Chronic alcohol link in severe lung injury

Recent studies indicate an association between alcohol use and acute lung injuries. It is established that alcohol use increases the incidence of pneumonia by three to four times.

In fact, chronic alcohol use has been shown to predispose to lung tissue-damaging caused by Klebsiella pneumoniae and infection inflicted by Streptococcus pneumoniae.

Klebsiella pneumoniae are bacteria that normally live in the intestines and faeces. They are harmless when in the intestines but, in another part of the body, they can cause severe infections. Streptococcus pneumoniae are responsible for most community-acquired pneumonia and reside in the respiratory tract. Alcohol use also increases chances for increased level of bacteria in blood circulation, a condition known as bacteremia.

In a study, three mechanisms through which alcohol promotes lung infections were identified. First, alcohol causes aspiration (swallowing) of gastric acid and gut microbes from the upper respiratory tract into the lungs — a major cause of lung infections among chronic alcoholic abusers.

The gastric juice and microbes from the gut are predominantly rich in pneumonia-causing pathogens. Useful gut microbes can turn out to be pathogenic in the lungs. Additionally, alcohol is a depressant of coughing and sneezing reflexes that promote removal of pathogens from the respiratory system.

Secondly, chronic alcoholic use impairs the mucus clearance mechanism in the lung and airways. Expectoration of pathogen and debris-laden mucus from the lungs is controlled by hair-like structures along the respiratory epithelial lining called cilia. Alcohol interferes with the controlled movement of the hairs, leading to accumulation of pathogen-contaminated mucus in the lungs that cause injuries.

Destroy pathogens

Thirdly, lungs substantially reduce the ability of the lung alveolar macrophages (dust cells) to internalise and destroy pathogens by phagocytosis (ingestion). This inhibition of the first line of the lung’s defence against invading pathogens is a major cause of lung injuries among alcoholics.

Chronic alcoholics are three times more likely to be hospitalised with lung injuries and infections than non-alcoholics. Further, mortality rates among hospitalised is four more times than among non-alcoholics.

Alcoholic victims of road or gun accidents, or those who suffer major trauma, are twice likely to suffer serious lung injuries, such as acute respiratory disease syndrome, due to bacteria and other pathogens spreading fast in the bloodstream. Chronic alcohol users are prone to Covid-19 infection with severe progression.

 There is a need to educate the public on the link between alcohol consumption and lung injuries and infection for them to make informed decision on their general wellbeing.

Dr P. M. Mutua (PhD), Makueni