Background

Wheeze - a high-pitched noise generated by the larynx or small air tubes during inhalation, exhalation or both. It is a rare phenomenon.

In the past, doctors would use an ear-to-the-chest method to hear these noises.¹ This all changed in 1816, when René Laennec invented the stethoscope, which made it easier to auscultate sounds from the heart, lungs and other organs. Loud wheezes might be heard with no aid, but most need a stethoscope to detect and make a prompt diagnosis.^{1, 2}

This shows how great Laennec's tool still is today. In this article, we'll look at whether wheezing might indicate a serious health issue.

Common causes of wheezing

• Blockage of small bronchial tubes in the chest, or in other larger airways 
• Obstruction in the vocal cords
• Allergies and environmental irritants
• Aspiration of a foreign substance
• Smoking and alcohol consumption
• Prolonged usage of medications
• Sleep apnoea

Symptoms observed in wheezing

• High-pitched sound (eg, whistle) heard during both inhalation and exhalation (Noisy audible breathing)
• Mild to severe dyspnoea
• Chest tightness and discomfort
• Coughing 
• Fatigue
• Cyanosis (affecting lips and skin)

Red flag: Indicating something more than just a wheeze

• When a previously healthy person suddenly develops wheezing. This could be due to exposure to an unknown allergen, foreign substance obstruction, or a long-term respiratory illness
• Severe symptoms such as a noticeable blue tinge to the skin and lips, chest discomfort, and shortness of breath may indicate status asthmaticus,³ chronic obstructive pulmonary disease,⁴ or heart failure
• ​​If the symptoms continue despite taking appropriate medication, this might suggest long-term respiratory infections
• Wheezing that lasts a few days to weeks and worsens may indicate the presence of underlying issues such as bronchiolitis, bronchiectasis, or interstitial lung disease
• Furthermore, wheezing with weight loss, night sweats, or coughing up blood may suggest severe life-threatening illnesses like Tuberculosis ⁵or lung cancer

Underlying conditions commonly associated with Wheezing

Asthma

• A chronic respiratory condition characterised by inflammation and narrowing of the airways, often resulting in wheezing
• It may occur due to obstructed airflow,  narrow air tubes, mucus accumulation and swollen airway lining mucosa
• In individuals with asthma, wheezing becomes noticeable if they come in contact with an allergen, smoke or excessively work out
• The condition worsens if wheezing persists, as this could result in other concomitant conditions, including other serious respiratory and cardiovascular illnesses³

Chronic obstructive pulmonary disease (COPD)

• A progressive respiratory disorder characterised by persistent airflow limitation and inflammation in the lungs
• It may occur due to narrow airways caused by bronchial inflammation, mucus accumulation, or bronchospasm
• Wheezing occurs in episodes and becomes prominent in COPD cases, because of severe inflammation and obstruction often triggered by allergies, infections or environmental irritants
• Poor management could also result in comorbidities including asthma, bronchiectasis and pulmonary hypertension⁴

Tuberculosis

• It is the most prevalent infectious disease worldwide caused by Mycobacterium Tuberculosis. TB mainly affects the lungs (intrapulmonary TB) and sometimes also affects other parts of the body(extrapulmonary TB)
• The most common symptoms observed are persistent cough, fever, night sweats and weight loss.
• Long-standing wheezing may be present from scarring, airway compression, or post-infective bronchiectasis⁵

Pneumonia

• Pneumonia occurs due to inflammation of the lungs caused by a bacterial or fungal infection. This condition can also occur as a comorbidity in Asthma and COPD cases
• The most common symptoms observed are fever, cough, cyanosis and chest pain
• Wheezing is observed in Pneumonia due to mucus-filled, obstructed airways⁶

Acute bronchitis 

• Swollen and inflamed bronchi (main passages) that carry air to the lungs are caused by a viral infection
• Wheezing is often observed for a short period of time in this condition. Due to the condition’s acute nature, the wheeze could be heard loud and clear without any aid. As the condition alleviates, wheezing should disappear⁷

Heart failure

• Wheezing is often an alarming symptom in cases of cardiac arrest. This usually occurs due to the interplay of functional roles between the heart and lungs (Oxygenation and circulation)⁸
• One of the main causes of a heart attack could be mucus-fluid accumulation in the lungs also referred to as pulmonary oedema. Other symptoms include severe dyspnoea, chest pain and discomfort, and exertion while lying flat due to fluid accumulation
• Systemic symptoms could be wheezing, nausea, sweating, lightheadedness, etc⁹

Lung cancer

• Wheezing in cases of lung cancer might be one of the crucial symptoms if it is persistent and unexplained.
• This can occur if a tumour partially or fully obstructs airways, causing inflammation and irritation in the airway lining, leading to turbulence in the airflow. It is often an advanced-stage symptom that depends on the size and location of the tumour.

Other symptoms include persistent coughing, haemoptysis, drastic and unexplained weight loss, chest pain, etc.

Diagnostic tools 

Wheezing is a subjective complaint. Some say they hear loud, difficult breathing (wheezy breaths), while others describe it as a noise like a whistle or rattling secretions in their throat. Let’s see how to hear these noisy yet musical sounds:

• Thorough clinical and physical examination
• Auscultation 
• Spirometry
• Bronchodilators
• Chest X-ray
• CT Scans
• Blood tests (Eosinophil count and Arterial Blood Gases (ABGs))
• Bronchoscopy
• Peak flow measurement

Management 

As we have seen earlier, wheezing is nothing but a symptom that can be addressed only when treating the underlying condition. Therefore, it is very important to seek medical attention and not make conclusions without a specialist’s advice. Always an early diagnosis, management and follow-ups are crucial for better outcomes.

Conclusion

Wheezing is a high-pitched sound that is generated by the larynx and can occur during inhalation, exhalation, or both. It is often associated with a range of conditions, from mild to severe, including the common cold, acute bronchitis, asthma, COPD, and heart failure. In addition to wheezing, individuals may experience symptoms such as fever, cough, chest pain, shortness of breath, and discomfort. The intensity of wheezing can vary, from faint to loud, and in cases where it is not easily audible, a stethoscope may be used for auscultation.

To diagnose the underlying cause of wheezing, healthcare providers may use several diagnostic tools, including blood tests, spirometry, chest X-rays, CT scans, and peak flow tests. Wheezing is a significant clinical symptom that should be promptly addressed to determine the cause and ensure timely treatment. Identifying the underlying condition early is crucial for managing symptoms and improving patient outcomes.