What EEG findings are characteristic of hypocalcemia and hypercalcemia?

Updated: Oct 09, 2019
  • Author: Eli S Neiman, DO, FACN; Chief Editor: Selim R Benbadis, MD  more...
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Hypocalcemia and hypercalcemia

Paresthesias, tetany, muscle spasm and, rarely, seizures may occur in hypocalcemia. EEG findings include theta and polymorphic delta slowing, polyspikes, sharp waves, and paroxysmal activity. Hypercalcemia is associated with renal failure, neoplasms, bone destruction, parathyroid hormone (PTH)-releasing tumors, and hypervitaminosis D. Muscle weakness, polydipsia, polyuria, nausea, anorexia, and coma may develop. EEG changes appear when serum calcium level is approximately 13 mg/dL; slowing and intermittent rhythmic delta activity is seen. Photic driving may be prominent, and TWs may be recorded.

When serum calcium is normalized, the EEG usually improves but not immediately. A hypercalcemic condition can be observed in association with hyperthyroidism. Confusional state and EEG alterations, among which diffuse monomorphic delta rhythms were remarkable, were shown by Juvarra. [64] As soon as normalization of calcium serum level was achieved, rapid clinical and EEG improvement ensued.

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