Endocrine disease (Parathyroid glands) Flashcards
(19 cards)
- What is the embryologic origin of parathyroid gland?
Third and fourth pharyngeal pouches
- What 2 types of cells in Parathyroid gland and hormones that it secretes?
i. Chief Cells (secrete Parathyroid Hormone)
ii. Oxyphil Cells (unknown function)
- What is the function of parathyroid hormone?
i. It is an important regulator of blood calcium levels.
ii. Stimulate the synthesis, secretion and release of PTH.
- Parathyroid hormone release is not affected by pituitary or hypothalamic stimulation.
- What are 4 physiologic effects of parathyroid hormone?
i. Increase calcium reabsorption at renal tubules
ii. Increase urinary phosphate excretion
iii. Increase renal conversion of vitamin D into its active form»_space; Increased gastrointestinal calcium absorption
iv. Increase osteoclastic activity, which releases calcium from the bones
- What is the net effect of parathyroid hormone?
Increases calcium in the blood, which feeds back to inhibit further parathyroid hormone secretion
- What is the difference between primary and secondary hyperparathyroidism?
Primary : Autonomous spontaneous overproduction of PTH
Secondary : Secondary phenomenon in patients with chronic renal failure
- What causes primary hyperparathyroidism?
i. Parathyroid Hyperplasia (multiglandular) or
ii. Adenoma (solitary)
- What is the prevalence of hyperparathyroidism in population?
This is common disorder in adults, particularly more common in women (4:1).
- What are 4 constellation symptoms reported by patients with hyperparathyroidism?
i. “Painful bones” (fractures associated with osteoporosis)
ii. “Renal stones” (kidney stones, which are frequently seen in patients)
iii. “Abdominal Groans” (constipation, peptic ulcers and gallstones common)
iv. “Psychic moans” (refers to depression, lethargy and seizures)
- What are other symptoms or constitutional symptoms reported by patients with hyperparathyroidism?
i. Weakness and fatigue
ii. Brown tumor with ground glass appearance in the jaw
iii. Metastatic calcifications
iv. Deposition of calcium throughout the body, including blood vessels
- because calcification can occur in blood vessels, blood tests are done to detect clinically silent hyperparathyroidism.
- What is the organ that is most commonly affected by secondary hyperparathyroidism?
Kidney (results in renal failure)
- Secondary hyperparathyroidism is associated with renal failure. What condition results as a result of renal failure?
Hyperphosphatemia (because of increased amounts of phosphate in the blood due to decreased excretion by the kidney)
- How does hyperplasia of parathyroid gland occurs with secondary hyperparathyroidism?
Renal failure > Hyperphosphatemia > Stimulates PTH production (this leads to parathyroid gland hyperplasia)
- How does renal failure affect production of parathyroid hormone?
When a patient has renal failure, damaged kidney is unable to produce Vitamin D. Absence of Vitamin D reduces calcium absorption in the intestine, which is necessary for stimulating the production of parathyroid hormone.
- For patients with secondary hyperparathyroidism, how is their blood calcium level?
The blood calcium level remains unaffected. (This is most likely due to multiple mechanisms that are in place by the body to maintain blood calcium level)
- What is Renal Osteodystrophy?
This is associated with secondary hyperparathyroidism and is characterized by bone mineralization deficiency.
- How would you treat secondary parathyroidism?
i. Surgical removal of hyperplastic parathyroid glands
ii. Kidney transplantation (may be beneficial)
- What are causes of hypoparathyroidism?
i. Surgical removal of parathyroid gland
ii. Auto-immune disease
iii. DiGeorge’s Syndrome (congenital absence)
* S A D(iGeorge)
- What are 4 clinical manifestations of hypoparathyroidism?
i. Cardiac arrhythmias
ii. Hypocalcemia
iii. Increased : a. Neuromuscular excitability
b. Intracranial pressure and seizures
