Pathophysiology of post-stroke hyperglycaemia and brain arterial patency

MacDougall, Niall John James (2013) Pathophysiology of post-stroke hyperglycaemia and brain arterial patency. MD thesis, University of Glasgow.

Full text available as:
[img]
Preview
PDF
Download (2MB) | Preview

Abstract

The pathophysiology of acute post-stroke hyperglycaemia (PSH) is important as
hyperglycaemia affects the majority of stroke patients, and is consistently associated with
poorer outcome in terms of survival, disability and markers of brain injury such as infarct
expansion. There appears to be an interaction between brain arterial patency and
hyperglycaemia that has not been fully characterised.
This thesis initially reviews the literature on hyperglycaemia and stroke before focusing on
animal models of PSH and clinical trials of insulin treatment for PSH in two systematic
reviews with meta-analysis. The thesis then looks at the relationship between glucose
profiles and clinical outcome in a historical population receiving IV thrombolysis for acute
ischaemic stroke, specifically exploring alternative indices of glycaemic state to compare
the optimal predictive index for functional outcome as measured by the modified Rankin
scale.
The main body of the thesis details a prospective observational clinical study which
recruited 108 patients within 6 hours of acute ischaemic stroke. These patients had careful
monitoring of blood glucose levels over a 48 hour period and detail brain imaging
including CT perfusion scanning to examine the ischaemic penumbra, CT angiography on
admission and at 24-48 hours to document brain arterial patency with follow-up CT brain
imaging to assess outcome infarct volume. The relationship between 48 hour blood
glucose profiles, clinical outcome and imaging findings is then explored.
The main findings of the thesis are summarized below.
· Animal models of PSH have shown that hyperglycaemia exacerbates infarct
volume in MCA occlusion models but studies are heterogeneous, and do not
address the common clinical problem of PSH because they have used either the
streptozotocin model of type I diabetes or extremely high glucose loads.
· Animal models show that insulin has a non-significant and significantly
heterogeneous effect on infarct growth.
3
· Clinical trials of insulin for post stroke hyperglycaemia have shown no benefit in
terms of improved functional outcomes or mortality. Insulin is associated with an
increased risk of hypoglycaemia.
· In a historical cohort mean capillary blood glucose over 48 hours was more
predictive of clinical outcome that admission blood glucose or two consecutive
elevated glucose measurements.
· A high proportion of acute stroke patients have a blood glucose level above
7mmol/L within 6 hours of onset. Different patterns of blood glucose levels define
different populations.
· Higher admission and mean glucose levels correlate with larger infarct volumes.
Larger core perfusion lesion volumes are associated with a greater risk of mortality.
Admission hyperglycaemia is more harmful than hyperglycaemia after 6 hours.
· In patients with angiographic evidence of an arterial occlusion infarct volume
varies significantly with glycaemic status. In some populations late
hyperglycaemia is associated with better imaging outcomes.
· Tandem occlusions are associated with bad outcomes after ischaemic stroke.

Item Type: Thesis (MD)
Qualification Level: Doctoral
Keywords: stroke, hyperglycaemia, CT, perfusion CT, animal models, met-analysis, human studies, brain arterial patency, CT angiography, acute stroke.
Subjects: R Medicine > RC Internal medicine > RC0321 Neuroscience. Biological psychiatry. Neuropsychiatry
Colleges/Schools: College of Medical Veterinary and Life Sciences > Institute of Neuroscience and Psychology
Supervisor's Name: Muir, Professor Keith W.
Date of Award: 2013
Depositing User: Dr Niall JJ MacDougall
Unique ID: glathesis:2013-4568
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 26 Oct 2013 11:07
Last Modified: 28 Oct 2016 15:14
URI: http://theses.gla.ac.uk/id/eprint/4568

Actions (login required)

View Item View Item