29 June 2018

Update on Bennett: Asthma

Bennett went to his quarterly CF appointment this week.  Overall, he received a good report, I think?

Bennett continues to have no GI issues at all, which is fantastic.  The main issue we are still dealing with is improving his overall nutrition.  Bennett is in the 4th percentile for BMI.  He should be in the 50th.  His height is staying on the growth curve but his weight continues to struggle to stay on it.

It's very defeating to watch his weight not be able to keep up with his height, even as he eats really well.  But, it's just a reminder that people with CF need a significant amount of calories to keep themselves healthy.

We continue to work towards more g-tube feeds per day, but the treatment burden for daytime g-tube feeds is really burdensome and challenging (think 3 30-minute feeds while at home in addition to 15 minutes of prep work each time, not including all of the other meds and treatments Bennett has to do + life).  Nighttime feeds, which many people with CF do instead of daytime feeds, is very disruptive to Bennett's and our family's sleep so, for now, we work for daytime feed success.

Avonlea and Bennett graciously obliged to my picture taking effort.  Avonlea was just about to devour a Hostess cupcake.  Bennett was drinking a Capri Sun.  Snacks are a bit part of making 2-3 hour CF clinic appointments manageable.  Oliver is missing from this picture because he was at camp for the morning.

Bennett's respiratory health check this time was an interesting one.  Although his lungs sound healthy and he is showing no respiratory symptoms (such as a cough or runny nose, etc.), Bennett's PFT (pulmonary function tests) results were not very good Tuesday.

Since age 4, Bennett has been doing a PFT test at every quarterly appointment.  One year ago, he blew a 96% FEV1.  At this appointment, he blew a 80% FEV1.  It's expected that people with CF will see a 2% FEV1 drop, on average, per year due to lung damage.  But, that 2% is a far cry from the 16% drop we saw this week. Typically, significant drops in FEV1 typically indicates evidence for lung infection.

When we saw a drop in Bennett's FEV1 during his last CF appointment 3 months ago, we hoped it was a fluke.  The doctor prescribed an oral antibiotic in hopes that it might address any possible lingering infection.  Upon our discussion, at that appointment, as to why Bennett's FEV1 was lower than normal, it occurred me that Bennett had not had time to do his albuterol treatment that morning (since we were rushing to get out of the door as we live 2 hours away from the CF Clinic).  Bennett's pulmonologist agreed that missing an albuterol treatment could potentially have a negative impact on his numbers.  She suggested that at our next appointment that we should get a PFT without albuterol and then get another with albuterol to see what difference it makes.

Here's what happened:

Turns out, albuterol makes a world of difference for Bennett.  He had a 11% change in FEV1 with albuterol and a 31% change in FEF 25-75% with albuterol.  This was significant, the doctor explained, because it means that the restriction of air Bennett has in his lungs (aka the reason his PFT numbers don't look good) is likely due to muscle constriction, not mucosal constriction.  In layman's terms, Bennett's lung issues may be being caused by a case of asthma, not infection.

This blew my mind.  Here we were afraid of a lurking infection and all the while it may simply be something much less worrisome - asthma.  This makes sense given the fact that Bennett has stayed very healthy and is showing no respiratory symptoms.  And yet, not knowing asthma might be the culprit, we were coasting towards having to treat an infection we could only believe might be causing silent damage to his lungs.

Bennett was prescribed an inhaled steroid in hopes that will help him gain back his full lung capacity.

As soon as we came home, I did some research to better understand any connections between asthma and CF.  Turns out there is one.

As this study reports, "patients with cystic fibrosis (CF) have a higher prevalence of asthma than the background population."  The study goes on to say, "when CFTR function is absent in new-born animals, airway smooth muscle dysfunction and airway obstruction develops independently of airway inflammation and infection....This supports a link between CFTR dysfunction and asthma...asthma has been suggested as a CFTR-related disorder, that may occur in CF heterozygotes when unknown additional factors further reduce CFTR function or interact with CFTR on asthma."

I find this interesting for several reasons.  It makes me wonder if people who are carriers of CF (people, like Brian and me, who carry 1 gene for CF) are at a higher risk for asthma.  It also makes me wonder if the CF community, particularly parents of young children with CF, should be more aware of the high numbers of asthma in children with CF and the potential role asthma might play in the person's with cystic fibrosis health.  Although I knew other CF families who had been diagnosed with asthma, I had not been aware, until now, what kind of impact it could have.  For me, it begs the question - should everyone with school-aged children with CF try a pre and post PFT with albuterol to see how they respond?

Bennett loves making the chicken "run" during his PFTs.  This chicken image moves across the screen while doing in-room Pulmonary Function Tests to help children blow out their breath a designated amount of time.

This experience of recognizing asthma in Bennett really surprised me because had we not found it, we would have been talking about IV antibiotics during this appointment.  IV antibiotics have not been completely ruled out.  If Bennett's PFTs don't improve in the next few weeks with his daily use of an inhaled steroid, we might be eventually looking at being admitted to the hospital for powerful meds to help out his lungs.

But, considering Bennett has not cultured anything other than MSSA, considering that his lungs sound clear and considering he is showing no respiratory symptoms (no runny nose, cough, etc) and has not been sick, I am feeling like his drop in PFT numbers is probably due to asthma.

Only time (and a PFT test in August) will tell.