Thrombolysis (Stroke)

Thrombolysis for stroke is a treatment that uses a clot-dissolving medicine, injected into a vein, to break up the blood clot that is blocking blood flow to part of the brain.

Most strokes happen when a blood clot plugs an artery (a blood vessel that carries oxygen-rich blood) inside the brain. Without oxygen, brain cells begin to die within minutes. Thrombolysis works by releasing a medicine called a thrombolytic (clot-breaker) into the bloodstream. The medicine travels to the clot and breaks it apart, restoring blood flow so that as many brain cells as possible can survive. Because time is critical, this treatment is almost always given in a hospital emergency setting.

Thrombolysis for stroke is used specifically for ischaemic stroke (a stroke caused by a blood clot), when the patient arrives at hospital within a narrow time window after symptoms start. The decision to use it depends on several factors checked by the treating doctor.

• Acute ischaemic stroke (sudden blockage of a brain artery by a clot) confirmed on brain imaging such as CT or MRI.
• Stroke symptoms that started within a time window that your doctor considers safe for treatment — this window is usually measured in hours from when symptoms were first noticed.
• Significant disability caused by the stroke, such as sudden weakness on one side of the body, difficulty speaking, or loss of vision.
• No other medical reason that makes clot-dissolving medicine dangerous for that patient.

There are situations where thrombolysis is not suitable. The doctor will carefully rule these out before proceeding.

• Haemorrhagic stroke (a stroke caused by bleeding in the brain rather than a clot) — dissolving a clot would make bleeding worse.
• Symptoms that started too long ago, outside the safe treatment window.
• Recent major surgery, serious injury, or invasive medical procedure that raises the risk of dangerous bleeding.
• Very high blood pressure that cannot be quickly controlled.
• A history of bleeding inside the brain.
• Active internal bleeding elsewhere in the body.
• Certain blood-clotting disorders or use of blood-thinning medicines that affect how safely the drug can be used.
• Very low or very high blood sugar at the time of arrival.

Thrombolysis carries real risks, and the doctor weighs these carefully against the harm the stroke itself is causing. The most important risks are:

• Bleeding in the brain (haemorrhagic transformation) — the most serious risk; the clot-dissolving medicine can sometimes cause or worsen bleeding inside the brain.
• Bleeding at the site where the intravenous (IV) line was inserted.
• Bleeding in other parts of the body, such as the digestive tract.
• Allergic reaction to the medicine, ranging from mild skin flushing to, rarely, a more serious response.
• Angioedema (sudden swelling of the lips, tongue, or throat) — uncommon but requires immediate attention.
• Drop in blood pressure during or shortly after the infusion.
• The treatment may not dissolve the clot completely, meaning some disability from the stroke may remain.
• In rare cases, the stroke symptoms may worsen despite treatment.

Because thrombolysis is an emergency treatment, there is usually very little time for preparation. Most steps happen simultaneously and rapidly in the emergency department. However, understanding what typically occurs can help patients and families feel less overwhelmed.

Fasting and medication pauses: In an emergency like stroke, fasting rules and planned medication pauses are generally not applied. The team will ask about any blood thinners or other medicines the patient is currently taking, because some affect whether thrombolysis can be given safely.

Tests that are usually run immediately on arrival include:

• Brain CT scan or MRI — to confirm the stroke is caused by a clot and not by bleeding.
• Blood tests — to check clotting ability, blood sugar, kidney function, and blood cell counts.
• Blood pressure measurement — taken multiple times, because very high blood pressure may need to be treated first.
• Heart tracing (ECG, or electrocardiogram) — to look for heart rhythm problems that can cause clots.
• Assessment of neurological function — the doctor or nurse scores how severely the stroke is affecting movement, speech, and vision using a standard scale.

What typically happens during the procedure, step by step:

• An intravenous (IV) cannula (a small plastic tube) is inserted into a vein, usually in the arm.
• The doctor reviews the test results and confirms that thrombolysis is appropriate.
• A small initial dose of the thrombolytic medicine is injected quickly into the IV line.
• The remaining portion of the medicine is then given as a slow infusion (drip) over about an hour — the exact time depends on the protocol used by the treating team.
• Throughout the infusion, nursing staff monitor blood pressure, level of consciousness, and any signs of bleeding or allergic reaction very closely.
• After the infusion ends, monitoring continues intensively, usually in a dedicated stroke unit or high-dependency area.

After thrombolysis, close monitoring is essential because the risk of complications — especially bleeding in the brain — is highest in the first hours and days after treatment. Most patients are observed in a dedicated stroke unit or a high-dependency care area where nurses can check their condition frequently.

• Blood pressure is measured very frequently in the hours following treatment, as sudden changes can signal a complication.
• Neurological checks (assessments of alertness, movement, and speech) are carried out regularly to track whether the stroke is improving or worsening.
• Blood thinners are usually withheld for a period after thrombolysis — the doctor will decide when it is safe to start or restart them.
• The patient typically stays flat or with minimal head elevation for a period after the infusion; the exact position depends on the treating team's instructions.
• Eating, drinking, and swallowing are assessed by a trained therapist before the patient is allowed to eat or drink, because stroke can affect the ability to swallow safely.
• If the patient is stable and improving, they may be moved from the high-dependency area to a general stroke ward, usually within a day or two.
• Rehabilitation — including physiotherapy (movement exercises), speech therapy, and occupational therapy — usually begins as soon as the patient is medically stable, often within the first day.
• A follow-up brain scan (CT or MRI) is commonly done within a day or two to check whether any bleeding has occurred.
• Before discharge, the team will review medicines to reduce the risk of another stroke, and arrange outpatient follow-up appointments.
• Lifestyle guidance on factors such as blood pressure control, diet, physical activity, and stopping smoking is usually provided before the patient leaves hospital.