Hypocalcemia: Management

00:01 Let's talk about the management of hypocalcemia.

00:04 Due to severe neuromuscular complications of hypocalcemia in the absence of prodromal muscle tetany, there is a requirement for urgent treatment with intravenous calcium for severe hypocalcemia usually in the range of less than 7.5 mg/dL.

00:22 Slow administration through a central venous catheter and electrocardiographic monitoring is preferred.

00:29 Alternatively, Teriparatide at 20 mcg twice per day rapidly eliminates hypocalcemic symptoms in the acute postsurgical hypoparathyroidism state.

00:40 This however is an off-label indication for this drug.

00:45 Vitamin D supplementation of 1000 to 4000 IU per day and oral calcium carbonate or citrate at doses of 1-3 grams/day in divided doses may normalize or sufficiently treat mild or chronic hypocalcemia.

01:03 Calcitriol may be needed in the setting of hypothyroidism with undetectable PTH and kidney failure.

01:10 Because 1,25-dihydroxyvitamin D activation requires both PTH and sufficient renal function Let's talk about the chronic management of hypoparathyroidism.

01:23 The goals of therapy are to eliminate symptoms while avoiding complications namely, hypercalcemia A reasonable goal is to keep serum calcium concentration at or just below the reference range without hypercalciuria.

01:40 Monitoring of urine calcium excretion is mandatory because hypercalciuria often limits therapy.

01:47 Correction of coexisting hypomagnesemia is also required.

01:52 Thiazide diuretics are commonly used because they reduce urine calcium excretion.

01:59 Let's go through a table that summarize the different causes of hypocalcemia.

02:03 We talked about hypoparathyroidism in which case parathyroid hormone is low, phosphorous is high and vitamin D levels may be either low or high, magnesium levels are usually normal and clinical clues here are invariably some form of neck surgery or irrradiation or an autoimmune disorder that has affected the parathyroid glands In vitamin D deficiency, we note that the PTH is high or normal.

02:30 The phosphorous is usually low and the vitamins D levels are low.

02:34 Magnesium again is usally normal and these patients may manifest with bone tenderness, weakness and osteomalacia.

02:41 The hungry bone syndrome that we've discussed will have a low PTH and a low phosphorous and invariably a low magnesium.

02:48 Here the acute uptake by the bone of calcium and phosphorous as well as magnesium occurs after parathyroidectomy and causes this condition.

02:59 Magnesium deficiency from impaired PTH secretion or PTH resistance can manifest with a normal or low parathyoid, normal phosphorous and vitamin D, obviously a low magnesium.

03:11 And the clinical clues here are patients who have diarrhea, or taking loop and thiazide diuretics, those who abuse alcohol and have dietary limitations in their magnesium intake and is also often associated with hypokalemia particularly where one is trying to replete the potassium but is unable to get anywhere because serum magnesium is also low.

03:35 And then finally, in chronic kidney disease where the PTH is high, phosphorous is high, vitamin D level is low.

03:43 Here the clinical clues are creatinine and BUN elevations and other features associated with renal insufficiency.