General Medicine: Endocrine (excl diabetes) Flashcards
Outline the basic pathway of thyroid hormone production
(Ant pituitary) –> TSH –> (thyroid) –> T3/4
How do hypo and hyperthyroidism compare with
Systemic symptoms
Cardiac
Skin
Gastrointestinal
Gynaecological
Neurological
Hypothyroidism // hyperthyroidism
weight gain, lethargy, cold intolerance // weight loss, restless, heat intolerance
none // palpitations
Dry, non hairy, non-pitting oedema // sweaty, bubbly tibia
constipation // diarrhoea
reduced reflex, carpal tunnel // tremor
Interpret the following
TSH: Low
T4: High
What are the causes of the following
Thyrotoxicosis
Causes
- Graves (60%)
- Toxic multinodular goitre
- Acute subacute thryoiditis/ acute hashimoto’s (before it goes hypo)
- Amiodarone therapy
In addition to TFTs, what clinical and lab tests would point towards
Grave’s disease
Toxic multinodular goitre
Grave’s
Clinical: big and palsied eyes, pre-tibial myxoedema, digital clubbing
Labs: anti-TSHR, anti-TPO, diffuse homogenous intake of radio-iodine
TMN
Nuclear scintigraphy reveals patchy uptake
Interpret the following TFT results
T4 // TSH
low, high
low, low
normal, high
Hashimoto’s
2ary cause, sick euthyroid
subclinical, poor compliance
How do you treat thyrotoxicosis?
Propranolol for tremor
Carbimazole to block T4 production
Radioiodine/surgery to remove if persistent
What is the treatment for hypothyroidism?
levothyroxine
How do you check if levothyroxine treatment is working/being complied with?
Check TSH in normal range
TSH high because low T4 so therapy should cause negative feedback
How does thryoid storm and myoedema coma compare in terms of
Hx
Presentation
TS // MC
Overactive thyroid // underactive
Confusion, fever, N+V (+/-jaundice) // Confusion and hypothermia
How do you manage myoxedema coma?
IV thyroxine
IV fluids
IV corticosteroids while adrenal insufficiency ruled out
How do you treat thyroid storm?
IV propranolol
Methimazole, PTU
Dexamethasone to reduce conversion
How can thyroid cancer be distinguished from other thyroid lumps
Lacks the features of hyper/hypothyroidism
What investigations are performed in suspected thyroid cancer?
1st line: Ultrasound
GS: Fine needle aspiration
‘mixture of papillary and colloidal filled follicles, tumour has papillary projections and pale empty nuclei’
Which thyroid cancer is this and how does it spread?
Papillary
Lymph node spread
‘encaspulated tumour with microscopic capsular invasion’
What thyroid cancer is this and how does it spread?
Follicular carcinoma
Vascular invasion predominates
How are papillary and follicular thyroid cancers treated?
Thyroidectomy + radioiodine 131 to kill residue cells
Yearly thyroglobulin levels
What endocrine disorders give you a high BP and outline their distinguishing characteristics
Hyperaldosteronism: hypokalaemia (muscle wasting), alkalosis
Phaeochromocytoma: intermittent headaches, palps, sweating, anxiety
Cushing’s syndrome: moon face, pigmented skin
Congenital adrenal hyperplasia: female virilisation
Acromegaly: Big head, hands and feet, headaches, bitemporal hemianopia, sweaty
Bronzed skin, thin, fatigue and salt craving indicates which endocrine disorder
Addison’s disease
What do the following aldosterone renin ratios suggest
high/high
high/low
2ary (renal artery stenosis)
1ary: Conn’s syndrome
If primary hyperaldosteronism is suspected from A:R testing, what further test should be performed?
Adrenal CT to visualise adeomas
if -ve adrenal venous sampling for unilateral adenoma vs bilateral hyperplasia
What is the most common cause of hyperaldosteronism?
Renal artery stenosis
chonic underperfusion of kidney leads to increased aldosterone production
How do you manage renal artery stenosis?
Antihypertensives, statin + antiplatelets
Stenting of renal artery
How do you manage primary hyperaldosteronism?
unilateral adenoma: surgery
Bilateral hyperplasia: spironolactone
How would you investigate and treat a patient with addison’s?
1st: 9am cortisol = 100-500
GS: short synACTHen test, cortisol does not double
+ APS 1/2 autoantibodies
+ CT for adrenals, MRI for pituitary
