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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.