Tammy, a 13-year-old girl, had a 7-year history of severe headaches when she came to our Adolescent Clinic. She had made numerous visits to outpatient pediatrie clinics and once, when she was 7 years old, had been hospitalized for an extensive workup. Physical examinations were consistently normal. Neurologic tests, including EEG and CT scan, were negative. Other complaints accompanying her headaches included chest pain, nausea, and tingling in her hands. These symptoms, however, did not occur consistently. Her physicians attributed her pain to psychological problems and treated her symptomatically- The diagnosis made after our assessment was the hyperventilation syndrome.
The purpose of this article is to give the practicing pediatrician an awareness of hyperventilation syndrome, to present procedures used in making a diagnosis, and to discuss treatment strategies.
Hyperventilation syndrome (HVS) in an infrequently recognized, often overlooked condition. First described in 1871 by Da Costa, the symptoms were clearly related in a 1938 study to involuntary hyperventilation and the resulting respiratory alkaíosis. In spite of this recognition, hype rventilat ion is usually given only cursory mention in medical school curricula. Pediatrie education and texts may be especially sparse in their consideration of HVS. For example, Nelson's Pediatrics does not include a discussion of HVS, and only a passing mention is made of its existence. The prevalence of this disorder among medical patients, however, is estimated to be approximately 10%.1
Herman and colleagues2 have documented the pattern of inappropriate referrals and the failure to institute treatment among pediatrie patients diagnosed with HVS. A longitudinal follow-up of pediatrie HVS patients revealed that nearly half were still showing symptoms as adults. In our own clinic, many patients have histories of several years of emergency room and clinic visits, even hospitaliza! ion, without definitive diagnosis.
PRESENTING SYMPTOMS AND DIAGNOSIS
Hyperventilation is produced by an excessive loss of PcO2, producing an increase in the frequency and depth of respiration. The resulting physiological consequences are well known. Hypocapnia and respiratory alkalosis develop soon after the onset of hyperventitation. The result is a decrease in cerebral oxygénation, cardiovascular reactions such as tachycardia and arrhythmias, an incomplete normalization of pH, and possible sympathetic arousal.3
The clinical manifestations of HVS are diverse and often mimic the presenting complaints of other disorders. The checklist above gives the symptoms most often reported to accompany hyperventilation. Unfortunately, many physicians associate the syndrome only with the acute symptoms of obvious overbreathing, tetany, and carpopedal spasms. This presentation is one of the least frequent for HVS. The most common presenting complaints are shortness of breath, chest pain, and dizziness. Upon questioning, "dizziness" often is not associated with spinning or vertigo and may be better understood as light-headedness. The physical examination and a complete history often reveal excessive sighing, thoracic breathing, easy fatigability, and paresthesias. The symptoms are typically reported to be recurrent.
Anxiety and fear are also commonly observed with these patients. Often the symptoms lead patients to conclude they are in danger of imminent death. In fact, earlier psychiatric theorists hypothesized that "death anxiety" was the principal etiologic agent in the onset of HVS. Although anxiety is still believed to precipitate hyperventilation in some cases, current emphasis is placed on the reciprocal relationship between anxiety and hyperventilatory states. Not only may anxiety lead to hyperventilation but the symptoms produced by hyperventilation can also cause further anxiety, thus setting the stage for a vicious cycle. This detrimental interaction may be further exacerbated by enhanced beta-adrenoceptor responsiveness. The relationship between anxiety and hyperventilation may have important implications for understanding the genesis of panic disorders and phobia.4
For the pediatrician making the diagnosis of HVS, the most important requirement is an awareness of the existence of the syndrome. Even with an increased awareness, however, making the diagnosis can be difficult because of the many forms that this syndrome can take and because its symptoms overlap with those of other disorders. The most frequently cited method for diagnosing HVS is the provocation test. This test requires patients to hyperventilate voluntarily for 2 to 3 minutes. The criteria for making a positive diagnosis is the patient's recognition of presenting complaints during the provocation test. One symptom which should not be reproduced is chest pain, because this symptom requires a significantly longer (and potentially dangerous) period of voluntary hyperventilation to reproduce. The provocation test is also contraindicated with patients suspected of sickle cell anemia, epilepsy, kidney, or heart disease. Given these cautions, the provocation test is currently the best method for diagnosing HVS. Diagnosis can be aided by monitoring end-tidal CO2 levels during the test. HVS patients exhibit a slow post-provocation-test recovery of CO2 levels to resting baseline levels. The physician is cautioned against making the diagnosis on the basis of the patient's reported complaints alone because this is likely to result in a significantly high number of misdiagnoses.
