- See:
Rickets:
- Discussion:
- this is the classic form of the disease;
- it usually results from a deficiency in dietary intake of vitamin D, often coupled with inadequate exposure to sunlight;
- reduced vitamin-D intake causes a diminution in the absorption of calcium from the GI tract;
- insufficient absorption results in a diminished serum calcium level, which subsequently causes a secondary
hyperparathyroidism and resultant increase of the serum Ca concentration to low normal and a phosphate diuresis;
- combination of a reduced amount of mineral (both ionized Ca & phos) & secondary hyperparathyroidism is
presumed to be principal factor responsible for pathological changes in
epiphyseal plates
(in rickets) & bones & resultant alterations in x-rays images;
-
chelators in the diet:
- see:
GI and biliary causes of rickets
- major dietary inclusions that can bind calcium and render it unabsorbable in the ionized state are
phytate (from some coarse cereals), oxalate (present principally in spinach), & excess of phosphate;
-
phosphorus deficiency:
- can occur with the introduction into diet of beryllium (as an industrial toxic material) or, much
more commonly, aluminum (present as
Al(OH) in many antacid preparations);
- Clinical Findings:
- children with this disorder usually show the abnormality by age of one year or, in florid cases, even earlier.
- they may display severe weakness, inability to walk, and remarkable deformities of the skeleton;
- adults, in contrast, have few localizing symptoms or findings;
- they may complain of malaise, easy fatigability, bone pain & tenderness, weakness, or a combination of these symptoms;
- physical findings in the adult are sparse but may include a Trendelenburg gait and tenderness over osseous prominences;
- great concern, particularly in dealing w/ elderly pt, is that osteopenia or fracture may be attributed
to osteoporosis when, in fact, it represents nutritional osteomalacia;
- Radiographs:
- Labs:
-
hypophosphatemia is common due to phosphate diuresis (may be normal in some patients);
-
hypocalcemia may be present (or may be low normal);
-
alkaline phosphatase is elevated;
- BUN and Cr are normal;
