How Do You Prepare for Surgery or a Medical Procedure With MCAS?
Surgery, IVs, dental work and imaging can be harder with MCAS. What the research on mast cell disease and anesthesia found, and what to bring to pre-op.
Photo: Elena Leya / Unsplash
Surgery, an IV, dental work, imaging with contrast dye, or a vaccination can all be more complicated with mast cell activation syndrome (MCAS). That's because a procedure brings several mast cell triggers together at once. Even so, two large studies in mastocytosis, a related mast cell disorder, found that serious reactions around anesthesia were uncommon. In the Mayo Clinic study, the one case of anaphylaxis during surgery was in someone not yet diagnosed. A lot of the preparation comes down to your team knowing your history ahead of time.
Why are procedures harder with MCAS?
MCAS is a condition in which mast cells, a type of immune cell found throughout the body, release histamine and other chemical messengers more easily than they should. In my experience, a routine procedure that someone else tolerates well can leave a person with MCAS feeling worse for a week or two, and sometimes for a month. That window is from my clinic experience; no study has measured it.
Lide and colleagues are anesthesiologists who described two MCAS surgeries in 2022. In their discussion of triggers, they explain that the hours around surgery bring many of them together: the stress of waiting, pressure from an IV catheter and a blood pressure cuff, temperature swings in the operating room, and the many medications the team gives along the way. If you think of triggers as filling a bucket that can overflow, a procedure day adds a lot at once, stress included. Some drugs can also activate mast cells without a true allergy.
What the research on surgery and mast cell disease found
Most of this research comes from mastocytosis, since an international working group only defined MCAS in 2012. Mastocytosis is a related condition where the body makes too many mast cells.
Lau and colleagues at Mayo Clinic looked back at 219 procedures under general anesthesia in 113 people with mastocytosis. In 178 of the 194 procedures done after diagnosis (about 92%), patients had ongoing mast cell treatment, preventive medication before surgery, or both. The researchers judged that mast cell activation may have complicated 10 of those 178 procedures, about one in eighteen. Anaphylaxis is a severe, whole-body allergic-type reaction that needs emergency treatment. There was one case of it during surgery, in a patient who hadn't been diagnosed yet and hadn't received preventive treatment.
The Spanish Network on Mastocytosis reviewed 726 anesthetic procedures in 501 people. In the adult group, mast cell symptoms happened in 2% (about one in fifty) and anaphylaxis in 0.4% (about one in 250). Among adults, reactions were more frequent after previous anaphylaxis, with major surgery or general anesthesia, and when the team gave no preventive medication in the hour before anesthesia. Matito and colleagues wrote that anaphylaxis around anesthesia appears to be more frequent in mastocytosis than in the general population. Nonetheless, they concluded that mastocytosis shouldn't rule out anesthesia, since preventive medication and careful drug choice appeared to prevent or control symptoms.
For MCAS itself, the published surgical work is mostly individual case reports, so there isn't enough direct evidence for numbers like these. Premedication means medication given before a procedure to lower the chance of a reaction. Lide and colleagues note reports that premedication helps prevent anaphylaxis in these patients, but no randomized controlled trials have tested whether it's needed or which regimen works best, which is why that decision belongs to your anesthesia and prescribing team.
Why an early conversation with your team is the most useful step
My view is that a procedure isn't a reason to avoid care you need. I think preparation, and an open conversation about the pros and cons of each choice, make the biggest difference. If the person doing your procedure isn't the one who manages your MCAS, it's very important for the two of them to talk about how and where your system is sensitive. I would ask for a call or appointment with the anesthesia team well before the procedure.
What to bring to your pre-op conversation
- A written list of every reaction you've had, including to medications, anesthesia, adhesive tape, latex, skin cleansers, or contrast dye.
- Your current medications, so the team can plan around them.
- Your diagnosis paperwork, with contact details for the clinician who manages your MCAS so the two teams can talk.
- Your emergency plan, including any anaphylaxis plan from your clinician, so you can ask how the team would handle a reaction.
- Your non-drug triggers, like heat, cold, pressure, friction, or fragrances and chemicals, so staff can make changes where possible.
Dental work and imaging
Dental work usually involves local anesthetic. Lide and colleagues write that there's no conclusive evidence that local anesthetics lead to more adverse events in people with MCAS than in the general population. Your dentist should still see your reaction list.
When you book a scan with contrast dye, you can tell the imaging team about your diagnosis and past reactions at the same time. The studies here didn't look at contrast reactions in MCAS.
Planning for recovery
In the second of Lide's two cases, the patient had breathing symptoms about 2 hours after surgery and another reaction about 22 hours after, and the team treated both. There's no way to know from one patient how common delayed reactions are. Still, after reading that case, I would ask how long the team will monitor you and who to call once you're home. I also plan for the recovery ahead of time, so the preparation doesn't stop once you leave. The MCAS hub has more.
If you're living with MCAS and want a structured starting point, MCAS: What You Need to Know First walks through what the diagnosis actually means, where to begin, and what to do when diet alone isn't enough.
FAQ
Is it safe to have surgery if you have MCAS?
In two large studies of mastocytosis, a related mast cell disorder, serious reactions around anesthesia were uncommon. MCAS research on surgery is mostly case reports, so an early talk with your anesthesia team is the most useful step.
Should I tell my anesthesiologist I have MCAS?
Yes, and as early as you can. In a Mayo Clinic review of 219 procedures in people with mastocytosis, the one anaphylaxis case during surgery was in someone not yet diagnosed.
Can local anesthetic at the dentist cause an MCAS reaction?
Anesthesiologists writing in 2022 found no conclusive evidence that local anesthetics cause more problems in MCAS than in the general population. Your dentist should still see your reaction list.
Can you react hours after surgery with MCAS?
It can happen. In one published MCAS case, a patient reacted about 2 hours and again about 22 hours after surgery, so it's sensible to ask how long the team will monitor you.
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