Author(s): Morton E Travel
Hyperventilation syndrome is far more common than generally believed, and thus usually unrecognized. It often produces misleading complaints that include alterations of consciousness, inexplicable sensory and motor sensations, and it is often masked by coexisting somatic symptoms such as unusual chest pains. Obscuring recognition further, symptoms attributed to the panic disorder are often, in reality, those of hyperventilation. Proper diagnosis of this breathing disorder depends upon a heightened awareness of its various manifestations, which can then lead to effective means of diagnosis and management.
For more than a century, we have encountered a condition? now called the ?hyperventilation syndrome??characterized primarily by breathlessness, lightheadedness or dizziness, weakness, numbness and tingling (paresthesias) and chest pain [1,2]. Rarely have organic diseases been found to account for the symptoms in such cases, and lacking effective management, symptoms usually persist. Contributing to the confusion, the hyperventilation syndrome has been given many names that include irritable heart, soldier’s heart, Da Costa’s syndrome effort syndrome, neurocirculatory asthenia and, more recently, panic disorder (panic attacks). These episodes occur in many persons under the stresses of daily living, but in those not overtly stressed, anxious or depressed, they may also appear in those who appear outwardly calm as they ?bottle up? their feelings, possibly because of undeveloped or lack of acceptable emotional outlets. These episodes are surprisingly common, occurring with an estimated prevalence in the range of 10% of all general medical patients [2]. I have personally encountered them as an explanation or contributor to approximately 15% of patients applying for long-term disability.
Most medical caregivers readily recognize acute hyperventilation attacks occurring under acute stress. However, chronic or recurrent hyperventilation problems often are unrecognized probably for a variety of reasons, including the frequent lack of obvious over breathing, a tendency to focus on one or two complaints that alone are not particularly suggestive of hyperventilation, compounded by absence of discussion of the topic in healthcare schools and cursory coverage in medical textbooks.
How emotional stress can induce an excessive respiratory response is likely rooted in the evolutionary ?flight or fight? reaction, wherein, in anticipation of imminent need for increased exertion combined with increased adrenergic drive, rapid respiration results.
If increased exertion is not required, however, excessive and inappropriate breathing (hyperventilation) produces hypocapnia (reduced blood carbon dioxide), respiratory alkalosis, and a complex array of physiologic changes, that include widespread vasoconstriction (importantly to the brain) with increased neurological excitability, and they are likely responsible for most of the signs and symptoms [3]. These changes may even produce bronchoconstriction that may actually result in audible wheezing, augmenting the sensation of dyspnea as well as simulating or intensifying preexisting asthma [4]. Thus since hyperventilation can complicate asthma, one should consider both asthma and hyperventilation when encountering features of both conditions.
Although these physiologic changes usually develop rapidly upon onset of hyperventilation, they can easily be maintained indefinitely, by nearly imperceptible hyperventilation, such as by taking an occasional deep breath while maintaining a normal respiratory rate. In this setting, caregivers may observe only the subtle, chronic form of hyperventilation without recognizing it or, upon considering the diagnosis, inappropriately reject it because the expected rapid breathing pattern is not present. Resulting symptoms may include atypical chest pain, chronic fatigue, mild dyspnea, or exercise intolerance. Air hunger is common, hinting the possible presence of hyperventilation.
Such patients demeanor may reveal cues in the form of occasional sighs and/or deep breaths together with other possible overt evidence of anxiety. The complaints also include one or more of several manifestations that include dyspnea, dizziness, numbness and tingling (usually widespread but sometimes most prominent on one side of the body), chest pain, dry mouth, hot or cold sensations, weakness, or fainting. If one is faced with any or all these features, hyperventilation should be considered before one considers referring such patients to various specialists such as neurologists or cardiologists.
Acknowledging the possibility of hyperventilation, the clinician should then instruct the patient to breathe as deeply and as rapidly as possible, preferably in the upright sitting position, for at least two or three minutes, or at least until some discomfort appears that includes numbness and tingling and/or a sensation of dizziness. If he/she responds affirmatively when asked if these sensations are similar or identical to any of those accompanying the spells, then the diagnosis is confirmed or strongly suspected. Further confirmation can be accomplished by explanation of the effects of hyperventilation, together with how to control and suppress its symptoms by first triggering it intentionally by rapid breathing and then terminating it with breath holding, maneuvers that should be practiced at home. Relieving symptoms through re-breathing into a paper bag has been suggested, but, in my opinion, is usually not required. The diagnosis is further confirmed if and when subsequent attacks are eliminated by these simple measures. I have noticed, however, that, in cases in which symptoms have been present for a long time, acceptance and control may be difficult, possibly owing to a deeply ingrained pattern of behavior, and in some cases, possibly owing to hoped for disability judgments or secondary gain from an attentive family or friends. Also, for uncertain reasons, the usual chest pain occurring during the attacks may not be reproduced promptly by the rapid breathing maneuver. A cardiac origin of such pain can usually be excluded by careful history taking and, when necessary, appropriate testing. In such cases, breath control and/or simple reassurance may be all that is required to minimize or eliminate pain and reduce superimposed anxiety.
The diagnosis of panic disorder offers a special therapeutic challenge and opportunity: ?Panic attacks,? according to the criteria listed in the current psychiatric handbook, include, among others, the following features: ?Trembling or shaking, sensations of shortness of breath or being smothered feeling of choking, chest pain or discomfort, feeling dizzy, unsteady, lightheaded, or faint, chills or hot flashes, and paresthesias (numbness or tingling sensations), chills or hot flashes, and palpitations, and/or accelerated heart rate [5].? Although these manifestations are listed as inherent to the panic disorder itself, they are identical to the typical features already cited for the hyperventilation syndrome. The fear and anxiety that initiate the panic response are often compounded by the unpleasant subjective complaints caused by the breathing disorder itself. This, in turn, further increases the fear and rapidity of ventilation, thus creating, in effect, a vicious cycle. By demonstrating the role played by the aggravating hyperventilation, the caregiver can interrupt this feedback cycle sufficiently to ameliorate, or even eliminate, the panic response itself. In order to accomplish this objective, however, this requires recognition that the breathing disorder is a major component of the panic state.
A wide variety of patients manifest features that strongly suggest the presence?or contributory role?of hyperventilation, but this diagnosis is seldom considered. Thus provocative testing is seldom, if ever, performed and accurate diagnosis is never established. Those managing large general medical populations would be well advised to consider this diagnosis far more frequently. Various specialty groups would also benefit from such awareness. The results could be very gratifying to both patients and caregivers alike!
