QD Clinic: Cellulitis Paradoxes Save

Hello everyone. Welcome to RheumNow QD Clinics. I'm Dr. Richard Conway from Dublin, Ireland and I'm going to present to you a case today called "Cellulitis and Paradoxes."

So this is the case of a man I was asked to see on the rheumatology consult service. He was 40 years old. He was a healthy young man, normal body weight, no other real medical problems. And he had come into the hospital for the second time within a month with cellulitis. And this is odd, right? You don't get cellulitis multiple times as a young person without something causing it — some immune deficiency or diabetes or something. He didn't have any of these things.

So I went up to see this man and I walked in to see him and had a look at this cellulitis in his leg and my immediate reaction was this is gout. This is clearly gout. Joints are swollen, they're red, there is cellulitis there — and remember cellulitis is inflammation of the skin. So while the commonest cause is infection, other things including crystal arthritis can cause cellulitis.

And I talked to this guy some more about his first episode. He said it was very similar to this, his right midfoot and his ankle, extending up his leg, and they'd given him intravenous antibiotics for a couple of weeks. Went away about a week into the treatment. And then he went home and was okay and then he had a sudden recurrence of this again. Came back in, was on intravenous antibiotics again. So obviously his primary team had had some inkling that this was a bit strange. They were asking a rheumatologist to come and see him. They thought there might be something rheumatic going on here. They'd even thought it might be gout. So they had sent a serum urate on him. And this had come back at 320 micromoles per liter, which is 5.4 milligrams per deciliter. And so they said it can't be gout. This is a normal urate. Which indeed it is. It's below the crystallization point. So their reaction was yeah, can't be gout. We asked rheumatology if there's something else going on.

And my reaction on seeing this was but this is gout. It's clearly what it is clinically. We should treat it as that, which is what we did with some steroids and he got better. So then the question is why is his serum urate normal and why does he have gout?

So his serum urate, you would think, is normal — as can happen during an acute flare. You get this paradoxical drop in the urate and I'm not sure we really know why that happens. But it does. It's quite a frequent thing and it can be very pronounced. So this guy had potentially dropped a bit into the normal range, but I've certainly seen patients where it's dropped down to two or three milligrams per deciliter from very high values. It can be a very pronounced paradoxical drop.

We went and I had a kind of deeper chat with him about gout and he told me that he had once been diagnosed with gout. He had an episode of podagra about four or five years before this. So I looked back — thankfully he had a urate done at that time with his primary care physician — and that urate was 436 micromoles per liter, which is 7.3 milligrams per deciliter. So that fits with gout.

So we have him. He has what appears to be gout. He's on steroids. He's getting better. I brought him back to my clinic and said, "Let's check your serum urate again." And this time it was 362 micromoles per liter, which is 6.1 milligrams per deciliter. So that's just about good enough for gout. It's odd to get gout at that level, but just about good enough. So I said, "Look, it's above the threshold. You have gout clearly clinically. We're going to start you on some allopurinol 100 milligrams, a bit of colchicine. We'll bring you back in four to six weeks and recheck this urate and see where we've gotten to."

So that's what we did. He came back to me, said he'd been fine, no more flare-ups on the colchicine. He kind of felt a little tingly — kind of maybe an impending flare at times — but seemed like the colchicine was suppressing it. Again, another support if we needed it that this is gout. We rechecked his urate. So he's on the allopurinol 100 milligrams. I'm 100% sure this guy is taking it. His urate is now 375 micromoles per liter or 6.3 milligrams per deciliter. So it's gone up despite being on allopurinol.

So what's happening here? Possibilities — he might not be taking the allopurinol. I don't think that's happening. I have confidence in him. The allopurinol might not be working. I don't think that's really a thing — it might not work well enough, but it certainly shouldn't be going the other way. So 100% I believe what was happening here is that we're seeing a kind of sustained paradoxical response — that actually the urate is still rising back to its actual level. And so we are seeing an effect of the allopurinol. It would be higher if he wasn't on allopurinol. It's just confusing
because of the paradoxical drop at the time of the flare. So we increased his allopurinol 200 milligrams, bring him back four to 6 weeks and his urate has now dropped down again. But it's still around 360, or 6 milligrams per deciliter. So increased the allopurinol again up to 300, bringing back in another 6 weeks his urate is now back down to 320 micromoles a liter, or 5.4 milligrams per deciliter. So I think we are seeing here the proper effect of the allopurinol in suppressing the uric acid.

So we left him like that. He's now been another good few months and haven't heard from him. He is due back in my clinic in a few months more time. I presume his gout is doing good and he's still taking his allopurinol and his colchicine.

So I've been Richard Conway. Keep an eye on RheumNow for all the gout QT clinics in this gout month.