Endocrine (inc MCQBank) Flashcards
What is HBA1c?
Glycosylation of N-terminal valine of B-chain haemoglobin
What is the equation of plasma osmolarity?
2Na + 2K + glucose + urea
Normal is 285-295mOsm/L
What is congenital adrenal hyperplasia?
Autosomal recessive
21-hydroxylase deficiency - results in deficient of cortisol +/- aldosterone and excess androgens
Clinical features:
- females are virilised at birth and post-pubertal amenorrhoea is common
- hyperpigmentation
- adrenal crisis
- life threatening hypoglycaemia
Tx: hydrocortisone and fludroccortisone
What is Chvostek sign?
facial muscle contraction upon tapping on the facial nerve
- associated with hypocalcaemia (causes reduced threshold for neurone to transmit a signal - hence causing hyperexcitement of nerve)
What is the Trousseau’s sign?
carpopedal spasm after compression of upper arm by blood pressure cuff
What is Frey’s syndrome?
facial sweating during meals
occurs post paratidectomy
Drug causes
- hypercalcaemia
- hypocalcaemia
HYPER: thiazide, lithium, antacids, vitamin D (>50000units per day OR 1250mcg)
HYPO: calcium chelators (citrate in blood transfusion), bone resorption inhibitors (bisphosphonate, calcitonin), drugs affecting vitamin D (phenytoin, ketonazole), foscarnet
Diagnosis for low calcium AND:
- raised phosphate + reduced PTH
- raised phosphate + raised PTH
- low phosphate + raised PTH
- low magnesium, hypoparathyroidism, drugs (cinacalcet)
- CKD, massive tumour lysis, early rhabdomyolysis
- vitamin D deficiency, acute pancreatitis, drugs (bsiphosphonates)
What is anion gap?
(Na + K) - (HCO3 + Cl)
Normal is 12-17mmol/L
High anion gap: bicarb reduced due to increased acid
Low anion gap:
HBA1c should not be done for these patients as it would create inaccurate reading:
<18y/o
pregnant lady and 2months post-partum
symptoms of diabetes <2 months
acutely ill
steroids
acute pancreatic damage
ESRD
HIV
Sheehan VS Kallman syndrome
Sheehan: postpartum hypopituitarism or postpartum pituitary necrosis due to blood loss/hypovolaemic shock
Kallman: delayed puberty or absent puberty with loss of smell - hypogonadotrophic hypogonadism
What is milk-alkali syndrome?
Hypercalcaemia + renal failure + metabolic alkalosis
3rd common cause of hypercalcaemia
- due to taking calcium carbonate medication/calcium/vitamin D medications (>50000units per day)
What diseases are associated with hypothyroidism?
PBC
Turner’s syndrome (20-50%)
Down’s syndrome (10-40%)
cystic fibrosis
POEMs syndrome (polyneuropathy, organomegaly, endocrinopathy, m-protein band from plasmacytoma & skin pigmentation/tethering)
What cut-off values to diagnose diabetes?
SYMPTOMATIC
Fasting >=7
Random >=11.1
HBa1c >=48 (6.5%)
ASYMPTOMATIC
2 separate occasions of one of the above (pick & mix)
What are the cut-off values for:
- impaired glucose tolerance
- impaired fasting glucose
- pre-diabetes
IFG : fasting 6.1-6.9
IGT: fasting <7 AND 2hr post drink: 7.8-11.1
Pre-diabetes: HbA1c 6-6.4%
What is a thyroid storm?
Hyperthyroid Crisis
presents as confusion, congestive heart failure, volume depletion, n&v, extreme agitation.
Tx: intensive care with the aim to cool patient, correct volume status, respiratory support and treat underlying sepsis (if applicable for any of them). Anti-thyroid medication, corticosteroids, beta-blockers, iodine solution (Lugol’s or SSKI saturated solution of potassium iodide) should be given
Most common cause of subclinical hypothyroidism
Chronic autoimmune thyroiditis
PS: always check the TFT 3 months to confirm. If TSH>10, positive antibodies, previously tx Grave’s or other autoimmune disease, prescribe levothyroxine.
What is the most common cause of SIADH? And what are the other causes?
Idiopathic - most common cause!
Cancer: lung, pancreas, thymoma, ovary, lymphoma
Respiratoty: tumour, pneumonia, COPD, lung abscess, TB, CF
CNS: tumour, trauma, infection, stroke, subarachnoid haemorrhage, GBS, MS, delirium tremens
Drugs: NSAIDs, nicotine, diuretics, chlorpropamide, carbamezepine, TCA, SSRI, vincristine,
Surgery: post-op
Muscle pain, fatigue, polyuria, polydipsia. K 2.5, renin 1.0ng/ml/hr (normal is 1.9-3.7)
?diagnosis
Conn’s syndrome
- also 2x more common in women
- presents in 3rd to 6th decade of life
The most common cause of hyperaldosteronism
Conn’s syndrome (60%)
idiopathic OR bilateral adrenal hyperplasia (40%)
What tests need to be done if BM < 2.8
serum insulin
C-peptide
proinsulin
ethanol
beta-hydroxybutyrate
LFT
U&E
Insulin secretagogues (eg sulfonylureas)
Drugs that causes diabetes
Steroids
Thiazide
What drugs causes hypokalaemia?
