Cerebral abscess post angioembolization of Vein of Galen Malformation

A preterm baby (36 weeks) with polyhydramnios delivered via LSCS, was diagnosed with vein of Galen malformation (VOGM) antenatally. Further evaluation with postnatal MRI and then Endovascular glue embolization was done on third day of life. Post embolization, baby was alright up to 3 months, then developed multiple episodes of vomiting, non-bilious and projectile. No history of fever.

Preoperative MRI - Dilated prosencephalic vein draining into dilated falcine sinus and then into superior sagittal sinus - suggestive of VOGM.

Post embolization after 3 months CT shows post embolization cast with conglomerated cystic lesions involving left thalamus with moderate perilesional oedema and moderate supratentorial hydrocephalus with periventricular ooze.

Further MRI confirmed ring-enhancing lesions in thalami, associated with moderate oedema extending into midbrain suggestive of brain abscess.

Leptomeningeal enhancement in quadrigeminal and ambient cisterns, aqueduct and roof of fourth ventricle suggestive of meningitis.

Background

One of the treatments of VOGM is endovascular embolization. Embolizing agents such as N-butyl cyanoacrylate and ethylene-vinyl alcohol copolymer derivatives, such as Onyx etc. are commonly used [1]. Postoperative complications associated with embolization includes intracranial haemorrhage ischemic stroke, hydrocephalus and intracranial infections [1].

Development of cerebral abscess post embolization of VOGM is rare, only few cases has been reported. Although these are rare complication, but it needs detailed evaluation [2].

The pathogenesis of this is unclear. Disruption of the blood-brain barrier is one of the risk factors [3]. Most reports suggest that these are result of direct hematogenous spread to susceptible tissue, from either exogenous or endogenous sources [1].

Clinical Perspective 

Clinically many cases having nonspecific inflammatory or septic symptoms. Symptoms of raised intracranial pressure, seizures, fever and focal neurological deficits are common forms of presentation [4].

Imaging Perspective 

Plain CT brain shows a lesion with outer hyperdense rim and central hypodensity (double rim sign). MRI is more sensitive than CT in diagnosing brain abscess. The lesions show central hypointense signal on T1WI with peripheral hyperintensity on T2W/FLAIR images. On post-contrast images, the lesion shows ring enhancement. They show true restriction on DWI and elevated lipid-lactate peaks on MR spectroscopy [4].

Outcome 

Antibiotics remain the mainstay of treatment, however, they can also be surgically managed.

Teaching Points

Post-procedure imaging is necessary to assess for hydrocephalus and complications such as intracranial haemorrhage and abscess.

MRI is more sensitive in diagnosing brain abscess.