A child with hypoparathyroidism is receiving vitamin D therapy. The parents should be advised to watch for which sign of vitamin D toxicity?

A) Headache and seizures
B) Physical restlessness and voracious appetite without weight gain
C) Weakness and lassitude
D) Anorexia and insomnia

Vitamin D toxicity can be a serious consequence of therapy. Parents are advised to watch for signs, including weakness, fatigue, lassitude, headache, nausea, vomiting, and diarrhea. Renal impairment is manifested through polyuria, polydipsia, and nocturia. Headaches may be a sign of vitamin D toxicity, but seizures are not. Physical restlessness and a voracious appetite with weight loss are manifestations of hyperthyroidism. Anorexia and insomnia are not characteristic of vitamin D toxicity.