Abstract
Introduction
Dealing with the clinical presentation of a patient with alternating level of consciousness can be challenging. A systematic approach is required and a wide set of differential diagnoses is needed to maximise the chances of a diagnosis. Intracranial (parenchymal) brain abscesses can have a varied presentation especially in the younger patent.
Case Presentation
A gentleman in his 40s was brought into the Emergency Department by his concerned parents with 3-day history of alternating consciousness and worsening head and neck pain over the preceding 24 hours. On clinical examination the Glasgow Coma Scale (GCS) altered between 14 (E4 M6 V4) to 13 (E4 M5 V4), he was only able to concentrate for a period of seconds prior to periods with his eye rolling upwards and then return to baseline GCS of 14. He had extensive neuro-imaging as initial CT Brain was noted to be inconclusive, Detailed MRI imaging revealed a large right frontal abscess. On an emergency basis he had frameless stereotactic biopsy of the right frontal abscess which grew Gram negative bacilli and was negative for Tuberculosis. He subsequently had an External Ventricular Drain inserted. He was treated with intravenous antibiotics and he subsequently improved following a prolonged of period of treatment.
Discussion
The main sources of brain abscess are from traumatic brain injury, as a sequela of neurosurgical procedures, spread from a local source or haematogenous spread from systemic infections. However, in a large proportion of cases no under aetiologies can be elicited. CT and MRI imaging remain the cornerstone of imaging for brain abscesses and where the diagnosis is equivocal these patients would undergo biopsy to assess the underlying cause. High clinical suspicion is needed as the abscess presentation can be variable and imaging modalities have limited specificities
Conclusion
Clinicians need to be aware of the varying presentations of intracranial abscesses, a life-threatening condition unless timely treated. The importance of early involvement of a multidisciplinary team approach to the management of such complex cases in order to optimise the chances of a favourable outcome for the patient. Early targeted therapy can be challenging especially if the diagnosis is equivocal, hence the requirement of early use of neuro-imaging to ascertain the underlying cause.

Key words: Glasgow Coma Scale (GCS), Intracranial abscess, Neuro-imaging