ABSTRACT Pendimethalin is a dinitroaniline compound that is primarily used as a soil-applied herbicide. It is usually considered nontoxic on inhalation and has mild toxicity on ingestion or through skin exposure. Hypercalcemic crisis associated with it is extremely rare. The mechanism of which is not very clear, it is believed to be due to elevated thyroid levels which lead to increase born turnover and thus finally causing significantly elevated calcium levels. We report the case of a 25-year-old male with significantly elevated serum calcium and suppressed parathyroid hormone levels, who was diagnosed with a hyperthyroidism-induced hypercalcemic crisis. After detailed workup for the cause of hyperthyroidism, it was considered to be linked to pendimethalin. The patient was treated with methimazole and propranolol for hyperthyroidism and received intravenous fluids, salmon calcitonin, and furosemide to manage hypercalcemia. The symptoms and calcium levels normalized promptly following treatment. Although rare, clinicians should consider hyperthyroidism as a potential cause of hypercalcemic crisis and ensure prompt management, including ruling out other underlying causes and addressing both the calcium imbalance and the thyroid disorder.
Agrawal et al. (Fri,) studied this question.