Endocrinology Flashcards
granulomatous inflammation of tender thyroid what disease?
Subacute (de Quervain’s) granulomatous thyroiditis
bone path 2ary to hyperPTH?
osteitis fibrosa cystica -resporption of bone leading to fibrosis and cystic spaces
3 disease associated with phaeochromocytoma
- MEN 2A/B
- VHL disease
- NF type 1
what boney cell type does PTH activate?
osteoblasts - which then themselves activate osteoclasts and secrete Alk Phos
head trauma precipitating central DI
what is the difference in lesion to hypothalamus and posterior pituitary?
hypothalamus - permanent loss of ADHergic neurons, permanent disease
posterior pit - ADHergic neruons will regenerate after some time and disease will remit
what is the receptor implicated in familial hypocalciuric hypercalaemia?
GPCR - calcium-sensing receptor (CaSR)
Ca binding CaSR inhibits PTH release
‘scalloping’ of colloid suggests what?
graves disease
what is the treatment for post-thyroidectomy hypoPTH?
calcitriol
not calcidiol because it requires conversion under control of PTH
what arrhythmia occurs with hyperT4?
atrial fib esp in elderly
epidemiology of Reidel fibrosing thyroiditis
young female
Rx graves disease
- beta-blockers 2. thioamide 3. radioiodine ablation
how does cortisol affect the immune system?
inhibits phospholipase A2
inhibits IL-2
inhibits mast cell degranulation
what thyroid neoplasm?
Follicular adenoma
benign proliferation of follicles surrounded by fibrous capsule
in CAH with 17 hydroxylase deficiency, what hormones are not made?
cortisol and sex steroids
natural history of de Quervain thyroiditis?
self-limiting rarely (15%) progress to hypothyroidism
metabolic effects of hyperT4?
hypocholesterolaemia hyperglycaemia
what is the mechanism and side effects of biguanides?
metformin
binds to AMPK to decrease glucose production and insulin resistance
lactic acidosis - so contraindicated in renal insufficiency
chronic inflammation and extensive fibrosis of the thyroid on biopsy what disease?
Reidel fibrosing thyroiditis
what is sevelamer?
phosphate-binding polymer that reduces absorption of phosphate in the GI tract
used for hyperphosphataemia in CKD
anterior neck mass of thyroid origin?
thyroglossal duct cyst
symptoms of phaeochromocytoma? (5)
headaches, episodic HTN, palpitations, tachycardia and diaphoresis
phaeochromocytoma rule of 10 (4)
- 10% extramedullary
- 10% malignant
- 10% familial
- 10% bilateral
what is the major side effect of GLP-1 analogues?
pancreatitis
modest weight loss :)
follicular adeoma malignant or benign?
benign
common metformin toxicity?
lactic acidosis
what is the mechanism for fibrate drugs?
fenofibrate, gemfibrozil
activating PPAR-alpha, increases lipoprotein lipase
Rx cushing syndrome
surgical resection if tumour
medical - ketokonazole or metyrapone
how does cortisol impact blood pressure?
cortisol increases expression of alpha1-adrenoceptors, which are vasoconstrictive
in CAH with 11 hydroxylase deficiency, what hormones are not made?
strong mineralocorticoids and cortisol
so you get clitoral enlargement/precocious puberty but HTN with hypokalaemia.
low renin and aldosterone (b/c pregnenolone being shunted to DHEA and DOC)
‘hard as wood’, nontender thyroid suggests what disease?
Reidel fibrosing thyroiditis
thyroid biopsy shows chronic inflammation with formation of germinal centres
hashimoto thyroiditis
MEN1 neoplasms
pancreatic endocrine tumour
parathyroid hyperplasia
pituitary adenoma
which thyroid CA?
anaplastic CA
very undifferentiated tumour not really making any structures
1 common and 2 uncommon causes of primary hyperPTH
parathyroid adenoma
sporadic parathyroid hyperplasia and parathyroid carcinoma
decreased glucose
increased insulin
increased c-peptide
what pathology?
insulinoma
always check for MEN1!
two aetiologies of nephrogenic DI
inherited mutations drugs - lithium, demeclocycline (antibiotic)
arrhythmia, hyperthermia, vomiting and hypovolaemic shock … diagnosis?
thyroid storm
symptoms of cholinergic crisis?
