The severity of symptoms is not always related to the degree of hypercalcaemia, but often reflects the rapidity of onset. Patients do not always exhibit all of the clinical features. The onset of hypercalcaemia may be insidious.
Neurological
Fatigue, lethargy, confusion, myopathy, hyporeflexia, seizures, psychosis and coma. The most frequent effect of hypercalcaemia is delirium.
General
Dehydration, polydipsia, polyuria, pruritis. Weakness and bone pain may also be present.
Gastrointestinal
Anorexia, nausea and vomiting, weight loss, constipation, ileus and abdominal pain.
Cardiac
Shortened QT, prolonged PR, Wide and flattened T waves, J waves, Ventricular and Atrial Arrhythmias and Bradycardia which can be fatal
Renal
Polyuria, polydipsia, dehydration and development of kidney stones.
Early
Polyuria, nocturia, polydipsia, dehydration, anorexia, easy fatigability, weakness, hyporeflexia, pain may be precipitated or exacerbated by hypercalcaemia.
Late
Apathy, irritability, depression, decreased ability to concentrate, obtundation, coma, profound muscle weakness, nausea and vomiting, constipation, increased gastric acid secretion, acute pancreatitis, pruritus, visual disturbances, sudden death from cardiac dysrhythmias may occur if calcium rises quickly, especially in patients taking digoxin.
Learning bite
In unexplained vomiting, thirst, polyuria or confusion, it is prudent to check serum calcium.