Anxiety Disorders

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Chapter 112

Anxiety Disorders

Perspective

Acute anxiety and apprehension are common in emergency department (ED) patients. However, many medical conditions mimic anxiety disorders, and up to 42% of patients initially thought to have anxiety disorders are later found to have organic disease. Therefore, emergency physicians should thoroughly assess the anxious patient to identify and distinguish any underlying medical conditions and then appropriately treat that which is determined.1

Anxiety is a specific unpleasurable state of tension that forewarns the presence of danger, real or imagined, known or unrecognized, and is often verbalized as an intense feeling of worry. Vigilance is a positive consequence of anxiety that helps people to be alert to imminent danger. This awareness produces a greater ability to experience and manage extreme agitation.1

Up to a point, anxiety can improve performance with well-described adrenergic responses to stress that contribute to survival. However, when these responses go beyond a manageable point, further increases in anxiety add to the stress of the patient and lead to deterioration of performance and nonadaptive responses, resulting in pathologic anxiety (anxiety disorder). For instance, the threshold for pain may decrease, or the person may become more aware of body discomfort, with respiratory, cardiovascular, gastrointestinal, genitourinary, and neuromuscular complaints becoming prominent.1

The emergency physician should be able to distinguish between the anxiety and the illness and, if necessary, treat both entities. Because an anxiety state makes significant metabolic demands that can actually cause a marginally compensated organ system to fail, one should not assume anxiety to be purely functional; physical discomfort and illness often trigger an anxiety attack.

Epidemiology

Approximately 40 million Americans older than 18 years, nearly 20% of adults, are affected by anxiety disorders each year.2 Anxiety disorders are among the most prevalent psychiatric disorders and are the most common psychiatric problems seen by primary care physicians, with 20% of these patients experiencing a type of anxiety disorder.3 Many primary care patients have significant mood and anxiety symptoms, such as panic disorders, generalized anxiety disorders, and depression, but nearly half of these symptomatic patients never receive appropriate treatment.4 Many patients would rather present with a physical complaint and try to disguise their anxiety than bear the perceived stigma associated with psychiatric complaints.5 Patients with chronic illness and those who make frequent medical visits have higher rates of anxiety and depression. The prevalence of anxiety disorders surpasses that of any other mental health disorder, including substance abuse. There is a close relationship between alcohol abuse and anxiety disorders; those with anxiety disorders often turn to alcohol and substance abuse as a form of self-medication, and the substance abuser frequently has underlying anxiety in relation to the use of alcohol and drugs.6

Principles of Disease

The precise mechanisms underlying the development of anxiety have not been fully established. Noradrenergic, serotonergic, and other neurotransmitter systems all play a role in the body’s response to stress. The serotonin system and the noradrenergic systems are common pathways implicated in anxiety. It is believed that low serotonin system activity and elevated noradrenergic system activity are involved, and thus selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs) have become a focus of treatment. The well-established effectiveness of benzodiazepines in the treatment of anxiety has led to the study of the γ-aminobutyric acid (GABA) system and its relationship to anxiety. GABA is the principal inhibitory neurotransmitter in the central nervous system, and benzodiazepines act on the GABAA receptors. Studies have focused on the role that corticosteroids may play in fear and anxiety. Steroids are thought to induce chemical changes in select neurons that strengthen or weaken certain neural pathways to affect behavior under stress.7

Anxiety reactions are also associated with aberrant metabolic changes induced by lactate infusion and hypersensitivity of the brainstem to carbon dioxide receptors. Studies focus on the regulatory centers found in the cerebral hemispheres. The hippocampus and the amygdala regulate emotion and memory and are important areas mediating an individual’s response to fear.8 Family research suggests genetic factors in anxiety, but the precise nature of the inherited vulnerability is unknown. Psychological and environmental factors, as outlined in psychodynamic, behavioral, and cognitive theories, also contribute in the generation of anxiety in biologically predisposed individuals.8

Clinical Features

Many patients entering the ED experience anxiety, and for some this can be a significant clinical issue. The ED patient encounters many internal and external dangers: assaults on body integrity in the form of uncomfortable procedures and forced intimacy with strangers; the atmosphere of illness, pain, and death; and separation from loved ones and unfamiliar surroundings. In addition, the patient may experience uncertainty about his or her illness, the implications that the illness may have on personal relationships and employment, and the financial burden that may accompany the illness.

