Last updated
SynonymsSibilant rhonchi
The sound of wheezing as heard with a stethoscope.
Specialty Respirology

A wheeze is a continuous, coarse, whistling sound produced in the respiratory airways during breathing. [1] For wheezes to occur, some part of the respiratory tree must be narrowed or obstructed, or airflow velocity within the respiratory tree must be heightened. Wheezing is commonly experienced by persons with a lung disease; the most common cause of recurrent wheezing is asthma attacks, though it can also be a symptom of lung cancer, congestive heart failure, and certain types of heart diseases.

Lung cancer cancer in the lung

Lung cancer, also known as lung carcinoma, is a malignant lung tumor characterized by uncontrolled cell growth in tissues of the lung. This growth can spread beyond the lung by the process of metastasis into nearby tissue or other parts of the body. Most cancers that start in the lung, known as primary lung cancers, are carcinomas. The two main types are small-cell lung carcinoma (SCLC) and non-small-cell lung carcinoma (NSCLC). The most common symptoms are coughing, weight loss, shortness of breath, and chest pains.


The differential diagnosis of wheezing is wide, and the reason for wheezing in a given patient is determined by considering the characteristics of the wheezes and the historical and clinical findings made by the examining physician.

In medicine, a differential diagnosis is the distinguishing of a particular disease or condition from others that present similar clinical features. Differential diagnostic procedures are used by physicians to diagnose the specific disease in a patient, or, at least, to eliminate any imminently life-threatening conditions. Often, each individual option of a possible disease is called a differential diagnosis.



Wheezes occupy different portions of the respiratory cycle depending on the site of airway obstruction and its nature. The fraction of the respiratory cycle during which a wheeze is produced roughly corresponds to the degree of airway obstruction. [2] [3] Bronchiolar disease usually causes wheezing that occurs in the expiratory phase of respiration. The presence of expiratory phase wheezing signifies that the patient's peak expiratory flow rate is less than 50% of normal. [4] Wheezing heard in the inspiratory phase, on the other hand, is often a sign of a stiff stenosis, usually caused by tumors, foreign bodies or scarring. This is especially true if the wheeze is monotonal, occurs throughout the inspiratory phase (i.e. is "holoinspiratory"), and is heard more proximally, in the trachea. Inspiratory wheezing also occurs in hypersensitivity pneumonitis. [5] Wheezes heard at the end of both expiratory and inspiratory phases usually signify the periodic opening of deflated alveoli, as occurs in some diseases that lead to collapse of parts of the lungs.

In physiology, respiration is the movement of oxygen from the outside environment to the cells within tissues, and the transport of carbon dioxide in the opposite direction.

Bronchiole passageways by which air passes through the nose or mouth to the alveoli of the lungs

The bronchioles or bronchioli are the passageways by which air passes through the nose or mouth to the alveoli of the lungs, in which branches no longer contain cartilage or glands in their submucosa. They are branches of the bronchi, and are part of the conducting zone of the respiratory system. The bronchioles divide further into smaller terminal bronchioles which are still in the conducting zone and these then divide into the smaller respiratory bronchioles which mark the beginning of the respiratory region.


Spirometry is the most common of the pulmonary function tests (PFTs). It measures lung function, specifically the amount (volume) and/or speed (flow) of air that can be inhaled and exhaled. Spirometry is helpful in assessing breathing patterns that identify conditions such as asthma, pulmonary fibrosis, cystic fibrosis, and COPD. It is also helpful as part of a system of health surveillance, in which breathing patterns are measured over time.

The location of the wheeze can also be an important clue to the diagnosis. Diffuse processes that affect most parts of the lungs are more likely to produce wheezing that may be heard throughout the chest via a stethoscope. Localized processes, such as the occlusion of a portion of the respiratory tree, are more likely to produce wheezing at that location, hence the sound will be loudest and radiate outwardly. The pitch of a wheeze does not reliably predict the degree of narrowing in the affected airway. [6]


A special type of wheeze is stridor. Stridor — the word is from the Latin, strīdor [7] — is a harsh, high-pitched, vibrating sound that is heard in respiratory tract obstruction. Stridor heard solely in the expiratory phase of respiration usually indicates a lower respiratory tract obstruction, "as with aspiration of a foreign body (such as the fabled pediatric peanut)." [8] Stridor in the inspiratory phase is usually heard with obstruction in the upper airways, such as the trachea, epiglottis, or larynx; because a block here means that no air may reach either lung, this condition is a medical emergency. Biphasic stridor (occurring during both the inspiratory and expiratory phases) indicates narrowing at the level of the glottis or subglottis, the point between the upper and lower airways.

Stridor is a high-pitched breath sound resulting from turbulent air flow in the larynx or lower in the bronchial tree. It is different from a stertor which is a noise originating in the pharynx. Stridor is a physical sign which is caused by a narrowed or obstructed airway. It can be inspiratory, expiratory or biphasic, although it is usually heard during inspiration. Inspiratory stridor often occurs in children with croup. It may be indicative of serious airway obstruction from severe conditions such as epiglottitis, a foreign body lodged in the airway, or a laryngeal tumor. Stridor should always command attention to establish its cause. Visualization of the airway by medical experts equipped to control the airway may be needed.

