Hypercalcemia
Hypercalcemia, or elevated blood calcium, is above the normal
range of 2.2-2.6 mmol/L (9-10.5 mg/dL). Symptoms begin appearing above
3 mmol/L, while hypercalcemia above 3.75 mmol/L (15-16 mg/dL) is
considered a medical emergency. Ionized calcium should be less than 1.23.
Causes and Risk Factors
Hypercalcemia can result from a number of
processes:
- increased osteoclastic bone resorption or decreased bone minieralizatio
- excess GI absorption or impaired renal excretion
Causes include
Hyperparathyroidism
- adenoma, hyperplasia, carcinoma
Malignancy: ectopic production of PTHrP, osteolytic cytokines (lymphotoxin, TNF,
IL-1a and b, TGFa) calcitriol
- lung, breast, prostate, renal, thyroid, GI, melanoma, sarcoma, multiple myeloma, lymphoma, leukemia
drug induced
- vitamin A, thiazides, lithium, tamoxifen
|
granulomatous conditions
- sarcoid can increase vitamin D
- infections such as TB)
endocrine
- Addison's,
hyperthyroidism, acromegaly
familial, renal failure |
Signs, Symptoms, and Diagnosis
Clinical features depend on duration and severity, and include:
- history
and physical exam
- lab
investigations
- ECG
changes
- diagnostic
imaging
History and Physical Exam
stones, moans, bones, psychiatric overtones
neurologic symptoms
- fatigue, drowsiness, decreased concentration,
confusion
- weakness, decreased reflexes
- depression
- psychosis
- coma
GI symptoms
- abdominal pain
- loss of appetite, weight loss
- constipation
- nausea, vomiting
- pacreatitis, peptic ulcer disease
renal sypmtoms
- impaired concentrating ability
- polyuria, polydypsia (early symptoms)
- nephrolithiasis (1e hyperparathyroidism)
- nephrocalcinosis
skin lesions
- purpura, ecchymosis, petechiae
look for enlarged lymph nodes, speen, liver if malignincy is suspected
Lab Investigations
It is important to use corrected Ca2+. Take measured albumin: 40-x. Multiply this by 0.02 and add to measured Ca2+.
blood tests
- calcium and albumin
- Mg, PO4
- PTH, PTHrP
- Alk Phos - bone involvement
- vitamin D
- serum protein electrophoresis
- tumour markers
- ESR - malignancy
urinalyisis
- 24 hour urine collection for Ca PO4, and creatinine
ECG Changes
- shortened Q-T interval
- bradycardia
- primary AV block
Diagnostic Imaging
Chest X-ray can assess for lung cancer and sarcoidosis.
Pevlic X-ray.
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Treatments
Fluids are very important to flush calcium from the body. Urine calcium loss can be enhanced using
diuretics (furosemide) or calcitonin. Glucocorticoids can also assist renal excretion.
Decreased intestinal absorption
(glucocorticoids, phosphate) and by inhibiting osteoclasts
- bisphosphonates (zolendronic acid, pamidronate): longer onset and duration; dangerous with impaired renal function
- calcitonin: onset 4-6 hours, shorter
Dialysis can be used if calcium levels are not dropping, if patient is in congetive heart failure.
The underlying cause should be identified and treated as calcium levels are controlled.
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Consequences and Course
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Resources and References