Duke Orthopaedics
Wheeless' Textbook of Orthopaedics


- 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 

- 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

Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Tuesday, December 6, 2011 1:16 pm

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