Loop diuretic
steroids
Causes of:
- hypothyroidism
- hyperthyroidism
Hypo
- Hashimoto’s
- Atrophic thyroiditis
- Riedel’s thyroiditis
- Post-total thyroidectomy
- silent lymphocytic thyroiditis (occur in post-partum period)
Hyper
- Grave’s
- Toxic multinodular goitre (Plummer disease)
- Toxic adenoma
- Subacute thyroiditis
Diabetes + arthralgia/cirrhosis + skin pigmentation
?diagnosis
haemochromatosis
Grave’s VS toxic multinodular goitre
Grave: has exopthalmos/opthalmopathy
radioactive iodine uptake will show diffuse uptake
Toxic multinodular goitre:
radioactive iodine uptake will show solitary or regional uptake
What is Plummer’s disease
toxic multinodular goitre
second most common cause of hyperthyroidism in the west
what other diseases are associated with phaeochromocytoma?
MENIIa, MENIIb, neurofibromatosis, VHL disease
examples of short-acting insulin
highly purified animal sourced
- soluble insulin (hypurin)
human sequencedt
- actrapid
- humulin s
- insuman rapid
human insulin analogues
- aspart (novorapid)
- glulisine (apidra)
- lispro (humalog)
causes of hypoglycaemia
EXPLAIN mnemonic
EXogenous drugs (insulin, oral hypoglycaemics, alcohol binge, aspirin, quinine, pentamidine)
Pituitary insufficiency
Liver failure
Addison’s disease
Islet cell tumours (insulinoma)
Non-pancreatic neoplasms (retroperitoneal fibrosarcomas due to IGF-1 secretion)
treatment of idiopathic axillary hyperhidrosis
Topical:
- aluminium chloride hexahydrate - 1st line topical
- iontophoresis
- botulinum toxin
- topical anticholinergics
systemic: anticholinergics, calcium channel blockers/
surgical: sympathectomy, surgical excision, subcutaneous liposuction, laser
Multiple Endocrine Neoplasia
1, 2a, 2b
1 (Wermer Syndrome) - high PTH, pancreatic cancer, pituitary cancer
2a (Sipple Syndrome) - HTN, high Ca, low Mg -> high PTH
2b (Wagenmann-Froboese syndrome) - medullary thyroid cancer, pheochromocytoma, medullary thyroid cancer, MARFANOID, mucosal neuromas
what diabetic drug should not be used for patient with heart failure?
pioglitazone
if HbA1c is still high and patient is on metformin, what drugs must be added on?
sulphonylurea (eg gliclazide)
pioglitazone
DPP-IV inhibitor
Antibodies for:
Grave’s
Hashimoto’s thyroiditis
Grave: TSH-receptor, thyroid stimulating immunoglobulin (TSI), thyroid peroxidase (75%)
Hashimoto: thyroid peroxidase, thyroglobulin
Congenital adrenal hyperplasia - what is it?
autosomal recessive disease
2 forms:
- classic/severe (deficient in cortisol with or without aldosterone deficiency and androgen excess) -> present as females with ambiguous genitalia or after 1-2weeks of life with acute salt-losing crisis with vomit, weight loss, hyponatraemia, hyperkalaemia
- milder (sufficient cortisol but high androgen) -> precocious puberty if male and if female, amenorrhoea, virilisation, hirsuitism, acne, male-pattern baldness
what thyroid problem is caused by excessive alcohol?
hypothyroidism caused by chronic excessive alcohol consumption
what is the criteria for referral for parathyroid surgery?
any one of the following:
- adj ca >2.85
- end organ disease (renal stones, fragility fractures, osteoporosis)
- symptoms of high calcium
what is metyrapone used for?
what is phenoxybenzamine used for?
diagnose and treat cushing’s syndrome
it reduces the amount of aldosterone and cortisol in the body
treat phaeochromocytoma
what is a thyrotoxic storm?
fever >38.5, tachycardia, coma, delirium, vomit, diarrhoea, jaundice
relationship between metanephrine and catecholamine
metanephrine is the breakdown of catecholamine
?diagnosis - swelling adjacent to thyroid gland. no change in voice. sweating at night. weight loss. swelling in groin and left axilla.
Lymphoma
? diagnosis - swelling adjacent to thyroid. euthyroid.
