Pituitary 1

Question 1

What 2 hormones are released from the Posterior Pituitary?

Answer 1

• Oxytocin
• ADH

Question 2

Where is the pituitary located?

Which cranial nerves?

Answer 2

Sits in sella turcica of sphenoid bone

3, 4, 5, 6

Question 3

Which method of testing is used for majority of tests run on blood?

Answer 3

Venipuncture

Question 4

Describe a 24 hour urine

• Measurement of what 2 things for Pheochromocytoma?

Answer 4

• Discard the first morning void
• Collect for next 24 hours (including void at end of 24 hours)
• Record last voiding time
• Keep urine cool
• If ANY urine is lost, discard entire specimen, begin collection again next day
• Pheo: catecholamines & metabolites

Question 5

What is being measured?

• Hormone w/ longer half life
• NOT bound by proteins
• Measured directly w random test

Answer 5

TSH

Question 6

What is being measured?

• Hormones BOUND to proteins (albumin & binding proteins)

Answer 6

Free & total fractions

Total T4 and Free T4

Question 7

When should cortisol be measured and how?

Answer 7

Blood, perform first venipuncture between 6 am - 8am

(cortisol is highest in the AM)

Question 8

What type of test do you use?

• Hyperfunctioning of gland is suspected
• Pt w/ excess cortisol

Answer 8

Suppression test

• Dexamethasone suppression test (synthetic glucocorticoid)

Question 9

Which test do you use?

• Test for HYPOfunctioning gland
• Pt w/ low cortisol

Answer 9

Stimulation test

• ACTH stimulation test (tests adrenals response to ACTH)

Question 10

What is the most abundant pituitary hormone?

Answer 10

Growth Hormone (GH)

Somatotrope cells

Question 11

GH secretion is controlled by what 2 factors?

Answer 11

• Hypothalamic
• Peripheral

Question 12

What do GHRH and GHIH do?

Answer 12

• GHRH: stimulates GH secretion
• GHIH: (somatostatin) inhibits GH secretion

Question 13

T/F

• GH secretion is pulsatile and is undetectable between pulses

Answer 13

True

Question 14

When is GH at its peak?

Answer 14

Within an hour after the onset of DEEP SLEEP

Question 15

What is produced in the liver after stimulation of GH?

GH stimulates what type of growth in children?

Answer 15

• IGF-1
• linear growth

Question 16

What stimulates growth of epiphyseal plates of long bones?

Answer 16

IGF-1

Question 17

Absence of IGF-1 produces what condition?

Answer 17

Dwarfism (Laron type dwarfism)

Question 18

What are the 3 phases of post-natal growth?

Answer 18

• Infantile
• Childhood
• Pubertal

Question 19

Which post-natal growth phase?

• Rapid growth
• first 2 yrs of life
• 30-35 cm

Answer 19

Infantile phase

Question 20

Which post-natal growth phase?

• Growth is constant (5-7 cm/yr)
• Slight slowing later in childhood “prepubertal dip”

Answer 20

Childhood

Question 21

Which post-natal growth phase?

• Growth spurt of 8-14 cm/yr
• Effects of increasing gonadal steroids/GH secretion

Answer 21

Pubertal Phase

Question 22

Velocity falls to what number when approaching final adult height?

Answer 22

0

Question 23

Definition of what?

◦Variation of normal

◦2 SDs or more below the mean height for children of that sex and chronologic age

Answer 23

Constitutional Short Stature

Question 24

Definition of what?

◦Constitutional short stature in children of short parents

–Child is growing within the parental target range

–Growth curve is consistently at or below the 3-5th percentile

–Growth velocity is typically normal

Answer 24

Genetic Short Stature

Question 25

What are 6 pathologic causes of short stature?

Answer 25

* GH deficiency * IUGR * Infections (rubella, CMV) * Maternal drug/alcohol usage * Genetic syndromes (Turner's syndrome, etc.) * Chronic systemic disease (cancer, cystic fibrosis, renal insufficiency, GI disease) * Psychosocial dwarfism – poor growth associated with emotional and nutritional deprivation

Question 26

What are 3 basic steps to dx short stature

Answer 26

1. H&P 2. IGF-1 levels 3. GH stimulation tests (DEEP SLEEP)

Question 27

What are 4 MC reasons a pt might have _noticeable dysmorphic features / disproportionate short stature?_

Answer 27

1. Chromosomal abnormalities (Trisomy 21/Turners) 2. Intrauterine infections 3. Maternal exposures (toxins, ETOH, smoking) 4. Disproportionate short stature (Skeletal dysplasia or Rickets)

Question 28

What are some "genetic factors" which could lead to short stature? (3)

Answer 28

* Height of relatives * Health problems in family * Hx of early/late puberty in family members

Question 29

**Dx of Short Stature** _Does the child have growth failure?_ * Children should grow __ cm / year from age 2 y/o until onset of puberty * What 2 structures should be x-rayed to compare bone development to height & chronological age? (bone age vs. chronological age)

Answer 29

* 5cm * Hand & wrist

Question 30

A patient's H&P suggests GH deficiency. What is the next step in diagnosing short stature?

Answer 30

**Measure plasma IGF-1 levels** (concentration of IGF-1 reflects concentration of secreted GH) (IGF is stable during the day w/ serum half life of 12-16 hrs)

Question 31

In what 4 circumstances would IGF-1 levels be lowered, but GH is normal?

Answer 31

* Poor nutrition * Hypothyroidism * DM * Renal Failure

Question 32

**Dx of short stature** * What is "GOLD STANDARD" in dx of GH deficiency and is used when IGF-1 is low?

Answer 32

GH stimulation tests (2 types)

Question 33

**Which GH stimulation test?** * Measure serum glucose and serum GH before and 15, 30, 60, 90 and 120 minutes after the injection of insulin

Answer 33

Insulin induced hypoglycemia

Question 34

**Which GH stimulation test?** * Measure serum GH at 0, 30, 60, 90 and 120 minutes

Answer 34

Arginine

Question 35

What should be corrected before doing any GH stimulation tests??

Answer 35

Thyroid deficiency

Question 36

What are 2 hypothalamic causes of GH deficiency?

Answer 36

–Idiopathic ↓ GHRH secretion –Hypothalamic tumors

Question 37

What are pituitary causes of GH deficiency?

Answer 37

**–Pituitary tumors** –Trauma –Surgical removal **–Irradiation** –Idiopathic –Secretion of abnormal GH molecules

Question 38

Psychosocial Dwarfism is due to what?

Answer 38

Severe neglect

Question 39

What is a pharm tx option for GH deficiency in children?

Answer 39

**Humatrope Pen** * Synthetic GHRH (if pituitary capable of producing GH) Depot- 1 - 2 doses/month * 3x/week - daily therapy * Multiple dose pen devices * **MC sub-q administration of Somatropin!**

Question 40

**Growth Hormone Therapy in Children** * Continue therapy until when? * May develop normal GH secretion... * Stimulatory effects of which hormones? * When should GH be retested? * Children w/ what rarely recover GH as an adult?

Answer 40

* Until growth ceases * gonadal steroid hormones * after completion of growth * multiple pituitary hormone deficiencies

Question 41

**Summary of Short Stature Management:** * Get a good H&P!! * FOLLOW growth curves! * If suspicious for pathologic short stature, follow what 4 steps?

Answer 41

1. Obtain bone age w/ wrist x-ray 2. IGF-1 3. Confirm w/ GH stimulation test 4. Refer to pediatric endocrinologist