The symposium explored various aspects of stroke management, including the urgent need to treat stroke as an emergency, the immediate diagnosis and prioritisation of critical patients, the ongoing debate between thrombolysis and thrombectomy, the complexities of atypical stroke presentations, navigating intracranial haemorrhage and addressing ethical dilemmas in stroke care. This issue will focus on the first three presentations, while the October and November issues will highlight the remaining topics.

Is stroke an emergency?

Dr Louis Kroon, neurologist, Steve Biko Academic Hospital and a lecturer at the University of Pretoria

Stroke is a critical medical emergency that requires immediate intervention, particularly because the timing of treatment significantly influences patient outcomes. Historically, the administration of tissue plasminogen activator (TPA) was limited to a six-hour window. However, landmark trials expanded this treatment window to 24 hours, which led to updated guidelines that now inform current stroke management protocols.

The importance of early treatment is underscored when examining stroke outcomes within the initial three-hour window. During this period, TPA administration is most effective, showing considerable benefits, especially in patients without large vessel occlusions (LVOs). However, when LVOs are present, the effectiveness of TPA alone diminishes, necessitating additional interventions like thrombectomy.

When TPA is combined with thrombectomy, the results are compelling, with one in four patients experiencing significantly improved outcomes. This combination makes it one of the most effective treatments currently available in medicine.

The necessity of such timely interventions is amplified by the global burden of stroke, which remains one of the leading causes of mortality worldwide. In low- and middle-income countries, stroke incidence has doubled from the 1990s to 2016, while it has declined by 42% in higher-income countries during the same period.

Notably, Africa experiences nearly a threefold higher stroke incidence and prevalence compared to Western Europe and the United States, translating to one stroke every three seconds globally, with potentially one in three people in South Africa expected to suffer a stroke.

The introduction of these new treatment guidelines has transformed stroke care, particularly in units like the one at Steve Biko Academic Hospital. From December 2020 to July 2024, the hospital's stroke unit evaluated >4100 patients, achieving high sensitivity in identifying strokes, albeit at the cost of some specificity, leading to a number of stroke mimics.

Nevertheless, prioritising sensitivity is crucial, as some strokes, particularly those presenting with atypical symptoms or mild deficits, can be easily missed, which would delay critical treatment.

One of the most significant challenges in stroke management is overcoming the reluctance to urgently image patients due to concerns over contrast-related kidney injuries. However, a meta-analysis of 14 studies emphasised that brain angioperfusion studies are not associated with a significant increase in acute kidney injury risk, even in patients with chronic kidney disease.

Another challenge is the misconception surrounding iodine allergies, often believed to be related to contrast media. The truth is that iodine, a normal trace element in the body, cannot be an allergen. Rather, the allergenic reactions are caused by parvalbumin, a protein found in seafood.

Furthermore, the concern over radiation exposure during CT perfusion imaging has been mitigated by advancements in technology, allowing for effective scans with minimal radiation exposure, comparable to background radiation levels in certain geographic regions.

Immediate diagnosis for all patients - prioritising the critical

Dr Ebrahim Kader, interventional and diagnostic neuroradiologist at Morton and Partners Radiologists and past-president Radiological Society of South Africa

Stroke, often described as a 'brain attack', represents a critical neurological emergency where timely intervention is essential to minimise damage and improve outcomes.

Stroke occurs when there is an interruption of blood supply to the brain, either due to a blockage (ischaemic stroke) or a bleed (haemorrhagic stroke). The brain's dependence on glucose and oxygen makes it highly vulnerable to disruptions in blood flow.

Under normal conditions, the brain consumes about 40% of the available oxygen and maintains a delicate balance of blood flow through various compensatory mechanisms. However, when blood flow drops to around 30%-40% of normal levels, symptomatic ischaemia ensues, and cell death becomes a risk when blood flow falls below 20%.

In cases of ischaemic stroke, the affected brain tissue undergoes rapid changes. Initially, there is a failure of the sodium-potassium pump due to insufficient oxygen and adenosine triphosphate, leading to cellular swelling and loss of brain structure differentiation. The critical threshold for irreversible damage is reached when cerebral blood flow (CBF) falls to 20% of normal levels.

