josephdhar
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Panic disorder
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08.30.08 (2 months ago)
#13
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Definition
Panic disorder is characterized by the occurrence of recurrent, unexpected panic attacks, together with concern about having another panic attack, or about the implications of the panic attacks, or a change in behavior related to the attacks. Panic disorder can occur with or without agoraphobia.
Etiology
The following have been proposed as etiological factors:
• neurotransmitter abnormalities (e.g. of norepinephrine, serotonin, gamma-aminobutyric acid);
• abnormalities in the locus ceruleus, median raphe nucleus, limbic system, prefrontal cortex or temporal lobes.
Panic attacks can be induced by increasing inhaled carbon dioxide, sodium lactate, yohimbine, fenfluramine, cholecystokinin, caffeine and isoproterenol.
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Epidemiology
The lifetime prevalence is 1.5-3.0%. Females are two or three times more likely to suffer from panic disorder than males. Often there is a recent history of divorce or separation. Panic disorder usually begins in young adulthood (the mean age of onset is 25 years).
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Diagnostic criteria
The DSM-IV diagnostic criteria for panic disorder can be summarized as the presence of recurrent and unexpected panic attacks, with at least one of the attacks being followed by one month (or more) of one (or more) of:
• persistent concern about another attack;
• worry about the implications or consequences of the attack;
• a significant change in behavior as a result of the attacks.
In addition, the panic attacks must not be due to a the effects of a substance, drug, a general medical condition or another psychiatric disorder.
The DSM-IV criterion for a panic attack is that it should be a discrete period of intense fear or discomfort with four or more of the following developing abruptly:
• palpitations or increased heart rate;
• sweating;
• trembling;
• shortness of breath or a sense of being smothered;
• a choking feeling;
• chest pain or discomfort;
• nausea or abdominal distress;
• dizziness or feeling unsteady, lightheaded or faint;
• feelings of unreality or depersonalization;
• fear of losing control;
• fear of dying;
• numbness or tingling sensations;
• chills or hot flushes.
Panic disorder can exist with or without agoraphobia, described by DSM-IV as anxiety about being in places or situations from which escape might be difficult or embarrassing, or in which help might not be available if needed.
The ICD-10 criteria for the diagnosis of panic attack and panic disorder are broadly similar to those of DSM-IV, differing only in details. The ICD-10 criteria for agoraphobia are more specific than DSM-IV, listing specific situations that are feared or avoided, and listing specific symptoms of anxiety, which must occur predominantly or only in the context of the feared situation.
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Symptoms and signs
Common symptoms and signs of a panic attack are:
• prodromal period of up to 10 minutes of rapidly increasing symptoms of fear and `a sense of impending doom and death';
• confusion and inability to concentrate;
• tachycardia, palpitations, dyspnea, and sweating;
• impaired memory;
• concern about cardiac or respiratory death - syncope occurs in 20% of patients;
• inability to pinpoint a cause.
Symptoms appear unexpectedly and may disappear rapidly or slowly; they usually last 20-30 minutes.
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Investigations
The diagnosis of panic disorder is made on the history alone; there are no investigative tests to assist in the diagnosis. A family history of panic disorder is associated with a four to eight times greater probability of having the disorder.
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Complications
Complications of panic disorder include:
• a restriction of normal activities;
• avoidance behaviors (e.g. of driving a car or going shopping);
• depression;
• alcohol and other substance abuse;
• increased risk of suicide;
• adverse effects on family life, school or work.
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Differential diagnosis
The differential diagnosis includes:
• cardiovascular diseases (e.g. congestive heart failure, angina, hypertension, myocardial infarction, paroxysmal atrial tachycardia);
• lung diseases (e.g. asthma, hyperventilation, pulmonary thromboembolism);
• neurological diseases (e.g. epilepsy, transient ischemic attack, Meniere's disease);
• endocrine diseases and conditions (e.g. Addison's disease, Cushing's syndrome, diabetes mellitus, hyperthyroidism, hypoparathyroidism, menopause, premenstrual syndrome);
• drug intoxication (e.g. from amphetamines, amyl nitrite, anticholinergic agents, cocaine, marijuana, nicotine);
• drug withdrawal (e.g. from alcohol, antihypertensive agents, opiates, sedatives, hypnotics).
