Transient Ischemic Attacks - Emergency Management

Introduction:

A stroke is a life-threatening medical emergency in which the blood and oxygen flow to the brain is interrupted, causing the brain cells to die. Transient ischemic attacks (TIA) is a mini-stroke. It is caused by focal loss of blood and oxygen supply to the brain.

The most common cause is the presence of obstruction or clots in the major blood vessels supplying the brain (carotid or vertebral artery). It causes transient symptoms mimicking stroke, which begins suddenly and lasts two to thirty minutes. The symptoms resolve completely, as there is no permanent damage to the brain cells during a transient ischemic attack. However, they increase the risk of stroke markedly within the following days to weeks. Transient ischemic attacks are common among the elderly and should be considered a warning sign of the possibility of future strokes.

What Are the Factors That Increase the Risk of Transient Ischemic Attacks?

The various risk factors for stroke and transient ischemic attack include the following:

• Age greater than 55.

• History of stroke in the family.

• Men have a higher risk.

• Ethnicity or race (African Americans and Hispanics are at greater risk).

• Hypertension (increased blood pressure).

• High blood cholesterol levels.

• Diabetes (insulin resistance).

• Physically inactive people.

• Patients with heart disease.

• Smoking.

• Heart rhythm problems.

• Drug abuse (such as cocaine).

• High-risk diet.

• Stress and depression.

• Increased risk of blood clots (hypercoagulability).

• Obesity.

What Are the Symptoms of Transient Ischemic Attacks?

In transient ischemic attacks, the patients experience similar symptoms as a stroke. Most transient ischemic attacks last less than five minutes. The symptoms resolve within one hour without permanent brain damage or disability. The symptoms come on abruptly and include the following:

• Vision disturbances (transient monocular blindness) and blurred vision make seeing from one or both eyes difficult.

• Severe headache.

• Difficulty speaking (slurred speech).

• Weakness and numbness in one side of the face, arms, or legs.

• Dizziness (lightheaded or vertigo).

• Loss of coordination and balance.

• Muscle weakness.

• Confusion.

• Memory loss.

• Difficulty walking.

• Difficulty understanding words.

• Difficulty swallowing.

• Reduced sense of touch.

• Some may have increased heart rate and labile blood pressure.

How Is the Definitive Diagnosis of a Transient Ischemic Attack Made?

As transient ischemic attacks and strokes produce similar symptoms, it is important to rush to the emergency department immediately (even if the symptoms resolve). In addition, it is crucial to diagnose promptly to distinguish a transient ischemic attack from a life-threatening stroke. The diagnosis depends upon the resolution of symptoms (in less than an hour), imaging tests, and evaluation of the cause. The healthcare providers examine the patients and perform several diagnostic tests. The patient’s vision, ability to think, speak, and muscle strength are assessed. The diagnostic tests include the following:

1. Imaging and scans are done to check the brain and the blood vessels in and around the brain and to identify the cause. These include computed tomography (CT) and magnetic resonance imaging (MRI). The absence of brain damage (infarction) in diffusion-weighted magnetic resonance imaging indicates a transient ischemic attack.

2. Electrocardiograms (ECG) of the heart are done to assess the heart’s electrical activity and rhythm.

3. The patient’s body temperature and heart rate are tested.

4. A sleep study is performed to look for breathing problems during sleep (sleep apnea).

5. Blood tests are performed to look for the risk factors for stroke. The blood electrolyte levels, complete blood count, blood glucose levels, creatinine, and factors that control clot formation are checked.

How Is Transient Ischemic Attack Managed in the Emergency Department?

The general approach to managing transient ischemic attacks is almost the same as treating and preventing strokes. The treatment aims to prevent strokes and administer medications that reduce the formation of blood clots and those that lower the blood cholesterol levels (statins) to prevent further blocks (fatty deposits or clots) in the brain’s blood supply. The risk of stroke is the highest in the next 24 to 48 hours after a transient ischemic attack. So, if a transient ischemic attack is suspected, the patient may be admitted immediately for further evaluation and treatment (depending on the individual risk of stroke).

On arrival at the emergency department, the patient’s airway, breathing, and circulation (blood flow) are promptly evaluated. If needed, necessary emergency measures are initiated to maintain a patent airway, breathing, and circulation.

• A neurological examination is performed to assess the patient’s condition. The patient’s blood pressure, heart rate, rhythm, and presence of seizure activity are checked. In addition, the patient’s blood oxygen levels and hydration status are assessed.

• Blood tests are conducted to determine the cause.

• Brain and neurovascular imaging are performed to check for the presence of blood vessel abnormalities or blocks and assess brain damage. Acute blood pressure management is initiated whenever needed. In addition, blood glucose levels and the heart are also evaluated.

• Neurologic consultation is essential to arrive at a definitive diagnosis and initiate treatment. Quick treatment can help prevent strokes and save lives.

• Medications: Various medications are used to treat transient ischemic attacks. They are:

• Aspirin and Clopidogrel - If there is severe narrowing of the major blood vessels in the brain, medications such as Aspirin and Clopidogrel (blood thinners) are prescribed for 90 days to prevent stroke.

• Medications that prevent blood clots -In case of heart rhythm problems or irregular heartbeat, drugs that prevent blood clots, such as Warfarin, Apixaban, Rivaroxaban, or Dabigatran, are administered.

• Surgery: If any clots or obstructions (such as fatty deposits or clots) are found in the brain’s major blood supply (carotid arteries), surgery may be needed to prevent strokes and transient ischemic attacks. The surgical treatment includes the following:

• Surgical removal of the block (plaque or fatty deposits) within the blood vessel (carotid endarterectomy).

• Carotid angioplasty and stenting (less invasive procedure) is performed as an alternative to major surgery. It involves flattening the plaque against the walls of the blood vessels leading to increased blood flow to the brain. Then, a small metal mesh tube (stent) is inserted into the blood vessel to keep it open and to allow uninterrupted blood flow to the brain.

Conclusion:

A transient ischemic attack is a condition that occurs due to a temporary loss of blood supply to part of the brain. This can be due to blocks (clots, plaques, fatty deposits) in the major blood vessels of the brain (carotid arteries). It mimics a life-threatening condition called a stroke and requires emergency evaluation and treatment. The symptoms resolve completely, as there is no permanent damage to the brain cells in a transient ischemic attack. However, patients are more likely to develop stroke after a transient ischemic or recurrent attack. Thus, these patients must visit the emergency department (even if the symptoms have resolved) for evaluation and investigations to confirm the diagnosis, initiate treatment, and develop a plan for further management and care.