Lung microbiome: new insights into the pathogenesis of respiratory diseases

Solving Your Chronic Cough: Symptoms, Diagnosis & Treatments

An occasional cough—a normal reaction to a tickling sensation in your throat—helps clear irritants and secretions from your lungs and prevents infection. But if you develop a chronic bothersome cough, you should get evaluated. In adults, a cough lasting longer than eight weeks is considered a chronic cough. While it can sometimes be difficult to pinpoint the problem triggering a chronic cough, the most common causes include: 

Chronic bronchitis

Asthma and allergies

Respiratory infections

Tobacco use

Chronic obstructive pulmonary disease

Interstitial lung disease

Postnasal drip

Allergies

Acid reflux

Some medicines, including ACE inhibitors prescribed to treat hypertension and cardiac conditions

Upper airway hypersensitivity 

In severe cases, chronic coughing can also be accompanied by vomiting, lightheadedness, headaches, loss of bladder control, or fractured ribs. 

A chronic cough is usually diagnosed by method of exclusion. Health care professionals may use multiple methods to determine the cause of a persistent, disabling cough. These can include: 

Brief trials of medications  

Pulmonary function testing

Chest x-ray 

Sometimes a small scope is inserted into the upper airway to look for abnormalities that could cause a cough. Evaluation by a specialist may be needed to assess for pulmonary, ear, nose, and throat (ENT), laryngeal, or sleep problems that might cause your cough. 

A common cause of persistent cough is a condition called cough hypersensitivity syndrome. When your cough reflex gets more sensitive, it can cause you to cough when you're exposed to even small stimuli like talking, smelling perfumes, and drinking cold liquids. Cough hypersensitivity syndrome often gets better after behavioral speech therapy techniques. 

However, a cough can persist in a substantial number of patients  despite an extensive investigation into possible clinical causes. Many of these patients' chronic coughs can't be attributed to a common cause. 

If an underlying condition is determined to be causing your chronic cough, a health care professional may combine pulmonary, ENT, and behavioral speech therapies, as well as standard treatments when other remedies haven't worked. 

H20: You can ease your cough with water, whether you drink it or add it to the air with a steamy shower or vaporizer. Your provider may recommend a non-medical-grade or medical-grade nebulizer with saline solution to help directly hydrate your throat and vocal folds (vocal cords) to avoid drying irritation that may worsen a cough.

Antihistamines or cough medicine: If you have a cold or flu, you may find antihistamines work better than non-prescription cough medicines. Some people find that cough drops containing menthol products worsen their cough and should be avoided. 

Quit tobacco use: If your chronic cough is caused by tobacco use, your best bet is to quit. Be patient as you may cough even more after quitting because cough receptors start to grow back as the lining of air tubes heals. When that occurs, you may think quitting is making your coughing worse. By four weeks, your cough should subside, and you'll be on your way to a tobacco- and cough-free existence.

Diagnostic testing: For other causes of persistent coughs, treatments usually follow the standard therapy for the underlying causes discovered during diagnostic testing. For example, for acid reflux cough, a patient may be put on an eight-week trial of powerful antacids. For postnasal drip—the most common cause of chronic cough—the patient may be prescribed a nasal saltwater rinse, antihistamines, decongestants, or nasal steroids. 

If you have concerns about your cough, contact your primary care doctor. They can refer you to a specialist or a chronic cough clinic to help improve your cough. 

Pulmonary Barriers To Pneumonia And Sepsis

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Matthay, M., Su, X. Pulmonary barriers to pneumonia and sepsis. Nat Med 13, 780–781 (2007). Https://doi.Org/10.1038/nm0707-780

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Predictive Biomarkers May Boost Pulmonary Mycobacterium Abscessus Infection Treatment

Photo Credit: iStock.Com/Rasi Bhadramani

In Mycobacterium abscessus complex pulmonary disease, elevated levels of IFN-γ and IL-17F may signal higher risk for disease progression, researchers reported.

Elevated levels of interferon-γ (IFN-γ) and interleukin-17F (IL-17F) may indicate an increased risk for disease progression and the need for timely intervention in patients with Mycobacterium abscessus complex pulmonary disease (MABC-PD), according to study findings published online in PLOS Neglected Tropical Diseases.

"Mycobacterium abscessus complex pulmonary disease (MABC-PD) is a chronic and often relapsing disease with considerable morbidity, especially among individuals with other chronic pulmonary conditions," wrote corresponding author Dorothy Hui Lin Ng, MBBS, PhD, of Singapore General Hospital, and coauthors in an uncorrected proof on the journal website. "A major clinical challenge lies in distinguishing infection-related symptoms from underlying lung disease and identifying reliable prognosticators to guide treatment decisions and monitoring therapeutic response."

Analysis Addresses the Challenge

To address this challenge, researchers evaluated the whole blood transcriptome and measured 45 plasma proteins across different disease stages and treatment phases. The study cohort included four patients with MABC-PD receiving intensive phase treatment, four undergoing continuation phase therapy, seven in remission after treatment, seven patients managed with watchful waiting, and eight healthy control participants.

Study analysis of whole blood bulk RNA sequencing data revealed that patients experiencing progressive MABC-PD showed an elevated expression of genes associated with innate immune responses and inflammatory pathways. In contrast, these patients exhibited a reduction in the abundance of genes linked to peripheral T cells and natural killer (NK) cells.

Despite the diminished presence of these immune cell markers, patients with disease progression demonstrated significantly reduced plasma levels of TNFSF10 (also known as tumor necrosis factor–related apoptosis-inducing ligand) and concurrently displayed elevated concentrations of IFN-γ, IL-17F, and IL-17C.

The researchers wrote that "elevated levels of IFN-γ, IL17-F, and IL-17C—cytokines produced by activated T cells—argue against T cell exhaustion as a primary explanation. Instead, these findings suggest robust T cell activation and potential relocalization to the infection sites in the lungs."

Receiver operating curve analyses further highlighted the clinical utility of these biomarkers. Interferon-γ and IL-17F showed strong predictive performance, with area under the curve (AUC) values of 0.9464 and 0.875, respectively. In contrast, IL-17C's AUC value of 0.7857 did not reach statistical significance.

Beneficial Biomarkers

"Collectively, our findings suggest that IFN-γ and IL-17F could potentially serve as biomarkers for identifying MABC-PD patients who may benefit from treatment and differentiate them from those who can be managed with continued watchful waiting," the authors concluded.

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