Coughing: Causes and Breathing Difficulties Explained - Otolaryngology

Dr. Ye Dawei reply Otolaryngology

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Hello, Ms.
Lu:
In the context of medication treatment or X-ray examinations, there are local sayings that resonate with the challenges faced by physicians, such as "Building a house is afraid of leaks, and doctors are afraid of treating coughs." Coughing patients make up a significant portion of daily visits for family medicine, internal medicine, otolaryngology, and even obstetrics and gynecology.
Beyond prescribing cough suppressants and syrups, it is essential to discuss some fundamental concepts related to cough.
Viral Infections – Viral Bronchitis
Coughing occurs due to the presence of "cough receptors" located in the throat, trachea, bronchi, sinuses, and ears.
When these areas are stimulated or inflamed, they trigger a cough reflex.
Similar to fever, in addition to administering antipyretics to soothe patients (or their families), it is crucial not to overlook identifying the underlying causes of symptoms (fever, cough).
Generally, common colds (caused by rhinoviruses, adenoviruses, respiratory syncytial viruses, parainfluenza viruses, coronaviruses, etc.) primarily present with nasal symptoms (runny nose, nasal congestion) and rarely cause coughing.
Sometimes, coughing is triggered by post-nasal drip irritating the "cough receptors." The most common cause of cough is "viral bronchitis." As mentioned, common colds rarely lead to cough symptoms; if a cough persists for several days, it should be diagnosed as bronchitis, with the causative viruses being similar to those of the common cold.
The bronchi are part of the respiratory tract, and viral infections do not selectively target only the bronchi, so patients often present with conjunctivitis, runny nose, sore throat, hoarseness, fever, or fatigue as systemic symptoms.
Bacterial Infections – Bacterial Bronchitis, Sinusitis
Bacterial bronchitis due to bacterial infections is less common but should not be overlooked to avoid delaying antibiotic treatment.
For instance, during the recent flu outbreak, Hsinchu Hospital reported multiple cases of cough patients infected with "Mycoplasma." Focusing solely on diagnosing influenza viruses can lead to severe pneumonia complications.
The typical duration of a common cold rarely exceeds one week, while bronchitis or pneumonia can last two to three weeks.
If a patient has a persistent cough and high fever, in addition to considering asthma or allergic conditions and foreign body aspiration, it is crucial to be vigilant for Mycoplasma infections.
Because this infection often does not present with specific findings during auscultation, X-ray examinations frequently reveal significant pneumonia or pleural effusion.
The inconsistency between X-ray findings and clinical auscultation can often lead to diagnostic delays.
Mycoplasma serological antibodies are a type of cold agglutinin that can be used for diagnosis, as they exhibit agglutination at low temperatures (4 °C).
Mycoplasma lacks a cell wall, making standard antibiotics like cephalosporins or penicillin ineffective; the standard treatment is erythromycin for two weeks.
Another less common cause of bacterial bronchitis is Bordetella pertussis.
Recent reports of antibiotic misuse in the media are related to the use of erythromycin to prevent neonatal whooping cough, which has been linked to infant pyloric stenosis, but that is a separate issue.
Allergic Conditions – Bronchial Allergy (Asthma), Cough Variant Asthma
For a patient with a cough lasting more than two weeks without improvement, it should not merely be considered an unresolved cold.
At this point, one should be alert to the previously mentioned bacterial infections, lobar collapse (often due to foreign body aspiration), and asthma.
The vast majority of post-cold coughs are caused by asthma, and many children with asthma or sinusitis may only present with a cough.
Therefore, differential diagnosis of cough should not solely focus on whether there is redness or swelling in the throat (which is not significantly related to cough); it is essential to examine the nasal passages and auscultate the chest.
This is to avoid missing a diagnosis of sinusitis that requires timely antibiotic treatment or misdiagnosing asthma as a cold or heart disease.
Asthma symptoms can vary widely, with each patient presenting differently, making it easy to confuse with common diseases across various specialties.
Coughing is often attributed to post-nasal drip or unresolved colds; palpitations and chest pain are considered heart disease; shortness of breath while climbing stairs is attributed to obesity or lack of exercise.
Just as otolaryngologists are often the first clinicians to diagnose HIV patients, they also frequently diagnose asthma.
Patients often visit the clinic for a cold, and if they present with a persistent cough along with other allergic symptoms such as runny nose, sneezing, and itchy eyes, one should suspect asthma.
There is also a condition known as cough variant asthma (CVA), where chronic cough is the only symptom, with no history of asthma or respiratory distress, and normal lung function tests, but the airways are abnormally sensitive, and cough resolves with bronchodilator use.

You may wonder why an otolaryngologist discusses asthma; the current specialization system is often criticized for being overly detailed.
While it allows for more precise diagnoses and treatments for specific diseases, it has led to peculiar phenomena where patients with dizziness are diagnosed with Meniere's disease in ENT clinics, while in neurology, they are labeled as neuroasthenia.
Similarly, cough patients in ENT clinics are often diagnosed with post-nasal drip, while in internal medicine, they may be diagnosed with asthma.
I believe that a practicing physician should pay more attention to related diseases outside their specialty.

In summary, unless the cough is due to the aforementioned secondary bacterial infections or asthma, most bronchitis cases can resolve naturally.
The first type, viral bronchitis (the most common cause of cough), has a defined course, often transitioning from a dry cough to a productive cough with phlegm after a few days.
Patients may mistakenly believe that their condition worsens with medication as they begin to cough up more phlegm.
Medications for Cough Treatment
In outpatient settings, medications related to cough treatment can be broadly categorized into three types: cough suppressants, expectorants, and throat soothers, in addition to antibiotics.
Commonly prescribed cough suppressants include medications like dextromethorphan and codeine (which contains narcotic components).
Their mechanism of action suppresses the cough reflex in the central nervous system and is mainly used for early dry cough or non-productive cough patients.
Expectorants work by thinning secretions to facilitate the expulsion of mucus; physicians often recommend patients drink plenty of water and inhale steam to achieve expectorant effects.
Over-the-counter throat soothers include honey, licorice, glycerin, citric acid, and loquat syrup, which can alleviate throat discomfort.

Theoretically, productive coughs should not be treated with strong cough suppressants, as this can lead to mucus accumulation in the lower respiratory tract, especially in children under two years old, to avoid potential damage to the trachea or lung function.
In conclusion, when addressing cough, it is crucial to be aware of the underlying causes rather than merely suppressing the cough.
Most coughs should resolve naturally, and for patients with persistent coughs, it is essential to remain vigilant and rule out the potential causes mentioned above.

Dr.
Yeh Da-Wei, Director of the Otolaryngology Department, Hsinchu Hospital

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Reply Date: 2008/10/21