Wednesday, February 20, 2013

Hypercalcemia




Hypercalcemia:

Causes of hypercalcemia:
1) PTH mediated: 
  • Primary- sporadic
  • Secondary - Chronic renal failure
  • Teritary - post renal transplant - autonomous production from hypertrophied parathyroid glands
2) Non-PTH mediated
  • Malignancy mediated:
  1. PTH rP - SCC (lung, H+N), solid tumours (renal, breast, bladder, ovarian)
  2. Lymphoma - from activation of extra-renal 1-alpha OH and production of calcitriol
  3. Bony mets: Osteoblastic (prostate, carcinoid, SCLC, hodgkins), osteolytic (myeloma, RCC, nonSCLC, NHL, melanoma)
  • Non-malignancy related
  1. Granulomas: Sarcoid, TB (activation of extra-renal 1-alpha OH and production of calcitriol)
  2. Paget's disease: Regional areas of accelerated rate of bone remodelling resulting in abnormal bone architecture, bony pain, fractures and hypercalcemia.
  3. Immobilization (often concomitant with another cause of hypercalcemia)
  4. Medications: Thiazide, lithium
  5. Endocrine: Hyperthyroidism, adrenal insufficiency
  6. Milk alkali
Symptoms:
  • Moans: Abdominal pain/constipation, nausea, anorexia
  • Bones: Bony pain
  • Groans: Calcium kidney stones (CaPhos or Caoxalate)
  • Psychic overtones: Change in LOC, delirium
Treatment:
  • The cornerstone of treatment is: FLUIDS, FLUIDS, FLUIDS. Patients are often quite hypovolemic secondary to their inability to concentrate urine and nephrogenic diabetes insipidus. The kidneys should be able to excrete the majority of excess calcium  
  • Calcitonin:  4u/kg IM/SC rapid reduction in serum Ca by 1-2mmol/L. Works in 4-6 hrs.  
  • Bisphosphonates:  Pamidronate 30mg, 60mg, 90mg IV. More sustained reduction in Ca, takes 1-2 days to start working.  
  • Lasix:  Caution as this can cause worsening hypercalcemia from hypovolemia. Only used of pt is showing signs of volume overload from fluid resuscitation. see article from Annals of Internal Medicine: Furosemide from Hypercalcemia: An unproven yet common practice

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