Hypophosphatemia

Question 1

chronically malnourished pt will likely develop

Answer 1

severe hypophosphatemia due to IV dextrose

Question 2

hypophosphatemia is due to

Answer 2

malnutrition, vitamin D deficiency, and diarrhea

Question 3

causes of low phosphate levels:

Answer 3

internal redistribution

• increased insulin secretion (esp after refeeding malnourished pts)
• acute resp alkalosis (stimulates glycolysis)
• hungry bone syndrome (after parathyroidectomy)

decreased intestinal absorption

• chronic poor intake
• aluminum or magnesium containing antacid (bind phosphate)
• steatorrhea or chronic diarrhea

increased urinary excretion

• primary and secondary hyperparathyroidism
• vitamin D deficieny (lower GI absorption, and increased urinary excretion)
• primary renal phosphate wasting syndromes
• falconi syndrome

Question 4

how does refeeding syndrome happen?

Answer 4

in chronic malnourished pts the insulin release that comes with giving glucose will drive phosphate into cells and phosphorus can drop to severely low levels which can deplete ATP and cause symptoms (decreased diaphragmatic strength, cardiac function and neurological function)

Question 5

how to replace phosphorus

Answer 5

<2 mg/dl give oral phosphate
<1 mg/dl need IV phosphorus

do not give pts with low phosphate at presentation unless there’s a clear indication like hypoglycemia.

Question 6

what is longterm effect of severe hypophosphatemia without replacement and get IV dextrose?

Answer 6

can develop rhabdomyolysis within first 72 hrs.

Question 7

Wernicke’s encephalopathy is

Answer 7

acute encephalopathy and oculomotor defects and gait ataxia.