44444444 - guest1

[ArchivalUser]

A 65-year old man, who underwent neck surgery to remove a cancerous lesion two days previously, complains of
thigh and calf cramps and tingling around the lips. Laboratory data show that serum calcium is 8 mg/dL and serum
phosphate is 5.5 mg/dL. Which of the following is the most likely explanation for these findings?


A. Primary hypoparathyroidism

B. Pseudohypoparathyroidism

C. Pseudopseudohypoparathyroidism

D. Renal failure

E. Vitamin D deficiency

[ArchivalUser]

a...

[ArchivalUser]

a.

[ArchivalUser]

a?

[ArchivalUser]

A. complication of thyroid cut is to damage parathyroid

[ArchivalUser]

Explanation:

The correct answer is A. Surgical hypoparathyroidism is the most common cause of primary hypoparathyroidism.
Exploration of the anterior neck during thyroidectomy, parathyroidectomy, or removal of neck lesions can all
compromise parathyroid gland function. Often, the problem occurs because the blood supply to the parathyroid
glands is interrupted during the surgery. The decrease in plasma parathyroid hormone leads to hypocalcemia
and hyperphosphatemia. The decreased serum calcium is due to decreased absorption of dietary calcium
(because vitamin D activation is decreased) and decreased movement of calcium from bone to extracellular fluid.
Low serum calcium can lead to tetany and paresthesias because of destabilization of excitable tissue
membranes. Tetany is most often observed when there is a rapid decrease in serum calcium, such as that
occurring with surgical hypoparathyroidism. The increased serum phosphate is due to decreased renal excretion.