Term
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Definition
• Calcium level >10.5 is mild, >12 severe
• Always get a corrected calcium or ionized calcium. Low albumin levels will cause a falsely low calcium level. There are calculators for this on Epocrates on mdcalc |
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Term
| Parathyroid disease etiology |
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Definition
• 2 categories of etiology:
1. Parathyroid hormone-dependent
• Primary hyperparathyroidism from benign parathyroid tumor/hyperplasia
• Familial hypocalciuric hypercalcemia (FHH) – calcium sensor defect that is genetic and leads to mild elevated Ca and PTH but low 24hr urine calcium (<0.01)
2. Parathyroid hormone-independent
• Malignancy (breast with bone mets, SCC lung, lymphomas, pheochromocytoma) with PTH-related peptide and low PTH
• Milk-alkali syndrome – pts taking excessive antacids or supplements for osteoporosis
• Excessive vitamin D2 /D3 or A ingestion
• Hyperthyroidism - due to increase in bone turnover
• Immobilization
• Medications – thiazide diuretics |
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Term
| parathyroid disease causes |
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Definition
| • Primary hyperparathyroidism (PHP) and malignancy accounts for 50-90% of all cases |
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Term
| parathyroid disease symptoms |
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Definition
• Mild hypercalcemia usually has no symptoms
• “Stones, bones, (psychiatric) moans, (abdominal) groans with fatigue undertones”
• Polyuria
• EKG changes – shortened QT interval and first degree AV block |
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Term
| parathyroid disease treatment |
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Definition
• Mild hyperCa – find underlying cause
• Ca Level >12 and symptoms, admit for hydration with NS and loop diuretic (Lasix) to enhance Ca excretion. HD if needed
- IV bisphosphonates - reclast or pamidronate particularly in hypercalcemia of malignancy
- Could also try calcitonin |
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Term
| Primary Hyperparathyroidism |
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Definition
• One or more of the parathyroid glands produce an excessive amount of parathyroid hormone
• Occurs in 1% of population
• Women > men by 3:1 ratio
• Most commonly presents after age 45
• 80-85% of cases is due to a
single benign parathyroid adenoma
• 4 gland hyperplasia in 6% of cases
• Parathyroid Cancer 0.5-5% of cases |
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Term
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Definition
Function to increase serum calcium by:
• Increase the level of 1,25 OHD in the kidney which increases absorption of calcium by small intestine
• Increase calcium reabsorption in the kidney in distal convoluted tubule
• Mobilizes calcium from bone via osteoclasts = bone resorption
-When given intermittently (Forteo) it actually leads to increased bone mass via unknown mechanism |
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Term
| Primary Hyperparathyroidism Signs and Symptoms |
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Definition
• Elevated serum Ca
• Elevated intact-PTH
• Normal vitamin D (25OHD) level
• Hypophosphatemia
• Mild symptoms if 10.5-12, more severe >12 • Parathyroid adenoma seen on US
• NM parathyroid scan (Tc-sestamibi)
• Osteopenia/osteoporosis on DXA
• Elevated 24hr urine calcium |
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Term
| Primary Hyperparathyroidism Treatment |
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Definition
Parathyroidectomy by Endocrine surgeon is curative. Need 1 of these to qualify:
• Serum calcium >1.0 ULN
• Osteoporosis on DXA or vertebral fracture
• 24hr urine calcium >400mg/day or nephrolithiasis
• Age <50
- Patientsmayelecttostillhavesurgeryevenif one of these is not met since it is definitive therapy |
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Term
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Definition
• Endocrine surgeon
• Intraoperative parathyroid monitoring
• Minimally invasive
• Localization of adenoma pre-operatively
• Complications:
• Hematoma
- Hungry bone syndrome – profound hypocalcemia requiring IV calcium. Occurs more with multi-gland disease
- Permanent hypoparathyroidism due to devascularization of other glands
- Recurrent laryngeal nerve injury
- Palpation thyroiditis |
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Term
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Definition
• Poor surgical candidates or refuse surgery
• Avoid thiazide diuretics
• Hydration
• Fosamax for osteoporosis
• Cinacalcet (Sensipar) – increases the sensitivity of calcium receptor to calcium thereby decreasing PTH. FDA approved for secondary hyperpara and parathyroid cancer |
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Term
Secondary Hyperparathyroidism
• Caused by 2 factors: |
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Definition
1. Vitamin D deficiency
2. Chronic kidney disease
• Decreased production of 1,25 OHD
• Decreased Phos excretion causing hyperphosphatemia
• Decreased Ca absorption in gut
• Leads to increased PTH levels |
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Term
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Definition
• Nutritional, inert forms = Vitamin D3 (cholecalciferol) and Vitamin D2 (ergocalciferol)
• Active hormonal form = 1,25OHD
• Role is calcium and phosphorus homeostasis
• Vitamin D3 is initially absorbed in the small intestine through food and produced on the skin via UVB rays |
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Term
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Definition
So this is a schematic of the vitamin D synthesis, how it-- so you have the two forms. You have the sun producing some from the skin, and then the diet. And you have the D3. And then you go to the liver, where it gets converted to 25OHD. And that's the part we can measure.
And then you can also go to the kidney. And then you can measure-- and then that will feed back to the parathyroid glands. So I think I wrote that in this slide. Vitamin D metabolism, so I wrote it out in this slide.
So vitamin D3 gets converted to 25OHD in the liver. That's the major circulating form. It's proportional to the cutaneous synthesis and dietary intake. And that's the one that you measure when you do labs.
