun Sharma, Anita Jagetia, Poonam Loomba, Daljit Singh, Monica Tandon

Department of Neurosurgery and Microbiology, G. B. Pant Hospital, New Delhi, India
Correspondence Address: Daljit Singh, Department of Neurosurgery, G. B. Pant Hospital, New Delhi, India, drdaljit@hotmail.com

Date of Submission: 16-Apr-2011
Date of Decision: 08-May-2011
Date of Acceptance: 27-May-2011

Code Number: ni11184

PMID: 21891947

DOI: 10.4103/0028-3886.84351

Abstract

Keywords: Arteriovenous malformation, brain abscess, endovascular embolization, Burkholderia caeci

Introduction

Endovascular procedures are being increasingly performed to treat intracranial vascular disease. These procedures are not devoid of potential complications, and the most frequent complications include hemorrhagic and thromboembolic events. ^[1] Central nervous system (CNS) infections are rare complications and review of literature revealed only four documented cases of brain abscess complicating embolization of intracranial arterio-venous malformations (AVMs). ^[1] We report two other cases.

Case Reports

Case 1

A 38-year-old right-handed male was admitted in March 2009 for treatment of seizures, and investigations revealed right parieto-occipital AVM. He was readmitted in December 2008 for rupture of the AVM. During this admission, he was conscious and well oriented with no focal neurological deficits. A magnetic resonance imaging (MRI) of brain revealed an AVM in the right parieto-occipital region with a subacute hemorrhage in right occipital lobe. Digital subtraction angiogram (DSA) revealed an AVM fed by right posterior cerebral artery (PCA), right middle cerebral artery (MCA) draining into right transverse sinus and vein of Galen. In April 2009, embolization of the AVM (Spetzler Martin Grade III) was done using nectacryl^® glue, N-butyl cyanoacrylate (NBCA). After embolization, major portion of nidus was not visualized. All routine aseptic precautions for neuroradiological angiographic procedures were maintained. Intra- and post-procedure antibiotic (ceftriaxone 1 g IV) for 3 days was given as per the departmental protocol. The patient was discharged 3 days after embolization with no neurological deficit. At the time of discharge, the patient was afebrile and there was no clinical sign of any infection. A follow-up computed tomography (CT) scan after 9 months revealed post-embolization cast and encephalomalacic changes in the area adjoining the embolized AVM [Figure - 1]. After 10 months, he was admitted for headache associated with fever, left hemiparesis and obtundation. On examination, the patient was drowsy [Glasgow Coma Scale (GCS) of E3M5V4], febrile 100°F and had left hemiparesis. There was no neck rigidity and Kernig sign. No primary focus of infection could be identified. Investigations showed the following: Chest X-ray was normal, WBC count 8400/mm ³ with 75% polymorphs and 20% lymphocytes, negative blood cultures, and normal 2D Echo study of heart. Brain MRI revealed multiple ring-enhancing lesions suggestive of brain abscesses with mild hydrocephalus [Figure - 2]. Cerebrospinal fluid (CSF) analysis obtained from left external ventricular drain revealed proteins 150 mg/dl, sugar 15 mg/dl, and 12 cells, all polymorphs, and no growth on CSF culture.

The indication of removing the multiple brain abscesses was initially considered with high risk, but the consent to operate was not given. The patient showed some improvement with intravenous antibiotics and after ventricular drain. While the patient was being managed conservatively with intravenous antibiotics (ceftriaxone and amikacin), the patient's condition deteriorated and he succumbed to the illness.

Case 2

A 25-year-old female had undergone endovascular embolization of left frontal AVM using nectacryl^® glue (NBCA) in April 2010. It was a high flow AVM with feeders from left MCA and was draining into superior sagittal sinus [Figure - 3]. The embolization was complete with no residual AVM under all aseptic precautions. Intra- and post-procedure antibiotic (ceftriaxone 1 g IV) for 3 days was given as per the departmental protocol. She presented with headache and recurrent generalized seizures. She was asymptomatic for 5 months when she presented with headache and fever. Headache was moderate and left hemicranial, and there was no significant relief with medication. There was no history of ear discharge. On examination, she was conscious, oriented, with no papilledema and no focal motor or sensory deficits. Total WBC count was 10,200/mm ³ with 80% polymorphs, 18% lymphocytes, and 2 eosinophlis. Other investigations were within normal limits. Contrast CT of the brain and contrast MRI brain revealed multiple brain abscesses with mass effect [Figure - 4] and [Figure - 5]. She underwent a left frontal craniotomy and excision of multiple abscesses. The pus was non-foul smelling, purulent material. Pus culture revealed Burkholderia caeci, sensitive to tazobactum. Patient responded to treatment and was discharged after 15 days.

Discussion

Bacteremia and septicemia have been documented after diagnostic and therapeutic angiographic procedures and this can also complicate pyogenic abscesses in lungs, perineum, retroperitoneal space, liver, and spleen. ^[2] The risk factors for infection are unclear. Improper catheter handling, large amount of foreign material, and length of procedure have been suggested as probable risk factors for infection. ^[2],[3] Presence of urinary tract infection also adds to the list. A source unrelated to the procedure is also possible. ^[4] Aadil et al. have attributed 83% of postoperative infections to in-hospital contamination of medical devices. ^[4]

Normally, blood brain barrier provides resistance to infection, and infections like brain abscesses occur following damage to the blood brain barrier. ^[2] Brain abscess complicating embolization has been reported to occur between 4 months and 10 years of the procedure. Staphylococcus aureus or Pseudomonas aeruginosa are the reported causative organisms [Table - 1]. ^[5],[6] None of the reported cases had periprocedural infective complication. In one patient, the infection had been attributed to the leftover entangled microcatheter. ^[7] In the first patient, the encephalomalacic changes around the embolized AVM might have placed the patient at risk for infection and brain abscess formation. The prophylactic use of intravenous antibiotics during the procedure might have prevented bacteremia. Moreover, a long delay of 10 months does not support that bacteremia during the procedure might have resulted in brain abscess formation. In the second patient, a rare organism, B. caeci, an aerobic gram-negative bacillus, has been grown. B. caeci is found in various aquatic environments and is an organism of low virulence and a frequent colonizer of fluids (e.g., irrigation solutions, intravenous fluids) used in the hospital. It is possible that this organism was introduced during embolization procedure or through the fluids in the postoperative period as a contaminant of the irrigation fluids. Low virulence of the organism might have resulted in a latent period of 5 months for the abscess to develop.

As a protocol in our institution, we never reuse catheters or microcatheters. Thus, the possibility of compromised sterility is unlikely. In both the patients, brain abscess was a delayed complication. Thus, this complication was very unlikely related to primary infections due to embolization procedure. In the first patient, we feel that the ischemic changes surrounding the AVM might have resulted in the disruption of blood brain barrier, resulting in the spread of infection and brain abscess formation. However, it was uncertain regarding the source of infection. In the second patient, the infection is due to an uncommon organism and the probable source was IV fluids.

In all the patients, including our two patients, with this complication, NBCA was used as the embolizing material. Whether NBCA, probable compromised sterility, could be the source for the infection is a point to ponder. In the recent years, a new agent, onyx, is being used for the endovascular treatment of AVMs. Only long-term studies would show if onyx has advantage over NBCA in terms of delayed infection or abscess formation.

References

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