Endocrinology

Question 1

Acromegaly 
Path:
Pt:
Dx:
Tx:

Answer 1

Path: Somatotropinoma-> Growth hormone secreting pituitary adenoma

Pt: Acromegaly in adults (gigantism in children)
DM and glucose interlace

Dx:
Screening test= Inc insulin-like growth factor
Confirmatory test= oral glucose suppression test: inc growth hormone levels
MRI-> pituitary tumor

Tx:
Transsphenoidal surgery (TSS)
Bromocriptine: dopamine agonist dec growth hormone production
Octreotide: somatostatin analogue that inhibits GH secretion; S/E: diarrhea, cholecystitis

Question 2

Adrenal insufficiency 
Path:
Pt:
Dx:
Tx:

Answer 2

Path:
Primary (Addison’s disease)- destruction of adrenal gland-> lack of cortisol, aldosterone, and sex hormones
Secondary- deficient ACTH from pituitary-> lack of cortisol (aldosterone & RASS intact)
-Glucocorticoid cessation- esp w/ prolonged use and abrupt cessation
-Hypopituitarism (rare)

Pt:
Low cortisol:
weakness, myalgias, fatigue, weight/appetite loss, N/V/D, abdominal pain, headaches, sweats, irregular periods
Mild hyponatremia, salt craving, hypotension, hypoglycemia
Primary only (dec aldo and sex hormones, inc ACTH)
-Hyperpigmentation-> inc ATCH stimulation of melanocytes
-Dec aldo: orthostatic hypotension, hyponatremia, hyperkalemia, non-anion gap acidosis, hypoglycemia, dec BUN
-Dec sex hormones: dec libido, amenorrhea, loss of axillary and public hair

Dx:
-Cosyntropin (ACTH) stimulation test- screening for adrenal insufficiency, little/no inc cortisol-> adrenal insufficiency
-CRH stimulation test- differentiates etiologies
Primary/Addisons (Adrenal)- inc ACTH levels and dec cortisol
Secondary (pituitary)- dec ACTH and dec cortisol (pituitary can’t produce enough ACTH)

Tx:
Hormone replacement
Addisons-> glucocorticoids + mineralocorticoids
Synthetic glucocorticoids: hydrocortisone (1st line), prednisone, dexamethasone
Synthetic mineralocorticoid: fludrocortisone (aldosterone)
Secondary-> only glucocorticoids

Question 3

Cushing Disease
Path:
Pt:
Dx:
Tx:

Answer 3

Path: ACTH-secreting pituitary tumor

Pt: amenorrhea, central obesity, depressive symptoms, and easy bruising
bitemporal hemianopsia (pituitary adenoma)
PE: purple striae, moon face (facial adiposity), buffalo hump (increased adipose tissue in the neck and upper back), and hypertension

Dx: 24 hr urine cortisol and testing ACTH levels

Tx: transsphenoidal removal

Question 4

Diabetes insipidus 
Path:
Pt:
Dx:
Tx:

Answer 4

Path: 
ADH deficiency (central DI)-> dec release of ADH -> Idiopathic MC, autoimmune destruction of posterior pituitary, head trauma, tumor, infection, sarcoid granuloma 

Insensitivity to ADH (nephrogenic DI)-> resistance to ADH at level of kidneys
Inability of the kidney to concentrate urine-> large amount of dilute urine
Drugs: lithium, amp B, demeclocycline
Hypercalcemia & hypokalemia
Acute tubular necrosis
Hyperparathyroidism

Pt:
Polyuria, polydipsia, nocturia
Hypernatremia
dehydration, hypotension, rapid vascular collapse

Dx:
Fluid deprivation test: established dx of DI
Normal response-> progressive urine concentration
DI-> continued production of dilute urine (low urine osm in the setting of inc serum osm)

Desmopressin (ADH) suppression tests: differentiates nephrogenic from central
Central-> reduction in urine output indicating a response to ADH
Nephrogenic-> continued production of dilute urine (no response to ADH)

Tx:
Central
-Desmopressin/DDAVP
-Carbamazepine

Nephrogenic

• Low solute diet
• HCTZ
• Indomethacin

Hypotonic fluid
-D5W, 1/2 NS

Question 5

Diabetes- type I
Path:
Pt:
Dx:
Tx:

Answer 5

Path: complete destruction beta islet cells of pancreas

Pt: polydipsia, polyphagia, polyuria, weight loss, blurry vision

Dx: C-peptide: endogenous insulin production (will be very low in type 1)
GAD antibodies: attack islet cells (will be elevated in type 1)
-Symptoms + random plasma glucose >/= 200
-Fasting plasma glucose >/= 126 on 2 separate occasions
-Plasma glucose >200 2 hours after a 75g glucose load during oral glucose tolerance test

Tx: insulin, carb counting

Question 6

Diabetes- type II
Path:
Pt:
Dx:

Answer 6

Path: Abnormal carbohydrate metabolism

Pt:polydipsia, polyphagia, polyuria, weight loss, blurry vision

Dx:

• Symptoms + random plasma glucose >/= 200
• Fasting plasma glucose >/= 126 on 2 separate occasions
• Plasma glucose >200 2 hours after a 75g glucose load during oral glucose tolerance test
• HgA1c >/= 6.5% (adults only)