Endocrine Abstracts

Introduction

Hyperthyroidism is a very common disease due to an overactive thyroid gland. Antithyroid drugs (ATD) represent the first line treatement. Their side effects can be severe and even potentially fatal. Among them, agranulocytosis, defined as an absolute neutrophils count less than 500/µl is the most feared one.

Observation

We report the case of 57 year-old woman with no medical history, recently diagnosed with hyperthyroidism due to Grave’s disease (Anti R-TSH antibodies 19.2 UI/l). She was put under thiamazol and beta-blockers treatement. One month later, she consulted for fever (40°C), a poor state of health, labial herpes, buccal aphthous and a sore throat. The blood count revealed a leucopenia at 1660 /µl, an agranulocytosis at 0/µl and an anemia at 8.4 g/dl. The CRP level was high at 77 mg/dl. Four blood cultures were performed with a normal result, and the cytobacteriological examination of the urine as well as the chest x-ray and the abdominopelvic ultrasound did not show any abnormalities. The bone marrow biopsy concluded to a toxic agranulocytosis due to the antithyroid treatement. The thiamazol was immediately interrupted and the patient received antibiotherapy and granulocyte colony-stimulating factor (G-CSF). After 10 days of treatement, the blood count improved significantly with a white blood cell level at 13290/µl and a polynuclear neutrophils level at 10170/µl. Thus, all antithyroid drugs are contraindicated in this case and the patient benefited from a radioactive iodine therapy and she is currently with hypothyroidism.

Conclusion

Even though agranulocytosis is a rare complication that occurs in around 0.2–0.5% of patients under ATD, it can be life threatening. There for blood count surveillance before and after the initiation of the ATD is the key to an early diagnosis and an effective treatement.