Transient Ischaemic Attack (TIA)

Definition

A Transient Ischaemic Attack (TIA) is a temporary period of neurological dysfunction caused by a brief interruption in blood supply to part of the brain. Often referred to as a "mini-stroke," a TIA does not cause permanent damage but is a warning sign for potential future strokes.

Aetiology

TIAs can be caused by various factors, including:

• Atherosclerosis: Plaque buildup in the arteries that supply blood to the brain
• Embolism: Blood clots or debris from other parts of the body traveling to the brain
• Arterial dissection: Tear in the artery wall
• Cardiac conditions: Atrial fibrillation, heart attack, or valve disease
• Blood disorders: Such as sickle cell disease or clotting disorders

Pathophysiology

TIAs occur when there is a temporary reduction in blood flow to part of the brain. This can be due to a clot blocking a blood vessel (thromboembolism), decreased blood flow due to narrowed arteries (atherosclerosis), or other causes that reduce blood supply. The lack of oxygen and nutrients temporarily disrupts brain function, leading to the symptoms of a TIA.

Risk Factors

• Age (older age increases risk)
• Hypertension (high blood pressure)
• Diabetes
• High cholesterol levels
• Smoking
• Obesity
• Physical inactivity
• Family history of stroke or TIA
• Cardiac conditions (e.g., atrial fibrillation)
• Excessive alcohol consumption

Signs and Symptoms

• Sudden numbness or weakness, especially on one side of the body
• Sudden confusion or trouble speaking or understanding speech
• Sudden trouble seeing in one or both eyes
• Sudden trouble walking, dizziness, or loss of balance or coordination
• Sudden severe headache with no known cause

Duration Compared to Stroke

The duration of a TIA is typically short, lasting less than 24 hours and often only a few minutes to a couple of hours. Unlike a stroke, which can cause permanent neurological damage, the symptoms of a TIA resolve completely within this time frame. A stroke, on the other hand, can last longer and lead to lasting brain injury, disability, or death if not promptly treated.

Investigations

• Clinical history and physical examination
• Blood tests to check for underlying conditions (e.g., cholesterol, glucose levels)
• Electrocardiogram (ECG) to check for heart conditions
• Brain imaging (MRI or CT scan) to rule out stroke or other abnormalities
• Carotid ultrasound to assess blood flow in the carotid arteries
• Echocardiogram to evaluate heart function and identify potential sources of emboli

Aspirin Treatment if Suspected TIA

If a TIA is suspected, it is recommended to administer aspirin immediately to reduce the risk of a subsequent stroke. The typical dose is 300 mg of aspirin as soon as possible after the onset of symptoms. This is based on NICE guidelines which emphasise the importance of rapid antiplatelet therapy to minimise the risk of further vascular events.

Management

Primary Care Management

• Initial assessment and diagnosis based on clinical history and physical examination
• Immediate referral to a specialist for further evaluation and management
• Blood pressure management with antihypertensive medications
• Blood sugar control in patients with diabetes
• Lifestyle modifications (e.g., smoking cessation, diet, exercise)

Specialist Management

• Antiplatelet therapy (e.g., aspirin, clopidogrel) to reduce the risk of stroke
• Anticoagulant therapy for patients with atrial fibrillation (e.g., warfarin, NOACs)
• Carotid endarterectomy or stenting for significant carotid artery stenosis
• Management of underlying conditions (e.g., atrial fibrillation, diabetes, hyperlipidaemia)
• Patient education on recognising stroke symptoms and when to seek emergency care
• Regular follow-up to monitor and adjust treatment plans as necessary

Example Management for Transient Ischaemic Attack

A patient presenting with TIA symptoms should be referred to the hospital immediately for further evaluation. Initial management includes brain imaging (MRI or CT scan) to rule out stroke, blood tests to identify underlying conditions, and an ECG to check for heart issues. If atrial fibrillation is detected, anticoagulant therapy (e.g., warfarin or NOACs) should be initiated. Antiplatelet therapy with aspirin or clopidogrel may be started to reduce the risk of stroke. Lifestyle modifications such as smoking cessation, dietary changes, and regular exercise should be advised. Regular follow-up is necessary to monitor the patient’s condition and adjust treatment as needed.

References

1. NICE. (2024). Stroke and Transient Ischaemic Attack in Over 16s: Diagnosis and Initial Management. Retrieved from NICE
2. NHS. (2023). Transient Ischaemic Attack (TIA). Retrieved from NHS
3. Johnston, S. C., et al. (2000). Validation and Refinement of Scores to Predict Very Early Stroke Risk After Transient Ischaemic Attack. The Lancet.
4. Easton, J. D., et al. (2009). Definition and Evaluation of Transient Ischaemic Attack. Stroke.
5. Amarenco, P., et al. (2016). One-Year Risk of Stroke After Transient Ischaemic Attack or Minor Stroke. New England Journal of Medicine.