There is an increased incidence of young people with stroke (age ≤45years) in Human immunodeficiency virus (HIV) endemic countries; this has been largely attributed to hypertension. However, hospital based surveys in countries like Malawi and South Africa have shown that the prevalence of hypertension in these young people is lower than expected, but HIV infection is substantially higher, implicating HIV as a risk factor. For many years a link between HIV and stroke has been postulated, but the relationship is uncertain. Whilst HIV may be a risk factor for stroke directly through mechanisms linked with HIV-associated vasculopathy, or indirectly through opportunistic infections, the drugs that treat HIV infection may also increase the risk of stroke because of their metabolic effects. Many studies, almost all retrospective, have failed to separate the direct effect of HIV infection from the indirect effects, including combined antiretroviral therapy, on cerebrovascular risk. HIV infection increases the risk of stroke mimics such as intracranial toxoplasma infection. The Recognition of Stroke in the Emergency Room (ROSIER) score is commonly used to screen for a stroke and triage patients for computer tomography (CT) of the brain. However, the accuracy of the ROSIER score and CT brain to reliably differentiate a stroke diagnosis from those with a stroke mimic in people with HIV infection is uncertain. I found that the ROSIER score and CT brain imaging had poor diagnostic accuracy in an HIV positive population. Therefore, in my thesis, every patient with an acute neurological symptom was fully assessed for a stroke as part of the screening process and confirmation was by magnetic resonance brain imaging. I subsequently investigated the risk factors and aetiology of stroke through a prospective case-control study in an HIV endemic country. Through this work, I showed that HIV infection is associated with cerebrovascular disease. Although hypertension was the leading risk factor in the population overall, HIV infection and its treatment was the second most important, and the most important in younger patients. Unexpectedly, I found that starting combined antiretroviral therapy in a subgroup of people living with HIV infection independently increased the risk of stroke. In this cohort, ischaemic stroke was the predominant stroke type and opportunistic infections only accounted for less than a third of these cases. The heterogeneity of HIV stroke with respect to risk factors for stroke, the degree of immunosuppression and HIV activity, and prior or current opportunistic infection has made it difficult to generalise epidemiological findings in some studies to populations at large. My study, to some extent unravels some of this ambiguity. I speculate that HIV related strokes evolves through the introduction of cART and then transitions into an aging population, accelerating atherosclerotic stroke and potentially contributing to an anticipated stroke epidemic in countries like Malawi.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:617504 |
| Date | January 2014 |
| Creators | Benjamin, Laura |
| Contributors | Solomon, Tom; Allain, Theresa |
| Publisher | University of Liverpool |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://livrepository.liverpool.ac.uk/16133/ |
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