TREATMENT OF HVS
Once a definitive diagnosis of hyperventilation syndrome is made, many physicians are prone to dismiss the patient with vague reassurances that nothing is really wrong and perhaps the advice to "try to relax. " Such an approach is unlikely to be effective because the patient is suffering from pain, anxiety, dizziness, or whatever the particular manifestations of the illness happen to be, and no method of changing the problem (faulty breathing) has been prescribed. For effective treatment of hyperventilation syndrome, three steps are required. These steps are reassurance, education, and prescribing a strategy for changing the breathing habits.
Reassurance is the important foundation of effective treatment. After the extensive work-ups which many of these patients receive, teenagers may have difficulty believing they do not have a life-threatening illness. Furthermore, months of diagnostic tests may encourage patients to adopt a "sick role, " leading to increasing withdrawal from normal activities. Patients need to be reassured in specific terms relevant to their fears. For example, a 16-year-old football player who is concerned about heart attacks needs to be specifically told that he is not having cardiac problems. The 14-yearold girl with dizziness and weakness needs to be told that a neurological problem is not involved.
Second, education is necessary to provide an explanation for what is causing the problem. Often, the provocation test is sufficient for the patient to realize that symptoms are related to a relatively benign process. The pediatrician may then explain, in depth of detail appropriate to the patient's level of understanding, the process of hyperventilation as shown in the
inset on the previous page. Rmicular attention should be given to the symptoms the patient is actually experiencing. In this way, the adolescent is given an understandable explanation for the illness and groundwork is laid for the illness' remediation.
Occasionally, a young person will agree that symptoms experienced during the provocation test are the same as their complaints, but will argue that they are not aware of hyperventilating during attacks. In most cases, this will be true. The question may be answered by telling the patient that a habit of exhaling more than is inhaled may have developed. Lowered CO2 often makes the patient vulnerable to even slight hyperventilating episodes.
After the patient has been reassured and understands the nature of the illness, the final step in treatment is to provide a strategy for counteracting the underlying problem. Teaching diaphragmatic breathing is likely the simplest and easiest way of accomplishing this goal. Diaphragmatic breathing may be simply taught by having patients place one hand on the abdomen and the other hand on the chest. Patients are then instructed to make the lower hand move while breathing, but to keep the upper hand still. Until the new breathing habit is established, the patient may need a way of controlling hyperventilation symptoms. Having the patient breathe into a paper bag at the onset of symptoms is effective. This action will circumvent the depletion of CO2 and bring rapid relief. Care should be taken that the patient not become dependent on carrying a paper bag. Hyperventilation syndrome is a chronic condition and requires intervention not only to handle the acute attack, but also the ongoing cause.
Patients should be followed up in approximately 1 to 2 weeks to check on their progress. Treatment should begin to have discernible effects within that time. A complicating factor in hyperventilation syndrome may be the presence of pervasive psychopathology along with HVS. Usually, some anxiety disorder will be involved, but depression, somatoform disorders, or personality disorders may also be included. If the simple procedure of reassurance, education, and retraining is not effective, then referral to a clinical psychologist or psychiatrist is indicated for further assessment and treatment.
Hyperventilation is a common, though often unrecognized, disorder of adolescents. While relatively benign, the lack of recognition may lead to extensive, expensive, and unnecessary medical work-ups. The single most important factor in making the diagnosis of HVS lies in the awareness of the disorder's existence.
HVS may be diagnosed through a positive response to the provocation test. Patients are asked to hyperventilate and questioned as to whether they experience the symptoms of which they have complained. Successful treatment involves reassurance, education, and giving the patient a strategy for controlling the hyperventilation. If treatment is not successful in a short period, patients should be referred to a qualified mental health professional. While the relationship between hyperventilation and anxiety disorders is unclear, some correlation between them does appear to exist.
1 . Rice RL: Symptom patterns of the hyperventilation syndrome. Am J Med Sci 1950: 8:691.
2. Herman SP, Ounnar BS. Alexander RL: Hypcrvcmilatiim svnjrome in children and adolescents: Long-tern follow-up. Pediatrics 1981; 67:183-187.
3. Margarian GJ: Hvpervetinlatikon syndromes. Infrequently recognized common expresssion of anxiety and stress. Medicine 1982; 61:219-2?6.
4. Clark DM, Salkowskis PM. Chalkley A]: Respiratory control as a treatment fut panic attacks. J Behav Ther Exp, Psychiary 1985; 16:23-30.