- See:
Action of Parathyroid Hormone:
- Discussion:
- most common cause of hypoparathyroidism is inadvertant damage or removal of the parathyroids
during surgical removal of the thyroid;
- in idiopathic cases, look for ectodermal changes, mental retardation, monilial infections, low Ca;
- congenital hypoparathyroid & late onset hypoparathyroidism from other causes in adulthood
are rare conditions;
-
pseudohypoparathyroidism is another cause of this disorder;
- end organ unresponsiveness to parathyroid hormone;
- patients tend to be short and may have short metacarpals (index, ring, little);
- Laboratory Findings:
- decreased plasma calcium; (see
hypo Ca)
- in the disorder of pseudopseudohypoparathyroidism, all of the clinical features of pseudoparathyroidism
are present, but the serum calcium is normal;
- increase in plasma phosphate;
(see
hyperphosphatemia)
- increase in renal tubualar reabsorption of phosphate
- decrease in the number of bone remodeling centers;
- Radiographs:
- eventhough in hypoparathyroidism there are fewer "bites" taken out of bone by the
remodeling centers, this causes very few abnormalities in bones in adults;
- majority of these patients are treated w/ relatively high doses of Vit D to maintain their
plasma Ca levels, which can, in itself, stimulate the bone remodely system;
- subcutaneous calcifications may be present in
pseudohypoparathyroidism, where as basal ganglia
calcifications are seen in idiopathic hypoparathyroidism;
- Treatment:
-
Ca supplements are generally used and it is important to add to diet at least 1 gm/day elemental calcium;
- milk and cheese products (that are high in phospate content) should be avoided;
