Brain abscess

Introduction

Cerebral abscesses are a suppurative process within the brain parenchyma owing to inflammation and infection. The most common locations are the frontal, temporal, parietal, cerebellar, and occipital lobes, which receive the majority of cerebral blood supply. The major predisposing factors are an associated contiguous infection in 40% to 50% (otitis media in young children and older adults, paranasal sinusitis in older children and young adults), trauma or iatrogenic in 10%, hematogenous spread in 25%, and cryptogenic in 15%. The microbial etiology is dependent on the site of primary infection, in which the most commonly isolated are anaerobes, streptococci, Enterobacteriaceae, and Staphylococcus aureus , in which 30% to 60% are polymicrobial. Successful treatment of cerebral abscess is dependent on early identification, drainage, and specific antibiotic therapy. In this chapter, we present a case of a patient with a deep-seated, basal ganglia cerebral abscess.

Example case

Chief complaint: headaches and left-sided weakness

History of present illness

A 33-year-old, right-handed woman with no significant past medical history presented with progressive headaches and left-sided weakness. Over the past couple of days, she noted increasing headaches with left arm and leg weakness. She complained of fevers and chills for several days prior. She was seen in the emergency room where imaging revealed a brain lesion ( Fig. 73.1 ).

Medications: None.
Allergies: No known drug allergies.
Past medical and surgical history: None.
Family history: No history of intracranial malignancies.
Social history: Homemaker with two kids, no alcohol, no smoking, no illicit drug use.
Physical examination: Awake, alert, oriented to person, place, time; Cranial nerves II to XII intact; Left drift, moves all extremities with good strength, except left upper and lower extremities 4/5.
Imaging: Chest/abdomen/pelvis computed tomography negative for primary lesion.
Labs : Elevated white blood cells (13K), erythrocyte sedimentation rate, C-reactive protein; Blood, urine cultures pending.

	Arturo Ayala-Arcipreste, MD, Hospital Juarez de Mexico, Mexico City, Mexico	Bernard R. Bendok, MD, Devi Prasad Patra, MD, Mayo Clinic, Phoenix, AZ, United States	Reid C. Thompson, MD, Vanderbilt University, Nashville, TN, United States	Claudio Gustavo Yampolsky, MD, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
Preoperative
Additional tests requested	MRS DTI CSF analysis HIV serology Neuropsychological assessment	MRS fMRI DTI/DWI	Cardiac echo Panorex x-rays	MRSfMRI DTI Neurooncology evaluation Radiation oncology evaluation
Surgical approach selected	Right frontal stereotactic frame-based needle biopsy and aspiration	Right frontotemporal awake craniotomy with motor cortical and subcortical mapping	Right frontotemporal craniotomy	Right awake frontotemporal craniotomy
Anatomic corridor	Frontal transcortical	Trans-Sylvian, frontal operculum	Trans-Sylvian, transinsular	Trans-Sylvian, trans-opercular
Goal of surgery	Aspiration of purulent material and size reduction	Maximal safe resection, decompression of the lesion	Establish diagnosis, remove enhancing portion, preserve neurologic function especially CST	Maximal safe resection without affecting function
Perioperative
Positioning	Right supine	Right supine with left head rotation	Right supine left rotation	Right supine left rotation
Surgical equipment	Surgical navigation IOM (SSEP/MEP)	Surgical navigation IOM Surgical microscope	Surgical navigation Surgical microscope Ultrasound	Surgical navigation IOM Monopolar and bipolar brain stimulator Surgical microscopeUltrasonic aspirator
Medications	Steroids Antiepileptics	Steroids Mannitol, hypertonic saline Antiepileptics	Steroids Mannitol Antiepileptics	Steroids Antiepileptics
Anatomic considerations	Frontal lobe, basal ganglia, frontal cortical veins, right lateral ventricle	Sylvian fissure vessels, M2–M3 branches, motor cortex, internal capsule	MCA branches, internal capsule, caudate	MCA M2 branches, internal capsule
Complications feared with approach chosen	Motor deficit, hemorrhage, cerebral edema	Motor deficit, MCA injury	Sylvian vascular injury, motor deficit	Motor deficits
Intraoperative
Anesthesia	General	General	General	Awake
Skin incision	Right linear	Right pterional	Right pterional	Right pterional
Bone opening	Right frontal	Right frontotemporal	Right frontotemporal	Right frontotemporal
Brain exposure	Right frontal	Right frontotemporal	Right frontotemporal	Right frontotemporal
Method of resection	Application of stereotactic headframe with ring parallel to skull base, acquire head CT images, check fiducials, enter coordinates into computer to get coordiantes for frame, attach frame, mark entry point, vertical incision, burr hole with high speed drill, expand burr hole, open dura, visualize cortical surface, avoid vessels, cauterize pia with bipolar, insert needle through burr hole, aspirate abscess with syringe, needle is inserted to different depths until no more purulence is aspirated, needle withdrawn	Myocutaneous flap, right pterional craniotomy with keyhole burr hole, C-shaped dural opening based on sphenoid wing, wide opening of Sylvian fissure anteriorly and posteriorly with care of MCA lenticulostriate perforators with microscopic visualization, motor mapping of frontal and temporal opercula, identify sulcus with negative mapping closest to the lesion in frontal operculum, transsulcal dissection to identify lesion capsule, decompress lesion and biopsy capsule, dissect capsule from surrounding white matter with mapping in deeper location if biopsy negative for malignancy, capsule may be adherent to MCA branches inferomedially, leave layer of capsule along Sylvian fissure if adherent, dura closure with pericranium if needed	Right pterional craniotomy (~5 cm) centered on Sylvian fissure, cruciate dural opening, Sylvian fissure split under microscopic visualization, enter mass directly, if approach unfavorable then through frontal operculum, enter mass and send specimen on nonnecrotic tissue, remove enhancing components along edges if obvious tumor, debulk until normal white matter seen but do not chase deep portions, remove organized wall only if separates easily if abscess, ultrasound and navigation to guide completeness	Scalp block, patient remains awake, right frontotemporal craniotomy, dural opening, cortical mapping for language/motor/cognitive, frontal opercular corticectomy based on negative mapping sites, expose insular cortex, identify M2 perforators and lenticulostriate arteries, resect insular portions of tumor, subcortical mapping to identify CST within internal capsule
Complication avoidance	Stereotactic headframe placement, needle aspiration, avoid sulcal vessels	Cortical and subcortical mapping, Sylvian fissure opening, careful dissection of the capsule from MCA branches	Sylvian fissure opening, intratumoral biopsy to guide further resection, ultrasound	Awake surgery, motor/language. Executive functioning, identify M2 and lenticulostriates, transopercular approach based on negative mapping
Postoperative
Admission	ICU	Intermediate care	ICU	ICU
Postoperative complications feared	Hemorrhage, edema, motor deficit	Cerebral edema, MCA vasospasm, motor deficit, language dysfunction, meningitis, CSF leak	Hemiplegia, seizures, MCA stroke	Motor deficit
Follow-up testing	CT within 24 hours after surgery MRI 2 weeks after surgery	MRI within 72 hours and 6 weeks after surgeryCulture and sensitivity testing	MRI night of surgery	MRI within 24 hours after surgery
Follow-up visits	14 days after surgery	14 days and 6 weeks after surgery	14 days and 6 weeks after surgery	7 days after surgery