Internal Medicine

0521779407-23 CUNY1086/Karliner 0 521 77940 7 June 4, 2007 21:24

1558 X-Linked Hypophosphatemia Zinc Deficiency

■High fractional excretion of phosphate (>20% of filtered phosphate)

■Rickets on X-ray

■Increased levels of FGF-23 and likely other phosphatonins

differential diagnosis

■X-linked dominant disorder due to defect in PHEX gene (phosphate

regulating neutral endopeptidase of the X chromosome)

■Distinguish from other causes of rickets.

management

n/a

specific therapy

■Phosphate and pharmacologic doses of Vitamin D improve growth

and rickets.

■Growth hormone improves growth.

follow-up

To ensure optimal growth and healing of rickets

complications and prognosis

Hypercalcemia, hyperparathyroidism and nephrocalcinosis can be

complications of therapy.

ZINC DEFICIENCY

ELISABETH RYZEN, MD

history & physical

History

■pica, vegetarianism, alcoholism, malabsorption syndromes, pro-

longed TPN, sickle cell anemia, autosomal recessive genetic abnor-

malities

Signs & Symptoms

■non-specific in mild cases; growth retardation & delayed sexual mat-

uration in children; hypogeusia; impaired wound healing; immune

dysfunction, anorexia, night blindness, acrodermatitis enteropath-

ica

tests

Laboratory

■Basic blood studies:

➣plasma zinc <70 mcg/dL