More Than "Just Another Conversion Reaction!" A Case of Hyperventilation Syndrome
Authors:

Turan Set¹, Nezih Dagdeviren², Zekeriya Akturk2, Cahit Ozer3

¹ Resident, Trakya University Medical Faculty, Department of Family
  Medicine
² Assistant Professor, Trakya University Medical Faculty, Department
  of Family Medicine
3 Clinical instructer, Trakya University Medical Faculty, Department of
  Family Medicine

Correspondence:
Dr. Cahit OZER
Trakya University Medical Faculty 
Department of Family Medicine, 
22030 Edirne, Turkey
Mobile Phone: +90 533 4530917
Phone :+902842356380
Fax: +90 284 2357652
e-mail: cahitozer@yahoo.com
e-mail: cahitozer@trakya.edu.tr

Key words: hyperventilation syndrome, paresthesia, contractions, respiratory alkalosis, ionized calcium

Summary
Although hyperventilation occurs in many different clinical specialties, family physicians differ in that they have the responsibility to provide their patients the best available health care without increasing the burden of the health system by asking for unnecessary referrals. Hyperventilation syndrome is a clinical entity with the potential to be easily overlooked as conversion reaction or referred to higher centers with the doubt of potentially serious disease. 

In this paper, we report a case admitted to the emergency unit. She was first considered as having a conversion reaction, but history, physical examination, and laboratory test revealed decreased ionized calcium levels caused by respiratory alkalosis, induced by a hyperventilation syndrome. She rapidly recovered by re-breathing into a bag. 

If family physicians become alert to the diagnosis and knowledgeable about the treatment of hyperventilation syndrome, such clinical presentations can easily be handled with high patient satisfaction at the primary care level.

Introduction
Hyperventilation occurs in many different specialties including neurology, cardiology, chest medicine, psychiatry, and family practice. The importance of family practice comes from the responsibility to provide patients the best available health care without increasing the burden of the health system by asking for unnecessary referrals. The prevalence of hyperventilation syndrome in primary care is 6-11% (1). Hyperventilation can be described as breathing more than metabolic needs of body resulting excess CO2 excretion, respiratory alkalosis and elevation of the blood pH (2). Hyperventilation syndrome is characterized with somatic symptoms emerging with volunteer inappropriate hyperventilation. 

Diagnostic criteria of hyperventilation syndrome are as follows: 

  1. The patient should hyperventilate and have low PaCO2, 
  2. Somatic diseases causing hyperventilation should have been excluded, and 
  3. The patient should have a number of complaints that are, or have been, related to the hypocapnia (2). 

Hypocalcemic crisis presents with the classical symptomatology of tetany plus extrapyramidal symptoms and a disordering of consciousness extending even to coma. 

Clinical findings of hypocalcaemia are as follows: 

  1. Nonspecific symptoms such as fatigue, irritability, acral or oral paresthesia, muscle spasms and fasciculations, 
  2. Overt tetany, 
  3. Convulsions, 
  4. Latent tetany which can usually appear by provocation (Chvostek and Trousseau signs), and 
  5. Elongation of Q-T and S-T intervals; very rarely a 2:1 A-V block. 

It develops when the concentration of ionized serum calcium declines rapidly, and is very rarely found in chronic hypocalcaemia. In terms of its etiology, various forms of parathyroid deficiency, and nonparathyrogenic diseases associated with hypocalcaemia may be involved (3). Since in the latter, the concentration of albumin is also diminished, and thus ionized calcium decreases to only a small extent, hypocalcemic crisis in these conditions is rare. The most common clinical form is normocalcemic tetany, that occurs within the framework of the hyperventilation syndrome (3). In hyperventilation syndrome, the ionized calcium fraction is temporarily reduced by marked alkalosis.