Endocrinology Flashcards
Features of addison’s disease
Fatigue, weakness, weight loss, mucocutaneous hyperpigmentation, hypoglycaemia, hypovolaemia, low blood pressure, hyponatraemia and hyperkalaemia
Features of NF1
2 out of 7:
Six or more café-au-lait spots or hyperpigmented macules greater than 5 mm in diameter in prepubertal children and greater than 15 mm postpubertal
Axillary or inguinal freckles (>2 freckles)
Two or more typical neurofibromas or one plexiform neurofibroma
Optic nerve glioma
Two or more iris hamartomas (Lisch nodules), often identified only through slit-lamp examination by an ophthalmologist
Sphenoid dysplasia or typical long-bone abnormalities such as pseudarthrosis
First-degree relative (eg, mother, father, sister, brother) with NF1
Common tumours in NF2
Meningiomas, vestibular schwannoma’s (especially bilateral), posterior subcapsular lenticular opacities, neurofibromas
Which NF is associated with which MEN
NF-1 with MEN-2B
What is Sheehan’s syndrome?
Pituitary infarct. Happens in child birth due to large blood loss or extremely low BP during or after childbirth. Leads to decreased cortisol but normal aldosterone.
Order of hormone loss from pituitary due to mass effect
GH, LH, FSH, TSH, ACTH and finally prolactin
Main cause of t3 toxicosis (normal t4)
Autonomous nodule
Test for diabetes insipidus
Fluid supression test - urine will fail to concentrate if have DI
Causes of pseudo-hyponatraemia
Hyperglycaemia, hypertriglyceridaemia and and non-physiological osmolyte - correct these hyponatraemia resolves
Indicators of SIADH
Hyponatraemia
Urine osmol >100mOsm/kg
Urine Na >20mmol/L
Renal AQP2 excretion
Signs suggesting against SIADH
Hypotension and hypovolaemia
Non-osmotic AVP release
Oedema
Adrenal Failure
Management of hypokalaemia
Mild (3-3.4) Sando K 2 tablets TDS
Moderate (2.5-2.9) Sando K 2 tablets QDS
Severe (<2.5) or symptomatic - 40mmol KCL in litre normal saline (max 20mmol/hr). Check Mg and Phos
Barrter’s syndrome -what is it and what effect on serum electrolytes
TAL Na and Cl transport defect - leads to metabolic alkalosis, low K in blood, high Ca in urine
Gitelmans’ syndrome - what is it and what effect on serum electrolyte
Thiazide like effect in DCT NaCl transporter - Metabolic alakalosis and hypokalaemia with low Ca in urine
Effect of cushing’s syndrome on calcium and phosphate levels
Both drop, leading to a secondary hyperpararthyroidism
Effect of secondary hyperparathyroidism on bone
Increased osteoclast activity and osteoblast dysfunction, causing diffuse osteoporosis, bone pain and pathological fractures
Initial management of DKA
1L 0.9% NaCl over an hour, then fixed rate insulin (0.1units/kg/hr)
Other name for Somatomedin C
IGF-1
What do psammoma bodies on thyroid nodule FNA suggest?
Papillary thyroid cancer (have hypochromatic empty nuclei)
Which other hormone is raised by medullary thyroid cancer?
Calcitonin
Which cells are the origin of medullary thyroid cancer?
C-cells
Effect of Addisonal crisis on U&Es
Hyponatraemia and hyperkalaemia (+hypoglycaemia)
Deficiency of which 2 molecules can cause familial hypercholesterolaemia?
Apo B-100 deficiency or LDL receptor deficiency
What is pseudo-hypoparathryoroidism?
Low serum calcium and high phosphate causing PTH to rise
What is pseudopseudo-hypoparathyroidism?
Albright’s heriditary osteodystrophy. Normal lab tests
Effect of secondary adrenal insufficiency on cortisol and aldosterone
Cortisol reduced, aldosterone normal
What percentage of diabetes in the UK is type 1?
