Hypercalcemia, Hyperparathyroidism and other Imbalances Flashcards
90% of cases of hypercalcemia are caused by what? 2
Hyperparathyroidism and malignancy
Etiologies of Hypercalcemia:
- Primary HPT causes what?
- Malignancy causes what?
Primary HPT*
1. Increase bone resorption
Usually small elevations in calcium
Malignancy*
2. Occurs w/ solid tumors and leukemia’s
Calcium values are high
In nonmetastatic solid tumors secretion of PTHrP
Milk-Alkali syndrome?
What does it cause?
High intake of milk or calcium carbonate
Metabolic alkalosis stimulates Ca2+ reabsorption
Medications that cause hypercalcemia?
6
- Lithium (increased secretion PTH)
- Thiazide diuretics (lower urinary Ca2+ excretion)
- Thyroid hormone
- Estrogens and progesterones
- Hypervitaminosis A
- Hypervitaminosis D (increase calcitriol)
Pseudohypercalcemia is what?
What causes this? 5
Elevation in total Ca2+, but not ionized, more bound calcium
- Thyrotoxicosis
- Pheochromocytoma
- Adrenal insufficiency
4, Islet cell tumors of the pancreas - Elevated platelet count
Manifestations of Hypercalcemia?
4
“bones, stones, abdominal pain and psychic overtones”
Bones: c/o bone pain and muscle weakness
Stones: nephrolithiasis
Abdominal pain: constipation, nausea, anorexia
Psychic: anxiety, depression and cognitive dysfunction
Clinical Presentation of Hypercalcemia:
Renal? 2
CV? 3
Musculoseletal? 1
CNS? 1
Renal:
Polydipsia
Polyuria
CV:
Bradycardia
Shortening of the QT interval
Varying arrhythmias
Muscle weakness
CNS depression
Work -Up for hypercalcemia:
First thing to do?
(what can make this a false elevation? 3)
Normal calcium level?
What do we get after the serum calcium level?
(normal?)
Elevated Ca2+ found on a asymptomatic patient what do we need to know?
How do we do the calcium correction for abnormal albumen levels?
What is usually slightly decreased in hypercalcemia?
What is increased?
(why?)
WHat do we have to rule out?
What is the last thing we check?
2
Serum Calcium level:
1. Artificially elevated if tourniquet left on too long or if
2. patient dehydrated
Can be artificially increased by
3. elevated albumin or decreased if albumin is decreased
Normal: 8.2-10.2 mg/dL
Ionized calcium:
50% of calcium in this form
Changed by blood pH**
Normal: 1.15-1.35 mg/dL
Need to know albumin!
Correction for abnormal albumen level: Corrected Ca = 7.6 + (0.8 x ( 4.5- alb))
For example measured values:
7.6mg/dL (Ca2+)
2.5g/dL (albumen)
Corrected Ca2+ = 7.6 + (0.8 x (4.5 -2.5)) = 9.2
Phosphate usually slightly decreased
ALP may be slightly increased (liver and bone are getting turned over)
R/O thyroid dysfunction
Check PTH level and if normal check PTHrP
How do we confirm elevated Ca2 levels?
Confirm elevated Ca2+ with two readings with albumin
When will a calcium be be low in a 24 hr urine sample?
- Milk -alkali syndrome
- Thiazide diuretic use
- Familial hypocalciuric hypercalcemia
Treatment of hypercalcemia?
Depends on etiology
Treating the underlying etiology will correct the hypercalcemia
How do we treat a hypercalcemic crisis?
3
1. Saline diuresis: Ca2+ > 14mg/dL Pt usually dehydrated Infuse 250-500 mL/hr of saline to rehydrate 2. Give IV synthetic calcitonin 3. Give IV bisphosphonates: Maximum effect 2-4 days Zoledronic acid or pamidronate
Etiologies of Primary Hyperparathyroidism (HPT)?
3
Parathyroid adenoma: 80%
Hyperplasia: 15%
Parathyroid carcinoma: less than 5%
s
s
Parathyroid Carcinoma
is rare. How does it present?
4
Presentation:
- Mean Ca2+ concentration: 14.6-15.9. Elevated
- Neck mass: 34-52%
- Bone disease: 34-73%
- Renal disease: 32-70 %
Two criteria diagnosing PT cancer
- Local invasion of contiguous structures
2. Lymph node or metastatic spread
What is the primary method of treatment for parathyroid cancer?
There is three outcome with this treatment. What are they?
- Surgery primary method of treatment
Chemo and radiation not very helpful
Three outcomes:
1/3 patients cured at surgery
1/3 recur and may be cured w/ reoperation
1/3 short, aggressive course
If not surgically treatable manage hypercalcemia
Presentation of Primary HPT
3
- Hypercalcemia (asymptomatic)
- PTH-mediated bone resorption:
- CV affects
HPT PTH-mediated bone resorption causes what?
2
- Decreased bone mineral density (BMD)
2. Increased risk of vertebral fractures (fractures you dont see on other ppl)
CV affects of HPT?
2
- HTN
2. Left ventricular hypertrophy/diastolic dysfunction
Secondary HPT
due to malignancy etiologies? 7
Workup?
Etiologies:
- multiple myeloma,
- lung,
- kidney,
- esophagus,
- head and neck,
- breast and skin
- bladder cancers
are some of the more common
Work-up: PTHrH
Chronic to advanced renal disease of HPT findings in the lab?
3
- hypocalcemia/hyperphosphatemia
- Cr/BUN elevated
- PTH increased
Workup for HPT
(whats the most important one?)
5
- Intact PTH: normal 10-50 pg/mL*****
- Serum Creatinine: assess renal function
- Bone-specific alkaline phosphate: assess bone turn-over
- calcitriol: vitamin D metabolites—suppressed in hypercalcemia: normal 1.5 pmol/L
- Bone density measurement (DEXA-scan)
Where is a DEXA-scan usually used to find fractures in HPT?
3
Used to measure bone density of the
- femoral neck,
- lumbar spine and
- wrist
Management of Primary HPT
1
Patients w/ sx or progressive disease: surgical treatment
General surgeons usually, although ENT also can do the surgery
Dont treat if they dont have symptoms
Surgery for PHPT:
What is really important before we do the surgery?
Three imaging studies we do?
Preoperative localization: (not to dx)
Use technetium-99m-sestamibi schintigraphy w/ SPECT imaging
Ultrasonography
CT scan or MRI
Used prior to minimally invasive parathyroidectomy (MIP)
Used if 1st surgery unsuccessful and need to do more extensive procedure or locate ectopic tissue