Clinical Vignette

A 33-year-old woman was referred to a psychiatric clinic after presenting to a hospital emergency department (ED) on four consecutive nights, complaining of chest pain, dyspnea, and faintness. Each time a careful cardiac and pulmonary examination was unremarkable, and the patient was sent home with a benzodiazepine prescription and reassurance from the ED staff that she was not ill.

She reported similar attacks since childhood, but not as frequently as recently. She felt a desperate need to have help available if an attack occurred and rarely left home unaccompanied. This lady worried that she would lose consciousness during an attack or lose control of her bowels but admitted that neither had ever happened.

Recently she had given up both driving and air travel. She worked at an undemanding job near home. Her lack of any substantive social life was something that significantly troubled her, but despite such she felt helpless to socialize any more. Caffeine made her feel “wired,” and she presented the psychiatrist with a long list of medications to which she was “allergic.” She acknowledged occasional excess alcohol consumption in order to lessen her anxiety.

Clinical Presentation

Patients with panic disorder are invariably focused on the details of their bodily sensations and tend to reach catastrophic conclusions based on minor aches, palpitations, and shortness of breath (Fig. 24-1). They may present repeatedly in the ED with dyspnea, chest pain, tachycardia, and faintness. Extremity numbness or paresthesia suggest that patients are vasoconstricted from hyperventilation-induced respiratory alkalosis. Typically, patients are not reassured by a negative examination and may present again a few days later with the same complaints. Between episodes they may feel entirely well, but more commonly remain anxious and vigilant for signs of the next attack.

Figure 24-1 Panic Disorder.

Many individuals with panic attacks develop agoraphobia. (Probably all agoraphobic patients have had panic attacks.) Agoraphobia is not—as the word would suggest—a fear of open spaces but a fear of being isolated from help and support. Agoraphobic patients avoid novel places and circumstances and may also avoid driving on familiar highways, fearing isolation in a traffic jam. Eventually, patients may become so fearful that they cannot leave home without accompaniment or at all. The presence of panic or intense anxiety in mood-disordered patients is a well-established risk factor for suicide. It is controversial as to whether panic disorder unassociated with depression, per se, heightens the risk for suicide.

Diagnosis

Intravenous lactic acid infusion, which mimics respiratory acidosis but has no subjective effects in normal controls, reproduces the panic attacks in many patients. This and other evidence has suggested the “suffocation alarm” theory of panic disorder that asserts affected individuals are overly sensitive to minor changes in blood pH and PCO₂. Hence severe asthma, chronic obstructive pulmonary disorder, and a pulmonary embolus are some of the respiratory disorders that must be excluded in panicky patients. Other considerations include cardiac arrhythmias, myocardial infarction, ingestion of sympathomimetics (particularly cocaine), excess caffeine, alcohol and sedative-hypnotic withdrawal, hypoglycemia, partial complex seizures, and, rarely, pheochromocytoma or carcinoid tumors. Some of these diagnostic possibilities are eliminated by the chronicity of the illness; for example, no one survives daily pulmonary emboli.

Patients with panic disorder are more likely than most to smoke cigarettes. The suffocation alarm theory suggests that the high concentration of carbon dioxide in smoke and the chronic pulmonary dysfunction caused by smoking might both trigger panic attacks. In fact, initiation of smoking seems to precede the onset of panic attacks in most patients.

Treatment

Psychotherapeutic approaches to panic disorder include patient education about the syndrome’s medically benign natural history and remediation of patients’ catastrophic thinking and overgeneralizations. For some this is sufficient, although most phobic patients also need a course of graded exposure to feared situations.

Many patients also require pharmacologic management. Benzodiazepines abort panic attacks quickly and can be used as needed if attacks are infrequent. Most antidepressant medications (possibly excepting bupropion) have antipanic efficacy; they are the first choice for extended treatment. Anxious patients are sensitive to the initial activating or anxiogenic effects of antidepressants and need to begin with lower than usual doses. MAO inhibitors may work when other antidepressants are ineffective. However caution is needed with MAO inhibitors because of their potential for serious side effects (see Chapter 29).