Silent Strokes: Symptoms, Risk Factors, and Importance of Early Detection - Dr Aditya Kulkarni

Silent stroke means there are no noticeable symptoms. Strokes are caused by a clot in the blood vessel of the brain. As a result, the brain area is deprived of oxygen and glucose.

Consequently, the cells in the brain area are irreversibly damaged. Symptoms of stroke vary depending on the affected brain area. Common symptoms include weakness of an arm and leg, difficulty in speech, trouble seeing etc.

These symptoms at times do not manifest during a stroke if a small part of the brain Is affected which does not control any vital function. These strokes are found when CT or MRI of the brain is performed for another indication.

Symptoms of Silent Strokes

Even though silent strokes don't exhibit dramatic signs, there are subtle changes that may indicate one has occurred:

• Sudden memory loss or difficulty with tasks that require memory.
• Unexplained confusion or trouble concentrating.
• Mild coordination issues or clumsiness.
• Mood changes, including irritability or apathy.
• Small, unnoticed changes in movement or walking patterns.

Since these symptoms can be gradual or mistaken for other conditions, silent strokes often go unrecognized. They are typically discovered through brain imaging, such as MRI or CT scans, where damage to the brain tissue can be seen.

With repeated silent strokes, the damage is cumulative. Neurological symptoms become apparent after a person has several silent strokes. Typically, this condition manifests with disturbance in memory/ cognitive functions.

In an advanced state, the symptoms are disabling such that a person loses functional independence. This state is known as multi-infarct dementia or vascular dementia. Other non-specific symptoms of silent stroke include balance problems, frequent fall, urine leakage.

Risk Factors for Silent Strokes

The risk factors for silent strokes overlap with those for regular strokes. They include:

1. High Blood Pressure: Chronic hypertension is the leading risk factor for both silent and traditional strokes, as it puts extra pressure on the blood vessels in the brain.
2. Diabetes: Uncontrolled blood sugar levels can damage blood vessels, increasing the risk of blood clots and restricted blood flow to the brain.
3. Atrial Fibrillation (AFib): An irregular heart rhythm can cause blood clots to form in the heart, which may travel to the brain and cause strokes, including silent ones.
4. Smoking: Smoking damages blood vessels, increasing the likelihood of clot formation and arterial blockage.
5. High Cholesterol: Elevated cholesterol can lead to plaque build-up in arteries, reducing blood flow to the brain and increasing stroke risk.
6. Obesity and Sedentary Lifestyle: Both are associated with increased risk of hypertension, diabetes, and other stroke-related conditions.
7. Age and Family History: As people age, the risk of silent strokes rises. A family history of stroke also increases susceptibility.
8. Previous Stroke or Transient Ischemic Attack (TIA): If someone has already experienced a stroke or a "mini-stroke," their risk for silent strokes increases significantly.

Importance of Early Detection

While silent strokes may not present with obvious warning signs, they are not harmless. Repeated silent strokes can accumulate over time, leading to:

• Vascular dementia: A type of dementia caused by reduced blood flow to the brain.
• Cognitive decline: Problems with memory, reasoning, and decision-making can develop as brain cells die.
• Increased risk of major stroke: Silent strokes are often precursors to larger, more debilitating strokes that can result in severe disability or death.

Early detection is essential for preventing long-term damage. Brain scans, especially MRI, can identify areas of the brain affected by silent strokes. Once diagnosed, doctors can address underlying risk factors, such as prescribing blood pressure medication, advising on cholesterol management, or recommending lifestyle changes like a healthier diet and regular physical activity.

After having silent strokes, healthy parts of the brain take over functions of the damaged areas. This provides a way of compensation for the silent strokes. Eventually, the brain’s ability to compensate is overwhelmed.

Physical and occupational therapy, speech therapy and mental health interventions are useful for rehabilitation. For patients in whom memory is significantly impacted, Alzheimer disease medications are prescribed.

Silent strokes are partly preventable by modification of risk factors. Important recommendations in this regard are to manage blood pressure, blood glucose, cholesterol; reduce salt intake; avoid smoking; and stay physically active.

One can reduce risk of having a stroke by regularly exercising, eating healthy foods and by leading a stress-free life.