Endocrinology Flashcards
What is the function of thyroglobulin?
- Protein found only in the thyroid
- Used to make thyroid hormone
What is the function of thyroxine binding globulin?
TBG is responsible for carrying thyroid hormones in the blood
What is thyroxine?
T4
INACTIVE hormone bound to TBG in the blood
What are the lab findings for Hashimoto’s thyroiditis?
aka, Chronic Lymphocytic Thyroiditis
+ anti-TPO
+ anti-thyroglobulins
Low T4
High TSH
What is a thyroglossal duct cyst?
- 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
What is a ranula?
Painless, mucus and cystic mass usually near the inner lips or under the tongue.
What are the treatment options for Graves’ disease?
Methimazole
Iodine ablation
Beta blocker (propranolol, for symptomatic relief)
Thyroidectomy
PTU (toxic!, but ok to use during pregnancy)
Which form of vitamin D do you check to assess for any nutritional deficiency?
25-Vitamin D level
Which form of vitamin D do you supplement when there is a deficiency?
1,25-Vitamin D
What are the possible causes for the following lab pattern:
Normal (or low) calcium + Low phosphorus?
- 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
What are the possible causes for the following lab pattern:
Low calcium + Low phosphorus?
Severe Vitamin D deficiency: high PTH
What are the possible causes for the following lab pattern:
Low calcium + Normal phosphorus?
Early Vitamin D repletion
What are the possible causes for the following lab pattern:
Low calcium + High phosphorus?
- Hypoparathyroidism (low PTH)
- Phosphorus overload
- Pseudohypoparathyroidism (high PTH)
What are the possible causes for the following lab pattern:
Normal calcium + High phosphorus?
- Renal Disease
- Growth hormone excess
- High phosphorus diet
What are the features of Cushing’s syndrome?
- Hypercortisolism
- Poor growth
- Obesity
- Striae
- Buffalo hump
- Muscle weakness
What are the features of Addison disease?
- 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
What is the treatment for Addison disease?
- Primary adrenal insufficiency: hydrocortisone (replace cortisol) + fludrocortisone (replace aldosterone)
- Secondary adrenal insufficiency: hydrocortisone
What are the layers of the adrenal gland?
GFR; The deeper you go, the sweeter it is
Glomerulosa = aldosterone (salty) Fasiculata = cortisol/glucocorticoids (sweet) Reticularis = androgens (sex steroids)
What are the features of 21-Hydroxylase deficiency?
- 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
What are the features of 11-hydroxylase deficiency?
- Features consistent with congenital adrenal hyperplasia + HTN
- Non-salt wasting -> normal sodium level
What are the features of 17-hydroxylase deficiency?
- Decrease cortisol and sex steroid synthesis
- Increased mineralocorticoid synthesis
- HTN, hypokalemia
What is the default gender for embryos?
Female
What does the regression of Mullerian Ducts create?
Male internal phenotype
What three components are needed to create external male genitalia?
- Y chromosome
- Androgens
- Functional receptors
What causes the regression of female internal structures?
- Y chromosome
2. Mullerian Inhibitor Hormone (MIH)
What are the features of Mullerian Inhibitor Hormone deficiency?
- Normal testes and penis (androgens are present)
- Rudimentary uterus and fallopian tubes
What are the features of Turner syndrome?
"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).”
How do you calculate percent solution of a dextrose solution?
Grams of dextrose per 100 mL water.
D50 = 50% dextrose
50 grams of dextrose in 100 mL of water
What are the features of metabolic syndrome?
- Truncated obesity
- Low HDL
- High LDL
- High BP
- +/- FBG > 100
