Hypocalcemia is the most likely diagnosis, as it causes hyperactive reflexes and can occur following multiple blood transfusions.
Hypocalcemia can be asymptomatic or symptomatic, depending on the serum level of ionized calcium. Asymptomatic hypocalcemia often results from volume expansion and hypoalbuminemia, where ionized calcium remains at normal levels. Symptoms occur when ionized calcium is also decreased, which can result from citrate binding from blood transfusions. Severe hypomagnesemia may decrease the secretion and peripheral response to parathyroid hormone, resulting in symptoms of hypocalcemia.
Fong and Khan review the signs and symptoms of acute hypocalcemia. Symptoms of hypocalcemia include paresthesia, muscle spasms, cramps, tetany, circumoral numbness, and seizures. Hypocalcemia can also present with laryngospasm, neuromuscular irritability, cognitive impairment, prolonged QT intervals, electrocardiographic signs of myocardial infarction, or heart failure. Chvostek and Trousseau signs are classic findings.
French et al. discuss the management of hypocalcemia in hospitalized patients. Hypocalcemia has been associated with hypotension, an increased need for vasopressor support, and significantly increased mortality. Although prolongation of the QT interval can occur, the significance of this phenomenon is controversial. It is unclear whether this is directly related to ventricular arrhythmias or whether correction of the abnormalities reduces the incidence of arrhythmias.
Illustration A lists several etiologies of hypocalcemia.
Illustration B shows how to elicit Chvostek's sign.
Illustration C shows the appearance of carpopedal spasm seen in Trousseau's sign.
Answer 1: Hypercalcemia is associated with nausea and vomiting, constipation, abdominal pain, muscle aches, and confusion.
Answer 3: Hyperkalemia causes muscle fatigue, weakness, paralysis, arrhythmias, and nausea.
Answer 4: Hypokalemia causes weakness, fatigue, muscle cramps, constipation, and arrhythmias.
Answer 5: Symptoms of hypermagnesemia include somnolence, diminished deep tendon reflexes, muscle paralysis, bradycardia, and hypotension.
Fong J, Khan A. Hypocalcemia: updates in diagnosis and management for primary care. Can Fam Physician. 2012 Feb;58(2):158-62.
PMID: 22439169 (Link to Abstract)
French S, Subauste J, Geraci S. Calcium abnormalities in hospitalized patients. South Med J. 2012 Apr;105(4):231-7.
PMID: 22475676 (Link to Abstract)