The anxious patient can be a diagnostic challenge. Anxiety may represent the patient’s reaction to medical illness or the medical setting, or it may be a manifestation of the physical disorder itself. The anxiety may also be an expression of an underlying psychiatric disorder. It may be difficult to make the distinction between anxiety as a symptom and anxiety as a syndrome in the ED. There is an overlap between normal situational anxiety and fear, anxiety-like symptoms resulting from a variety of organic disease states and their treatments, and the characteristic presentation of anxiety itself.

The physical symptoms of autonomic arousal (e.g., tachypnea, tachycardia, diaphoresis, lightheadedness) may be the only manifestation of anxiety (Box 112-1). Patients may complain only of overall poor health or vague subjective findings when they visit the physician. Classic panic disorder symptoms of chest pain, shortness of breath, and the sense of impending doom will often lead the patient to the ED, especially if it is the very first episode.7 Anxiety associated with organic causes is more likely to be manifested with physical symptoms and less likely to be associated with avoidance behavior.9

Differential Considerations

Medical Illness Presenting as Anxiety

Patients with anxiety disorders may present with apparent physical disease, and many physical diseases may be strongly associated with symptoms of anxiety. Somatic symptoms can be so prominent that they occupy most of the patient’s attention, making it difficult to differentiate between a primary anxiety disorder and reactive anxiety to a situation or disease. Several factors help distinguish an organic anxiety syndrome from a primary anxiety disorder10 (Box 112-2). Anxiety disorder classifications, in the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), include anxiety caused by a general medical condition11 (Box 112-3).

BOX 112-3

Definitions of Anxiety Disorders

Panic attack is a discrete period in which there is a sudden onset of intense apprehension, fearfulness, or terror, often associated with feelings of impending doom.

Agoraphobia is an anxiety about, or avoidance of, places or situations from which escape might be difficult.

Panic disorder with agoraphobia is characterized by both recurrent, unexpected panic attacks and agoraphobia.

Agoraphobia without a history of panic disorder is characterized by the presence of agoraphobia and panic-like symptoms without a history of unexpected panic attacks.

Specific phobia is characterized by clinically significant anxiety provoked by exposure to a specific feared object or situation, often leading to avoidance behavior.

Social phobia is characterized by clinically significant anxiety provoked by exposure to certain types of social or performance situations, often leading to avoidance behavior. Blushing is the cardinal characteristic symptom.

Obsessive-compulsive disorder is characterized by obsessions that cause marked anxiety or distress and by compulsions that serve to neutralize anxiety.

Post-traumatic stress disorder is characterized by experiencing of an extremely traumatic event, accompanied by symptoms of increased arousal and by avoidance of stimuli associated with trauma.

Acute stress disorder is characterized by symptoms similar to those of post-traumatic stress disorder that occur immediately in the aftermath of an extremely traumatic event.

Generalized anxiety disorder is characterized by at least 6 months of persistent and excessive anxiety and worry.

Anxiety disorder caused by a general medical condition is characterized by prominent symptoms of anxiety that are judged to be a direct physiologic consequence of a general medical condition.

Substance-induced anxiety disorder is characterized by prominent symptoms of anxiety that are judged to be a direct physiologic consequence of a drug of abuse or medication or toxin exposure.

Anxiety disorder not otherwise specified is included for coding (1) disorders with prominent anxiety or phobic avoidance that do not meet criteria for specific anxiety disorders and (2) anxiety symptoms with inadequate or contradictory information.

From American Psychiatric Association: Diagnostic and Statistical Manual of Mental Disorders, 4th ed, text rev. Washington, DC, American Psychiatric Association, 2000.

