Hypercalcemia

Today we had some discussion about hypercalcemia. Some points:

Symptoms:
GI- anorexia, n/v, abdo pain, constipation.
Renal: stones, polyuria.
Neuro: weakness.
Cardiac: arrhythmias

Etiology:
Useful first division is by PTH level
1) High PTH- expect high Ca, low PO4.
-primary/secondary/teriary hyperparathydoidism, parathyroid hyperplasia
-lithium
-familial hypercalcemic hypocalciuria

2) Low PTH
-PTHrP from malignancy (esp. SCC- lung, H+N)
-hypervitaminosis D- expect high Ca and high PO4- from granulomatous disease, lymphoma)C) -OAF = IL6 (local paracrine effect; in breast and hematological cancers)
-Direct effect of mets (e.g. prostate, lung, etc.)
-Myeloma
-Medications- HCTZ, Ca, vit. D
-Milk alkali syndrome
-Hyperthyroidism

As inpatient, #1 cause = malignancy
As outpatient, #1 cause = primary hyperparathyrodisim

Tx:
Fluids!
Consider bisphosphonate if malignancy-related or v. high (but takes days to work)
Calcitonin by nasal spray or subq.
If hyper D from sarcoid or lymphoma, possible steroids.
Avoid lasix since most patients are profoundly volume depleted.
Last resort is dialysis

Milk-Alkali syndrome
Triad of hypercalcemia, met alk, renal failure assoc with ingestion of large amts calcium, alkali
Once common because of PUD treatement. Making resurgence b/c of calcium for osteoporosis, and prevention of secondary hyperparathyroidism in CKD
Sequence: hypercalcemia, dec GFR, met alkalosis ("contraction"). Hypercalcemia per se stimulates renal bicarb fomation.
Pts on vit D, thiazides, vol contraction, CKD are at higher risk

Some links:

Click here for NEJM clinical problem solving case on hypercalcemia
Click here for a review of calcium disorders in renal disease