47. PHYSIOLOGY AND PATHOLOGY OF CALCIUM-PHOSPHORUS METABOLISM. RICKETS

Question 1

Tetany can be detected by the

Answer 1

Chvostek sign (facial spasms produced by lightly tapping over the facial nerve just in front of the ear) or by the Trousseau sign (carpal spasms exhibited when arterial blood flow to the hand is occluded for 3 to 5 minutes with a blood pressure cuff inflated to 15 mm Hg above systolic blood pressure).

Question 2

Hypophosphatemic rickets etiology:

Answer 2

Hypophosphatemic (phosphopenic):

A. Increased loss of phosphates
Familial hypophosphatemia- X-linked, autosomal recessive or autosomal dominant forms; with hypercalciuria (Tieder rickets)
Fanconi syndrome- idiopathic, in cystinosis, in tyrosinemia type I, in fructose intolerance, lead poisoning, antibiotic treatment
Renal tubular acidosis
Tumors

B. Reduced phosphate intake

Question 3

Lab readings in severe rickets:

Answer 3

In severe rickets, hypocalcemia, hypophosphatemia with hyperphosphaturia are found with a marked increase in PTH and AF, decreased 25(OH)D level, anemia and leukocytosis.