Endocrinology

Question 1

What is the function of thyroglobulin?

Answer 1

• Protein found only in the thyroid

- Used to make thyroid hormone

Question 2

What is the function of thyroxine binding globulin?

Answer 2

TBG is responsible for carrying thyroid hormones in the blood

Question 3

What is thyroxine?

Answer 3

T4

INACTIVE hormone bound to TBG in the blood

Question 4

What are the lab findings for Hashimoto’s thyroiditis?

Answer 4

aka, Chronic Lymphocytic Thyroiditis

+ anti-TPO
+ anti-thyroglobulins
Low T4
High TSH

Question 5

What is a thyroglossal duct cyst?

Answer 5

• A midline lesion on the anterior neck
• Half get infected, which increases the chance of recurrence
• Diagnosed with ultrasound and do a thyroid scan to make sure that the cyst does not contain the only functioning thyroid tissue before surgical removal

Question 6

What is a ranula?

Answer 6

Painless, mucus and cystic mass usually near the inner lips or under the tongue.

Question 7

What are the treatment options for Graves’ disease?

Answer 7

Methimazole
Iodine ablation
Beta blocker (propranolol, for symptomatic relief)
Thyroidectomy
PTU (toxic!, but ok to use during pregnancy)

Question 8

Which form of vitamin D do you check to assess for any nutritional deficiency?

Answer 8

25-Vitamin D level

Question 9

Which form of vitamin D do you supplement when there is a deficiency?

Answer 9

1,25-Vitamin D

Question 10

What are the possible causes for the following lab pattern:

Normal (or low) calcium + Low phosphorus?

Answer 10

• Familial hypophosphatemic rickets: (Nml PTH, high alk phos) defect phosphate reabsorption and a defect of the kidney to convert 25-Vit D to 1,25-Vit D
• Early Vitamin D deficiency: high PTH, low 25-Vit D

Question 11

What are the possible causes for the following lab pattern:

Low calcium + Low phosphorus?

Answer 11

Severe Vitamin D deficiency: high PTH

Question 12

What are the possible causes for the following lab pattern:

Low calcium + Normal phosphorus?

Answer 12

Early Vitamin D repletion

Question 13

What are the possible causes for the following lab pattern:

Low calcium + High phosphorus?

Answer 13

• Hypoparathyroidism (low PTH)
• Phosphorus overload
• Pseudohypoparathyroidism (high PTH)

Question 14

What are the possible causes for the following lab pattern:

Normal calcium + High phosphorus?

Answer 14

• Renal Disease
• Growth hormone excess
• High phosphorus diet

Question 15

What are the features of Cushing’s syndrome?

Answer 15

• Hypercortisolism
• Poor growth
• Obesity
• Striae
• Buffalo hump
• Muscle weakness

Question 16

What are the features of Addison disease?

Answer 16

• Adrenal insufficiency
• Low aldosterone, low cortisol
• Weakness, myalgias, malaise, nausea, vomiting
• Hypoglycemia secondary to low cortisol
• High ACTH level-> hyperpigmentation
• ACTH stim test -> no increase in cortisol level
• Secondary adrenal insufficiency:
  
  • Problem with pituitary gland
  • ACTH stim test -> improved cortisol level

Question 17

What is the treatment for Addison disease?

Answer 17

• Primary adrenal insufficiency: hydrocortisone (replace cortisol) + fludrocortisone (replace aldosterone)
• Secondary adrenal insufficiency: hydrocortisone

Question 18

What are the layers of the adrenal gland?

Answer 18

GFR; The deeper you go, the sweeter it is

Glomerulosa = aldosterone (salty)
Fasiculata = cortisol/glucocorticoids (sweet)
Reticularis = androgens (sex steroids)

Question 19

What are the features of 21-Hydroxylase deficiency?

Answer 19

• Autosomal recessive
• If either parent is a known carrier or has the disorder, start dexamethasone to mom until the sex of baby is determined. If male, treatment can stop. If female, continue to prevent female virilization.
• Lack of aldosterone -> salt wasting = hyponatremia, hyperkalemia, NO HTN.
• High 17-hydroxyprogesterone

Question 20

What are the features of 11-hydroxylase deficiency?

Answer 20

• Features consistent with congenital adrenal hyperplasia + HTN
• Non-salt wasting -> normal sodium level

Question 21

What are the features of 17-hydroxylase deficiency?

Answer 21

• Decrease cortisol and sex steroid synthesis
• Increased mineralocorticoid synthesis
• HTN, hypokalemia

Question 22

What is the default gender for embryos?

Answer 22

Female

Question 23

What does the regression of Mullerian Ducts create?

Answer 23

Male internal phenotype

Question 24

What three components are needed to create external male genitalia?

Answer 24

1. Y chromosome
2. Androgens
3. Functional receptors

Question 25

What causes the regression of female internal structures?

Answer 25

1. Y chromosome | 2. Mullerian Inhibitor Hormone (MIH)

Question 26

What are the features of Mullerian Inhibitor Hormone deficiency?

Answer 26

- Normal testes and penis (androgens are present) | - Rudimentary uterus and fallopian tubes

Question 27

What are the features of Turner syndrome?

Answer 27

``` "Tina Turner will SURPASS all other performers despite her tiny little stature." S: short stature U: uterus present R: renal anomalies (horseshoe kidney) P: pedal edema A: amenorrhea S: short 4th and 5th metacarpals S: streak ovaries ``` "Her WEBBED NECK and WIDELY SPACED NIPPLES on top of her BREAST BUDS cover up her COARC'ed AORTA. But she has NO PUBIC HAIR as half of her karyotype is missing (XO)."

Question 28

How do you calculate percent solution of a dextrose solution?

Answer 28

Grams of dextrose per 100 mL water. D50 = 50% dextrose 50 grams of dextrose in 100 mL of water

Question 29

What are the features of metabolic syndrome?

Answer 29

1. Truncated obesity 2. Low HDL 3. High LDL 4. High BP 5. +/- FBG > 100