CT-guided drainage of a brainstem abscess in a cat as an emergency treatment procedure

Abstract

Case summary A 3-year-old male neutered domestic shorthair cat was presented with a 1-week progressive and rapidly deteriorating history of lethargy and abnormal behaviour. Neurolocalisation indicated multifocal intracranial lesions (right oculomotor nerve, brainstem [obtundation, non-ambulatory tetraparesis, vestibular dysfunction and intermittent decerebrate rigidity] and possibly the thalamus [left-sided pleurothotonus]), or more likely a single brainstem lesion with mass effect. MRI of the brain demonstrated a brainstem abscess causing severe dorsal displacement particularly affecting the pons and the medulla oblongata causing cerebellar vermis herniation through the foramen magnum. CT-guided free-hand technique drainage of the brain abscess was performed and broad spectrum antibiotics were started based on sensitivity results. The cat recovered uneventfully from anaesthesia displaying marked improvement immediately after the procedure. Antibiotics were continued for 8 months; repeat imaging prior to withdrawal found complete resolution of the brainstem abscess. Relevance and novel information Free-hand CT-guided drainage of a brainstem abscess is not without risk; however, in this case it led to significant clinical improvement and stabilisation likely owing to reduced intracranial pressure. It also provided a diagnostic sample that allowed successful medical treatment planning and outcome. To our knowledge, this is the first report describing the successful management of a brainstem abscess by CT-guided drainage in the veterinary literature. It suggests that stereotactic drainage followed by medical therapy can be considered a successful therapeutic alternative to brain surgery or medical treatment alone, providing an emergency treatment in cases of acute brainstem dysfunction.

Can MRI differentiate between ring‐enhancing gliomas and intra‐axial abscesses?

“…[24][25][26] Since the two diseases require very different treatment and have a different prognosis, a correct imaging interpretation is paramount. 13,17,27,28 The aims of the current study were to compare the MRI features of confirmed ring-enhancing gliomas and intra-axial brain abscesses in dogs and cats and to identify the imaging features that might help to differentiate them. The authors' hypotheses were that (1) some MRI qualitative characteristics would be associated with brain abscess/glioma classification and (2) a threshold value for the ratio between lesion diameter and capsule thickness in T1W postcontrast sequences could be used as a cutoff for discriminating between brain abscesses and gliomas.…”

“…However, overlapping imaging features have been reported 24–26 . Since the two diseases require very different treatment and have a different prognosis, a correct imaging interpretation is paramount 13,17,27,28 …”

Clinical presentation, treatment, and outcome of 24 dogs with bacterial meningitis or meningoencephalitis without empyema (2010‐2020)

“…A diagnosis of BM was considered to include (1) the presence of intracellular bacteria on CSF cytological evaluation or (2) positive CSF bacteriological culture or (3) neutrophilic pleocytosis (specifically degenerate neutrophils) on CSF cytological evaluation with clinical improvement after initiation of administration of antibiotics, or these findings in combination. Cases were excluded if they had incomplete medical records or imaging findings consistent with empyema (evidence of accumulation of T1W‐hypointense, T2W‐ and FLAIR‐hyperintense extra‐axial material with peripheral heterogenous contrast enhancement) 10,12 or suspected intracranial abscess formation indicated by a well demarcated mass lesion with a T1W‐hypointense, T2W‐hyperintense center, and strongly contrast enhancing rim 24 …”

Computed Tomography-Guided Fine Needle Biopsies of Vertebral and Paravertebral Lesions in Small Animals

“…The use of CT-guidance to obtain diagnostic samples from lesions was first described in 1994 in veterinary medicine [2,3]. Since then, several studies have been published in small animals using both stereotactic free-hand CT-guided techniques and CT-guidance devices [4][5][6][7][8][9][10][11][12]. Computed tomographic-guidance provides advantages in comparison to ultrasound-guided techniques, which are the most common sampling techniques in veterinary medicine.…”

“…Therefore, sampling under CT-guidance is especially indicated for inaccessible or hardly accessible lesions under ultrasound-guidance, like intrathoracic lesions, intracranial lesions and vertebral and paravertebral lesions. There are several studies of CT-guided sampling of intrathoracic lesions [4][5][6], brain lesions [8][9][10]12] and bone lesions too [7].…”