Letters to the Editor
Respiratory Symptoms in Nocturnal Panic Attacks
Dear Editor:
There is a connection between respiratory system dysfunction and
panic disorder (1). Subjects with panic disorder and respiratory
problems appear as a distinct subtype: nocturnal panic attacks present
with a closer relation to the respiratory system (2). We describe
2 clinical cases of panic disorders (diagnosed according to DSM-IV
criteria) with prominent respiratory symptoms during nocturnal panic
attacks. Both were treated at the Laboratory of Panic and Respiration,
Institute of Psychiatry, Federal University of Rio de Janeiro.
Case Report 1
Ms A is a 42-year-old Caucasian who, while awake, had spontaneous
attacks with palpitations, shortness of breath, choking, chest pain,
dizziness, and fear of losing control. All laboratory tests were
within the normal range. She then developed panic attacks during
sleep that were associated with her waking attacks. Her nocturnal
panic attacks were more intense, occurred every night, and were
accompanied by prominent respiratory symptoms (that is, shortness
of breath, chest pain, tingling, severe choking, and fear of losing
control and dying). An agoraphobic pattern developed, and she could
only sleep seated. She presented an intense anticipatory anxiety
at nightfall. Her waking panic attacks changed from a spontaneous
pattern to situational attacks with nausea, diarrhoea, dizziness,
and tachycardia.
She was initially treated with nortriptyline 10 mg daily. At the
dosage of 75 mg daily, her nocturnal panic attacks remitted, but
she was still presenting limited symptom attacks. At 100 mg daily,
her panic attacks fully remitted.
Case Report 2
Mr BN is a 24-year-old Caucasian with a chief complaint of choking
and shortness of breath while sleeping. He presented panic attacks
during sleep, with shortness of breath, chest pain, dyspnea, choking,
paresthesias, sweating, tachycardia, and severe fear of dying. His
laboratory tests were within normal limits. His clinical picture
was marked by intense fear of having a panic attack while sleeping.
He developed an avoidant pattern of falling asleep while working
at his usual daily activities during the night. A diurnal drowsiness
resulted in difficulty in maintaining concentration.
We instituted treatment with nortriptyline, with a gradual increase
of the dosage. At 20 mg daily, the patient experienced a lessening
in the frequency and intensity of his panic attacks, and the respiratory
symptoms remitted. A complete remission of the panic attacks, agoraphobia,
and anticipatory anxiety was achieved at 75 mg daily, and the patient
has been without any panic attacks at 1-year follow-up.
Nocturnal panic attacks are common and often neglected. These case
reports suggest major findings in regard to them: 1) the prominent
respiratory symptoms; 2) the overlapping with sleep disorders symptoms;
and 3) a change in the pattern of diurnal panic attacks, from spontaneous
situational. A hypothesis to account for these findings exists in
the pathophysiology of the sleep, when blood carbon dioxide (CO2)
levels rise significantly (3). The panic disorder patients, who
have heightened CO2 sensitivity (2,3), according to Klein’s
false suffocation alarm theory (4), start a cycle in which enhanced
CO2 leads to more frequent sighing in an attempt to reduce arterial
CO2 levels (3).
References
1. Gorman JM, Fyer MR, Goetz R, Askanazi J, Liebowitz
MR, Fryer AJ, and others. Ventilatory phisiology of patients with
of panic disorder. Arch Gen Psychiatry 1988;45:31–9.
2. Briggs AC, Stretch DD, Brandon S. Subtyping of panic
disorder by symptom profile. Br J Psychiatry 1993;163:201–9.
3. Preter M, Klein DF. Panic disorder and the suffocation
false alarm theory: current state of knowledge and further implications
for neurobiologic theory testing. In: Bellodi L, Perna G, editors.
The panic respiration connection. Milan: MDM Medical Media Srl;
1998. p 1–24.
4. Klein DF. False suffocation alarms, spontaneous
panics, and related conditions: an integrative hypothesis. Arch
Gen Psychiatry 1993;50:306–17.
Fabiana L Lopes, MD
Isabella Nascimento, MD
Alexandre M Valença, MD
M<rcio Versiani, MD
Antonio E Nardi, MD
Rio de Janeiro, Brazil
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