A client who has been taking colchicine calls the clinic with reports of an acute gout attack of the right great toe. The client has a history of kidney stones and esophageal reflux. Which finding warrants immediate intervention by the nurse?

Rationale: A. Watery diarrhea: While a known side effect of colchicine toxicity, it is typically an early sign. It requires follow-up but is not the most urgent compared to neurological changes. B. Heartburn: Esophageal irritation is a possible reaction due to colchicine's GI side effects, but this symptom is not immediately life-threatening. C. Confusion: Neurological changes such as confusion may indicate severe colchicine toxicity or systemic complications like renal failure or CNS involvement, and warrant immediate evaluation. D. Hematuria: Although significant in a patient with a history of kidney stones, hematuria is not the most urgent sign unless accompanied by flank pain, fever, or decreased output.