Symptom To Diagnosis - Hypercalcemia Flashcards
Most cases of hypercalcemia are due to only a handful of conditions:
- Primary hyperparathyroidism.
- Hypercalcemia of malignancy.
- Renal failure.
- Milk-alkali syndrome.
Etiology of hypercalcemia - PTH-related:
- Primary hyperparathyroidism. 2. 2o hyperparathyroidism (due to renal insufficiency and Ca or vitD supplementation). 3. Tertiary hyperparathyroidism. 4. Lithium therapy (10%). 5. FHH.
Hypercalcemia of malignancy:
- Secretion of PTHrP: SCC, adenoCA of lung, pancreas, kidney, others. 2. Osteolytic metastases: Breast, MM. 3. Production of calcitriol: HL.
Hypercalcemia related to vitD:
- Hypervitaminosis D. 2. Granulomatous diseases.
Other relatively common causes of hypercalcemia:
- Milk-alkali syndrome (chronic renal failure who are taking calcium carbonate). 2. Hyperthyroidism. 3. Thiazides. 4. Falsely elevated serum calcium (2o to increased serum binding protein) –> Hyperalbuminemia + MM.
Primary hyperparathyroidism accounts for more than …% of cases of hypercalcemia in otherwise healthy ambulatory patients.
90%.
Nephrolithiasis is seen in …-…% of patients with primary hyperparathyroidism.
15-20%.
Other symptoms of primary hyperparathyroidism probably include:
- Increased frequency of HTN. 2. Gout. 3. Ca pyrophosphate deposition disease.
Besides hypercalcemia, are other effects of PTH (HypoPh, hypercalciuria, hyperphosphaturia) useful in differentiating primary hyperparathyroidism from hypercalcemia of malignancy?
Seldom useful.
About …% of patients with primary hyperparathyroidism have normal PTH levels (a finding that is in fact inappropriate given the hypercalcemia).
10%. FHH must be excluded.
Indications for surgery:
- Symptoms of hypercalcemia. 2. Elevated serum Ca >1mg/dL above normal. 3. Cr clearance reduction of 30% compared with age-matched controls. 4. 24h urine Ca>400mg/d. 5. T score <50. 7. Patient preference or patient inability to comply with long term monitoring.
Primary hyperparathyroidism - Monitoring for patients not undergoing surgery:
- Assessment of symptoms, calcium level, renal function every 6-12months. 2. Bone density screening yearly of the hip, spine, and wrist. 3. Monitoring, possibly radiographically, for development of nephrolithiasis.
Other than primary hyperparathyroidism - DDX of hypercalcemia with elevated PTH:
- Lithium use. 2. MEN. 3. 2o or 3o hyperparathyroidism. 4. FHH.
FHH - Textbook presentation:
- Usually made at childhood during evaluation of asymptomatic hypercalcemia or during screening because of a positive family history. 2. Condition may also present during adulthood as hypercalcemia with a normal to slightly elevated PTH.
FHH - Pathogenesis:
Makes the Ca sensing receptor, found on various tissues throughout the body, less sensitive to Ca. In the parathyroids this means that higher calcium levels are needed to suppress PTH release.