CC Hypercalcemia

echoecho's version from 2016-08-23 02:00


Question Answer
Serum calcium levels are tightly controlled in a narrow range, but serum calcium levels are NOT an accurate reflection of total body calcium stores, true or false?true
Serum levels represent about ___ % to _____% of extracellular calcium, which in turn is only ___% of total body calcium?0.1; 0.2; 1
The vast majority of calcium is located in the ______?bones
About ____% of serum calcium is NOT bound to circulating proteins and is metabolically active (ionized calcium)?40
As a result, albumin levels affect serum calcium levels, true or false?true
Serum calcium levels are INCREASED when serum albumin levels _______ (increase vs. decrease) for any reason?decrease
Every 1 mg/dL reduction in serum albumin is associated with a ______0.8 mg/dL increase in serum calcium?increase
In cases where albumin levels are ABNORMAL, measurement of ______ calcium is another option for assessing calcium status?ionized
Calcium metabolism is regulated by the actions of what hormone?parathyroid hormone (PTH)
Explain what PTH does?1) it increases bone resorption 2) increases renal calcium reabsorption 3) increases the conversion of 25-OH vit D to 1,25 dihydroxy vit D which promotes gastrointestinal absorption of calcium 4) all these lead to circulating levels of calcium
Once serum calcium levels are normal, secretion of PTH ______ ?decreases
GI absorption of calcium occurs in what 2 ways?1) vit D dependent manner 2) vit D-independent manner
Calcium resorption in the kidney primarily occurs via what?passive reabsorption in the proximal tubule due to a sodium gradient; a minor amount is reabsorbed in the distal convoluted tubule
Signs and symptoms of hypercalcemia have been described as what?"stones", "bones", "abdominal groans", "thrones", and "psychiatric overtones"
List the medical conditions under "stones"?1) nephrolithiasis 2) nephrocalcinosis 3) nephrogenic diabetes insipidus
List the medical conditions under "bones"?1) osteoporosis 2) osteomalacia 3) osteitis fibrosa cystica
List the medical conditions under "abdominal groans"?1) constipation 2) indigestion 3) nausea 4) vomiting 5) acute pancreatitis
List the medical conditions under "thrones"?polyuria
List the medical conditions under "psychiatric overtones"?1) lethargy 2) fatigue 3) depression 4) memory loss 5) delirium 6) ataxia
*** Hyperparathyroidism and malignancy combined account for _____% ot ____% of all cases of hypercalcemia?80; 90
What is the cause for the majority of cases of asymptomatic hyperparathyroidism?hyperparathyroidism
What are the causes of hyperparathyroidism?1) most commonly caused by a benign adenoma of a single gland, but it may also be genetic or part of the MEN (multiple endocrine neoplasia) syndrome
Most cases of hyperthyroidism are ______, although secondary and tertiary forms also exist?primary
List the mechanisms of hypercalcemia in malignancy?1) direct invasion 2) destruction of bone (breast cancer, multiple myeloma) 3) production of factors that stimulate osteoclastic activity and increased production of 1,25-dihydroxy vit D (calcitriol)[Hodgkin's lymphoma)
Is hypercalcemia a poor prognostic sign in a patient with malignancy?yes
List other potential causes of hypercalcemia?1) vit D excess (usually due to excessive intake of calcitriol) 2) familial hypocalciuric hypercalcemia (a rare autosomal dse characterized by excessive resorption of calcium from the renal tubules) 3) prolonged immobilization 4) thyrotoxicosis 5) total parenteral nutrition (TPN) 6) sarcoidosis
List the drugs that can also induce hypercalcemia?1) thiazide diurectics 2) estrogen 3) androgens 4) vitamin A 5) lithium
The diagnostic approach to a patient with hypercalcemia begins with a serum _____ ?PTH
What will the above diagnostic approach differentiate between?PTH-mediated hypercalcemia (primary and familial hypercalcemias) FROM non-PTH-mediated hypercalcemia (malignancy, vit D intoxication, granulomatous disease)
In the face of elevated serum levels of calcium, the PTH should be _______?suppressed
In hyperparathyroidism, the PTH is usually elevated, although 10-20% of patients will have levels in the _____ normal range? Is this inappropriately elevated?1)high 2) yes
PTH-related protein is elevated in patients with what?malignancy
Measurement is usually not necessary when the malignancy is already know, true or false?true
When is vitamin D metabolites helpful?if there is no known malignancy and both PTH and PTH-related protein are normal
If primary hyperparathyroidism is suspected, what scan may be helpful in locating the enlarged gland?nuclear medicine sestamibi scan
What definitive treatment of hyperparathyroidism? indicated in what type of patientsurgical and indicated in symptomatic patients
*** Indications for surgery in ASYMPTOMATIC patients include what?1) calcium level > 1.0 mg/dL above the upper limit of normal 2) age < 50 years 3) creatinine clearance < 60 mL/min/1.73m2 4) osteoporosis (diagnosed either via a T-score < 2.5 or a hx of fragility fracture)
Serum alkaline phosphatase may be elevated when hypercalcemia is the result of what? What can be used to identify the metastatic lesions?1) rapid bone turnover from invasive disease 2) bone scan
What lab tests are useful in dx of multiple myeloma?1) urine protein electrophoesis 2) SPEP
True or false? a review of meds may also identify a potential causative agent?true
Urinary calcium excretion should be _____ in the face of hypercalcemia? If it is ______, it may suggest familial hypocalciuric hypercalcemia?1) elevated 2) suppressed
*** Treatment for acute s/s of hypercalcemia?aggressive fluid hydration using IV normal saline
What type of patients may the above treatment be challenging?heart failure or renal failure patients
Once a pt has adequate fluid status, what can be given to block sodium exchange in the kidney and reduce the drive to reabsorb calcium?1) loop diuretics like furosemide (Lasix)
If patients fail to respond to the above treatments, what may be required?IV bisphosphonate therapy (either with pamidronate (Aredia), zoledronic acid (Reclast), if INCREASED osteoclastic activity is the underlying cause
How long does bisphosphonate therapy usually take to be effective?several days
Comment on calcitonin?it is a less effective option but may play a role in patients with contraindications to biphosphonates
What should be used if elevated calcitriol is the etiology (e.g. sarcoidosis or lymphoma)?oral glucocorticoids
Recent studies suggest what medication in patients who are UNRESPONSIVE to bisphosphonate therapy?monoclonal antibodies (like denosumab (Prolia)
*** SUMMARY = How is calcium homeostasis controlled?1) PTH 2) bone calcium 3) kidney excretion 4) resorption 5) vitamin D
*** SUMMARY = What two conditions account for the majority of cases of hypercalcemia?1) malignancy 2) hyperparathyroidism
*** SUMMARY = List the symptoms of hypercalcemia?1) renal colic 2) bone pain 3) abdominal discomfort 4) polyuria 5) neuropsychiatric manifestation
*** SUMMARY = How is acute symptomatic hypercalcemia treated?1) aggressive fluid hydration FOLLOWED by 2) a loop directive 3) addition of medications like biphosphonates may be considered if necessary to achieve control