Basics
Description
- Hyperventilation syndrome describes a constellation of symptoms:
- Most commonly: Dyspnea, chest pain, lightheadedness, and paresthesias
- Produced by a nonphysiologic increase in minute ventilation:
- Minute ventilation may be increased by increasing respiratory rate or tidal volume (sighs).
- Pathologic or physiologic causes of hyperventilation must be excluded before the diagnosis of hyperventilation syndrome can be assigned.
- Prevalence:
- 10-15% in the general population
- More common in women (may be related to progesterone)
Etiology
- Etiology of symptoms is unclear:
- Usually a response to psychological stressors
- Controversy exists regarding underlying disorders that may contribute to hyperventilation:
- Hypocapnia
- Hypophosphatemia
- Hypocalcemia
Diagnosis
Signs and Symptoms
History
- Past episodes
- Duration
- Triggers
- Past treatment
- Typical time point of onset during the day
- Cardiac:
- Chest pain
- Dyspnea
- "Air hunger"�
- Palpitations
- Neurologic:
- Dizziness
- Lightheadedness
- Syncope
- Paresthesias
- Headache
- Carpopedal spasm
- Tetany
- Psychiatric:
- Intense fear, anxiety
- Giddiness
- Feeling of unreality
- General:
Physical Exam
- Clinical signs are rare and varied:
- Tachypnea most common
- However, tachypnea may not be present. Patient may increase tidal volume rather than respiratory rate.
- Carpopedal spasm:
- Chvostek sign may be present
Essential Workup
- Diagnosis of exclusion:
- Primary pathologic or physiologic causes of hyperventilation must be investigated and excluded.
- Clinical diagnosis based on the history and physical exam
- Vital signs including pulse oximetry
- Hyperventilation syndrome will not result in hypoxia.
Diagnosis Tests & Interpretation
Lab
- Consider an ABG in any hypoxic patient.
- Electrolytes, BUN, creatinine, and glucose levels for suspected acidosis/diabetic ketoacidosis
- EKG if chest pain present
Imaging
CXR of any patient with hypoxia or focal findings on lung exam �
Diagnostic Procedures/Surgery
- Hyperventilation provocation test after resolution of symptoms:
- Forced overbreathing for 3 min may be attempted to reproduce the symptoms.
- Diagnostic accuracy is controversial.
- Reproducibility of the symptoms may help the patient understand the role of overbreathing and help manage future attacks.
Differential Diagnosis
- Pathologic
- Hypoxia:
- Asthma
- CHF
- Pulmonary embolus
- Pneumonia
- Severe pain
- CNS lesions
- Acidosis (DKA)
- Pulmonary HTN
- Pulmonary embolus
- Hypoglycemia
- Mild asthma
- Drugs:
- Aspirin intoxication
- Withdrawal syndrome (e.g., alcohol, benzodiazepines)
- Physiologic
- Pregnancy
- Pyrexia
- Altitude
Treatment
Pre-Hospital
- Patients with abnormal vital signs require IV access and pulse oximetry.
- Supplemental oxygen if hypoxic
Initial Stabilization/Therapy
- Patients with abnormal vital signs require IV access and pulse oximetry.
- Initiate therapy for pathologic or physiologic cause of hyperventilation.
Ed Treatment/Procedures
- Initiate treatment of hyperventilation syndrome if initial workup does not support a pathologic or physiologic cause, and history and physical exam findings suggest the diagnosis of hyperventilation syndrome.
- Reassurance, calming, and explanation of the voluntary component of the patients symptoms often have immediate dramatic results.
- Do not use paper bag rebreathing to increase the PCO2. This has not been supported in the literature:
- It may be dangerous in patients with hypoxia or a pathologic or physiologic cause for hyperventilation.
- Clarification of the psychological stressors helps the patient avoid further attacks.
- Assess for need of psychiatric evaluation (i.e., suicidal ideation).
- Anxiolytics:
- Benzodiazepine if symptoms persist to break the cycle of anxiety and hyperventilation
- Short course of anxiolytics may benefit patients with definable temporary stressors.
Medication
- Alprazolam 0.25-0.5 mg PO
- Lorazepam: 1-2 mg PO or IV
- Diazepam: 2-5 mg PO or IV
- Outpatient treatment:
- Buspirone: 5 mg PO TID
- Diazepam: 2-5 mg PO BID-QID
Follow-Up
Disposition
Admission Criteria
Hyperventilation syndrome does not require admission. �
Discharge Criteria
- Exclusion or successful treatment of primary pathologic or physiologic causes of hyperventilation
- No acute psychiatric issues
- Adequate follow-up with a primary care physician
Follow-Up Recommendations
- Follow-up with primary care physician
- Assess the need for psychiatric follow-up.
Pearls and Pitfalls
- Exclude pathologic or physiologic causes of hyperventilation.
- Hyperventilation syndrome will not result in hypoxia.
Additional Reading
- Gardner �WN. The pathophysiology of hyperventilation disorders. Chest. 1996;109:516-534.
- Nardi �AE, Freire �RC, Zin, �WA. Panic disorder and control of breathing. Respir Physiol Neurobiol. 2009;167(1):133-143.
- Niggerman �B. How to diagnose psychogenic and functional breathing disorders in children and adolescents. Pediatr Allergy Immunol. 2010;21:895-899.
- Rizzolo �CL, Taylor �JE, Cerciello �RL. Anxiety and anxiety-related disorders in the adolescent population: An overview of diagnosis and treatment. Adolesc Med State Art Rev. 2009:20(1):188-202.
- Saisch �SG, Wessely �S, Gardner �WN. Patients with acute hyperventilation presenting to an inner-city emergency department. Chest. 1996;110(4):952-957.
Codes
ICD9
306.1 Respiratory malfunction arising from mental factors �
ICD10
F45.8 Other somatoform disorders �
SNOMED
- 191956005 Psychogenic hyperventilation (finding)