Parathyroid Gland Pathology Flashcards
What do the chief cells of the PT gland produce?
PTH
Is there fat in the thyroid?
No
Is there fat in the parathyroid?
Yes - increases with age
What is the function of PTH?
Increases the levels of free Ca2+ in the blood
What are the effects of PTH?
- Activates osteoclasts
- Increased renal Ca2+ reabsorption
- Increased conversion to active Vitamin D
- Decreases Pi
What is the most common cause of hypercalcemia that is clinically apparent?
Malignancy
What is the most common cause of incidental hypercalcemia?
Hyperparathyroidism
What gender is mainly affected by Primary Hyperparathyroidism?
Females
Parathyroid Adenoma
- Almost always solitary
- Increased radionuclide uptake
- Encapsulated lesion
Parathyroid Hyperplasia
Usually multiple glands and can be diffuse or nodular
Parathyroid Carcinoma
Infiltrate adjacent structures
What are the clinical manifestations of primary hyperparathyroidism?
“Painful bones, renal stones, abdominal groans and psychic moans”
What is the most common cause of secondary hyperparathyroidism?
Renal Failure
Tertiary Hyperparathyrooidism
Autonomous hyperparathyroidism with symptomatic hypercalcemia
Hypoparathyroidism
Decreased PTH and hypocalcemia
What are the features of hypoparathyroidism?
- Tetany
- Numbness
- Parathesia
- Seizures
- Laryngospasm
Chvostek Sign
Contraction of facial muscles from tapping facial nerve
Trousseau Sign
Carpal spasms from occlusion of blood in the forearm by a BP cuff
Pseudohypoparathyroidism
Normal PTH with hypocalcemia due to end organ resistance.
A 38-year-old man sees his physician because of abdominal pain, nausea, and constipation for the past 3 days. On physical examination he has no palpable abdominal masses and bowel sounds are present. His lungs are clear to auscultation. He has a heart rate of 80 with an irregular rhythm. An EKG demonstrates a shortened QT(corrected) interval and a prolonged PR interval. He has a stool positive for occult blood. Upper GI
endoscopy reveals multiple 1 cm diameter shallow ulcerations of the gastric antrum. Which of the following laboratory test findings is most likely to be present in this man?
A) Thyroid peroxidase antibody of 4 IU/mL
B) Serum calcium of 12.4 mg/dL (ref 8.5 -10.5 mg/dl)
C) Blood glucose of 225 mg/dL (ref 70- 100 mg/dl)
D) Total serum thyroxine of 21 ug/dL (ref 5-11 ug/dl)
E) Plasma cortisol of 45 ug/dL at 8 am (ref 4-22 ug/dl)
B) Serum calcium of 12.4 mg/dL (ref 8.5 -10.5 mg/dl)
A 50 year old man diagnosed with papillary thyroid carcinoma underwent total thyroidectomy. Within a few hours of surgery the patient complained of tingling of his fingers.
Which of the following laboratory tests should be ordered to direct further therapy for this patient.
A. serum TSH
B. serum parathormone
C. serum ionized calcium
D. serum Total T4
C. serum ionized calcium
