Rales and rhonchi, along with other adventitious respiratory sounds, are signs of an underlying health problem. But while the two are closely related, they are completely different sounds that require specific intervention.
Summary Table
| Rales | Rhonchi |
| Caused by fluid buildup in the small airways | Caused by a blockage to the major airways |
| More prominent near the end of inspiration | More prominent during expiration |
| Divided into two according to sound: 1. Fine rales – an irregular series of high-pitched, crackling sounds 2. Coarse rales – a series of short, low-pitched, explosive sounds | A round, deep sound similar to gurgling or snoring |
| A possible symptom of health disorders such as COPD (chronic obstructive pulmonary disease), pulmonary edema (fluid accumulation in pulmonary air spaces), asthma, pneumonia, adult respiratory distress syndrome, cardiac disease, or pulmonary fibrosis | A possible symptom of health disorders such as COPD, cystic fibrosis, bronchitis, and pneumonia |
| Treatment is usually focused on minimizing inflammation and relaxing the airways | Treatment is usually focused on minimizing mucous and dilating the airways |
| Treatment may include the use of steroids, bronchodilators, and oxygen therapy | Treatment may include the use of medications and therapy |
Definitions
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Rales, also called crackles, are irregular clicking or rattling breath sounds.
Rhonchi, also known as sonorous wheezes, are low-pitched respiratory sounds.
Rales vs Rhonchi
Both fall under a huge umbrella of symptomatic lung disorders, but there is still a major difference between rales and rhonchi, specifically in terms of sound and medical indication.
Cause
Small airways are vulnerable to mucous or liquid accumulation. Once fluid builds up, the alveoli and the small airways collapse, causing the small airways to pop open. This popping or crackling sound is called rales or crackles.
Rhonchi, on the other hand, is an irregular breath sound generated by a blockage to the major airways. As mucous or any foreign bodies accumulate in any of these major branches, the airway becomes obstructed, producing a low-pitched sound.
Occurrence
While both can occur anytime during auscultation, rales are usually heard near the end of inspiration, while rhonchi are prominent during expiration.
Sound
In terms of sound, rales are divided into two major types: fine and coarse. Fine rales are an irregular series of high-pitched, crackling sounds, which are quite similar to the sound produced by frying salt in a pan. Coarse rales, by contrast, are short, explosive, low-pitched sounds that sound like someone pulling velcro apart.
Rhonchi are known as a “sonorous” wheeze because of its round and deep sound, which can be described as a gurgling or snoring sound.
Medical Indication
Rales and rhonchi are a sign of an impending respiratory problem. Depending on the type, rales are indicative of a variety of diseases including COPD (chronic obstructive pulmonary disease), pulmonary edema (fluid accumulation in pulmonary air spaces), asthma, pneumonia, adult respiratory distress syndrome, cardiac disease, or pulmonary fibrosis. Between the two types of rales, coarse rales are a sign of a more severe health problem and are commonly auscultated among patients with end-stage diseases.
Rhonchi, by comparison, are common among those suffering from COPD, cystic fibrosis, bronchitis, and pneumonia.
Treatment
Although there is no specific cure for rales and rhonchi, the medical approach for these two conditions greatly vary. Aside from addressing the underlying health problem, the treatment goal for patients with rales is to minimize inflammation and relax the airways. This commonly involves the use of steroids, bronchodilators, and oxygen therapy.
Comparatively, since rhonchi are caused by airway obstruction, medical care usually includes medications and therapy that aims to minimize mucous or dilate the airways.