Glottis Opening between the vocal folds

The glottis is the opening between the vocal folds.


The subglottis or subglottic region is the lower portion of the larynx, extending from just beneath the vocal cords down to the top of the trachea. The structures in the subglottis are implicated in the regulation of the temperature of the breath. Narrowing of the subglottis is known as subglottic stenosis and may require a tracheotomy to correct.


One out of 3 preschool children and 2 out of 3 school children with recurrent wheezing/coughing are allergic.[ citation needed ] The reaction creates an inflammation that, in turn, can lead to a variety of symptoms such as wheezing.

Over the last decade allergy has increased by 18% in the United States. [9] Today one child in four is allergic.[ citation needed ] Early diagnosis of allergy is important for the development of the child later in life.[ citation needed ] There are many patients with symptoms suggesting eczema, rhinitis, hay fever, asthma or wheezing.

See also

Related Research Articles

Asthma long-term disease involving poor airflow in the lungs

Asthma is a common long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and bronchospasm. Symptoms include episodes of wheezing, coughing, chest tightness, and shortness of breath. These may occur a few times a day or a few times per week. Depending on the person, they may become worse at night or with exercise.

Crackles are the clicking, rattling, or crackling noises that may be made by one or both lungs of a human with a respiratory disease during inhalation. They are often heard only with a stethoscope. Bilateral crackles refers to the presence of crackles in both lungs.

Bronchospasm lower respiratory tract disease that affects the airways leading into the lungs

Bronchospasm or a bronchial spasm is a sudden constriction of the muscles in the walls of the bronchioles. It is caused by the release (degranulation) of substances from mast cells or basophils under the influence of anaphylatoxins. It causes difficulty in breathing which can be very mild to severe.

Eosinophilic pneumonia (EP) is a disease in which an eosinophil, a type of white blood cell, accumulates in the lung. These cells cause disruption of the normal air spaces (alveoli) where oxygen is extracted from the atmosphere. Several different kinds of eosinophilic pneumonia exist and can occur in any age group. The most common symptoms include cough, fever, difficulty breathing, and sweating at night. EP is diagnosed by a combination of characteristic symptoms, findings on a physical examination by a health provider, and the results of blood tests and x-rays. Prognosis is excellent once most EP is recognized and treatment with corticosteroids is begun.

Acute severe asthma is an acute exacerbation of asthma that does not respond to standard treatments of bronchodilators (inhalers) and corticosteroids. Symptoms include chest tightness, rapidly progressive dyspnea, dry cough, use of accessory respiratory muscles, fast and/or labored breathing, and extreme wheezing. It is a life-threatening episode of airway obstruction and is considered a medical emergency. Complications include cardiac and/or respiratory arrest.

Exercise-induced asthma, or E.I.A., occurs when the airways narrow as a result of exercise. The preferred term for this condition is exercise-induced bronchoconstriction (EIB); exercise does not cause asthma, but is frequently an asthma trigger.

Feline asthma is a common allergic respiratory disease in cats, affecting at least one percent of all adult cats worldwide. It is a chronic progressive disease for which there is no cure. Common symptoms include wheezing, coughing, labored breathing and potentially life-threatening bronchoconstriction. There is conjecture that the disease is becoming more common due to increased exposure to industrial pollutants.

Respiratory sounds specific sound generated by the movement of air through the respiratory system

Respiratory sounds refer to the specific sounds generated by the movement of air through the respiratory system. These may be easily audible or identified through auscultation of the respiratory system through the lung fields with a stethoscope as well as from the spectral chacteristics of lung sounds. These include normal breath sounds and adventitious or "added" sounds such as rales, wheezes, pleural friction rubs, stertor and stridor.

Occupational asthma refers to new onset asthma or the recurrence of previously quiescent asthma directly caused by exposure to an agent at workplace. It is an occupational lung disease and a type of work-related asthma. Agents that can induce occupational asthma can be grouped into sensitizers and irritants.

Obstructive lung disease

Obstructive lung disease is a category of respiratory disease characterized by airway obstruction. Many obstructive diseases of the lung result from narrowing (obstruction) of the smaller bronchi and larger bronchioles, often because of excessive contraction of the smooth muscle itself. It is generally characterized by inflamed and easily collapsible airways, obstruction to airflow, problems exhaling and frequent medical clinic visits and hospitalizations. Types of obstructive lung disease include; asthma, bronchiectasis, bronchitis and chronic obstructive pulmonary disease (COPD). Although COPD shares similar characteristics with all other obstructive lung diseases, such as the signs of coughing and wheezing, they are distinct conditions in terms of disease onset, frequency of symptoms and reversibility of airway obstruction. Cystic fibrosis is also sometimes included in obstructive pulmonary disease.

