Brain abscess case reports from the General University Hospital Alicante
A 51-year-old male was admitted to the ICU due to status epilepticus secondary to a cerebral lesion under investigation. The patient is sedated and currently on mechanical ventilation. A brain MRI was requested to further assess the condition.
Imaging Findings:
The brain MRI, including sequences without and with intravenous contrast as well as a perfusion sequence, revealed a single space-occupying lesion. This lesion is situated in the left frontal white matter, presenting as a spherical structure with an approximate diameter of 2 cm.
Lesion Characteristics: The lesion appears predominantly necrotic, featuring a well-defined, homogeneous 2 mm thick wall with a smooth surface. On T2-weighted images, the lesion exhibits low signal intensity, while demonstrating intense contrast enhancement after administration. Notably, the central necrotic portion of the lesion displays restricted diffusion.
Edema and Mass Effect: The patient also presents with marked vasogenic edema surrounding the lesion. This edema is causing a mass effect on adjacent sulci and the frontal horn of the left lateral ventricle. A slight midline shift of approximately 3 mm is noted, without signs of brain herniation.
Perfusion Imaging: Both the lesion and the surrounding edema exhibit non-elevated relative cerebral blood volume (rCBV) values on perfusion imaging.
Additional Observations: There are no apparent parenchymal alterations of significance supra or infratentorial. No signs of venous thrombosis were identified, and the signal void of the major intracranial arterial vessels remains preserved. Ventricular size is conserved.
Diagnostic Impression: The imaging findings are suggestive of a left frontal space-occupying lesion, likely indicative of a brain abscess.
Recommendations: Appropriate interventions, such as drainage and antibiotic therapy, should be considered based on clinical and imaging findings.
Supine position with a neutral head. Fixation of navigation antenna on the right frontal region. Path for neuronavigation marked. Left frontal incision along the hairline. Trephination at this level after locating the entry point with neuronavigation. Coagulation and cruciate dural opening with corticotomy. Neuronavigated biopsy with extraction of approximately 3cc of purulent fluid. Hemostasis. Surgicel and trephine plate covering the entry point. Subcutaneous closure with absorbable material and skin closure with staples. A sample is sent for microbiological analysis.
Known space-occupying lesion, centered in the right frontal anterior white matter, with estimated diameters of 3.5 x 3 x 3.5 cm. It shows well-defined contours and a practically spherical shape. A predominantly hypointense signal on T1 and homogeneously hyperintense on T2, with a wall with hypointense behavior on T2-weighted sequences. After contrast administration, only enhancement of its wall was observed, in a fine and linear way, without identifying solid poles. The lesion shows diffusion sequence restriction and low values of rVSC in perfusion. Marked surrounding vasogenic edema, which causes a mass effect on the neighboring sulci, as well as mild subfalcian herniation, with a deviation from the midline of approximately 6 mm (significant improvement compared to previous CT control). The discrete mass effect is also on the knee of the corpus callosum and the frontal horn of the right ventricle. The findings are compatible with a brain abscess. A small solution of continuity is observed in its anterior wall, in contact with the meninge, which is thickened in a laminar manner in relation to inflammatory involvement, without clearly identifying empyema. Extensive occupation of the frontal sinus bilaterally, with an enhancement of its wall. Retrospectively, the CT study showed slight permeation on the posterior wall of one of the loculations of the frontal sinus close to the abscess. Small hyperintense foci in subcortical and periventricular white matter with a chronic ischemic profile of a small vessel, to a mild degree. Diagnostic impression: Findings compatible with a right frontal parenchymal abscess, 3.5 cm in diameter, with inflammatory changes and thickening of the adjacent pachymeninge, although without clear associated empyema.