Endocrine Flashcards
Why might diabetic patients gradually start presenting in hypo/DKA more commonly as they get older?
Loss of awareness of symptoms due to autonomic neuropathy
Teenager with DKA patient is treated and develops irritability, drowsiness, blurred vision and focal neurological symptoms - what are you worried about?
Next steps?
Cerebral oedema
Risk esp in young patients until about 25
Request CT head immediately
High calcium, low phosphate but normal PTH?
Still primary hyperparathyroidism probably from adenoma because PTH is inappropriately normal
Driving and insulin-dependent diabetes?
Driving and on tablets/exenatide
All patients treated with insulin must inform DVLA (applies to both T1 and T2)
Can drive if:
- No more than 1 hypo in past 12 months requiring assistance of other person
- Adequate hypoglycaemic awareness
- Regular BM monitoring shows good glycemic control
- Shows understanding of risk of hypo
No need to inform DVLA if on tablets/exenatide
If hypo induced (e.g. gliclazide) then must have been no more than 1 hypo in past year
Diagnosis of acromegaly?
Measure serum IGF-1 levels
If raised, then to OGTT:
- If GH doesn’t lower to <2mu/L after glucose then acromegaly confirmed
pituitary MRI may demonstrate tumour
Management of acromegaly?
Trans-sphenoidal surgery 1st line in majority
If inoperable/surgery ineffective then:
- Somatostatin analogue (Octreotide) - inhibits release
- GH receptor antagonist (Pegvisomant) - doesn’t reduce mass effect
- Dopamine agonist (Bromocriptine)
Features of acromegaly on:
- limbs?
- face?
- skin?
- mass effect?
- 1/3 also have?
- 6% related to?
- spade-like hands, rings no longer fit, increase shoe size (gigantism if epiphyseal fusion not occurred)
- Macrognathia, macroglossia, interdental spacing, coarse facial appearance
- excessive sweating and oily skin (acne) due to gland hypertrophy
- hypopituitarism, headache, bitemporal hemianopia
- Raised prolactin - galactorrhoea
- MEN1
4 complications of acromegaly?
Hypertension
Diabetes
Cardiomyopathy
Colorectal cancer
Rule of thumb for imaging in endocrine?
MRI for pituitary, CT for others
These are structural tests - if there is a structural abnormality (atrophy/adenoma) a nuclear medicine test may be required
Nuclear medicine test is giving radio-labelled precursors to see how they are taken up
How to test for tremor in hyperthyroidism?
Exercise tolerance?
Menstrual patterns?
Put a bit of paper on back of hands
Reduced - due to tachycardia/AF
Scanty periods/amenorrhiea
99.8% of thyroid hormone is bound to what?
What does this mean in terms of practice?
Thyroid binding globulin
Transthyretin
Albumin
It is best to measure free hormone levels rather than total - uninfluenced by factors like oestrogen and enzyme inducers
Primary vs secondary hyperthyroidism?
Primary - TSH low and T3/T4 high
Secondary - problem outwith thyroid - TSH inappropriately normal/high with High T3/T4
Causes of hyperthyroidism, primary and secondary?
Why does thyroiditis cause hyperthyroidism?
Primary: Toxic multinodular goitre Grave's disease Solitary toxic adenoma Subacute/silent thyroiditis
Secondary:
TSH- secreting tumour
Factitious administration of T3/T4
Ectopic thyroid tumour (struma ovarii)
Pre-formed hormone is stored in gland in vesicles, with inflammation these are all released causing transient hyperthyroidism
Causes: viral, hashimoto’s, post-partum
Ig in Grave’s?
3 signs of Grave’s?
Trabs antibodies (thyroid receptor antibodies)
Eye disease, pretibial myxoedema, acropachy (type of clubbing - much rarer)
Cause of thyroid eye disease?
Does it happen at the same time as thyrotoxicosis?
Rx for thyroid eye disease?
Antbodies binding to extra-ocular muscles causing swelling
Can happen at different time - either before or years after thyrotoxicosis
Selenium can help
Oral steroids, followed by IV steroids if severe
Rarely, may need radiotherapy or in emergency surgery to crack open orbit and relieve swelling
Basic diagnostic investigation ladder for hyperthyroidism?
