Cocaine Use and Interstitial Lung Disease
Interstitial lung disease is a wide-ranging term that doctors use to describe a group of approximately 200 ailments that involve damage to the interstitium, a part of the lungs surrounding tiny, oxygen-bearing sacs called alveoli. Humans rely on oxygen transfer from the lungs’ alveoli to the bloodstream for proper function in literally all of the body’s systems. People who use cocaine significantly increase their risks for developing a specific ailment called drug-induced interstitial lung disease. While all users of the drug bear some of this risk, most of the potential for harm appears in people who smoke “crack” cocaine.
Human lungs contain roughly 600 million individual alveoli (singular, alveolus). This incredibly tiny sac sit at the far end of a series of branching passageways that start at the lung entrances and extends in progressively thinner, smaller forms throughout the lungs’ tissues. The oxygen content in each inward breath filters down through these passageways until it reaches the interiors of the alveoli. Inside each alveolus, this oxygen passes through the sac’s wall and enters a network of extremely small blood vessels called capillaries; these capillaries carry oxygen-rich blood back to the heart, which then distributes this life-supporting blood to the rest of the body. Interstitium is the general anatomical term for any space that surrounds an organ or parts of an organ, or sits between various types of tissue. In the lungs, the term applies to either the spaces surrounding the alveoli, or these spaces and the alveoli themselves.
Interstitial Lung Disease Basics
Although they have distinctly different underlying causes, the various interstitial lung diseases are grouped together because they all produce coughing and shortness of breath, the Merck Manual Home Health Handbook reports. They also feature inflammation triggered by the abnormal accumulation of immune system components, called white blood cells and macrophages, inside the interstitium. If the inflammation associated with the presence of these components does not fade away, it can eventually trigger a condition called fibrosis, which occurs when normal, healthy tissue gets replaced by a buildup of scar tissue. This scarring can completely wipe out pockets of healthy alveoli within the lungs and replace them with gas- or liquid-filled sacs, called cysts, that can’t effectively contribute to the transfer of oxygen into the capillaries. Doctors refer to the condition produced by these lung changes as pulmonary fibrosis.
Cocaine does not directly trigger the onset of drug-induced interstitial lung disease, according to an extensive study review published in 2007 in the Radiological Society of North America journal RadioGraphics. Instead, the condition is the result of impurities contained within different forms of cocaine. Nasally inhaled powdered cocaine frequently contains the mineral talc, which is used as a filler to “cut” the drug, increase the size of cocaine batches, and thereby increase the profit margins of illicit drug distributors. People who intravenously inject cocaine can also introduce talc into the bloodstream, especially when they simultaneously inject crushed forms of medications (such as Ritalin or Valium) that contain talc as an inactive ingredient. People who smoke crack cocaine commonly inhale another chemical impurity, called silica, into their lungs.
When cocaine-related impurities enter the lungs, they gain the attention of the immune components called macrophages, which try to surround these impurities, wall them off and literally devour them. Eventually, macrophages pile up around molecules of talc or silica and form inflammation-inducing clumps called granulomas. In turn, the presence of granulomas can contribute to the development of pulmonary fibrosis, as well as a pneumonia-like condition called interstitial pneumonitis. Generally speaking, people who nasally inhale cocaine have the lowest risks for these problems. People who inject cocaine (with or without other talc-containing substances) have relatively moderate risks, while people who smoke crack cocaine have relatively high risks. Risks are likely higher in crack smokers because they can also develop another form of serious inflammation, called sarcoidosis, as a consequence of inhaling silica into their lungs.
People who develop drug-induced interstitial lung disease can often halt or diminish the disease’s effects by stopping their drug use, the Merck Manual explains. However, according to the authors of the study published in RadioGraphics, pulmonary fibrosis often continues to worsen in recovering cocaine users who stop taking the drug; potential consequences of this worsening include severe breathing problems and death. In line with these facts, almost 40 percent of all cocaine-related deaths involve some degree of fibrosis or pneumonitis in the lung interstitium.