Differential Analysis of Vitamin D Dysfunction and Deficiency

by Carlo Raj, MD

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    00:01 In this table, we’ll take a look at Vitamin D dysfunction.

    00:03 I said dysfunction because the first column here is actual Vitamin D deficiency whereas the second column is referring to pathology of the receptors for Vitamin D and if anything, you’d find increase in Vitamin D dysfunction.

    00:19 The most common cause of Vitamin D dys-deficiency in the United States, once again, is chronic renal failure.

    00:25 Do not ever forget this because of the kidney dysfunction, you have decreased Vitamin D, decreased calcium, secondary hypoparathyroidism; the PTH cannot work on the kidney, thus resulting in hyperphosphatemia, hypocalcemia and may result in renal osteodystrophy.

    00:44 Other cause of Vitamin D deficiency, which are quite different, would be lack of exposure to UV-rays, maybe dietary deficiency, rarely, maybe liver damage.

    00:53 And those, you want to keep that separate.

    00:58 Whereas if there’s resistance, then any type of resistance pathology, such as your diabetes haemolytis type 2, such as androgen-androgen insensitivity syndrome, such as your nephrogenic diabetes insipidus and in this case, we have Vitamin D and organ resistance.

    01:12 You can expect the proximal hormone to then be elevated; no exception here, we have an increase in Vitamin D.

    01:22 Whenever there is Vitamin D dysfunction, you can expect the calcium to be decreased; urine calcium, in fact, could be increased.

    01:33 We have plasma phosphate being decreased, urine phosphate being increased.

    01:43 The reason for all of this is because there isn’t enough Vitamin D. So, therefore, it’s being wasted away through the urine depleting it in your plasma.

    01:56 Osteomalacia, if rickets is to a child, osteomalacia is to an adult.

    02:03 So, there is no bowing of the leg, fontal bossing, rachitic rosary, the pectus carinatum and such; asymmetrical protrusion of the sternum.

    02:13 Osteomalacia is in adult.

    02:14 And here, if anything, we call the osteoid seam referring to that, once again, the epiphyseal plate which has been mineralized, remember that.

    02:23 Osteomalacia, we’re talking about adults, mineralization is taking place, most common cause again chronic renal failure.

    02:30 Usually, calcium phosphate deficiency due to dietary, malabsorption, decreased Vitamin D synthesis, that would be something like your kidney damage.

    02:39 Clinical symptoms: osteomalacia, hypocalcaemia, fatigue, diffused bone pain and muscle weakness is what you’re paying attention to in osteomalacia patient, adult.

    02:54 Often low or low-normal calcium, hypophosphatemia.

    02:59 Now, be careful here, the reason we call this hypophosphatemia, could this ever be caused by chronic renal failure? No.

    03:12 In chronic renal failure, it might result in osteomalacia, but the phosphate will be elevated.

    03:22 Any other cause of Vitamin D deficiency, you can expect there to be secondary hyperparathyroidism and wasting away all the phosphate.

    03:32 Mildly elevated alkaline phosphatase, once again, because of that secondary hypoparathyroidism which may then work upon that bone.

    03:39 So, this first bullet point will be dealing with every type of osteomalacia due to lack of sun exposures, so on and so forth except for chronic renal failure.

    03:48 That was a topic that we covered in great detail when we did nephrology.

    03:53 Confirmed by bone biopsy, the tetracycline labeling showing undermineralized bone.

    04:03 Both osteomalacia and rickets, you have a problem with mineralization.

    04:06 In rickets, however, as a child, all kinds of issues that we discussed, osteomalacia, osteoid seam will be widened because of lack of mineralization.

    04:18 Treat by repleting calcium and Vitamin D, depending as to what the cause was.

    04:23 Often require quite a bit, it’s called ergocalciferol.

    04:27 Here’s my dosage and timeline.

    About the Lecture

    The lecture Differential Analysis of Vitamin D Dysfunction and Deficiency by Carlo Raj, MD is from the course Parathyroid Gland Disorders.

    Included Quiz Questions

    1. Chronic kidney disease
    2. Malabsorption
    3. Lack of exposure to UV light
    4. Liver disease
    5. End organ resistance
    1. Bowing of long bones
    2. Fatigue
    3. Diffuse bone pain
    4. Muscle weakness
    5. Decreased vitamin D synthesis
    1. Normal calcium, decreased phosphate, increased alk phos, decreased vitamin D
    2. Increased calcium, decreased phosphate, increased alk phos, decreased vitamin D
    3. Normal calcium, increased phosphate, increased alk phos, decreased vitamin D
    4. Normal calcium, decreased phosphate, increased alk phos, increased vitamin D
    5. Decreased calcium, decreased phosphate, decreased alk phos, increased vitamin D

    Author of lecture Differential Analysis of Vitamin D Dysfunction and Deficiency

     Carlo Raj, MD

    Carlo Raj, MD

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