- TSH, fT4, fT3, TRAbs
- Ultrasound
- Nuclear medicine (technetium) uptake scan
2 rare SE of carbimazole?
How is it teratogenic?
PTU rare SE?
How to titrate treatment?
Agranulocytosis, cholestasis jaundice
Aplasia cutis (blad patch on head) and midline problems
Autoimmune hepatits
Titrate every 6 weeks until euthyroid.
Grave’s has 50% chance of cure in 18 months, other causes - control symptoms but not cure
2 specific risks of thyroidectomy?
Recurrent laryngeal nerve injury
Parathyroid damage - hypocalcaemia
often temporary ‘stunning’ of gland but sometimes permanent
Radioactive iodine: how long after before trying to conceive?
6 months
Thyroid storm
Symptomatic:
Lots of IV fluids (very dehydrated from diarrhoea/sweating)
Propanolol
PTU
Hydrocortisone (in case of addison’s as can be concomitant)
Stop thyroid:
Give lots of iodine - stuns thyroid briefly for about 10 days (to get thyroidectomy)
Lithium can be used - stops conversion of T4 to T3 in periphery
Supportive: Electrolytes Paracetamol (temp) Phenobarbital/Dantrolene (helps reduce shaking/seizure) Furosemide/ACEI if HF from arrhythmia
Selected:
Mechanical ventilation
Cooled mastresses
why do you get low Na and high MCV in hypothyroidism?
Need thyroxine to excrete water from kidneys, so retain fluid causing haemodilution
(can also get pedal oedema for this reason)
If someone has addison’s and has an infection what should they do with their meds?
Double hydrocortisone dose
(since no endogenous cortisol production so may not be able to mount a stress response)
Same Fludrocortisone dose
Why does splenectomy give falsely high HbA1c?
What else overestimates HbA1c?
Due to increased lifespan of RBC’s
Over-estimates:
- Iron deficiency anaemia
- B12/folate deficiency
Under-estimates:
- Sickle cell
- Spherocytosis
- G6PD deficiency
Dosing of hydrocortisone for addison’s?
Usually around 30mg a day - 20mg at 8am and 10mg at 5pm
Treatment of thyroid storm?
PTU Propanolol Dexamethasone (blocks peripheral conversion of T4 -> T3) Paracetamol Lots of fluids
Treat underlying cause
Management of myxoedema coma?
IV thyroxine IV fluid IV corticosteroids (until addison's ruled out) correct electrolytes Rewarming may be needed
Causes of addisonian crisis?
Management of addisonian crisis?
- Sepsis or surgery, causing acute exacerbation of chronic insufficiency (addison’s or hypopituitarism)
- Adrenal haemorrhage (Waterhouse friedrichson syndrome from mengicoccaemia)
- Steroid withdrawal
- 100mg hydrocortisone IM/IV
- 1L normal saline over 30-60 mins, with dextrose if hypoglycaemic
- Continue hydrocortisone 6 hourly
- Oral replacement after 23 hours, to be reduced to maintenance over 3-4 days
(no fludrocortisone needed as high dose hydrocortisone exerts weak mineralocorticoid effect)
Management of diabetic gastroparesis?
Options: - metoclopramide - domperidone - erythromycin (pro kinetic agents)
Why is goserilin given in prostate cancer?
How does it cause gynaecomastia?
Normally GnRH is released in a pulsatile manner to cause sperm production. When given high dose and long term, the endogenous feedback loops are lost, causing hypoandrogenism. This causes gynaecomastia
Why can antiemetics metoclopramide and domperidone cause galactorrhea?
Dopamine antagonists
Therefore can cause increased Prolactin
Haloperidol can also
How many units in 1ml insulin?
100
What drugs interfere with thyroxine absorption?
Iron and calcium tablets
Take at least 4 hours apart
Why to acromegaly patients get an echo?
Cardiomyopathy
Progression of de quervain’s thyroiditis?
Ix if unsure of diagnosis?
Rx?
1: hyperthyroid, tender goitre, raised ESR (3-6 weeks0
2: euthyroid (1-3 weeks)
3: hypothyroid (weeks-months)
4: normal
Scintigraphy: reduced uptake globally
Rx: usually none required - steroids if really bad