Hypercalcemia occurs with a serum calcium level above 10.5 mg/dL in the bloodstream, although clinical manifestations generally occur at concentrations exceeding 12 mg/dL. It develops when an influx of calcium into the circulation overwhelms the calcium regulatory hormones (parathyroid hormone [PTH] and metabolites of vitamin D) and renal calciuric mechanisms or when there is a primary abnormality of one or both of these hormones.
Calcium is vital to the body for the formation of bones and teeth, blood coagulation, nerve impulse transmission, cell permeability, and normal muscle contraction. Although 99% of the body’s calcium is found in the bones, three forms of serum calcium exist: free or ionized calcium, calcium bound to protein (primarily albumin), and calcium complexed with citrate or other organic ions. Ionized calcium is resorbed into bone, absorbed from the gastrointestinal (GI) mucosa, and excreted in urine and feces as regulated by the parathyroid glands. When extracellular calcium levels rise, a sedative effect occurs within the body, causing the neuromuscular excitability of cardiac and smooth muscles to decrease and impairing renal function. The calcium precipitates to a salt, causing calculi to form, and this leads to diuresis and volume depletion.
At levels above 13 mg/dL, renal failure and soft tissue calcification may occur. Hypercalcemic crisis exists when the serum level reaches 15 mg/dL. Serious cardiac dysrhythmias and hypokalemia can result as the body wastes potassium in preference to calcium. Hypercalcemia at this level can cause coma and cardiac arrest. It is considered to be a serious electrolyte imbalance, with a mortality rate as high as 50% when not treated quickly. Hypercalcemia is a common metabolic emergency, and approximately 10% to 20% of patients with cancer develop it at some point during their disease. Prognosis of hypercalcemia associated with malignancy is also poor, with a 1-year survival rate of 10% to 30%.
More than 90% of cases of hypercalcemia result from primary hyperparathyroidism or malignancy. Malignancies likely to cause hypercalcemia include squamous cell carcinoma of the lung; cancer of the breast, ovaries, prostate, bladder, kidney, neck, and head; leukemia; lymphoma; and multiple myeloma. These conditions raise serum calcium levels by destroying bone or by releasing PTH or a PTH-like substance (osteoclastic-activating factor), or prostaglandins. Other causes of hypercalcemia are vitamin D toxicity, the use of thiazide diuretics or lithium, sarcoidosis, immobilization, renal failure, excessive administration of calcium during cardiopulmonary arrest, and metabolic acidosis.
Nursing care plan assessment and physical examination
Determine a history of risk factors, with a particular focus on medications. Establish a history of anorexia, nausea, vomiting, constipation, polyuria, or polydipsia. Ask about muscular weakness or digital and perioral paresthesia (tingling) and muscle cramps. Ask family members if the patient has manifested personality changes.
The signs and symptoms are directly related to the serum calcium level. In some patients, hypercalcemia is discovered upon routine physical examination. Evaluate the patient’s neuromuscular status for muscle weakness, hypoflexia, and decreased muscle tone. Observe for signs of confusion. Hypercalcemia slows GI transit time; therefore, assess the patient for abdominal distension, hypoactive bowel sounds, and paralytic ileus. Strain the urine for renal calculi. Assess for fluid volume deficit by checking skin turgor and mucous membranes. Auscultate the apical pulse to determine heart irregularities.
Increased calcium in the cerebrinospinal fluid may result in behavior changes. The symptoms can range from slight personality changes to the manifestations of psychosis. They may include mental confusion, impaired memory, slurred speech, or hallucinations. Assess the patient’s mental status and the family’s response to alterations in it.
Nursing care plan primary nursing diagnosis: Risk for injury related to bone demineralization and confusion.
Nursing care plan intervention and treatment plan
The goals of treatment are to reduce the serum calcium level and to identify and correct the underlying cause. Conservative measures include administering fluids to restore volume and enhance renal excretion of calcium; prescribing a low-calcium diet; eliminating calciumcontaining medications (calcium supplements, calcium-containing antacids) or medications that impair calcium excretion (thiazide diuretics, lithium); and, when possible, keeping active. In severe cases of hypercalcemia, administer large volumes of normal saline (0.9% NaCl) at a rate of 300 to 500 mL per hour until the extracellular volume is restored (usually 3 to 4 L in the first 24 hours), at which time the rate is slowed and the infusion is maintained to promote renal calcium excretion. The physician may prescribe furosemide with the saline infusion, which helps prevent fluid volume overload. Monitor for signs of congestive heart failure in patients who are receiving 0.9% NaCl solution diuresis therapy. If hypercalcemiais the result of a malignancy, then surgery, chemotherapy, or radiation may be used.
Encourage sufficient fluid intake. Encourage ambulation as soon as possible and as frequently as allowed, being sure to handle the patient carefully to prevent fractures. Reposition bedridden patients frequently, and encourage range-of-motion exercises to promote circulation and prevent urinary stasis, as well as calcium loss from bone. Choose fluids containing sodium, unless contraindicated. Discourage a high intake of calcium-rich foods and fluids, and provide adequate bulk in the diet to help prevent constipation. If confusion or other mental symptoms occur, institute safety precautions as necessary. Orient the patient frequently, and design a safe environment to prevent falls.
Nursing care plan discharge and home health care guidelines
Encourage ambulation and a fluid intake of 3 to 4 L of fluid per day, including acid-ash juices (e.g., cranberry juice). Explain the importance of avoiding excessive amounts of calcium-rich foods and calcium-containing medications. Caution the patient against taking large doses of vitamin D. Be sure the patient understands any medication prescribed, including dosage, route, action, and side effects. Remind the patient to report to the physician the appearance of any symptoms of flank pain, hematuria, palpitations, or irregular pulse.