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Experimental Induction Of Panic-Like Symptoms In Patients With Postural Tachycardia Syndrome

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Found this in my research, thought i would share. Sorry about the vertical text, its from a pdf :)

Experimental induction of panic-like symptoms in patients with postural tachycardia syndrome

Khurana, Ramesh K ar_button.gif


. Clinical Autonomic Research spacer.gif16. 6 spacer.gif(Dec 2006): 371-7.


Patients with postural

tachycardia syndrome (POTS)

might be misdiagnosed with panic

disorder due to shared clinical

features. The first aim of our study

was to investigate the relationship

between symptoms of POTS and

panic disorder. The second aim

was to delineate clinical features

distinguishing symptoms of POTS

from panic disorder. A total of 11

patients with POTS and 11 control

subjects participated in an IRBapproved,

prospective, placebocontrolled

study. The experimentally

induced panic-like symptoms

of POTS were systematically studied

using the Acute Panic Inventory

(API) questionnaire. The

participants answered the questionnaire

after each placebo infusion

and after each of the three

provoking stimuli: head-up tilt

test (HUT), isoproterenol infusion

(ISI), and sodium lactate infusion

(SLI). API responses were

summed for each subject at each

time point of administration.

Individual API symptoms and

summed responses were analyzed

for statistical significance. All

patients with POTS developed

symptoms of orthostatic intolerance

during HUT. Pharmacologically

induced symptoms

subjectively mimicked spontaneous

symptoms in 5 of 11 patients

during ISI and in none of 11

patients during SLI. In contrast,

API scores in these patients

reached panic threshold in 0 of 11

following HUT, in 4 of 11 following

ISI and in 4 of 11 following

SLI. Individual symptoms analysis

revealed that significant increase

in scores was limited to the

somatic symptoms of palpitations,

dyspnea, and twitching or trembling.

In conclusion, the symptoms

of POTS are

phenomenologically different and

clinically distinguishable from

panic disorder symptoms


The control results in the current study are consistent

with previous studies. Balon and colleagues observed

the production of panic symptoms in response to ISI

in 4 out of 45 (8.9%) normal control subjects [3].

Liebowitz et al. reported the occurrence of SLI-induced

panic in 0–25% of control subjects [23]. Similarly,

the current study found that no control subjects

reached panic thresholds as compared with baseline

API in response to any of the three stimuli.

The lack of resemblance of SLI-induced symptoms

with spontaneous symptoms and a significant API

score elevation above baseline after SLI in only 4 of 11

patients suggest that POTS symptoms cannot be

equated with panic symptoms. Both ISI and SLI are

considered reliable and valid models of panic-induction.

SLI produces panic in panic disorder patients

with a sensitivity of 0.85 and specificity 0.77, and ISI

provokes panic with less sensitivity and more specificity

[2]. It is possible that panic-like episodes

occurring with pharmacologic stimuli in POTS patients

are associated with a subclinical panic disorder

[10], although the lack of similarity between the induced

and spontaneous episodes militates against it.

Goetz and colleagues (1996) used API questionnaires

to evaluate subjective ratings and symptoms in

panic disorder patients before and during SLI. Controlling

for baseline symptoms levels, these investigators

found that the symptoms most strongly

associated with panic were desire to flee (0.70), fear of

losing control (0.57), afraid in general (0.49), and

dyspnea (0.48). These psychological symptoms were

determined essential for the diagnosis of lactate-induced

panic [15]. Balon and colleagues (1990) compared

symptom responses to ISI in subjects with and

without panic disorder and found that fear of going

crazy, fear of dying, and shortness of breath best

discriminated between panic and non-panic [3]. In

our POTS patients, neither pharmacologic stimulus

produced increased API scores in the cognitive psychological

symptoms essential to the diagnosis of

panic disorder, such as fear of dying, fear in general,

and fear of going crazy. Our POTS patients demonstrated

a significant increase in palpitations, dyspnea,

and twitching or trembling, which are all somatic

symptoms. Palpitations were more prominent with

ISI, and trembling or twitching was more prominent

with SLI. This study, therefore, does not support the

phenomenologic equivalence of panic disorder in

POTS patients.

The current data suggest that, for a majority of

POTS patients, panic-like symptoms are phenomenologically

unrelated to panic disorder symptoms.

Despite clinical similarities that can lead to misdiagnosis,

several characteristics may be helpful in distinguishing

POTS patients from panic disorder

patients. First, a prior history of panic disorder may

be absent in POTS patients. Second, panic-like

symptoms in POTS patients are precipitated mostly

by change to an upright posture. Third, particular

panic symptoms such as fear of dying, fear in general,

sense of unreality, and feeling detached are infrequently

reported. Fourth, physical and psychophysiological

symptoms usually cease with recumbency.

Fifth, distinct differences in personality patterns exist

between these two groups of patients. A psychological

assessment using the Minnesota Multiphasic Personality

Inventory questionnaire demonstrated that T

scores for manifest anxiety were in the normal range

in POTS patients [21]. Sixth, sudomotor and other

autonomic abnormalities may be demonstrable in

these patients [19].

It is not known why patients with POTS present

with panic-like symptoms. POTS may act as organic

precipitant of these symptoms as previously described

in patients with various medical disorders such as

hyperthyroidism and hypoglycemia [33]. These patients

may be vulnerable based on innate biological

factors and anxiety sensitivity index [5, 16].


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Perfect! Thank you for posting this! It was my firm conviction that my symptoms and my daughters' symptoms were actually dysautonomia issues and not truly anxiety issues. When the POTS is mostly under control, so are the anxiety type symptoms. Printing this out for their pediatrician who we see this week!

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