Symptom To Diagnosis - Hypercalcemia

Question 1

Most cases of hypercalcemia are due to only a handful of conditions:

Answer 1

1. Primary hyperparathyroidism.
2. Hypercalcemia of malignancy.
3. Renal failure.
4. Milk-alkali syndrome.

Question 2

Etiology of hypercalcemia - PTH-related:

Answer 2

1. Primary hyperparathyroidism. 2. 2o hyperparathyroidism (due to renal insufficiency and Ca or vitD supplementation). 3. Tertiary hyperparathyroidism. 4. Lithium therapy (10%). 5. FHH.

Question 3

Hypercalcemia of malignancy:

Answer 3

1. Secretion of PTHrP: SCC, adenoCA of lung, pancreas, kidney, others. 2. Osteolytic metastases: Breast, MM. 3. Production of calcitriol: HL.

Question 4

Hypercalcemia related to vitD:

Answer 4

1. Hypervitaminosis D. 2. Granulomatous diseases.

Question 5

Other relatively common causes of hypercalcemia:

Answer 5

1. 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.

Question 6

Primary hyperparathyroidism accounts for more than …% of cases of hypercalcemia in otherwise healthy ambulatory patients.

Answer 6

90%.

Question 7

Nephrolithiasis is seen in …-…% of patients with primary hyperparathyroidism.

Answer 7

15-20%.

Question 8

Other symptoms of primary hyperparathyroidism probably include:

Answer 8

1. Increased frequency of HTN. 2. Gout. 3. Ca pyrophosphate deposition disease.

Question 9

Besides hypercalcemia, are other effects of PTH (HypoPh, hypercalciuria, hyperphosphaturia) useful in differentiating primary hyperparathyroidism from hypercalcemia of malignancy?

Answer 9

Seldom useful.

Question 10

About …% of patients with primary hyperparathyroidism have normal PTH levels (a finding that is in fact inappropriate given the hypercalcemia).

Answer 10

10%. FHH must be excluded.

Question 11

Indications for surgery:

Answer 11

1. 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.

Question 12

Primary hyperparathyroidism - Monitoring for patients not undergoing surgery:

Answer 12

1. 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.

Question 13

Other than primary hyperparathyroidism - DDX of hypercalcemia with elevated PTH:

Answer 13

1. Lithium use. 2. MEN. 3. 2o or 3o hyperparathyroidism. 4. FHH.

Question 14

FHH - Textbook presentation:

Answer 14

1. 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.

Question 15

FHH - Pathogenesis:

Answer 15

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.

Question 16

3 important features to distinguish FHH from primary hyperparathyroidism:

Answer 16

1. Family history. 2. Urinary Ca excretion is reduced (400). 3. Serum Mg is usually increased in FHH. –> Genetic testing is available when the diagnosis is difficult to make.

Question 17

Hypercalcemia of malignancy - Is it common for hypercalcemia to be the presenting symptom of a malignancy?

Answer 17

NO.

Question 18

Prognosis of hypercalcemia of malignancy:

Answer 18

50% 30-day mortality.

Question 19

MCC of hypercalcemia of malignancy?

Answer 19

PTHrP –> Called humoral hypercalcemia of malignancy (HHM).

Question 20

What is the rarest cause of hypercalcemia of malignancy?

Answer 20

Hypercalcemia by elaboration of vitD - Seen most commonly with lymphoma.

Question 21

Malignancies that commonly associated with hypercalcemia are in approximate order of frequency?

Answer 21

1. Lung. 2. Breast. 3. MM. 4. Lymphoma. 5. Head/Neck. 6. Renal. 7. Prostate.

Question 22

MM - Symptoms at presentation as reported in a recent study:

Answer 22

73% –> Anemia, normocytic, normochromic. 67% –> Lytic lesions on radiograph. 58% –> Bone pain. 19% –> Renal insufficiency. 13% –> Hypercalcemia >11.

Question 23

MM - M component:

Answer 23

82% –> Abnormal serum protein electrophoresis. M component most commonly appears in the gamma range and is most commonly IgG. 16% –> Have only free light chains.

Question 24

The diagnosis of MM is based on the identification of:

Answer 24

1. Marrow plasmacytosis (>10%). 2. Lytic bone lesions. 3. A serum or urine M component or both.

Question 25

Milk-Alkali syndrome - Textbook presentation:

Answer 25

There can be many presentations of the milk-alkali syndrome. Acute cases are often seen in women who can use calcium carbonate for dyspepsia or osteoporosis who develop hypercalcemia.

Question 26

What is the milk-alkali syndrome?

Answer 26

1. Hypercalcemia. 2. Metabolic alkalosis. 3. Renal insufficiency. caused by the absorption of calcium and an absorbable alkali.

Question 27

Is the milk-alkali syndrome a common cause of hypercalcemia?

Answer 27

It is a distant 3rd among the leading causes of hypercalcemia in HOSPITALIZED patients, after malignancy and primary hyperparathyroidism.

Question 28

Hypercalcemia is detected in 1 of 3 clinical circumstances:

Answer 28

1. During routine lab work-ups in asymptomatic patients (most cases). 2. During evaluation of patients with certain findings that suggest hypercalcemia (constipation, weakness, fatigue, depression, nephrolithiasis, osteopenia). 3. Severe hypercalcemia may present as altered mental status.