Hand numbness and leg cramps may be caused by low blood calcium, electrolytes should be measured, if blood calcium is reduced, calcium supplementation should be given promptly, either oral calcium gluconate or intravenous calcium gluconate push to quickly correct hypocalcemia, and if necessary, oral vitamin D should be taken at the same time to promote calcium absorption, and the patient should be instructed to get sunlight, which may also promote calcium absorption. Severe hypocalcemia in patients may also cause osteoporosis and predispose the elderly to fractures. If hypocalcemia occurs in adolescents, it may cause growth retardation. If hypocalcemia occurs in infants and children, it can cause incomplete closure of fontanelle and may cause rickets, etc. If the patient has hypertension, long-term application of calcium antagonists, also prone to hypocalcemia, hypocalcemia may cause cardiac arrest in serious cases, should be taken seriously.