11: Parathyroid disorders Flashcards
Hyperparathyroidism- sx
Painful bones
Renal stones
Abdominal groans
Psychic moans
CV: HTN, short QT interval, LV hypertrophy
Primary hyperparathyroidism- cc
- parathyroid adenoma
- parathyroid hyperplasia
Primary hyperparathyroidism- lab
An elevated PTH level with an elevated ionized serum calcium level is dx of primary hyperparathyroidism
- Low phosphate
- Mild increase in urinary calcium
Primary hyperparathyroidism- imaging
NOT routinely required
- US of the neck
- SPECT with Technetium 99
- CT
- Dual-energy x-ray absorptiometry (DXA): demonstrate the skeletal involvement in primary hyperparathyroidism
Primary parathyroidism- rx
-surgical excision- permanent and curative
-Bisphosphonate (i.e. alendronate): reduce bone loss
Acute hypercalcemia
-IV volume expansion with sodium chloride and loop diuretics (Furosemide) once te IV volume is restored
-Calcitonin and IV bisphosphonate: temporary prior to surgery
2ndary hyperparathyroidism- cc
- Chronic renal insufficiency
- VitD deficiency (osteomalacia with increased fracture and myopathy)
- Calcium malabsorption
2 hyperparathyroidism- lab
- Low-normal calcium and elevated PTH
- Phosphorus: High; renal insufficiency, low; vitD deficiency
- 25-hydroxyvitamin D: less than 20 ng/mL- deficiency
2 hyperparathyroidism; vitD def- rx
Vitamin D-2: 50,000-IU
2 hyperparathyroidism; renal failure- rx
- Dietary phosphate restriction
- Phosphate binders (calcium carbonate, calcium acetate, sevelamer hydrochloride)
- Calcium supplementation should be limited
- vitD and its analogs (calcitriol, paricalcitol)
- Calcimimetics (cinacalcet)
2 hyperparathyroidism; surgical- rx
-Total parathyroidectomy with autotransplantation
2 hyperparathyroidism- Indications for surgery
- Severe bone pain or fracture
- Pruritis
- Calciphylaxis (IV calcification leading to gangrene)
- Extraskeletal nonvascular calcifications
- Development of tertiary hyperparathyroidism
- Hyperphosphatemia
3 parathyroidism- cc
Excessive secretion of parathyroid hormone after longstanding secondary hyperparathyroidism and resulting in hypercalcemia
-Change in the calcium-sensing mechanism to hypercalcemic levels
3 hyperparathyroidism- rx
Total parathyroidectomy with autotransplantation or subtotal parathyroidectomy
Hyperparathyroidism in pregnancy
- Maternal calcium crosses the placenta resulting in chronic suppression of fetal parathyroid glands
- Following delivery, neonatal serum calcium drops and profound **perinatal hypocalcemia ensues
- Function returns in appro. 7-10 days
- Total parathyroidectomy and autotransplantation in mother during the second trimester if possible
MEN 1 (Wermer syndrome)
MEN1 gene mutation
- Parathyroid hyperplasia (MC)
- Pituitary adenoma
- Pancreatic islet cell tumors
MEN 2A
RET gene mutations
- Medullary carcinoma thyroid
- Pheochromocytoma
- Parathyroid hyperplasia/ tumor
Familial hypocalciuric hypercalcemia (FHH)
Dx: calcium-to-creatinine ratio of 99% of renal calcium resorption*
Hyperparathyroidism-Jaw tumor syndrome (HPT-JT_
HRPT2 gene mutation
- Hyperparathyroidism
- Cemento-ossifying fibromas of the jaws
- Wilm’s tumor
1 hypoparathyroidism- Congenital cc
- DiGeorge syndrome/Velocardiofacial syndrome (CATCH22: Cardiac, Abnormal facies, Thymic aplasia, Cleft palate, Hypocalcemia with 22q deletion)
- Kearns-Sayre syndrome: mitochondrial myopathy, ophthalmoplegia, retinal degeneration, cardiac conduction defects, primary hypoparathyroidism
- Barakat syndrome: primary hypoparathyroidism, nerve deafness, steroid-resistant nephrosis
1 hypoparathyroidism- sx
- Chvostek sign
- Trousseau sign
- Prolongation of QT interval
1 hypoparathyroidism- lab
- Hypocalcemia
- Serum albumin (low serum albumin can cause a reduction in the total, NOT the ionized, fraction of the serum calcium)
- PTH low
- Increased phosphate
- Serum magnesium (severe hypomagnesemia-> PTH deficiency-> hypocalcemia: Exclude hypomagnesemia from 1 hypoparathyroidism**)
- Alkaline phosphatase low (increased in pts with osteomalacia and rickets)*
1 hypoparathyroidism- rx
- Calcium administration
- VitD
NOT-> PTH (not approved by FDA)*
2 hypoparathyroidism- cc
- Malignancy*
- Hematological disorders* (MM, Lymphoma, Leukemia)
- Paget’s disease
- VitD toxicity
Pseudohypoparathyroidism (PHP)
GNAS1 gene mutation
-lack of response to PTH
PHP type Ia (Albright’s hereditary osteodystrophy: AHO)
- Hypocalcemia
- Short stature
- Rounded face
- Shortened fourth etacarpals
- Obesity
- Dental hypoplasia
PHP type Ib
- Hypocalcemia
- -only the kidneys affected
Ddx: 1, 2, pseudo- hypoparathyroidism**
1: low concentration of PTH with a low calcium level
2: the serum PTH concentration is low and the serum calcium concentration is elevated
Pseudo: the serum PTH concentration is elevated as a result of resistance to PTH with a low calcium level