Smoking causes COPD. There I said it. I said it because it’s true. Despite the billions of dollars invested in quashing evidence, silencing researchers, and in buying senators at their low, low, bargain prices, smoking does indeed cause COPD. And also a nefarious arsenal of other conditions like bad breath and cancer. But today let’s talk COPD.
COPD is the 3rd leading cause of death in the USA after the Big C and heart disease. The Big C is cancer, and also a bit of a cheat because “cancer” comes in a variety of forms with a variety of pathophysiological processes and a variety of causes and are really a variety of different diseases. But let’s not go down that disturbing, winding path toward understanding the taxonomical practice that names diseases. It’s about as logical as a Escher drawing. All I’m sayin’ is, COPD is a specific disease state, where cancer is not. Nor is “heart disease” really, so… my point is, and I do have one, is that if diseases were named in a more specific manner that defines the disease itself instead of the general process of the disease, COPD would have been titled “The Big C” not cancer.
COPD is understandably bitter about this. Cancer is like the Kanye of diseases and COPD is Taylor Swift.
Anyway, stuck in third (not win, not place, but *show*) COPD is the only one of the top three that is decidedly, explicitly preventable.
Without smoking, COPD would still exist but it would be a rare condition limited to occupational hazards and a genetic condition called alpha-1 antitrypsin deficiency. Without smoking, COPD wouldn’t even make top 20. In causes of death it would rank somewhere down there between being eaten by your exotic pet and spontaneous combustion.
While not everyone who smokes gets COPD, the vast majority of patients with COPD have smoked. The numbers quoted are somewhere around 25% of smokers with a 20 packyear history or more show symptoms of COPD. The guess is that there is a genetic predisposition and research is currently being done to pinpoint exactly where that flaw lies. But as far as I know and have read, nothing has been genetically specified yet. Unlike say Cystic Fibrosis, which has clear, hereditary, testable markers.
Of course the ability to test for a genetic predisposition to COPD isn’t a pathway toward rationalizing smoking. There are other things you can get. Like lung cancer. The Big C. But lets not talk about that because it makes COPD jealous. It’s OK COPD. You’re a deadly, deadly disease. Yes you are. *pat pat pat*.
So what exactly is COPD? In school we learned the almost-acronym, more of an initialism, yes there is a difference, CBABE to describe the 5 diseases that define COPD: Cystic Fibrosis, Bronchiectasis, Asthma, Bronchitis (chronic), and Emphysema.
Yes yes, I know this contradicts what I said earlier about COPD being a *specific* disease. Unbunch your secretly lacy panties, we’re getting to it.
More recently, CF, and it’s common counterpart Bronchiectasis, have been extracted from the general discourse and study of COPD. While they are indeed obstructive diseases, they are unique in their development and require their own realm of study. The same goes for Asthma, which has always been done a disservice by lumping it under the COPD umbrella. Asthma is such a complex and common domain of respiratory disasters itself, that it requires it’s own special category and specialists.
Essentially, if you make a foundation for it, it should be a separate disease. For example, many forms of cancer have their own separate foundations, and yet they are all called cancer, usurping the spotlight from COPD and reveling in the ‘Big C’ moniker. Which is just unfair. Disease gerrymandering. It’s a thing.
So in COPD we are left with Emphysema and Chronic Bronchitis. And while you may call them separate ‘diseases’, they are inextricably linked, always appear in some combination, and could be classified as symptoms of the same disease state known as COPD. So there. Take that.
The Chronic Bronchitis disease…er.. I mean symptom of COPD affects the non-cartilaginous airways, or bronchioles, that begin 4-5 generations of airway division into the lung. It involves increased mucus production, inflammation, chronic cough and decreases airway cilia.
Emphysema is a disease/symptom of the alveoli which destroys elastin fibers in the walls of the alveoli, increasing the lung compliance, and essentially turning your little happy alveolar balloons into saggy plastic bags easy to fill but impossible to empty. As the walls around the alveoli disintegrate like my integrity at an all-you-can-eat chocolate buffet, bullae, large air pockets that replace lung tissue, develop.
This may encourage you to joke with patients and make quips like, “I may be full of bull, but you’re full of bullae.”
COPD is first considered in patients with dyspnea, chronic cough, excess sputum production and/or a history of exposure to risk factors, mainly tobacco smoke. Once suspected, the diagnosis is confirmed through spirometry, specifically the forced vital capacity (FVC).
FVC is the amount of air one can exhale after maximum inhalation. FVC1 is the volume of that air that comes out in the first second of the FVC. Since obstructive disease interfere with expiration, the FVC1/FVC gives us a measurement of the level of obstruction.
An FVC1/FVC < 70% is a confirmation of existing obstruction.
The FVC1 itself is also compared to expected values based on age, height, gender and ethnicity. Once the existing obstruction is confirmed, the severity of the obstruction is based on the FVC1 / Expected FVC1. The details are on the chart below.
However, if one has a restrictive disease as a comorbidity to the obstructive disease, the severity of the COPD itself may need to be calibrated to the overall volumes of the restrictive disease. Pulmonologists I have discussed this with disagree. So I will die agnostic about it. Get it” “Die agnostic”? Yeah, I’m that good.
Treatment is also based on the severity of the disease. SABAs, LABAs, LAMAs, LABA + LAMAs, ICS, but I will save all that for another post. There’s only so much you can read in a day. I don’t want to burden you. Plus I have two episodes of Star Trek Discovery to catch up on. Priorities. Last episode Michael Burnham figured out how to use a giant multidimensional space Tardigrade to navigate the ship anywhere in the cosmos: The other “Big C”
Speaking of Cosmos. Neil deGrasse Tyson’s reboot of Carl Sagan’s Cosmos got one season. Duck Dynasty is now on season 8.
Oh America, you are dying of the Big I, Ignorance.