Transient Disorders of Awareness - 12/15/2010

Transient Disorders of Awareness
By: R. Starkey, MD - Neurology

Introduction

Some of the most abstract medical occurrences that may also prove to be legally challenging are transient disorders of awareness.  The very nature of their transient occurrence often results in an absence of objective laboratory or examination abnormalities.  Since these conditions result in an alteration of the patient’s awareness, there may also be inadequate historical information to assist in diagnosis.  Yet, these disorders can have very significant consequences that range from a loss of one’s driving privileges or job to the participation in a criminal event.  The two most common causes of altered awareness are seizures and reduced blood flow to the brain.

Seizures

Seizures are the result of transient and often episodic abnormalities of brain electrical activity.  Convulsions are a type of seizure that results in a loss of consciousness and often involuntary jerking or other abnormal movements.  These seizures are quite easy to recognize if the event is observed.  Even if not observed, there are often clues that a convulsion has occurred such as tongue biting, trauma, incontinence, muscle soreness, and confusion following the event.  However, seizures may also be nonconvulsive and not associated with abnormal movements or even a true loss of consciousness.  These nonconvulsive events may be manifested primarily by an alteration of awareness and incomplete recall of what occurred during the episode.  Automatic behaviors such as walking, talking, or even driving a car may be partially preserved during some nonconvulsive seizures even though the patient’s awareness of their actions may be compromised. 

Reduced Blood Flow to the Brain

A reduction of blood flow to the entire brain such as might occur with a drop in blood pressure or a cardiac arrhythmia can result in a loss of consciousness and muscle control.  This is called syncope.  A reduction of blood flow to a specific part of the brain is less likely to result in a loss of awareness, but this can occur.  These focal reductions of blood flow may produce a stroke if the resultant symptoms are prolonged or a transient ischemic attack (TIA) if they resolve within twenty-four hours. 

Medical-Legal Considerations

Even though a medical history and diagnostic testing may be inconclusive regarding the cause of a transient loss of awareness, there are significant ethical as well as possible legal considerations that are raised when a patient experiences a loss of awareness.  Having one of these events certainly increases the chances of having another future event, but the magnitude of this risk is often very difficult to determine.  Many states require that their department of motor vehicles be notified when a patient experiences a loss of awareness.  Even if a state does not require this notification, there is an ethical obligation for evaluating physicians to try and identify those patients who may no longer be safe to drive or who should no longer work in an environment that could be potentially dangerous should they experience a recurrent episode of altered awareness.

Balancing a patient’s desire to maintain quality of life and an opportunity to earn a livelihood against the obligation to avoid negligence in the maintenance of public and personal safety is a very complex medical and potentially legal dilemma that frequently confronts a patient who has suffered an alteration of awareness and the physicians who care for them.