Internal Medicine

0521779407-09 CUNY1086/Karliner 0 521 77940 7 June 4, 2007 21:13

778 Hypocalcemia

■Rachitic deformities

■Albright’s hereditary osteodystrophy:

➣Shortened 4th and 5th metacarpal bones

➣Obesity

➣Short stature

➣Round facies

tests

Laboratory

■Blood

➣Measure Ca, albumin, ionized Ca, P, PTH, 25-OH vitamin D

➣Hypoparathyroidism: low Ca, high normal or high P, low PTH

➣Vitamin D deficiency: low Ca, low or normal P, high PTH, low

25-OH vitamin D

➣Magnesium depletion: low Mg, low Ca, low PTH, normal P

➣Pseudohypoparathyroidism: low Ca, high or normal P, increased

PTH

■Urine

➣Measure Ca and creatinine

➣Vitamin D deficiency: low urine Ca

Ellsworth-Howard test

Reduced urinary P and cyclic AMP excretion with infusion of

PTH in pseudohypoparathyroidism

differential diagnosis

■Hypoparathyroidism: post-surgical, post-radiation, congenital,

autoimmune, autosomal dominant hypoparathyroidism (ADH) due

to activating calcium receptor mutations

■Vitamin D deficiency: renal failure, poor nutrition, malabsorption,

short bowel, cirrhosis

■Pancreatitis

■Pseudohypoparathyroidism

■Hypomagnesemia

■Rhabdomyolysis

■“Hungry bone” syndrome

■Tumor lysis

■Hyperphosphatemia

management

What to Do First

■Assess severity of symptoms