Papillary carcinoma of thyroid
? diagnosis - swelling over lobe of thyroid. clinically euthyroid. 2 opacities over the right upper lobe of lung.
Follicular carcinoma of thyroid
- solitary, encapsulated, invades vein and bone
- common in areas with low iodine intake
- more likely to metastasis to lungs
? diagnosis - woody, hard swelling in right lobe of thyroid. change of voice. swelling is enlarging.
Anaplastic cancer of thyroid
- most aggressive neoplasms
- more common in women and elderly
- stridor from tracheal deviation, dysphagia from oesophageal involvement and recurrent laryngeal nerve palsy are all common
- poor prognosis
what is waterhouse-friederichsen syndrome?
disease of adrenal glands most commonly caused by neisseria meningitidis.
- leads to massive haemorrhage into one or both adrenal glands.
- characterised by bacterial meningococcaemia, low BP, shock, DIC with widespread purpura and adrenocortical deficiency
calcium binding is pH dependent. explain the concentration of free calcium in alkalotic VS acidotic environment
alkalotic (ie less H+ and more HCO3-): calcium binds to more negative charged HCO3 & less concentration of free calcium
acidotic (ie more H+ and less HCO3-): calcium binds less & more concentration of free calcium
what drugs can cause hypercalcaemia
thiazide
lithium
Pseudohypoparathyroidism
PTH resistance
TSH - T3/4 - ?what condition
raised - low - ?1
raised - normal - ?2
raised/normal - raised - ?3
low/normal - low - ?4
low - normal - ?5
low - raised - ?6
- hypothyroidism, chronic autoimmune thyroiditis, post radioiodine, post thyroidectomy, transient thyroiditis - hypothyroid phase
- subclinical hypothyroidism
- TSH-secreting pituitary tumour
- non-thyroidal illness, recent treatment for hyperthyroidism
- subclinical hyperthyroidism
- primary hyperthyroidism, Grave’s, multinodular goitre, toxic nodule
most common thyroid cancer
papillary cancer
- women, 30-40yo & also in children
- irregular solid or cystic mass that can spread to cervical lymph nodes
primary hyperparathyroidism
secondary hyperparathyroidism
tertiary hyperparathyroidism
PTH, Ca, phosphate, vit D, ALP
primary: high/N, high, low, high, N
(due to adenoma of parathyroid gland)
secondary: high, low/N, high, low, high
(in response to hypocalcaemia - seen in chronic renal failure)
tertiary: very high, high, low, low, high
(after prolonged secondary hyperPTH)
Primary hypoparathyroidism
Secondary hypoparathyroidism
Pseudohypoparathyroidism
PTH, Ca, phosphate, ALP
Primary: low, low, high, N
(due to excision via surgery)
Secondary: low, high, high, N
(in response to primary process that causes hypercalcaemia)
Pseudo: high, low, high, N
(failure of ccells to respond to PTH - autosomal dominant)
- short stature, rounded face, shortened 4th metacarpal, obesity, dental hypoplasia, soft tissue calcifications/ossifications
Pseudopseudohypoparathyroidism is very rare. Morphological features of pseudohypoparathyroidism but normal biochemistry.
CNIII palsy with pupillary sparing VS no sparing - what does it mean?
Pupillary sparing - due to ischaemic or diabetic aetiology
No sparing: compressive cause (ie surgical palsy)
hypercalcaemia, renal failure and metabolic alkalosis
? diagnosis
clue: taken calcium carbonate or antacids
milk-alkali syndrome
20yo catwalk with low BMI came with ‘a lot of hair’ on her body
?diagnosis
lanugo
(NOT hisuitism as she has low BMI, hence, likely to have lanugo hair instead)
diarrhoea, facial flushing with enlarged nodule of the neck
? diagnosis
medullary thyroid cancer
Cushing syndrome VS pseudo-cushing syndrome
Cushing syndrome: due to exogenous steroid administration & involves the HPA axis
Pseudo-cushing syndrome: display signs/symptoms and abnormal hormone levels like in cushing’s syndrome BUT the problem is not within the HPA axis. It is idiopathic condition in alcoholics. Signs/symptoms will disappear on alcohol abstinence.
most common cause of subclinical hypothyroidism?
chronic autoimmune thyroiditis
who normally gets subclinical hypothyroidism
older people
presents with tiredness and weight gain
elevated lipids (but less markied/consistent compared to full hypothyroidism)
rate of conversion to full hypothyroidism - <3% per year (more if they have positive thyroid antibodies).
DO NOT START Tx in those who are antibody negative - repeat test in 3 months!
Tx: levothyroxine
MEN - the different types!
1: pituitary, pancreas, parathyroid
2a: medullary thyroid cancer, pheochromocytoma, parathyroid
2b: medullary thyroid cancer, pheochromocytoma, marfanoid, neuromas
