Musical sound of wheeze-Health awareness

Musical sound of wheeze

A wheeze is a musical sound produced by airflow through central and also distal part of the airways. Wheezes can be single toned or polyphonic. It can occur either during inspiration and expiration. It can be chronic and acute depending on the cause. Wheezing is a symptom and not a diagnosis.

All that wheezes do not necessary means asthma. The usual causes of asthma are viral lower respiratory tract infection and of course, asthma! In children less than 1 year, the airways are tiny and easily get narrowed by oedema and secretions. This is why it becomes a common feature when the infections involve the bronchi or bronchioles. Asthma is the most common cause of wheeze in children more than 2 years old. It may have its onset in the first year of life however it is difficult to distinguish from viral lower respiratory tract infection that may also manifests itself with episodic wheeze. 75% of childhood asthma presents with infrequent episodic wheeze and 20% will manifests as frequent episodic wheeze. Only 5% presents with persistent wheeze.

Wheezing is not always a consequence of airway obstruction. In other words, airway obstruction may not cause a wheeze. For example in severe airway obstruction where the obstruction is bad enough, there is not enough air movement in there to generate sound. This explain why silent chest is a life threatening in asthmatic attack rather than severe wheeze.

A polyphonic wheeze (a wheeze with multiple notes) indicates a dynamic compression of larger and central airways. Monophonic wheeze usually refers to smaller airway obstruction. Upper airway obstruction may be accompany with dyspnea (shortness of breath) on exertion when the airway diameter is <8 mm. If the obstruction occurs in airways with diameter < 5 mm, stridor may present.

Some differential diagnosis of wheeze:

Intrathoracic causes

Tracheal stenosis
Foreign body - suspect this if the child presents with sudden onset of wheeze
Benign tumors
Tracheomalacia
Malignancy

Lower airway obstruction

Asthma
Allergic bronchopulmonary aspergillosis (ABPA)
Aspiration
Bronchiolitis
Bronchiectasis
Cystic fibrosis (CF) – usually associated with failure to thrive and frequent chest infection
Chronic obstructive pulmonary disease (COPD)
Congestive heart failure (CHF)
Parasitic infection
Pulmonary embolus

Extrathoracic causes

Vocal cord dysfunction
Postnasal drip
Laryngeal edema – laryngeal pathology usually accompany with abnormal voice or cry
Malignancy
Relapsing polychondritis
Gastro-oesophageal reflux – usually accompany with excessive vomiting
Wegener’s granulomatosis

Diagnosis of wheezing can be made by taking good history. Pulmonary function tests (PFTs) with flow volume loops can be helpful in distinguish causes of wheeze either intrathoracic or extrathoracic obstruction. Treatment will be largely depends on the underlying cause. Response to specific treatment will help to confirm the diagnosis. Lack of response should prompt alteration of therapy. Other possible diagnosis should be made.

Reference:

Tao Le et al. First Aid for the Family Medicine Boards. 2008. McGraw Hill Lange.
Shyam Bhakthavalsala et al. Crash course paediatrics. 3rd edition. 2008. Mosby Elsevier.