And then the 25OHD goes to the-- can get converted into the 1,25OHD in the kidney. And then this feeds back to increase the PTH if there's hypocalcemia or decrease if it's hypercalcemia, so another feedback inhibition. And it also hooks onto the calcium and helps get calcium absorbed in the small intestine. So whenever you're replacing calcium, you want to make sure you're replacing the D2, because they kind of go together. |
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Term
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Definition
1. Vitamin D325OHD in the liver. Major circulating form and is proportional to cutaneous synthesis and dietary intake
2. 25OHD1,25OHDinkidney.Thisthenfeeds back to increase PTH if hypocalcemia or decrease PTH if hypercalcemia. Also hooks onto calcium and helps Ca get absorbed in small intestine |
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Term
| Vitamin D Deficiency Causes |
|
Definition
• African Americans > Caucasians and those that live in north > south
• Sunscreen
• Homebound/staying indoors
• Obesity
• Malabsorption– CF, Crohn’s, gastric bypass
• Medications – anticonvulsants, steroids, HAART
• Liver cirrhosis/ESLD
• Nephrotic syndrome
• CKD which causes decreased synthesis of 1,25 OHD
• Rickets – genetic
• Primary hyperparathyroidism – increases conversion of 25OHD to 1,25OHD |
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Term
| Complications of Vitamin D Deficiency |
|
Definition
- Rickets/osteomalcia in children
• Breast-feeding without vitamin D supplements
• Genetic forms
• Malabsorption
- Osteopenia/osteoporosis
• This can lead to fractures and increased morbidity/mortality |
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Term
| Can Vitamin D Impact Other Areas of Overall Health? |
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Definition
• Low levels lead to impaired insulin secretion and insulin resistanceType 2 and Type 1 DM
• Replacement leads to lower BP
• Low levels can contribute to vascular resistance and are seen in more patients with MI, CVA and in patients with DM2, increased carotid artery intima-media thickness
• Replacement boosts immunity
• Higher levels = lower risk of colon CA, prostate CA, and breast CA
• Low levels cause fatigue and muscle weakness |
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Term
| Vitamin D Deficiency Treatment |
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Definition
• Goal 25OHD level is >30
• Only 1 prescription available = ergocalciferol (D2)
- Vitamin D levels 0-15 = 50,000IU weekly x 12 weeks
- 16-20 = 50,000IU weekly x 8 weeks
- 21-25 = 50,000IU weekly x 6 weeks
• Recheck levels in 2-3 months
• Maintenance dose = 2000IU vitamin D3 daily or 50,000-100,000IU D2 monthly |
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Term
|
Definition
• Calcium less than 8.0 with normal albumin
• 4 causes
- PTH deficiency
- Insufficient response to PTH
- Vitamin D deficiency
- Insufficient response to vitamin D |
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Term
| Hypocalcemia Signs and Symptoms |
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Definition
• Tetany: circumoral parasthesias, distal extremity numbness and tingling, carpopedal spasm
- Seen by Chvostek’s sign and Trousseau’s sign
• Confusion, irritability and seizures
• Cardiopulmonary: prolonged QT interval leading to CHF and dysrhythmias
• Laryngeal stridor due to laryngeal spasm |
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Term
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Definition
So this is seen by Chvostek's sign and Trousseau's sign. I have a picture on the next slide. And then they can be confused, irritable. They can eventually progress to seizures. They can have a prolonged QT integral, leading to arrhythmia's.
Laryngeal stridor due to laryngeal spasm is also another scary symptom. And those people can be gasping for air. So this is Trousseau's sign and Chvostek's signs. So Chvostek's sign is when you tap on the facial nerve about two centimeters before the tragus of the ear, and they have ipsilateral muscle contraction on that side.
And then Trousseau's sign is-- which we would never do for a patient-- but you take a blood pressure cuff. And I think you inflate over 20 millimeters over the systolic. And you leave it there for like three minutes, and then you'll see this spasming of the hand. So you'll see this posturing of the hand, which we would never do-- so those signs. |
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Term
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Definition
• Low PTH, low calcium, high Phos
• Surgical following thyroidectomy or parathyroidectomy
- Post op days 1-3 most commonly
- Temporary most common and incidence is 7-37% depending on surgeon
- Permanent is 1-2%
• Polyglandular autoimmune syndrome
• Idiopathic
• DiGeorge syndrome |
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Term
|
Definition
• Decreased End-organ responses to PTH
• Low calcium, high Phos and high PTH
• Type1A:Albright’shereditaryosteodystrophy
- Short metatarsals/metacarpals, short stature, obesity, MR, rounded facies
• Type1B:defectivekidneyresponsetoPTH • Othersareveryrare |
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Term
| Pseudohypoparathyroidism Treatment |
|
Definition
• IV calcium gluconate or chloride if severe
• Calcium carbonate = cheapest - tums. To be absorbed more effectively, take no more than 500mg at a time and with food
• Calcium citrate = better absorbed than carbonate when taking PPI or H2 blocker
• Give calcitriol concurrently between 0.25-0.5mcg po daily
• Thiazide diuretics block calcium excretion and can cause hypercalcemia. Loop diuretics are opposite. |
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Term
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Definition
And this is one of my favorite graphs of all time. I refer to this almost once a week. So it's definitely good to have. So it'll show you exactly where-- so this is your calcium on the x-axis, and then your parathyroid hormone up here.
So if you have a patient with a blood calcium of 11, and their PTH is 100, then you know, right there, you're going in-- you're looking in the primary hyperthyroid range. And then calcium of malignancy, you can see, has a high calcium, but a low PTH. Hypoparathyroidism has a low PTH and a low calcium.
And then this is the normal range. So this is a great-- if you're trying to figure out what's happening, and you need some guidance, this is a great graph. All right, thanks. |
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