Case Description
A previously healthy four-year-old female with a new diagnosis of grade IV primitive neuroectodermal (PNET) brain tumor underwent surgical resection and came to our institution for chemo-radiation as standard of care. The patient was scheduled to receive vincristine during radiation therapy. During her initial infusion of vincristine she developed an anaphylactic reaction with facial flushing, cough, lip swelling and oxygen desaturation to 87% at room air within 3 minutes of starting the infusion. The infusion was stopped and the patient was given a dose of diphenhydramine and hydrocortisone, which abated her symptoms.
An extensive root cause analysis was done to determine the cause of the allergic reaction, since anaphylaxis to vincristine is rare. In the following 2 weeks the patient had similar anaphylactic reactions while receiving IV pentamidine and premedication with IV hydrocortisone, proving that anaphylaxis was not due to vincristine. The patient did not experience any reaction to saline flushes, chlorhexidine or alcohol wipes.
Our work up for multiple allergic reactions included complement levels, antibodies for rheumatologic and autoimmune diseases and thyroid function tests. Thyroid stimulating hormone (TSH) was elevated at 7.3 mcunit/mL (normal reference 0.27 - 4.20). No eosinophilia or immunodeficiency was detected in the work up and immunoglobulin levels were unremarkable. The patient was referred to endocrinology and a complete work up showed elevated prolactin 50.1 ng/mL (4.8 - 23.3 ng/mL) which was secondary to TSH elevation. The patient also had clear rhinorrhea for which an upper respiratory viral panel was sent and this was negative. She was diagnosed as having allergic rhinitis, a common co-exiting condition with Hashimotos thyroiditis, for which cetirizine was started with moderate improvement of her symptoms.
Further work up by endocrine team revealed elevated thyroid peroxidase antibodies at 29.8 IU/mL (reference range: 0.2 - 8.9 IU/mL) with subsequent normalization of TSH and Free T4 which was consistent with the diagnosis of Hashimoto thyroiditis.
The consistency found between all the allergic reactions was the IV tubing set used. When we changed from low sorb tubing to regular tubing, the patient did not experience any further allergic reactions to chemotherapeutic and non-chemotherapeutic agents, without the use of premedication. She was able to successfully receive additional doses of vincristine and proceed with maintenance chemotherapy as standard of care for PNET. The patient was referred to allergy and immunology for further work up but there were no significant findings.