I have been working a little medical mystery. I've become accustomed to a kind of gastrointestinal rhythm as the chemotherapy cycle rolls on. It's a 28-day cycle, with all the major drugs delivered on days 1, 8, and 15, and dexamethasone continuing on day 22 as well. All those days are Thursdays. The standard weekly pattern has been 2-3 days of constipation, followed by a day or two of something kind of "normal" (by chemo standards), and then a day or two of diarrhea. But it varies, and I've developed a tolerance for the variation that may be a little too tolerant.
Somewhere in the run-up to the wedding, it finally dawned on me that I'd had the diarrhea for a while, but not the constipation. In fact, the diarrhea was getting pretty bad, to the point where a longish dog walk could become a (mercifully--so far--internal) drama. I tried some probiotics, fiber (bad idea), and so forth. The impending wedding presented a potential Waterloo (sorry!), but the gods continued to be merciful and I thought perhaps the whole thing had passed.
When we returned to Louisville, though, the pattern resumed. Liz reminded me that Sunny tested positive for Giardia when we adopted her (Giardia can be transmitted from dog to human directly). She was treated at the time, of course, and tested negative afterward, but just try to stop a hound from drinking out of puddles, ponds, and the worst parts of streams. I have. I tried to schedule an appointment with my primary care doc to have a stool sample run. He couldn't see me for two weeks, which seemed excessive. His assistant suggested urgent care, or my hematologist. Urgent care seemed to be the better fit, so we headed over to a place we'd used before, conveniently operated by the same organization as my hematologist.
It turns out that this urgent care doc couldn't run a stool sample(!), because he couldn't do follow-up(!!), but he could prescribe flagyl, as if the Giardia diagnosis had been made (!!!). So he did. I bit my tongue, as I do, not being able to imagine how any critique of this system I leveled at him would get communicated back to the higher-ups at whatever meeting of whatever group he next attended. So I effectively agreed to do the experiment the wrong way around.
Meanwhile, it occurred to me that it was easy to get the dog re-tested. I picked up a stool sample kit at the vet's, and by the next day had a result back (cheap, too!)--negative for everything. Giardia was no longer looking like a strong contender, but I dutifully continued with my course of treatment, even though the early results were not promising. At my next hematology appointment, I asked if they could do a stool sample (they could), so I gave them one. C. diff. is the main concern for cancer patients, but hey, why not check everything? Negative there, too, although I'd like a little more detail on what exactly was tested.
Meanwhile, nothing has really changed, except my weight, which has declined, and my blood pressure, which has increased. I need to keep my fluid/electrolyte intake up, and take enough Imodium to manage my life in the interim. I have recently come to believe that the chemo cycle is the driving factor, probably the Revlimid (lenalidomide). The 28-day chemo cycle that I'm on is 3 weeks of Ninlaro + Revlimid, and 4 weeks of dexamethasone. Lately I've noticed that the 4th week has been better than the rest. Within the first 3 weeks, it seems the end is worse than the beginning. Within each of those weeks, I take Ninlaro at the beginning, and Revlimid every day, so the ratio of N/R declines through the week, and the diarrhea gets worse.
Tonight, as I was finding links to help with the technical stuff, I stumbled upon something that might explain the problem (if this were a podcast, I'd say it "rocked my world," but that seems overwrought in print). It turns out that Revlimid (for reasons I don't currently know) contains lactose. As a white guy, that wouldn't be likely to draw my attention, but it seems that I am lactose intolerant, according to
23andme:
Over the last few months, I've been trying to reduce my consumption of dairy products, with mixed results. but I had no idea that for 75% of each month I've been compromising my efforts (and paying handsomely for the experience!) with one of my go-to drugs.
I'll have a lot to discuss next week, when I have my annual follow-up review at Mayo.