Imaging is pivotal in diagnosing and managing stroke. The primary goal of initial imaging is not only to confirm the diagnosis of stroke but also to exclude contraindications to treatments like thrombolysis and identify alternative diagnoses. Imaging modalities used include:

• The first-line imaging tool for stroke, non-contrast CT (NCCT) is quick, cost-effective, and readily available. It helps to exclude intracranial hemorrhage and other structural abnormalities. However, it has limited sensitivity for detecting acute ischemia.
• CT angiography is used to visualise LVOs and can identify conditions such as aneurysms or dissections.
• CT venography is effective to assess collateral circulation and is useful for planning interventional procedures. It is particularly effective in detecting thrombus within vessels and understanding collateral circulation dynamics.
• CT perfusion provides a quantitative assessment of cerebral blood flow, blood volume, and mean transit time. It helps delineate the extent of ischaemic damage and differentiate between salvageable brain tissue (penumbra) and irreversibly damaged tissue (core). Key parameters include cerebral blood volume, CBF, and time to peak (TTP), with T-max indicating critical hypoperfusion.
• Magnetic resonance imaging offers detailed images and can reveal acute ischemic changes earlier than CT.
• MR perfusion assesses brain tissue viability and helps in planning thrombolysis or thrombectomy. It distinguishes between core infarct and penumbra using parameters such as diffusion-weighted imaging (DWI) and fluid-attenuated inversion recovery (FLAIR). DWI indicates areas of restricted diffusion, while FLAIR highlights areas with prolonged signal changes.

In stroke management, imaging results guide treatment decisions, such as thrombolysis or thrombectomy. Accurate and timely imaging can significantly impact patient outcomes by identifying patients with large penumbra who may benefit from mechanical thrombectomy.

Advanced imaging techniques, although more resource-intensive, provide critical insights into the extent of ischemic damage and the potential for tissue salvage.

The choice of imaging protocol should be consistent and tailored to each institution's capabilities and patient population. A standardised imaging protocol ensures reliable and reproducible results, minimising the risk of missed diagnoses or suboptimal treatment decisions. For example, protocols should address the timing of imaging and the interpretation of results to align with current guidelines and best practices.

The couch of controversy: Thrombolysis vs thrombectomy

Dr Wiebren Duim, neurologist based at Groenkloof Life Hospital in Pretoria

The pivotal National Institute of Neurological Disorders and Stroke Trial, published in 1995, demonstrated the efficacy of TPA in improving stroke outcomes.

The concept of 'time is brain' highlights the urgency of rapid intervention. Every minute counts, and delays in treatment can lead to worse outcomes. To emphasise the importance of swift action, consider the Ferrari Formula 1 pit stop analogy, said Dr Duim.

Just as pit stops are meticulously timed and executed, stroke treatment should be equally precise and prompt. This requires a well-coordinated effort among healthcare providers, from initial assessment to treatment.

Evidence from various trials and registries shows that timely TPA administration not only improves survival rates but also enhances functional recovery.

The 2021 European Stroke Organization guidelines strongly recommend intravenous thrombolysis within four and a half hours of symptom onset. Data from meta-analyses confirm that TPA offers a 46% improvement in achieving excellent outcomes.

As we move forward, let us remember the impact of effective stroke care on patients' lives. Investing in training, infrastructure, and rapid response systems is not just an option - it is a necessity for advancing stroke care in South Africa.

Key messages

1. Stroke should be treated as a critical emergency, as immediate intervention is crucial. The faster a stroke is identified and treated, the better the chances of minimising brain damage and improving patient outcomes. Delays in treatment can lead to irreversible damage and significantly worse outcomes.
2. Importance of imaging in stroke management: Accurate and timely imaging is essential in stroke management. Imaging not only confirms the diagnosis of stroke but also guides treatment decisions, helping to identify patients who can benefit from interventions like thrombolysis or thrombectomy. Advanced imaging techniques enable the precise assessment of brain tissue viability, which is critical in selecting the appropriate treatment.
3. Thrombolysis is a highly effective treatment when administered within the first few hours of symptom onset. It can significantly improve outcomes by dissolving the blood clots that block blood flow to the brain, thereby restoring circulation and reducing the extent of brain damage. When used promptly, thrombolysis can enhance the chances of a full recovery and minimise long-term disability, making it a crucial intervention in the early stages of stroke.