Bronchitis

• 1. Introduction

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  Bronchitis is inflammation of the bronchi, the large and medium-sized airways that branch through the lungs and carry air toward where breathing actually happens. It rarely starts there. It usually begins as an infection in the nose, ears, throat, or sinuses, then works its way downward until it reaches the bronchi and provokes a cough. That cough is the signature of the whole condition. Sometimes it clears in three weeks. Sometimes it settles in for years. The word covers two very different illnesses that share a name. One is a passing chest cold that most adults will meet at least once. The other is a long, productive cough measured not in days but in months and years. How did a single term come to hold both the brief and the chronic? Why does one resolve on its own while the other can narrow the airways for life? And how far back can we trace people noticing this same phlegm and cough? Those questions run through what follows, beginning with the version almost everyone has already had.

• 2. The Chest Cold

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  More than 90% of acute bronchitis cases come from a viral infection, the same kind of bug that spreads through the air when someone coughs or through direct contact. The viruses behind it are typically rhinovirus, adenovirus, parainfluenza, or influenza. A small number of cases trace instead to bacteria such as Mycoplasma pneumoniae or Bordetella pertussis. Exposure to tobacco smoke, dust, and other air pollutants raises the risk.

  The most common symptom is a cough, which may or may not bring up sputum. Alongside it can come wheezing, shortness of breath, chest discomfort, and a mild fever when fever appears at all. The infection itself may last only a few days to ten days, but the cough often lingers for several weeks. The total run of symptoms is usually around three weeks, and can stretch to six.

  Diagnosis leans on a person's signs and symptoms rather than lab work. The color of the sputum, despite a common belief, does not reveal whether the cause is viral or bacterial, and identifying the exact organism is usually unnecessary. A chest X-ray can help, mainly to rule out pneumonia, which along with asthma, bronchiolitis, bronchiectasis, and COPD can mimic the same picture. A cough that lasts longer than a month, rather than three weeks, hints at something turning chronic.

• 3. Treating What Time Heals

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  Antibiotics should generally not be used for acute bronchitis, since the cause is almost always viral. The one clear exception is when pertussis is behind it. The standard approach is far simpler: rest, fluids, paracetamol, which is also called acetaminophen, and NSAIDs to bring down fever. Frequent hand washing and avoiding smoke and other lung irritants help prevent it in the first place.

  Cough medicine has little support behind it and is not recommended for children under the age of six. Salbutamol has tentative evidence for easing wheezing, though it can cause nervousness and tremors. Honey and pelargonium have tentative support for symptoms, while Chinese medicinal herbs are of unclear effect.

  More than 10 million people in the United States see a healthcare provider for this condition each year, and about 70% of them walk away with antibiotics that are mostly unnecessary. That gap between what is prescribed and what actually works has driven active efforts to cut antibiotic use for acute bronchitis. The illness itself remains one of the most common diseases, affecting about 5% of adults and roughly 6% of children at least once a year, and it shows up most often in winter.

• 4. When The Cough Stays

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  Chronic bronchitis is defined by a productive cough that lasts three months or more per year for at least two years. It is often called a smoker's cough, because tobacco smoking is the most common cause. Cannabis smoking is associated with it too, and so is the chronic inhalation of air pollution, fumes, or dust from work in coal mining, grain handling, textile manufacturing, livestock farming, and metal moulding. Bronchitis from those exposures is often called industrial or occupational bronchitis. Higher levels of nitrogen dioxide and sulfur dioxide feed bronchial symptoms, and sulfur dioxide in particular can inflame the airways and invite infection. Rarely, genetic factors contribute.

  The disease is built on excess mucus. An increased number of goblet cells and enlarged submucosal glands, reacting to long-term irritation, pour out more mucus than normal, with the submucosal glands secreting more than the goblet cells. Mucins thicken that mucus, and their concentration runs high in chronic bronchitis, rising in step with how severe the disease is. The excess can narrow the airways, limit airflow, and speed the decline in lung function.

  Early on, coughing clears the secretions, and the cough is often worst soon after waking, bringing up sputum that may be yellow or green and streaked with specks of blood. But effective clearance depends on airway hydration, ciliary beating, and the rate of mucin secretion, and each of these is impaired in chronic bronchitis. Once the airways become obstructed, the cough turns ineffective, exacerbations grow more frequent, and lung function falls faster.

• 5. The COPD Connection

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  When chronic bronchitis occurs together with decreased airflow, it becomes chronic obstructive pulmonary disease, or COPD. The two are tangled but not identical. Many people with chronic bronchitis have COPD, yet most people with COPD do not also have chronic bronchitis. Estimates of how many COPD patients have chronic bronchitis range from 7% to 40%, while among people who smoke and have chronic bronchitis, roughly 60% also have COPD.

