Panic Attacks and Hyperventilation Syndrome

 

       A panic attack is an exaggeration of a normal and highly adaptive response to an unexpected and potentially aversive stimulus.  Under jungle conditions such a stimulus results in fighting or running at least a short distance.  Brief hyperventilation (over-breathing) prior to fighting , running or any athletic performance is preparation for the effort and is part of the explanation of why a world’s record is never achieved during ordinary practice.  It is immediately obvious that brief hyperventilation enhances ability to swim under water.  It is not quite so obvious that it occurs without conscious effort.

 

       Under modern civilized conditions anxiety is frequently prolonged and not defused by exertion.  Prolonged minimal hyperventilation can result in the same degree of change in body chemistry as brief but strenuous hyperventilation such as might occur after starting late to blow up balloons to decorate for a party or blowing up air mattresses while setting up camp under threat of rain.  These chemical changes are the result of expelling CO² (carbon dioxide) faster than it is formed from metabolizing food.  The sense of air hunger is the result of the initial stimulus making normal breathing seem like too little.  Suddenly getting rid of CO² (an acid substance) causes all the blood leaving the lungs to become more alkaline creating alarming symptoms such as dizziness and numbness around the mouth and in the fingers.  Secretion of adrenaline (epinephrine) also adds to the symptoms.  In the case of blowing up the balloons or air mattresses the cause of the symptoms is obvious and the stimulus of the symptoms does not feed more anxiety and a vicious cycle of severity of chemical changes and symptoms.

 

       Asthma is an interesting example: It increases the work of breathing because of narrowing of the smallest bronchial tubes feeding air to the tiniest air sacks (alveoli).  This increase in the work of breathing creates anxiety and results in excessive breathing and not in sub-optimal air exchange as one might expect.  Occasionally asthma presents as hyperventilation instead of wheezing or cough, but even in such cases it responds better to medication for asthma than to sedatives to reduce the anxiety.

 

       Sedatives suppress anxiety by the same mechanism as alcohol does and at some cost in loss of personal efficiency (for example, accidents).  Sedatives also become less effective with steady use, so we give them for rather occasional attacks in people whose responsibilities are not too demanding.  Many medications have secondary uses not closely related to their main usefulness.  Beta blockers are widely used for heart palpitations, angina pectoris (heart pains) and high blood pressure, but they greatly aggravate asthma.  The following experiment illustrates the sharp difference in the mechanism of action between sedatives and beta blockers in relieving anxiety.  A group of musicians subject to stage fright and a group of music critics were assembled to test various strategies for relieving stage fright.  Valium (a sedative) and alcohol relieved stage fright as reported by the musicians but at a cost of serious reduction in the quality of music performance as determined by the music critics.  Beta blockers relieved the stage fright with no discernable loss of musical quality.  In our present context this means that in many cases we need a strategy better than either of the above for panic attacks (severe stage fright if you will).

 

       A candidate drug for panic attacks, fluoxetine, is another example of a drug very useful for indications other than its original billing.  When fluoxetine was introduced as Prozac, it was the first of a new class of antidepressants.  It is so long acting that it can be effective on once per week dosing.  This can be inconvenient in treating severe depression because if it is ineffective, or must be discontinued because of important side effects, a waiting period of several weeks is required before effective doses of a new drug of similar action can be given.  Fluoxetine turned out to be very useful for panic attacks.  The prolonged action is smooth and helps to prevent recurrences even with  many missed doses.  Some patients are like Christian Scientists but without all the credentials.  All should know that psychotherapy and relaxation exercises can be quite helpful for panic attacks even in the absence of any medication.  Like the rest of the drugs in its class fluoxetine is not habit forming and does not reduce personal efficiency as do sedatives and alcohol.  For the occasional patient with panic attacks who do not tolerate fluoxetine, sedatives are an adequate temporary, prompt substitute (because of an entirely different mechanism of action) while waiting to try one of the close relatives of fluoxetine.

 

       I mention all this detail to reassure an informed public about this very useful class of drugs.  They can even be used to prevent migraine headaches.  In summary, we have effective treatment for panic attacks with the goal of long term prevention, not merely temporary suppression.  If you would like to read more about the impact of fluoxetine on medicine and psychiatry, an early account,  Listening to Prozac by Peter     Kramer M.D., is interesting and informative.

           

John. A. Frantz, M.D.

May 11, 2004

 

 

 

 

The role of a physician is frequently that of surrogate parent for adults.  In this role I would much prefer to be taken in by an imposter than to fail to meet a legitimate need of one of my “children”. (An imposter might be an addict seeking a fix).

 

                                                         

Caterpillars in Oshkosh

The Experimental Aircraft Association (EAA) of Oshkosh, Wisconsin puts on an air show every August.  Two caterpillars were watching the show and chatting when a butterfly happened to fly past.  One of the caterpillars turned to the other and said, “Boy, you’d never get me up in one of those!”