Pulmonary function testing test to evaluate respiratory system

Pulmonary function test (PFT) is a complete evaluation of the respiratory system including patient history, physical examinations, and tests of pulmonary function. The primary purpose of pulmonary function testing is to identify the severity of pulmonary impairment. Pulmonary function testing has diagnostic and therapeutic roles and helps clinicians answer some general questions about patients with lung disease. PFTs are normally performed by a respiratory therapist, physiotherapist and/or GP

Bronchomalacia congenital disorder of respiratory system

Bronchomalacia is a term for weak cartilage in the walls of the bronchial tubes, often occurring in children under six months. Bronchomalacia means 'floppiness' of some part of the bronchi. Patients present with noisy breathing and/or wheezing. There is collapse of a main stem bronchus on exhalation. If the trachea is also involved the term tracheobronchomalacia (TBM) is used. If only the upper airway the trachea is involved it is called tracheomalacia (TM). There are two types of bronchomalacia. Primary bronchomalacia is due to a deficiency in the cartilaginous rings. Secondary bronchomalacia may occur by extrinsic compression from an enlarged vessel, a vascular ring or a bronchogenic cyst. Though uncommon, idiopathic tracheobronchomalacia has been described in older adults.

Tracheobronchial injury damage to the tracheobronchial tree

Tracheobronchial injury (TBI) is damage to the tracheobronchial tree. It can result from blunt or penetrating trauma to the neck or chest, inhalation of harmful fumes or smoke, or aspiration of liquids or objects.

Vocal cord dysfunction(VCD), also known as Paradoxical Vocal Fold Motion(PVFM) or Paradoxical Vocal Cord Movement(PVCM), is a pathology affecting the vocal folds characterized by full or partial vocal fold closure causing difficulty and distress during respiration, especially during inhalation.

Double aortic arch is a relatively rare congenital cardiovascular malformation. DAA is an anomaly of the aortic arch in which two aortic arches form a complete vascular ring that can compress the trachea and/or esophagus. Most commonly there is a larger (dominant) right arch behind and a smaller (hypoplastic) left aortic arch in front of the trachea/esophagus. The two arches join to form the descending aorta which is usually on the left side. In some cases the end of the smaller left aortic arch closes and the vascular tissue becomes a fibrous cord. Although in these cases a complete ring of two patent aortic arches is not present, the term ‘vascular ring’ is the accepted generic term even in these anomalies.

Dynamic hyperinflation is a phenomenon that occurs when a new breath begins before the lung has reached the static equilibrium volume.

Foreign body aspiration

Foreign body aspiration occurs when a foreign body enters the airways and causes choking. Objects can enter the esophagus through the mouth, or enter the trachea through the mouth or nose.

Plastic bronchitis (PB) is a disorder in which branching casts of the airways are expectorated. PB has been previously identified by many names including fibrinous bronchitis, bronchitis pseudomembranosa, and Hoffmann bronchitis and is now uniformly termed plastic bronchitis. PB is not a single disease with a defined mechanism that explains the cast formation in all conditions. Examples of diseases associated with expectoration of casts, and which sometimes are labeled PB include tuberculosis, atypical mycobacterial disease, allergic bronchopulmonary aspergillosis and asthma.


  1. Sengupta, Nandini; Sahidullah, Md; Saha, Goutam (August 2016). "Lung sound classification using cepstral-based statistical features". Computers in Biology and Medicine. 75 (1): 118–129. doi:10.1016/j.compbiomed.2016.05.013. PMID   27286184.
  2. Baughman RP, Loudon RG (Nov 1984). "Quantitation of wheezing in acute asthma". Chest. 86 (5): 718–22. doi:10.1378/chest.86.5.718. PMID   6488909.
  3. Pasterkamp H, Tal A, Leahy F, Fenton R, Chernick V (Jul 1985). "The effect of anticholinergic treatment on postexertional wheezing in asthma studied by phonopneumography and spirometry". Am Rev Respir Dis. 132 (1): 16–21. doi:10.1164/arrd.1985.132.1.16 (inactive 2019-03-13). PMID   3160273.
  4. Shim CS, Williams MH (May 1983). "Relationship of wheezing to the severity of obstruction in asthma". Arch Intern Med. 143 (5): 890–2. doi:10.1001/archinte.143.5.890. PMID   6679232.
  5. Earis JE, Marsh K, Pearson MG, Ogilvie CM (Dec 1982). "The inspiratory "squawk" in extrinsic allergic alveolitis and other pulmonary fibroses". Thorax. 37 (12): 923–6. doi:10.1136/thx.37.12.923. PMC   459459 . PMID   7170682.
  6. Meslier N, Charbonneau G, Racineux JL (Nov 1995). "Wheezes". Eur Respir J. 8 (11): 1942–8. doi:10.1183/09031936.95.08111942. PMID   8620967.
  7. Simpson JA, Weiner ESC (eds). "stridor, n. 2." Oxford English Dictionary 2nd ed. Oxford: Clarendon Press, 1989. OED Online Oxford University Press. Accessed September 10, 2005. http://dictionary.oed.com.
  8. Sapira JD, Orient JM (2000). Sapira's art & science of bedside diagnosis (2nd ed.). Hagerstwon, MD: Lippincott Williams & Wilkins. ISBN   978-0-683-30714-6.
  9. Park, Alice (2009-02-26). "Why We're Going Nuts Over Nut Allergies - TIME". Time. Retrieved 2 March 2009.

Further reading

External resources