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Prognosis
Treatment yields dramatic improvement -30 to 40% of patients become free of symptoms and about 50% continue to have mild symptoms. Significant symptoms remain in 10 to 20% of patients.
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Treatment aims
The aims of treatment are:
• to provide education about the nature of symptoms, and the effects of caffeine, stress, etc.
• to eliminate or decrease symptoms sufficiently to permit normal functioning and activities.
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Diet and lifestyle
Patients should be advised to decrease or stop their intake of caffeine, nicotine, alcohol and marijuana.
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Pharmacological treatment
Drugs that are used in the treatment of panic disorder include:
• selective serotonin-reuptake inhibitors (SSRIs);
• tricyclic antidepressants;
• monoamine oxidase inhibitors;
• mirtazapine
• benzodiazepines.
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Standard dosages
• SSRIs (e.g. sertraline, paroxetine)and tricyclic antidepressants**, starting with about 25% the usual antidepressant dose and titrating to a higher dose if necessary by approximately this same dose every 2 weeks; doses higher than the standard antidepressant doses are not usually required.
• monoamine oxidase inhibitors, e.g. phenelzine** 45-90 mg/day.
• mirtazapine** 15-45 mg/day;
• benzodiazepines, e.g. clonazepam 0.5-4mg/day or alprazolam 0.75-1.5mg/day, in divided doses.
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Contraindications
Contraindications include:
• for the SSRIs - caution is needed in patients with epilepsy, cardiac disease, hepatic impairment or renal impairment;
• for the tricyclic antidepressants - concomitant administration of a monoamine oxidase inhibitor or a recent myocardial infarction;
• for the monoamine oxidase inhibitors - hepatic impairment, cerebrovascular disease, pheochromocytoma; caution is needed in patients with diabetes mellitus, cardiovascular disease, epilepsy and in elderly patients;
• for mirtazapine - concomitant administration of a monoamine oxidase inhibitor or a recent myocardial infarction;
• for the benzodiazepines - a history of substance abuse, narrow-angle glaucoma, hazardous activities undertaken as part of work or recreation.
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Main side effects
The SSRIs are generally less sedating and have fewer antimuscarinic side effects than the tricyclic antidepressants. Side effects of the SSRIs include:
• gastrointestinal effects (common);
• sleep disturbances;
• headache;
• sexual dysfunction;
• dyskinesias;
• convulsions.
Side effects of the tricyclic antidepressants include:
• cardiac dysrhythmias (usually with underlying cardiac disease);
• anticholinergic effects (e.g. dry mouth, constipation, urinary retention);
• a lowering of the seizure threshold.
Side effects of mirtazapine include short term sedation and weight gain;
Side effects of the benzodiazepines include:
• sedation;
• fatigue;
• impaired performance;
• cognitive impairment;
• dizziness;
• ataxia.
A discontinuation syndrome (depending on dose, half-life and duration of treatment) is common; it consists of:
• autonomic symptoms;
• anxiety;
• irritability;
• loss of appetite;
• insomnia;
• sweating;
• diarrhea and vomiting;
• dysphoria.
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Main drug interactions
Drug interactions include:
• for the SSRIs, tricyclic antidepressants and mirtazapine - monoamine oxidase inhibitors;
• for the monoamine oxidase inhibitors - significant interactions with many drugs (and with some foods);
• for the benzodiazepines - central nervous system depression in conjunction with alcohol or barbiturates.
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Non-pharmacological treatments
Other treatment options include:
• cognitive-behavioral therapy;
• family and group therapy;
• relaxation therapy;
• respiratory training to control hyperventilation.
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Follow-up and management
Most patients require at least 8-12 months of treatment.
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