Endocrinology8-2 Flashcards
Light microscopy of a liver biopsy shows: (1) spotty hepatocyte necrosis & (2) inflammatory cell infiltration. The sample was taken from a patient who had just returned from a trip to Mexico. What is the most likely diagnosis?
Hepatitis A
Hallmarks of acute viral Hepatitis: (1) hepatocye injury/”ballooning degeneration” (2) hepatocyte death/”bridging necrosis”
Recent travel to an endemic country + histological signs of acute viral hepatitis=Hep A
What serum molecule(s) is believed to increase insulin resistance in overweight individuals?
- Free fatty acids (FFA)
- Triglycerides (TG)
List two common causes of hyperosmotic volume contraction.
- diabetes insipidus
- profuse sweating
Preferred acute treatment for diabetic ketoacidosis.
Regular insulin IV
Diagnosis:
Your patient has N/V & abdominal pain. He is found to be hypotensive and tachycardic on physical exam. Urine analysis indicates ketones and glucose in the urine.
Diabetic ketoacidosis
This patient most likely has T1DM. Acute treatment is regular insulin.
Diagnosis:
Glucagonoma
Markedly elevated glucagon levels
Diagnosis:
Your patient is a 50-year-old male with a 6 month history of decreased libido and headaches. PE reveals: (1) bitermporal hemaniopsia & (2) ophthalmoplegia.
pituitary apoplexy (pituitary hemorrhage)
Often associated with a pre-existing adenoma (Prolactinoma: suggested by the headaches and decreased libido). The patients are a great risk for cardiovascular collapse due to adrenocortical deficiency. Treatement: glucocorticoids
Clinical Manifestation:
Glucagonoma
- Necrolytic migratory erythema: coalescing erythematous lesions, with bronze indurations in the center
- Diabetes mellitus
- Anemia
Diagnosis:
Fine-needle aspiration cytology shows: (1) Numerous intranuclear inclusion bodies (2) intranuclear grooves & (3) cells with large nuclei and sparse, finely dispersed chromatin.
Papillary carcinoma
Papillary carcinoma is the most common type of thyroid cancer. Psammoma bodies may aslo be detected.
Name that Drug!
Rapid-acting insulins (15 minutes until peak)
Short-acting insulin (30 minutes until peak)
intermediate acting insulin (4-12 hours until peak)
Long acting insulin (3-9 hours until peak)
insulin analog (No peak; lasts 24 hours)
Rapid-acting insulins: (1) Aspart (2) lispro (3) glulisine
Short-acting insulin: Regular insulin
Intermediate acting insulin: NPH
Long acting insulin: Detemir
Insulin analog: Glargine
What is the most common genotype that causes Klinefelter syndrome?
47XXY
46XY/47XXY mosaicism & 48XXXY are possible but less common.
Clinical Manifestation:
Klinefelter Syndrome
- Primary testicular failure: (1) Small, firm testes, (2) azoospermia, (3)infertility, (4) testosterone deficiency, (5) increased FSH and LH (6) cryptorchidism
- Eunuchoid body habitus: tall, sparse facial and body hair, gynecomastia, decreased muscle mass
- Intellectual disability: most are mild or normal, my have psychosocial abnormalities (i.e. lack of insight, poor judgement)
Age range at which a diagnosis of Klinefelter Syndrome is often made
Teenage years
Pathogenesis:
Klinefelter Syndrome
meiotic non-disjunction during meiosis I
Pathogenesis:
Secondary hyperparathyroidism due to ESRD
- Renal dysfunction prevents the production of 1,25 vitamin D (active form)
- In the absence of active vitamin D, the serum Ca2+ is low
- In response to low serum Ca2+, PTH levels increase
Where does the conversion from calicidiol (25VitD) to calcitriol (1,25VitD) occur?
Kidney
The kidneys are responsible for producing active vitamin D.
How would you expect the hypothalamic-pituitary-gonadal axis to be affected by a prolactinoma in a male?
GnRH –> Decreased due to Prl
LH –> Decreased due to Prl decreasing the GnRH
Testosterone –> Decreased b/c there is no LH
Secreting prolactinomas inhibit the entire axis of GnRH-LH/FSH-sex hormones
Clinical Manifestation:
Prolactinoma (Pituitary tumor) in a male
- bitemporal hemianopsia
- impotence
Often detected late because men do not experience galactorrhea or amenorrhea. Tumor is usually large.
Clinical Manifestation:
Prolactinoma (Pituitary tumor) in a female of reproductive age
- bitemporal hemianopsia
- amenorrhea
- galactorrhea
- infertility (due to elevated Prl supressing GnRH)
Clinical Manifestation:
Prolactinoma (Pituitary tumor) in a post-menopausal women
- bitemporal hemianopsia
- headaches
These women are already infertile and amenorrheic.
How does anorexia affect the the HPA axis for gonadotropic hormones?
Axis becomes hypogonadotropic (Decrease in LH, FSH and Estradiol)
Which GLUT transporter is the only transporter that is responsive to insulin concentrations?
GLUT-4
Structure:
Location of GLUT-4 receptors
skeletal tissue and adipocytes
Which domain of a GPCR contains 20 hydrophobic amino acids? What is the function of this domain?
The alpha-helical segments are the hydrophobic transmemebrane components of a GPCR. This domain integrates the GPCR into the cell membrane.
Which anti-hyperlipidemic drugs increase the risk of gallstone precipitation when combined together?
Fibrates (gemfibrozil) and bile acid-binding resins (cholestyramine)
What is the most effective lipid-lowering drug for primary and secondary prevention of cardiovascular events, regardless of baseline lipid levels?
HMG-CoA reductase inhibitors (statins)
Diagnosis:
Nests of polygonal cells with Congo red-positive deposits
Medullary carcinoma of the thyroid gland
Medullary thyroid cancer arises from neoplastic parafollicular C-cells. The cells secrete calcitonin which forms extracellular amyloid deposits.
What is the relationship between glucagon and insulin?
Insulin will decrease the secretion of glucagon.
Insulin brings glucose into the cells. This decreases the hypoglycemic message that stimulates glucagon secretion.
How does glucagon affect ketone body production?
Glucagon stimulates (1) ketone body production. It also stimulates (2) glycogenolysis (3) gluconeogenesis & (4) lipolysis.
What is the most important determinant of insulin resistance?
Visceral obesity/waist-to-hip ratio
Mechanism of Action:
Finasteride
(5 alpha reductase inhibitor): Prevents the peripheral conversion of testosterone to dihydrotestosterone.
Finasteride can be used to treat (1) BPH & (2) androgenetic alopecia
Clinical Manifestation:
Late-stage hemochromatosis/”bronze diabetes”
Classic triad: (1) skin hyperpigmentation (2) diabetes mellitus (3) hepatomegaly
How does primary hyperparathyroidism manifest in the skeletal system?
It manifests as osteitis fibrosa cystica.
(1) bone pain (2) subperiosteal erosions (3) “salt-and-pepper” skull (4) brown tumor bone cyts
Pathogenesis:
amenorrhea in a patient with anorexia nervosa
- Patients eating disorder results in low body fat
- low body fat causes pulsatile GnRH secretion to end
- the pituitary is no longer stimulated to release FSH and LH
- estrogen levels remain low
Function:
Thiazolidinediones (TZDs)
lower blood glucose by decreasing insulin resistance
Mechanism of action:
Thiazolidinediones (TZDs)
- Activate PPAR-_
- PPAR-_ alters the transcirption of genes that metabolize glucose and lipids (i.e. adiponectin)
- glucose is lowered
