A transient alteration of awareness is a temporary episode in which an individual’s consciousness is disrupted. It is not a specific diagnosis but an umbrella description for a range of experiences. These events can vary from moments of mild confusion and incomplete recall to a total, though brief, loss of consciousness. The temporary nature of these events means there are often no lasting abnormalities on examination, making the person’s account of the event important for understanding it.
Underlying Medical Causes
The origins of a temporary change in awareness can be grouped into several categories. Many causes are neurological, originating in the brain. Epileptic seizures, which are episodes of abnormal electrical activity, are a common cause. Another neurological reason is a transient ischemic attack (TIA), often called a “mini-stroke,” where blood flow to a part of the brain is briefly blocked, usually by a clot or fatty deposit.
Cardiovascular issues are another frequent source. A widespread reduction in blood flow to the brain can result in a loss of consciousness known as syncope. Vasovagal syncope, the common faint, may be triggered by factors like dehydration or emotional distress, causing a sudden drop in blood pressure and heart rate. Cardiac syncope is caused by a heart problem, such as an abnormal rhythm (arrhythmia) or a structural issue like a narrowed heart valve, that prevents the brain from getting enough blood.
Disruptions in the body’s chemistry, or metabolic disturbances, can also affect awareness. Hypoglycemia, or low blood sugar, is a primary example. The brain requires a constant supply of glucose, and when levels fall too low, it can lead to confusion, disorientation, and even loss of consciousness. Significant imbalances in electrolytes, which are minerals that help regulate nerve and muscle function, can also interfere with brain activity.
Recognizing Different Types of Episodes
The presentation of an episode can provide clues to its underlying cause. Fainting, or syncope, often begins with a set of warning signs known as a prodrome. A person might feel lightheaded, dizzy, or nauseous; their vision may seem to dim or tunnel; and they might become sweaty. This is typically followed by a brief loss of consciousness, after which recovery is usually quick and complete.
Seizures present differently and are more varied. Some seizures involve convulsions, with involuntary stiffening (tonic phase) and jerking (clonic phase) of the muscles. Other seizures are non-convulsive and can be subtle, manifesting as a blank stare, known as an absence seizure, or as automatic, repetitive behaviors like lip-smacking. After many seizures, there is often a period of confusion and fatigue called the postictal state, which is less common after simple fainting.
A transient ischemic attack (TIA) typically does not cause a complete loss of consciousness. Instead, it presents with sudden, specific neurological deficits that reflect the affected brain area. Symptoms can include weakness or numbness on one side of the body, a facial droop, or sudden difficulty with speaking or understanding language. These symptoms appear abruptly and then resolve as blood flow to the brain is restored, usually within minutes to an hour.
How Doctors Determine the Cause
Identifying the cause begins with a detailed clinical history, which is a primary part of the evaluation. A doctor will ask specific questions about the events leading up to, during, and after the episode. Information from any witnesses is valuable, as the person may not remember the event. The person’s medical history, family history, and a list of current medications are also reviewed.
A thorough physical examination follows the history. This includes checking vital signs such as blood pressure while lying and standing to look for orthostatic hypotension. The doctor will also listen carefully to the heart for murmurs or irregular rhythms and perform a neurological exam to check for abnormalities. These steps help narrow down the potential causes.
Based on the initial findings, specific diagnostic tests may be ordered. An electrocardiogram (ECG or EKG) records the heart’s electrical activity to detect arrhythmias that could cause syncope. An electroencephalogram (EEG) measures electrical activity in the brain and is the primary tool for identifying patterns suggestive of a seizure disorder. Brain imaging, such as a CT or MRI scan, can reveal structural problems like evidence of a stroke or tumor, while blood tests can identify metabolic causes like hypoglycemia or electrolyte imbalances.
When to Seek Medical Attention
Certain situations involving a transient alteration of awareness require emergency medical help. You should seek assistance if the episode involves any of the following:
- The person has a seizure for the first time.
- It is accompanied by chest pain, a severe headache, shortness of breath, or weakness on one side of the body.
- The event results in an injury, such as from a fall.
- It occurs after a head trauma.
- The individual does not return to their normal state of awareness within a few minutes.
For less severe or recurring episodes, a scheduled visit with a doctor is appropriate. If you experience events that have a predictable trigger, such as fainting when you stand up too quickly, discuss this with a healthcare provider. Similarly, if you have recurrent episodes of confusion, staring spells, or other unexplained alterations in awareness, a medical evaluation is necessary.