My asthma and the various sub-labels used to describe it seems to change day by day. First it was ACOS ( Asthma COPD overlap Syndrome), but because of it’s broad description it seems to be loosing favor with my doctors. One of my Pulmonologists even calls my asthma “Steve Gaudet Asthma” because to him it doesn’t behave the way typical asthma, or for that matter the way COPD does. Sure, I fit the general clinical definition of asthma, ie. I have the usual triggers, I wheeze, I get short of breath, I desaturate, I have bronchospasm, etc. But whats really unusual, is the frequency at which I exacerbate. My doctors are baffled at why I get sick so often and almost always to the point of requiring mechanical ventilation.
Also baffling to some clinicians is why my peak inspiratory pressures (PIPs)(the amount of pressure it takes to push a breath into the patients lungs while on the ventilator), are lower than normally seen in severe asthmatics. While asthma is a disease of both the large and small airways, it’s primarily a disease of the large airways that react during acute flare ups. When those larger airways become constricted, you typically see very high peak inspiratory pressures on the ventilator. High peak pressures are dangerous in that you can literally blow a hole through the lung tissue ( what they call a pneumothorax), but that’s for a different discussion. For now the question is, if I indeed have only asthma asthma, why are my peak inspiratory pressures on the lower side ? It’s this observation that has some of my doctors thinking that maybe my disease has more do to with my smaller airways than of the larger ones.
Because there are an exponentially larger number of smaller airways than larger airways in the lungs, the total surface area of these tiny airways is larger which means less resistance to air flow and therefore lower inspiratory peak pressures. However, if there is a lot of inflammation or obstruction in those smaller airways, peak pressure can still be quite high, so that doesn’t really answer the question as to why my PIPs are lower than usual. Another possible explanation for these lower peak pressures, are potent bronchodilating effects of drugs used to sedate a tight asthmatic during intubation and while on the ventilator. Some of these paralytic and sedative agent can relax and dilate the airways, rapidly lowering peak inspiratory pressures.
There is yet another explanation as to why my lung mechanics are different than most asthmatics and they flare and why I get so sick so often. It could be that I have a condition called Bronchiolitis Obliterans, also known as “BO” or Constrictive Bronchiolitis.
Bronchiolitis Obliterans, or “BO” for short is a condition where the bronchioles become inflamed and scarred, leading to permanent and progressive damage.This eventually results in air trapping, chronic breathless and other asthma or COPD like symptoms.
Having some form of bronchiolitis might explain why my asthma behaves the way it does and why I get get so sick so often, but we’re far from a confirmed diagnosis. Also I don’t have one of the main symptoms of BO, which is coughing. In fact, I rarely cough at all unless I have an active chest cold. So for the time being they’re using the term “BO” more semantically than anything else.
Just to cover all bases, theyve started me on long term azithromycin ( 250mg every other day). Though there is no cure for BO, some studies that suggest that long term antibiotic therapy can slow the progression of the disease. In some cases lung transplant is only option to prolong life. Ironically, BO is usually what kills most lung transplant patients, because of the immune lowering, anti rejection drugs that transplant patients have to take.
So that’s the newest asthma flavor of the month, next month it’ll probably be something different. Driven mostly by frustration, I think these alternative or hybrid diagnosis happen because my doctors cant figure out why the heck my lungs do what what they do.