Chapter 24- Parathyroid Flashcards
What is the result of using PTH during surgery in the cause of parathyroid carcinoma
Does not go down during or after surgery
In the case of a solitary parathyroid adenoma, what is the effect on the other parathyroid glands
Usually shrunken, because the increased PTH production from the adenoma will cause a feedback and stop production from the other glands
What is the likely diagnosis with:
- Low calcium
- High PTH
-Secondary hyperparathyroidism
What is the pathogenesis of pseudohypoparathyroidism
-Receptors are resistant to PTH, so low levels of calcium even in the presence of high levels of PTH
Where are the parathyroid glands located
4 spots on the back of the thyroid
What are the histological findings in the cause of parathyroid hyperplasia
-Lack of adipocytes without a normal rim of parathyroid tissue
What is the usual histological finding in the cause of a parathyroid adenoma
Abnormal tissue right directly next to normal tissue
Abnormal tissue: will have the secretory Chief cells with a follicular architecture, absence of adipose cells
Normal: Will contain chief cells, oxyphil cells, and Adipocytes
What are the bodily responses to PTH release from the parathyroid glands
- Calcium release from bone
- Vitamin D production in the kidney
- phosphate excretion form the kidney
- Calcium absorption in the gut
What are the clinal presentations of a patient with Digeorge syndome
- Lack of adaptive immunity (no thymus)
- Cardiac abnormalities
- Hypocalcemia (no parathyroids)
What is the major cause of primary hyperparathyroidism
Adenomas (85-95%)
What is the likely diagnosis with:
- Low calcium
- Low PTH
Hypoparathyroidism
What is the scan done to look for a parathyroid adenoma
Technetium scan of the parathyroid gland, where there will be an increased uptake if there is an adenoma
What is the telltale sign used to help differentiate parathyroid carcinoma
Metastasis***
- Also invasion into adjacent tissues
- Vascular invasion
What are the parathyroid tumors seen with mutations in MEN 1
Parathyroid adenomas
What is the meaning of the primary hyperparathyroidism saying renal stone
Nephrolithiasis
What is the meaning of the primary hyperparathyroidism saying psychic moans
- Depression
- weakness/fatigue
- Seuzures
What are the causes of parathyroid hyperplasia
- MEN syndromes can be present
- Secondary hyperplasia is most common *
Pathogensis of sarcoidosis causing hypercalcemia
Increases vitamin d producing, resulting in calcium absorption from the intestines
What are the potential abnormal causes of raised PTH
- Hyperparathyroidism (most likely primary adenoma)
- Familial hypocalciuric hypercalcemia (hyper sensitive calcium sensing receptors)
What are the signs for hypocalcemia
- Muscle cramps and spasms (tetany)
- Trousseau sign (blood pressure cuff induces hand movements)
- Chvostek sign (tapping trigeminal nerve induces a twitch)
What are the causes of secondary hyperparathyroidism
- Renal failure (cant convert to Vit D)
- Vitamin D deficiency
- Pseudohypoparathyroidsm
What are the general findings in osteitis fibrosis cystica
- Starts as a cystic brown tumor***
- Osteoclasts bone destruction
- Small Fractures
- Hemorrhae and reactive tissue
What are the congenital conditions commonly leading to hypoparathyroidism
- Digeorge syndrome
- CASR germline mutations
- Familial isolated hypoparathyroidism
What is the likely diagnosis with:
- High Calcium
- Low PTH
- Humoral hypercalcemia of malignancy
- other PTH independent cause
What is renal osteodystrophy
Dissecting osteitis in secondary hyperparathyroidism, in which loss of bone density
What are the potential abnormal causes of decreased PTH
- Hypercalcemia of malignancy (PTHrP or a PTH analog from a malignancy is being produced)
- Vitamin D toxicity
- Immobilization
- Granulomatous disease (sarcoidosis)
- Thiazide diuretics
When there is hyperparathyroidism due to anything other than a primary cause, what is the end result
Multifocal hyperplasia of the parathyroid glands
What is the pathogensis of familial isolated hypoparathyroidism
Precursor PTH can not become functional, resulting in hypoparathyroidism
What are the causes of tertiary hypocalcemia
Autonomous function of the parathyroud gland due to prolonged hypocalcemia
What are the common causes of local osteolytic hypercalcemia
Breast carcinomas
Myeloma
What are the general causes of symptomatic hypercalcemia
Malignancy***
What is the pathogenesis of local osteolytic hypercalcemia
Release of calcium from bone aka osteoclastic bone resorption
What are the tumors commonly causing PTHrP release
Most common tumor
- Breast
- Lung
- non-Hodgkin lymphoma
What is the product of chief cells in the parathyroid
PTH
What is the likely diagnosis with:
- high calcium
- high PTH
-Primary or tertiary hyperparathyroidism
What is the meaning of the primary hyperparathyroidism saying painful bones
- Osteoporosis
- Osteitis fibrosis cystica
What is the pathogenesis of Digeorge syndrome in development of hypoparathyroidism
-Defects in the 3rd and 4th pharyngeal ouches and the parathyroid glands are missing or underdeveloped
What is the consequence of caciphylaxis
Occlusion of blood vessels that result in ischemia, leading to gangrene and sepsis
What can be monitored during surgery to help predict a successful parathyroidectomy
PTH levels, as their short half life will give an indication in as little as 15 minutes
What are the cell types histologically present in normal parathyroid tissue
- Chief cells
- Oxyophil cells
- Adipocytes
What is a cause of the calciphylaxis
Secondary hyperparathyroidism, especially renal disease
What form of MEN1 is more common
Sporadic, but there is a familial aspect
What is the effect of parathyroid on other parathroid glands
Almost always find parathyroid hyperplasia in multiple glands
How does renal disease cause hyperparathyroidism
Kidneys can not secrete the phosphate, so therefore there is more in the blood, and more must be removed from the bones and absorbed to compensate
How are most osteitis fibrosis cystica cases found
IN the asymptomatic phase
What are the 4 sayings for hyperparathyroidism
- Painful bones
- Renal stone
- Abdominal groans
- Psychic moans
What is the pathogenesis of humoral hypercalcemia of malignancy
Overall are hypoparathyroid conditions:
1-PTH analog PTHrP mediated as it is released from squamous carcinomas
2-Vitamin D mediated as it is released from lymphomas and acts to inhibit PTH release and greatly increases intestinal calcium uptake
What is the classical finding in Renal osteodystrophy
Rugged jersey sign, in which the spinal vertebrae will look less dense than normal with large spaced between them
What is the cardiovascular effect of primary hyperparathyroidism
Heart valve calcification
What is the pathogenesis of CASR germline mutations
Aka familial hypocalcemia hypercalciuria:
- Hypersensitive Calcium receptors (thinks low calcium levels are normal)
- Causes decreased PTH and causes both hypoparathyroidism and hypocalcemia
What is the meaning of the primary hyperparathyroidism saying abdominal groans
- Constipation
- Gallstones
What is the general cause of asymptomatic hypercalcemia
Primary hyperparathyroidism
What is the pathogenesis of calciphylaxis
Sencondary hyperparathyroidism leads to calcification and occlusion of blood vessels that causes ischemia
