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