In the state of nephrotic syndrome, if there is a calcium deficiency, it may cause the patient's limbs to twitch, especially sudden twitches and pain in both lower limbs during sleep at night, waking the patient from sleep. If calcium deficiency persists for a long time, it may lead to osteoporosis in the patient, such as osteoporosis of the femoral head, which presents with hip pain, and necrosis of the femoral head, potentially affecting the patient's ability to walk. In children, calcium deficiency may cause night-time convulsions, and external manifestations such as hunchback, pigeon chest, and square skull might appear.