Aims
Thionamides are commonly used in the management of thyrotoxicosis. Eosinophilic reactions to antithyroid drugs are uncommon, and rarely involve the gastrointestinal tract. The literature reports one case of carbimazole induced eosinophilic gastritis.[1] Carbimazole induced eosinophilic granulomatous vasculitis of the stomach has also been reported.[2] We report a second case of eosinophilic gastritis in a patient on long term carbimazole treatment.
Methods
A 75 year old lady was referred for investigation of weight loss, nausea, abdominal pain and iron deficiency anaemia. This was on the background of recurrent Graves' disease, treated with carbimazole over the preceding 4 years.
Results
Initial gastroscopy demonstrated a high risk gastric ulcer and was treated with endotherapy. Repeated endoscopic and histologic examinations over 6 months demonstrated persistent ulceration and gastritis with a prominent eosinophilic infiltrate despite an adequate course of proton pump inhibitor therapy. No dysplastic changes or Helicobacter organisms were demonstrated. There was no evidence of a vasculitic process or granulomata. Neoplastic, infectious and primary autoimmune diseases were excluded. There was no peripheral eosinophilia and ANCA was negative. Imaging of the abdomen did not reveal any lymphadenopathy or infiltration of the gastric wall.
The eosinophilic infiltrate on biopsy, and lack of response to proton pump inhibitor therapy raised the possibility of drug induced injury. The patient was biochemically euthyroid and carbimazole was discontinued. Repeat gastroscopy 3 months after cessation of carbimazole demonstrated complete resolution of the gastric ulceration. Gastric biopsies showed no evidence of tissue eosinophilia. The patient reported full resolution of symptoms.
Conclusion
This is the second reported case of eosinophilic gastritis due to carbimazole therapy, with clinical and histological resolution following cessation of carbimazole. Awareness of this rare adverse reaction is important. Patients who are on carbimazole treatment with gastrointestinal symptoms who are not responding to conventional treatment should undergo further evaluation.