Surgical considerations in systemic mastocytosis
Question:
5/24/2019
I have a 35 year-old, Caucasian, female patient with a long history of well documented indolent systemic mastocytosis/ bone marrow biopsy and with a stable serum tryptase of 35,6 ng/mL. In the past she underwent a right nephrectomy for hypernephroma and was considered cured, and her current renal function is normal. She has ulcerative colitis controlled with mesalazine. About five years ago she had an uneventful cesarean section with raquianesthesia. She is presently well controlled with daily: Zyrtec 20mg hs, Singulair 10mg PM, Comolyn 400mg bid, Ketotifen 2mg qhs. She also was prescribed EpiPen 0,3mg auto-injector and prednisone 20mg tablets prn. She now has a large separation of both rectus abdominis muscles due to the previous surgeries. This leads to local discomfort and has an ugly esthetical look. She wants to undergo a corrective plastic surgery. The surgeon informed that this procedure may last about 4 hours with general anesthesia, using plenty of neuromuscular blockers/muscle relaxants.
Questions:
1-Surgical risk for her condition?
2-Need to add oral anti-H2?
3-Best analgesics/opioids prn postop?
4-Safety of SC heparin to prevent DVT?
5-Should she be discouraged of having this surgical intervention?
Answer:
We consulted Dr. Mariana Castells who kindly provided the following response. Systemic Mastocytosis patients have shown an increase rate of reactions to general anesthetics and morphine derivatives but the true incidence is unknown and premedication regimes have been elaborate to prevent reactions during radiological procedures and surgery to block mast cell mediators related symptoms and anaphylaxis. Tryptase levels above 11.4 ng/ml have been associated with increased risk for systemic reactions. The choice of morphine derivatives and general anesthetics is tailored to the patient previous surgical experiences and to the known actions of some commonly used drugs. Atracuronium and rocuronium can activate mast cells through MRGPRX2 non-IgE receptors and induce mast cell mediators release and possibly anaphylaxis. Avoidance of MRGPRX2 agonists containing THIQ motifs is recommended in patients with systemic mastocytosis (McNeil et al Nature Immunology 2016). Patients with cutaneous mastocytosis have less risk for reactions during anesthesia, except patients with diffuse cutaneous mastocytosis with elevated trytpase, who are also candidates for pre-medications. In regards to the specific questions:
1-Surgical risk for her condition? Similar to all patients with systemic mastocytosis and elevated tryptase and avoidance of MRGPRX2 agonists and morphine derivatives is recommended.
2-Need to add oral anti-H2? Cetirizine 10 gm and Pepcid 20 mg or ranitidine 150 mg are recommended 12 hour and 1 hour prior to surgery in addition to singulair 10 mg.
3-Best analgesics/opioids prn postop? Fentanyl has been recommended based on clinical anecdotal reports. About 30% of patients with systemic mastocytosis are aspirin and COX-1 inhibitors intolerant and a challenge in clinic prior to exposure is recommended, starting at 81 mg.
4-Safety of SC heparin to prevent DVT? Heparin is not contraindicated in patient with systemic mastocytosis.
5-Should she be discouraged of having this surgical intervention? Surgery is not contra-indicated in any patient with systemic mastocytosis.
I hope this helps you and your patient.
Jacqueline A. Pongracic, MD, FAAAAI