Introduction
-The four parathyroid glands produce and secrete PTH
-Hypoparathyroidism develops when the parathyroid glands fail to secrete sufficient quantities of PTH, resulting in a low calcium level and a high phosphorus level
-The most common cause of hypoparathyroidism is neck surgery with removal or destruction of the parathyroid glands
-Other causes include congenital abnormalities of the third and fourth pharyngeal pouches (DiGeorge syndrome), autoimmune or drug induced or radiation induced hypothyroidism
Symptoms & Signs
Skin: Dry, scaly skin, coarse hair
Ocular: Cataracts, Papilledema
Dental: enamel hypoplasia, defective root formation, delayed teeth eruption
Respiratory: Bronchospasm, laryngospasm, stridor
Cardiac: Heart failure, Prolonged QT interval on ECG
Psychological: Confusion, behavioral changes, psychosis
Neuromuscular: numbness, tingling, carpopedal spasms, seizures, Parkinsonism
Tetany: Spontaneous tonic muscular contractions; Classically diagnosed by Chvostek sign and Trousseau sign
Chvostek sign: twitching or contraction of the facial muscles in response to tapping the facial nerve at a point anterior to the ear and above the zygomatic bone
Trousseau sign: it is elicited by inflating the sphygmomanometer with the cuff around the arm above the systolic blood pressure for 3 min; The wrist and metacarpophalangeal joints flex, the DIP and PIP joints extend, and the fingers adduct
Diagnosis
Labs: Inappropriately low or undetectable PTH level, low calcium level, high phosphorus level
EKG: a prolonged QT interval on the ECG
Treatment