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Hyperventilation

Essentials

  • When investigating a patient's first hyperventilation attack, it is important to rule out serious diseases that may cause hyperventilation.
  • In the basic evaluation of any patient with hyperventilation the following examinations should be performed: basic blood count with platelet count, blood glucose, serum calcium, thyroid function (TSH, free T4), chest x-ray and ECG. If no other disease that would explain the symtoms can be found, attention should be placed on the treatment of panic disorder.

Definitions

  • Hyperventilation means increased alveolar ventilation causing a decrease in arterial blood pCO2, which in turn causes neurological symptoms and manifestations induced by vasoconstriction.
    • Hyperventilation-type symptoms are not necessarily connected with blood gas disturbances: e.g. in panic disorder, the patient may have a feeling that he/she does not get enough air and is therefore gasping for breath but is actually not hyperventilating.
    • Some patients get the symptom during physical exertion, or it may be related to a change in posture.
  • In practice hyperventilation syndrome means psychogenic recurring hyperventilation which often is connected with panic disorder Anxiety Disorder. Hyperventilation may, however, also be a symptom in many somatic diseases.

Pathophysiology

  • Pulmonary causes
    • Pneumonia
    • Pneumothorax
    • Pulmonary embolism Pulmonary Embolism
    • Asthma and chronic obstructive pulmonary disease (COPD)
    • Pulmonary parenchymal diseases
  • Other causes
    • Psychological distress, panic disorder Anxiety Disorder
    • Cardiac insufficiency
    • Metabolic acidosis
    • Neurological diseases (tumours of the brain stem)

Symptoms

  • Feeling of suffocation, increased oxygen requirement, dyspnoea
  • Chest pain
    • Often a stabbing pain on the left side
  • Tachycardia
  • Neurological symptoms
    • Dizziness, fainting
    • Weakness, tremor
    • Paraesthesias (sensation of tingling or numbness)
    • Clumsiness
    • Concentration difficulties
    • Convulsions
  • Psychological symptoms
    • Anxiety, panic attack
    • Depersonalization

Diagnosis

  • Patient history: psychogenic causes should be identified
  • Pulse oximetry Pulse Oximetry
    • If oxygen saturation is low even though the patient hyperventilates, the cause is usually an organic disease, but normal oxygen saturation does not exclude an organic disease.
  • Arterial or capillary blood sample
    • During an acute attack, alkalosis and low pCO2 support the diagnosis.
  • Hyperventilation test
    • If voluntary hyperventilation causes the familiar symptoms, the diagnosis is supported and the patient can better understand the pathophysiology of the symptoms.
    • Hyperventilation predisposition can be investigated by spiroergometry. In this case, an orthostatic test with respiratory gas monitoring is often done to complement the exercise test.
  • Chest x-ray
  • ECG, basic blood count with platelet count, blood glucose, serum calcium, thyroid function (TSH, free T4)
    • Hyperventilation may, by an unknown mechanism, cause similar ECG changes to those seen in ischaemia (ST-segment depression and T-wave negativity).
  • In suspicion of pulmonary embolism: see investigation strategy in the article Pulmonary Embolism.

Treatment

  • Causative treatment
  • Treatment of acute psychogenic hyperventilation
    • Calming the patient and making the patient talk is often helpful.
    • Breathing into a paper bag in an acute situation has been mostly abandoned.
    • Peroral diazepam either as tablets or as solution is given if needed.
    • Try to identify the triggering factor and make a plan of treatment for the patient.
      • In specialized care, the patient may also be referred to a physiotherapist specialized in breathing education.
  • Treatment of panic disorder: see Anxiety Disorder.

References

  • Boulding R, Stacey R, Niven R, et al. Dysfunctional breathing: a review of the literature and proposal for classification. Eur Respir Rev 2016;25(141):287-94.