Week 14 Endocrine System Diseases

Question 1

Endocrine organs discussed

Answer 1

hypothalamus
pituitary
thyroid
parathyroid
adrenal gland

Question 2

Hypothalamus/Pituitary diseases

Answer 2

Diabetes Insipidus
SIADH (syndrome of inappropriate ADH secretion
Sheehan Syndrome

Question 3

Adrenal Gland diseases

Answer 3

Addison Disease
Cushing Syndrome
Pheochromocytoma

Question 4

Thyroid diseases

Answer 4

Goiter
Thyroiditis
Graves Disease

Question 5

Parathyroid diseases

Answer 5

Osteomalacia
Hypercalcemia

Question 6

Interactions b/t Hypothalamus and Pituitary

Answer 6

Hypothalamus
- Releasing hormones act on adenohypophysis
-Neurohypophysis is the end of neurons that are in the hypothalamus
Neurohypophysis (posterior pituitary)
- Diabetes Insipidus decrease
- SIADH increase
Adenohypophysis (anterior pituitary)
- Adenomas increase
- Sheehan syndrome decrease
- regulation here is through the blood
- hypothalamus–> blood–> cells in anterior pituitary (acidophils/basophils)

Question 7

What is Diabetes Insipidus?

Answer 7

Deficient ADH (anti-diuretic hormone) production
- by the neurohypophysis
- results in excess water excretion
- serum Na+ and osmolarity increase b/c amount of H2O in blood serum has decreased

Question 8

What is diabetes insipidus caused by?

Answer 8

head trauma, tumors, inflammation of hypothalamus/pituitary

Question 9

What are the 2 types of DI?

Answer 9

Central DI–> insufficient ADH
Nephrogenic DI–> ADH insensitivity
* ADH acts on kidneys to increase H2O absorption, so even if you are producing ADH, kidneys are no longer sensitive to it and you still get excess H2O secretion

Question 10

What are the clinical symptoms of central diabetes insipidus?

Answer 10

-frequent urination
- extreme thirst
- can cause life-threatening dehydration

Question 11

What are the treatments of CDI?

Answer 11

Mild CDI
- drink more water to make up for what is lost
More severe
- Vasopressin (exogenous ADH) can be prescribed
* will only work for central DI b/c in nephrogenic DI, excess ADH would not work b/c kidneys are insensitive to it

Question 12

What is SIADH?

Answer 12

Syndrome of Inappropriate ADH Secretion
- inappropriate b/c sometimes it is NOT the pituitary secreting the ADH; coming from wrong place
- most frequently by ADH-secreting tumors like SCLC (small cell lung cancer)
- also certain drugs, CNS disorders
Excess ADH
- excessive water resorption
- dilutes blood–> hyponatremia

Question 13

What are does SIADH look like clinically?

Answer 13

• Hyponatremia
• Cerebral edema–> blood volume does not change, so no peripheral edema
• Neurologic dysfunction (think water intoxication)
  * due to cerebral edema

Question 14

Treatment for SIADH

Answer 14

Address underlying cause
- if caused by a drug, stop administering the drug; use alternate drug
- if it is a tumor, try to treat the tumor

Question 15

Water Intoxication slide from week 8

Answer 15

Water poisoning/ fatal hypernatremia
- urine excretion can be increased to 16ml/min when large quantities of hypotonic fluid are ingested
- if ingestion exceeds this or continues for too long, cells will swell due to water uptake to cope with hypotonic ECF
Symptoms:
- swelling of CNS neurons
- convulsions, coma (can kill)

Question 16

What is Sheehan Syndrome?

Answer 16

• During pregnancy, anterior pituitary (where FSH and LH are produced) undergoes hypertrophy
  * will nearly double in size
• Hormones of pregnancy
  * Progesterone produced by corpus luteum
  - blocks development of additional follicles
  - HCG stimulates production
  * LH and Prolactin–> adenohypophysis
  - support function of the corpus luteum
  - prolactin inhibits GnRH release; inhibited by estrogen and progesterone until parturition
  - prolactin release stimulated by estrogen

Question 17

Ischemic necrosis of the adenohypophysis

Answer 17

• excessive cell numbers w/out increased blood flow causes minor anoxia
• more sensitive to low blood pressure
  * hypovolemic shock due to hemorrhage
  * infarct will develop in anterior pituitary
  * necrosis leading to fibrosis

Question 18

Symptoms of sheehan

Answer 18

Ischemic tissue is replaced by fibrotic nodule, which causes Postpartum Hypopituitarism
Symptoms include:
- amenorrhea
- infertility
- lactation failure
- hypothyroidism
- pallor (loss of melanocyte stimulation

Question 19

Treatment for Sheehan syndrome

Answer 19

Try to replace the hormones

Question 20

Adrenal Hormones

Answer 20

• Released into nearby blood vessels
• Steroid hormones in the cortex
• Peptide hormones (catecholamines) in the medulla
  * release induced by nerve signal

Question 21

Overview of diseases of Adrenal Gland

Answer 21

Addison Disease
- primary chronic adrenocortical insufficiency
Cushing Syndrome
- aka hypercortisolism
- exogenous and endogenous causes
Pheochromocytoma
- medullary tumor

Question 22

What is Addison disease?

Answer 22

Progressive destruction of the adrenal cortex
- 60-70%: autoimmune adrenalitis
- Infections: tuberculosis or fungal
- AIDS
- Metastatic cancer
Gross appearance of gland varies
- Autoimmune: shrunken
- Infection: inflammatory reaction
- Cancer: enlarged with tumor