Anxious patients are frequently convinced that their problem is purely physical. The emergency physician should realize that the patient with anxiety is not in control of the symptoms and frequently cannot immediately identify the correct precipitant. Even though the patient may be uncomfortable, uncooperative, impatient, and unreasonable, triage medical personnel should recognize that the patient believes an illness truly exists and is not being consciously manipulative. Because anxiety may be the most obvious symptom of an underlying disease or condition, the patient should be evaluated for exacerbation of known preexisting disease as well as for onset of new illness since anxiety increases the risk of acute medical exacerbation of chronic illness.12

The classic scenarios of pulmonary embolism and hyperthyroidism causing anxiety are well documented. Cardiac disease studies indicate poorer outcomes in post–myocardial infarction patients with anxiety than in those without documented anxiety. Patients with respiratory diseases, such as asthma and chronic obstructive pulmonary disease, often have anxiety with their long-standing illnesses. In addition, many of the medications used to treat these illnesses may induce anxiety.5 The most common organic cause of anxiety is alcohol and drug use from either intoxication or, more typically, withdrawal states.

Cardiac Diseases

Various psychiatric conditions may be manifested with complaints of chest pain. Approximately 25% of patients with chest pain who present to the ED have panic disorder. Their disorder often goes undiagnosed, resulting in multiple visits and expensive cardiac evaluations.13 Some of the symptoms of myocardial infarction and angina pectoris may include crushing chest pain, shortness of breath, nausea, palpitations, heavy perspiration, and a feeling of impending death. These are also the primary symptoms of acute anxiety, but the pain is usually described as atypical, and patients are generally female and younger.14 Because of the morbidity and mortality of cardiovascular disease, a patient warrants a full cardiac evaluation when the differentiation between myocardial infarction and acute anxiety is unclear.

Cardiac dysrhythmias can cause palpitations, discomfort, dizziness, respiratory distress, and fainting. An anxious patient with a panic disorder will frequently have similar symptoms. Fortunately, most dysrhythmias can be documented and characterized on cardiac monitors or by electrocardiography. Mitral valve prolapse syndrome can be associated with palpitations and panic attacks indistinguishable from a panic disorder. Benzodiazepines can be used to provide symptomatic relief to patients who experience chest pain. Studies have shown that benzodiazepines reduce anxiety, pain, and cardiovascular activation. It is hypothesized that secondary to the reduction in circulating catecholamines, benzodiazepines may cause coronary vasodilation, prevent dysrhythmias, and block platelet aggregation.15

Endocrine Diseases

The DSM-IV defines the most common endocrinologic conditions associated with anxiety states as hypoparathyroidism, hyperthyroidism and hypothyroidism, hypoglycemia, pheochromocytoma, and hyperadrenocorticism.11 Anxiety is the predominant symptom in 20% of patients with hypoparathyroidism. Other symptoms include paresthesias, muscle cramps, muscle spasm, and tetany. Most cases are idiopathic or the result of surgical removal of the parathyroid glands during thyroidectomy. Studies indicate a higher incidence of anxiety in the subset of patients with surgically removed glands.16 The diagnosis of hypoparathyroidism is suggested by a low serum calcium level and a high phosphate level and confirmed by a parathyroid hormone assay.

Anxiety symptoms are seen in up to 40% of diabetics, and 14% of diabetic patients suffer from anxiety disorders. There is evidence that diabetics who are treated with antianxiety medication not only reduce their anxiety but also decrease their glycosylated hemoglobin levels and high-density lipoprotein concentration.17 Many patients with anxiety, somatoform, or characterologic disorders are convinced that they have reactive hypoglycemia. A normal result of a fingerstick blood glucose analysis done during an attack can exclude this diagnosis.

Pheochromocytomas are rare tumors that produce elevated levels of catecholamine in the body. Common symptoms include paroxysmal hypertension, headache, anxiety, sweating, flushing, abdominal and back pain, vomiting, and diarrhea. Pheochromocytoma attacks can be manifested just like panic attacks and can be precipitated by emotional stress. Whereas the sweating associated with pheochromocytoma attacks involves the whole body, the sweating in panic attacks is more likely to be confined to the hands, feet, and forehead. Elevated urinary catecholamine or plasma metanephrine levels can confirm a pheochromocytoma.18

Hyperthyroidism

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