Handwritten Video Lecture on Hypercalcemia for USMLE Step 1 and USMLE Step2.
Hypercalcemia is defined as a serum calcium level greater than 10.5
PHYSIOLOGY OF HYPERCALCEMIA
Calcium is absorbed in duodenum and absorbed into ECF. The 55 percent ionized calcium is metabolically active. Bones store approximately 98 percent of calcium and acts as a reservoir. Calcium is primarily excreted from the kidney.
Influences of calcium. In hypocalcemia the CaSR detects this within the parathyroid gland. Parathyroid stimulates bone to increase osteoclastic activity which breakdown bone and increase calcium leading to hypercalcemia. Alaos works on kidney to reabsorb more calcium and increase vitamin D to increase reabsorption in duodenum.
CAUSES OF HYPERCALCEMIA
Hyperparathyroidism is a very common cause of hypercalcemia. This can be due to adenoma (Primary) or secondary to renal failure. Tertiary causes of hypercalcemia is due to autonomous PTH secretion.
Malignancy can be osteolytic which leads to hypercalcemia. Ectopic parathyroid hormone production. PTH related peptide which activates PTH hormone, but is not PTH itself. This can also lead to hypercalcemia with low PTH. Some cancers release vitamin D which increase reasborption in duodenum and leads to hypercalcemia.
Granulomatous disorders have macrophages that release vita mind D.
Hormons such as thyroid, acrogmegaly, Pheo, Adrenal insufficieny which also cause hypercalcemia.
Drugs such as thiazides and theophyline can cause hypercalcemia.
Familial Hypotkinetic Hypercalcemia which leads to inhibit PTH and increase CaSR.
SIGNS AND SYMPTOMS OF HYPERCALCEMIA
If less than 12 then usually asymtompatic. If calcium is between 12 to 14 it can be symptomatic if acute.
Kidney stones due to RTA Type 1, Nephrogenic Diabestes Insipidus. Hypercalcemia can also cause muscular pain and neuropsychological symptoms. GIT symptoms such as constipation and abomdinal pain. Hypercalcemia can lead to short QT interval and increase vessel deposition.
TREATMENT OF HYPERCALCEMIA
If hypercalcemia s less than 14 than avoid aggravating factors.
If greater than 14 then give hydration, calcitonin, and bisphosphonates. Denosumab if chronic kidney disease.
Glucocorticoids if hypercalcemia is caused by granulomatous diasese.
Dialysis is the last resort if they have renal insufficiency.