A nurse is reviewing the laboratory results of a client who has hypothyroidism. The client's calcium level is 7.6 mg/dL. When assessing the client, which of the following findings should the nurse expect?

A calcium level of 7.6 mg/dL is below the normal range of 8.5–10.5 mg/dL, indicating hypocalcemia. When serum calcium falls, the neuromuscular system becomes hyperexcitable because calcium normally stabilizes nerve cell membranes. This hyperexcitability manifests as muscle twitching, tetany, numbness, tingling, and positive Chvostek's or Trousseau's signs. Hypothyroidism is relevant context because the parathyroid glands, which regulate calcium, are in proximity to the thyroid and can be affected. Hypertension is not associated with hypocalcemia; if anything, low calcium is linked to vasodilation and decreased cardiac contractility. Hypoactive bowel sounds are a manifestation of hypercalcemia, which slows smooth muscle motility, not of hypocalcemia. A bounding pulse is characteristic of hypercalcemia or other high-output states. Hypocalcemia instead tends to produce bradycardia and decreased cardiac output. Therefore, muscle twitching is the expected finding when calcium is low, reflecting the increased neuronal excitability that is the hallmark of this electrolyte imbalance. Students often confuse hypo- and hypercalcemia manifestations; remember that low calcium equals over-excitation while high calcium equals under-excitation of nerve and muscle tissue.