Critical Care Medicine-Endocrine Disorders>>>>>Parathyroid and Calcium
Question 2#

Which of the following is NOT a symptom of acute hypoparathyroidism?

A. Focal seizure
B. Laryngospasm
C. PR interval prolongation
D. Anxiety

Correct Answer is C


Correct Answer: C

Acute hypoparathyroidism is often the result of postsurgical or autoimmune damage to the parathyroid glands. Its clinical manifestations are due to acute hypocalcemia, of which the hallmark is tetany. Calcium normally blocks sodium channels and inhibits nerve depolarization; reduced calcium levels lower the threshold for depolarization. This is the reason for Trousseau sign (carpal spasm elicited by inflating the blood pressure cuff) and Chvostek sign (facial spasm elicited by tapping of the cheekbone), as well as hyperactive tendon reflexes.

Laryngospasm, bronchospasm, and diaphragmatic weakness secondary to hypocalcemia can contribute to respiratory failure requiring intubation. Cardiac arrhythmias can occur, and QT prolongation can place the patient at high risk for torsades de pointes. However, PR interval prolongation is not reported. Hypocalcemia itself causes both a negative chronotropic and inotropic effect on the heart and can lead to acute heart failure and cardiogenic shock. 

Neurological complications can include focal or generalized seizures, as well as less specific symptoms such as fatigue, hyperirritability, anxiety, and depression.


  1. Tohme JF, Bilezikian JP. Hypocalcemic emergencies. Endocrinol Metab Clin North Am. 1993;22:363.
  2. Levine SN, Rheams CN. Hypocalcemic heart failure. Am J Med. 1985;78:1033.