- salivation
- lacrimation
- urination
- defactation
(SLUD)
what is Winter formula?
when is it used?
PaCO2 = (1.5 * HCO3-) + 8 +/- 2
expected compensatory range for PaCO2 in metabolic acidosis
in DKA is PaCO2 is above the range this indicates a degree of respiratory failure (pulmonary oedema, respiratoy fatigue or decreased GCS)
perioral tingling, muscle spasm, Trousseu and Chvostek signs … eventually seizures.
lab findings?
causes? (4)
- hypocalcaemia
causes - damage to parathyroids (iatrogenic/autoimmune), tumour lysis syndrome, severe vitamin D deficiency, sepsis
mental retardation, short stature, coarse facial features, umbilical hernia, enlarged tongue diagnosis?
cretinism
what is the side effect of PTU?
agranulocytosis
how to tell the difference between ACTH from pit adenoma or paraneoplastic ACTH?
dex suppression test - will reduce ACTH from pit adenoma but not from paraneoplastic source
three layers of adrenal cortex
glomerulosa, fasiculata, reticularis
watery diarrhoea
hypokalaemia
achlorhydria
what pathology?
VIPoma
what are the classes of antihyperlipidaemic drugs and how do they work?
- statins - HMG-CoA reducase inhibitor. stop hepatic synthesis of cholesterol
- ezetemibe - block intestinal absorption through NPC1L1 transporter, increase hepatic cholesterol production, decease serum LDL
- Niacin, fish oil, fibrates - block hepatic production of triglycerides and conversion of VLDL to LDL
- PCSK1 inhibitor - block internalisation of LDL receptor, increasing hepatic clearance of LDL
- bile acid-binding resins - induce bile acid wasting, increase hepatic comsuption of cholesterol in regeneration of bile acids, decrease serum LDL
what is cinacalcet? indication?
‘calcimimetic’ - activates Ca-sensing receptor in parathyroids, decreasing PTH
indicated in 2ary hypercalcaemia (CKD)
walk through - CRF leading to secondary hyperPTH and renal osteodystrophy
renal failure, unable to excrete phosphate
increase serum Pi binds free Ca2+
decrease Ca++ stimulates PTH (all four glands)
PTH stimulates boney resorption
Lab findings: ++ PTH, - Ca2+, ++ Alk Phos, ++ Pi
what thyroid neoplasm with ionizing radiation during childhood?
papillary carcinoma
prognosis of papillary CA?
excellent
serum glucose definition in HONC?
why are ketones absent?
>500 mg/dL
small amount of circulating insulin prevents ketogenesis
what changes in FBC when starting steroids?
neutrophilia
neutrophil demargination from lung vasculature
increased urine cAMP suggests what pathology?
hyperPTH
what thyroid CA? what feature helps distinguish this?
medullary CA
local deposition of amyloid (malignant cells in amyloid stroma)
what muscle and nerve can be damaged in thyroidectomy (caudal end)
muscles - intrinsic muscles of the larynx, except cricothyroid
nerve - recurrent laryngeal
R laryngeal runs in close proximity to inferior thyroid artery, which must be ligated in total thyroidectomy
what drugs can lead to SIADH (3)?
carbamazepine
cyclophosphamide
SSRIs
Rx SIADH?
water restriction demeclocycline (blocks effect of ADH)
four thyroid neoplasms?
- papillary
- anaplastic
- medullary
- follicular
decrease 131-I uptake suggests…
adenoma or carcinoma warrants FNA biopsy