Bilateral Basal Ganglia Haemorrhage Secondary to Carbon Monoxide Poisoning

Simultaneous bilateral ICHs are exceptionally rare and an association with carbon monoxide poisoning is yet to be described (Neau et al., 1997). Only 19 case reports exist to date that describe an association between carbon monoxide poisoning and haemorrhagic infarction. Whilst the chronic effects of carbon monoxide poisoning are poorly understood, we propose that in this case carbon monoxide poisoning may have been a significant predisposing factor to the Abstract


Simultaneous
bilateral ICHs are exceptionally rare and an association with carbon monoxide poisoning is yet to be described (Neau et al., 1997).Only 19 case reports exist to date that describe an association between carbon monoxide poisoning and haemorrhagic infarction.Whilst the chronic effects of carbon monoxide poisoning are poorly understood, we propose that in this case carbon monoxide poisoning may have been a significant predisposing factor to the Abstract Background and Importance: Simultaneous bilateral intracerebral haemorrhages (ICH) are exceedingly rare with only a few cases reported in the literature.Identified causes include systemic arterial hypertension, amyloid angiopathy, vasculitis, diabetic ketoacidosis and cerebral mucormycosis.Only 19 cases report an association between haemorrhagic infarct and preceding carbon monoxide (CO) poisoning.Clinical Presentation: We describe a case in which recent CO poisoning may have been a significant predisposing factor to the development of bilateral basal ganglia haemorrhages.When maximum medical management failed to control raised intracranial pressure, bilateral decompressive craniectomies were undertaken.Conclusion: To our knowledge there have been no reported cases of CO poisoning causing spontaneous bilateral basal ganglia haemorrhage, managed with decompressive craniectomy.development of basal ganglia haemorrhage.To our knowledge, there have been no reported cases of carbon monoxide poisoning leading to ICH.
Moreover, the utilisation of decompressive craniectomy in the management of simultaneous bilateral ICH has not previously been reported.The rational of the operative procedure in the setting of ICH is to prevent the associated haematoma mass effect as well as the toxic effects of haematoma degradation (Fung et al., 2012).Decompressive craniectomy has been successfully applied in various other causes of intracranial space-occupying pathology, including major ischaemic stroke and trauma, with studies showing significant clinical benefit.The role of decompressive craniectomy in the setting of ICH, however, is far more questionable, and current studies remain inconclusive about its value (Fung et al., 2012).However there is evidence of benefit in certain subgroups of patients with ICH, and we maintain that its role in the setting of ICH has not yet been fully elucidated.

Case Report
A 49 year old Afro-Caribbean man was found unconscious at home with vomit around their mouth, and evidence of both faecal and urinary incontinence.The patient had no significant past medical history, lived alone, and worked as a data analyst.During their hospital stay it emerged that one month prior to admission, the patient had been fixing his boiler, when he involuntarily inhaled a large volume of released gas, carbon monoxide (CO).
On admission, the patient was tachycardic (130bpm) and hypertensive (160/90mmHg) with a Glasgow Coma Scale (GCS) of 5 (E1V1M3).He was resuscitated, intubated and ventilated, and a CT head performed.This revealed bilateral basal ganglia haemorrhages (Figure 1).The patient was transferred to their local ITU with a GCS of 6 (E2, V1, M3).At discharge from our unit, the patient had been successfully weaned off the ventilator, and was breathing independently.His brain stem reflexes were all intact, however he remained quadriplegic.
Bilateral ICH typically affects the thalamic and putaminal regions, not unlike unilateral solitary ICH (Neau et al., 1997).However, the former have been shown to carry a grave prognosis.This is thought to be linked to the concomitant effect on both decussating and non-decussating tracts.The uncrossed pyramidal tracts and the sensory tracts may remain unaffected in a solitary, unilateral ICH and hence aid neurological recovery.However in bilateral ICH, these tracts are compromised, dramatically worsening neurological dysfunction, and therefore impacting negatively on morbidity and mortality.Furthermore, the diaschisis effect of bilateral ICH exaggerates the neurological deficits of these patients.

Carbon monoxide as a cause of intracerebral haemorrhage
In the case described, the CO leak from the boiler was the only identifiable risk factor.CO poisoning is known to have many neurological sequela, including diffuse hypoxic-ischaemic encephalopathy (Bianco & Floris, 1996) (Ernst & Zibrak, 1998).With regard to metabolic cellular injury, this is related to mitochondrial dysfunction and the activation of polymorphonuclear leukocytes with brain lipid peroxidation (Lo et al., 2007).These mechanisms lead to central nervous system complications via many pathways, and more complex downstream metabolic changes.One of the major mechanisms is through injury to the endothelium and vascular compromise within the brain (Quinn et al., 2009).This is supported by neuroimaging evidence of foci of haemorrhage and necrosis occurring after CO toxicity (Bianco & Floris, 1996), as well as haemorrhagic infarcts occurring as a complication of CO exposure (Bianco & Floris, 1996;Finelli & DiMario, 2004).This is highly significant with regards to a link to ICH development, as small vessel damage is integral to the pathogenesis of ICH (Smith & Eskey, 2011).The major recognised causes of ICH, including hypertension and cerebral amyloid angiopathy, lead to haemorrhage via gradual damage and weakening of the small vessels of the brain (Smith & Eskey, 2011; Thanvi & Robinson, 2006).Therefore, the evidence of CO damage to the penetrating vessels of the brain describes a rational predisposition to the development of ICH.

Figure 1 :
Figure 1: Axial CT head showing bilateral basal ganglia haemorrhages (red arrows).The sulci, ventricles, and cisterns are effaced demonstrating the significant mass effect exerted by the haemorrhages