Aging is associated with decreased concentrations of 7-dehydrocholesterol, the precursor of vitamin D 3 in the skin. A 70-y-old has ≈25% of the 7-dehydrocholesterol that a young adult does and thus has a 75% reduced capacity to make vitamin D 3 in the skin ( 43 ). Because vitamin D is fat soluble, it is readily taken up by fat cells. Obesity is associated with vitamin D deficiency, and it is believed to be due to the sequestration of vitamin D by the large body fat pool ( 44 ). Medications including antiseizure medications and glucocorticoids and fat malabsorption are also common causes of deficiency ( 45 ; Figure 3 ).
Frequent monitoring of kidney function and electrolytes is still necessary after going home. Typically, function needs to be monitored every 12-24 hours while hospitalized, and every 2-3 days once home.
Ultimately, the goal is to prevent hypercalcemia and secondary acute kidney failure. Even after hospitalization and treatment, some dogs and cats may need to go home on oral diuretics and steroids for weeks. Even with aggressive treatment, chronic renal failure may be a secondary condition.
If your dog or cat got into a source of vitamin D, contact your veterinarian or APCC immediately for guidance. While treatment is often expensive (as it requires hospitalization for typically 2-7 days), it can be life saving for your dog or cat. Unfortunately, as with most poisoning cases, the longer you wait, the more expensive it is to treat and the worse the prognosis.
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