  The term chronic bronchitis appeared in earlier definitions of COPD but is no longer part of the definition, though clinicians still use it. Neither chronic bronchitis nor emphysema is required to diagnose COPD. The ICD-11 does list chronic bronchitis with emphysema, called emphysematous bronchitis, as a certain specified COPD. People with the chronic bronchitic phenotype, carrying that load of constant excess mucus, report a worse quality of life than those without it.

  Stopping smoking can slow the decline in lung function, and treatment may add medications, pulmonary rehabilitation, and occasionally oxygen therapy. A distinction is drawn between exacerbations, the sudden worsenings, and otherwise stable disease; stable chronic bronchitis means the standard definition plus no acute exacerbation in the previous four weeks. Mucolytics matter here. A Cochrane review found they may slightly lower the chance of an exacerbation. Guaifenesin is described as safe and effective for stable chronic bronchitis and comes as a twelve-hour extended-use tablet. Erdosteine, recommended by NICE, carries antioxidant properties and has been shown to reduce the risk of exacerbations and shorten both their duration and hospital stays. For the chronic bronchitic phenotype of COPD, the phosphodiesterase-4 inhibitor roflumilast may cut significant exacerbations.

• 6. Centuries Of Phlegm

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  The condition has been recognised for many centuries across Ancient Greek, Chinese, and Indian cultures, each noting the same pairing of excess phlegm and cough. Early treatments for the chronic form reached for garlic, cinnamon, and ipecac, among others, while the modern treatments arrived only in the second half of the 20th century.

  The British physician Charles Badham was the first to describe the condition and to name its acute form acute bronchitis, in his 1808 book Observations on the inflammatory affections of the mucous membrane of the bronchiae. He distinguished three forms, including acute and chronic, and used the term catarrh for the cardinal signs of chronic cough and mucus hypersecretion, calling chronic bronchitis a disabling disorder. A second, expanded edition followed in 1814 under the title An essay on bronchitis.

  In 1901 an article on treating chronic bronchitis in the elderly blamed dampness, cold weather, and fog, and prescribed cough mixtures, respiratory stimulants, and tonics, though it admitted something other than the weather seemed to be at work. The piece cited another physician, Harry Campbell, who had written in the British Medical Journal a week earlier that toxic substances were the real cause and urged pure air, simple food, and exercise to flush them out. Decades before, in excerpts dating from 1864, Charles Parsons had recorded emphysema developing out of bronchitis among pottery workers, a sequence noted again in 1957 amid investigations into dust-exposed industrial workers.

  Between 1951 and 1953 a joint research programme in Chicago and London detailed the clinical features of one thousand cases of chronic bronchitis, publishing the findings in the Lancet in 1953. It noted that since Badham introduced the term, the diagnosis had grown increasingly popular, and concluded that chronic bronchitis invariably led to emphysema, especially when it persisted. A CIBA meeting in 1959, with CIBA now Novartis, and an American Thoracic Society meeting in 1962 then defined chronic bronchitis as a component of COPD in terms that have not changed since.

• 7. The Rarer Forms

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  Plastic bronchitis is a rare condition in which thickened secretions plug the bronchi with rubbery, plastic-feeling material, which is where the name comes from. The light-colored plugs take the branching shape of the airways they fill and are called bronchial casts. When coughed up, they are firmer than ordinary phlegm or the soft mucus plugs some people with asthma produce, though some asthma plugs are larger, firmer, and more complex. The casts tied to asthma contain eosinophils and Charcot-Leyden crystals; those linked to congenital heart disease or lymphatic vessel abnormalities do not. The plugs obstruct airflow and can overinflate the opposite lung. The condition usually appears in children, and advanced cases can resemble bronchiectasis on imaging. Its subtype, eosinophilic plastic bronchitis, is also more common in children and may show a completely collapsed lung on imaging; depending on the size and location of the casts, it can stay mild or prove fatal.

  Eosinophilic bronchitis is something else entirely, a chronic dry cough marked by an increased number of eosinophils, a type of white blood cell. It shows a normal chest X-ray and brings no airflow limitation. Protracted bacterial bronchitis appears in children as a chronic productive cough with a positive bronchoalveolar lavage that clears with antibiotics, usually caused by Streptococcus pneumoniae, non-typable Haemophilus influenzae, or Moraxella catarrhalis, and especially when it lasts more than four weeks.

  Aspergillus bronchitis stands apart as a fungal infection, a type of aspergillosis caused by Aspergillus, a common mold. Unlike other forms of pulmonary aspergillosis, it can strike people who are not immunocompromised. In those with healthy immune systems it can look like persistent respiratory infections or symptoms that shrug off antibiotics but improve with antifungals, a reminder that not every stubborn cough answers to the same drug.