Delayed methimazole-induced agranulocytosis in a 6-year old patient with Graves’ disease

Neutropenia Occurs More Often Under Carbimazole than Under Methimazole Treatment in Pediatric Graves' Disease Patients

Background: Agranulocytosis is a rare antithyroid drug treatment (ATD) side effect seen in children suffering from Graves' disease (GD). Neutropenia is a recognized adverse event associated with ATD but has also been reported as pre-treatment neutropenia in GD. Methods: We performed a retrospective cohort study to analyze the longitudinal clinical and biochemical data of 161 pediatric patients with GD who received either methimazole (MMI) or carbimazole (CBZ) as ATD. The inclusion criteria were elevated free thyroxine (fT4 >25 pmol/L), suppressed thyrotropin (TSH <0.05 mlU/mL), and elevated thyrotropin receptor antibodies (TSHRAbs >2.5 IU/L). Absolute neutrophil count (ANC) was used to define neutropenia (ANC <1800/µL) and agranulocytosis (ANC <500/µL). Results: Nine of the 161 patients had neutropenia at diagnosis (ANC: 1348/µL ± 250) without further deterioration under ATD. In this subgroup, we found higher levels of free triiodothyronine (fT3: 31.45 pmol/L ± 3.99) at diagnosis in comparison with those who developed neutropenia (26.29 pmol/L ± 12.96; p = 0.07) and those without neutropenia before and during therapy (23.12 pmol/L ± 13.7; p = 0.003). Thirty-eight patients (23.6%) became neutropenic (ANC: 1479/µL ± 262) while receiving ATD. Neutropenia occurred after a mean of 551.8 (range: 10-1376) days, mostly without further deterioration. Two of these 38 patients developed agranulocytosis and underwent emergency thyroidectomy. The patients with neutropenia were significantly younger (p = 0.031). Neutropenia occurred significantly more often in patients receiving CBZ (50%; n = 20/40) than in those receiving MMI (16.5%; n = 18/110; p = 0.001). The minimum ANC was significantly lower in the CBZ (1971/µL ± 1008) than in the MMI group (2546 ± 959); p = 0.004. Conclusions: Neutropenia occurred significantly more often under CBZ than MMI. As this is potentially due to higher immunogenicity, we suggest that children with GD should be treated with MMI. Frequent measurements of ANC may be needed to detect severe agranulocytosis, although low pre-treatment ANC may not necessarily be a contraindication to ATD treatment. Young age may be potentially associated with an increased risk of reduced ANC. Further investigation is necessary to fully understand risk factors for neutropenia in children with GD.

The characteristics of Grave's disease in children and adolescent patients in Al-Madinah Al-Munawwarah: A retrospective chart review

OBJECTIVES

To determine the characteristics of Graves' disease in children and adolescents in Medina, the Kingdom of Saudi Arabia, and compare them to those observed in other countries.

METHODS

This is a retrospective chart review of children and adolescents diagnosed with Graves' disease between January 2010 and May 2021.

RESULTS

Fifty-eight patients aged 12.02 ± 4.85 years were identified, of which 44 (75.9%) were females. Exophthalmos (63.8%), neck swelling (60.3%), palpitations (46.6%), and tremors (29.3%) were the most common manifestations. Vitiligo (1.72%) and alopecia (1.72%) were the only autoimmune diseases observed in our patients. The median (IQR) value was 0.01 (0.36) (ulU/mL) for thyroid-stimulating hormone (TSH) and 24.89 (29.50) (pmol/L) for FT4. In terms of treatment modalities, 55 (94.8%) received antithyroid medication, 6 (10.3%) underwent thyroidectomy and one patient (1.72%) was treated with radioactive iodine.

CONCLUSION

In general, Graves' disease is more common in females. Neck swelling, palpitation, and tremors were the main manifestations. Compared with other countries, there was a higher frequency of exophthalmos and a lower frequency of associated autoimmune conditions. The primary treatment was antithyroid drugs; thyroidectomy and radioactive iodine were used less frequently.

Approach to the Patient: Management and the Long-term Consequences of Graves' Disease in Children

In children, Graves' disease (GD) is the most common cause of hyperthyroidism. Most pediatric patients with GD will not go into lasting remission, even following many years of antidrug therapy. Thus, most pediatric patients will require radioactive iodine (RAI) or surgery. When antithyroid drugs are used, methimazole is the drug of choice. When methimazole is used in children, up to 20% will have minor adverse reactions and serious adverse events occur in up to 1%. RAI is an effective form of therapy when the thyroid size is less than 80 g. Because of concerns of whole-body radiation exposure, it is recommended that RAI be avoided in children under 5 years of age, and dosages less than 10 mCi be used between 5 and 10 years of age. Surgery is an effective treatment in children if performed by a high-volume thyroid surgeon. Because of the scarcity of high-volume pediatric thyroid surgeons, a multidisciplinary approach using pediatric surgeons and endocrine surgeons can be considered. Whereas there is a trend toward long-term antithyroid drug therapy in adults, for several reasons, this approach may not be practical for children. Determining the optimal treatment for the pediatric patient with GD, requires consideration of the risks and benefits relating to age and likelihood of remission.

A case of antithyroid drug-induced agranulocytosis from a second antithyroid drugs (ATD) administration in a relapsed Graves' disease patient who was tolerant to the first ATD treatment

Agranulocytosis is a rare side effect of antithyroid drugs (ATD) that usually develops within the first 3-6 months after starting treatment. We present a 64-year-old patient who developed agranulocytosis after starting ATD to treat relapsed Graves' disease. This patient had tolerated the first course of ATD for 72 months. This was an unusual case in which a serious side effect developed during a second ATD course. It is essential that clinicians remain vigilant to the fact that antithyroid drugs can induce agranulocytosis several years after initiated.