Endocrine Disorders

Question 1

Revise negative feedback control of the hypothalamic-pituitary axis

Answer 1

hypothalamus = TRH = + production on pituitary = + production of TSH = + production of T4 /T3 on thyroid gland
high t4/t3 = inhibitory effect on TRH & TSH

Question 2

Describe disorders of the thyroid gland - hyper- and hypothyroidism and understand how laboratory tests of thyroid hormones can diagnose these conditions

Answer 2

PER: Graves Disease
PO: Hashimotos

Question 2

Describe disorders of the adrenal cortex

Answer 2

glomerulosa = mineralocorticoids
fasciculata = glucocorticoids
reticularis = adreno androgens

Cushings = XS cortisol

Conns = XS aldosterone (1*) overactivation of RAAS or adrenal adernoma (distal efferent = increase ECF = increase blood vol and pressure = increase b.p) increased K+ EXCRETION = hypokalaemia
- measure aldosterone levels
- measure renin: aldosterone ratio

Addisons = LOW cortisol

Question 3

Understand the laboratory tests that can aid differential diagnosis of disorders involving adrenal steroid excess (e.g., Cushing’s syndrome)

Answer 3

• 24 hour urine cortisol test
• dexamethasone test
• synacthen test (ADDISONS)

Question 4

Understand the laboratory tests that can aid differential diagnosis of disorders involving adrenal steroid deficit (e.g., Addison’s disease)

Answer 4

• adrenal insuffiency (low ADH) = osmolarity
  absence of - feedback it will cause inapporpriate increase ADH conc
  SYMPTOMS:
  N/L Na+ = moderate/hypotension from decreased blood volume from decreased H2O retention from decreased Na+
  hyperpigmentation from increased ACTH (prolonged melanocyte stimulation)
  N/H K+