10%
Treatment of Graves during first trimester
Propylthiouracil. Avoid carbimazole as teratogenic in first trimester but use after this period
Effect of high dose Dex suppression on Cushing’s disease
Reduction in Cortisol
HbA1c for pre diabetes
Between 42-47
Effect of congenital adrenal hyperplasia on adrenal hormones
Decrease gluco and mineralocorticoids with increased sex steroids
Effect of congenital adrenal hyperplasia on adrenal hormones
Decrease gluco and mineralocorticoids with increased sex steroids (causing penile enlargement in boys and ambiguous sex in girls)
Consequences of thyrotoxic storm if left untreated
Acute congestive HF, shock and death
Main cause of secondary hyperparathyroidism
Chronic renal failure
Blood results in primary hyperparathyroidism
Raised Ca, Raised vit D, raised (or inappropriately normal) PTH and decreased phos
Blood results in secondary hyperparathyroidism
Decreased or normal Ca, decreased Vit D, increased PTH and Inc or dec phos
Blood results in tertiary hyperparathyroidism
High Ca, low vit D, very high PTH and increased phos
What is De Quervain’s thyroiditis?
A subacute, granulomatous thyroiditis. Can cause hyperthyroidism initially progressing to hypothyroidism with destrcution of the thyroid gland. Can finally resolve or persist
Effect of insulin on protein synthesis
Increases protein synthesis in the muscles
Effect of primary hyperparathyroidism on acid-base balance
Mild hyperchloraemic metabolic acidosis
What are Brown tumours?
Cystic lesions in the bone formed of osteoclasts occuring in primary hyperparathyroidism - can result in pathological fractures
Clinical signs of primary hyperparathyroidism
Arcus senilis, reddened conjunctiva due to Ca2+ spilling out (usually lateral and medial effected rather than sup. and inf.). Often have erosion of the terminal phalynx on x-ray as well if long standing
Dietary advice for those with primary hyper parathyroidism
Don’t avoid Ca containing foods as this can make it worse
Which class of tumours are most strongly related with humoral hypercalcemia of malignancy?
Squamous cell carcinomas (multiple organs of origin)
What is the mechanism of humoral hypercalcaemia of malignancy?
Release of PTHrP by tumour cells - acts like PTH in the tissues.
Effect of myeloma on Ca2+ and phos levels
Both can be raised - phosphate raised due to effect of all the Ig secreted by plasma cells on the kidney
Specific treatment of hypercalcaemia in myeloma
Steroids - high doses
ECG sign of hypocalcaemia
Prolonged QTc interval
Most common cause of hypoparathyroidism
Post-surgical (
Mechanism of Albright’s hereditary osteodystrophy
Tissue resistance to PTH (+/- other hormone resistances). Also known as pseudohypoparathyroidism
Which electrolyte must be corrected in order to correct calcium
Magnesium - hypocalcaemia can’t be corrected if hypomagnesaemia
Difference between osteoporosis and osteomalacia
Osteoporosis is normal bone but less of it whereas osteomalacia is decreased concentration of mineral in bone
Difference between pseudohypoparathyroidism and pseudopseudohypoparathyroidism
Both caused by GNAS genes and have same phenotypic appearance but normal lab tests (inc PTH and Ca)
Cause of tertiary hyperparathyroidism
Uncorrected secondary hyperparathyroidism - high Ca. Usually raised phos and low vit D as main cause is Vit D deficiency.
Second line medication in type 2 diabetes for patients with high BMI
DPP-4 inhibitors
When does subacute lymphocytic thyroiditis usually occur?
After pregancy - also known as postpartum thyroiditis. Can present with thyrotoxicosis progressing to hypothyroid
Fasting glucose cut off for diagnosis of T2DM
7mmol/L
2 hour glucose level after 75g glucose cut off for T2DM
11.1mmol/L (also applies for a random sample in patient with classical symptoms of diabetes)
HbA1c cut off for T2DM diagnosis
48 or more
Management of hyponatraemia in SIADH
Fluid restricition - 800ml in 24 hours
Avoid giving fluids as makes worse - all of Na excreted but some of the water retained
Target increase in serum Na in profound hyponatraemia
5-8mmol/L per day
Inheritance pattern of MEN1
Autosomal dominant
Anaplastic thyroid cancer histological appearance
Large pleomorphic giant cells
What type of receptor and pathway does GH act on?
Tyrosine kinase receptor on JAK/STAT pathway
What is reifenstein syndrome?
Male. Partial androgen insensitivity. Present with enlarged breasts and erectile dysfunction
Treatment for MODY
Glucokinase - none
HNF-1a and 4a - low dose sulphonureas
HNF-1b - insulin
Clinical features of MODY
Residual insulin secretion 3 years after diagnosis of type 1 diabetes
Young age of onset
Lack of metabolic syndrome in those with presumed type 2 DM
2 main classes of MODY
Glucokinase and transcription factor
Which MODY is associated with renal cysts/failure?
HNF-1b
Classic triad of Graves disease
Pretibial myxoedema
Thyroid opthalmology
Thyroid acropatchy
