Endocrine Flashcards
What is the most common type of thyroid cancer?
Papillary - 70-80%
20-40y
early lymphatic spread
What type of thyroid cancer need a diagnostic thyroidectomy?
Follicular carcinoma (20%) spread by haematgenous route** so worse prognosis. (Follicular adenoma -80%)
What type of thyroid cancer get genetic testing?
Medullary. 20% Associated with MEN 2A and 2B
What are the types of thyroid cancer and their key features?
Papillary - most common - 70-80%
Follicular - spread via blood and need diagnostic hemithyroidectomy. Chronic TSH stimulation (usually due to iodine deficiency)
Medullary - C-cells (calcitonin and CEA) associated with MEN 2A and MEN 2B. usually in upper 2/3 of thyroid
Anaplastic - Undifferentiated follicular cells. poor prognosis <6months. Rapidly infiltrates local structures and mets. dysphagia, hoarse voice, compromised airway
Lymphoma - from non-hodgkins B cell. elderly women. Usually on a back ground of Hashimotos
How is a thyroglossal cyst formed?
Remnant of the foramen cecum
Give some differentials of a neck lump.
Thyroid nodule, lipoma, skin cancer, parotid tumour (or other salivary gland tumour), reactive lymphadenopathy, thyroglossal cyst.
What are the features of MEN 1 (on Ch 11, encoded Menin)
3 P’s
Parathyroid tumour
Pancreatic islet cell tumour
Anterior pituitary tumour
What are the features of MEN 2 (ch 10, mutation to RET photo-oncogene)
MEN 2A - Medullary thyroid carcinoma, Pheochromocytoma, Primary hyperparathyroidism
MEN 2B - Medullary thyroid carcinoma, pheochromocytoma, Mucosal neuroma
What signs may indicate a retrosternal goitre?
Facial flushing and venous distention
What is secondary hyperparathyroidism?
Usually due to CKD or vit D deficiency. PTH increased in response to hypocalcaemia
What conditions can hyperparathyroidism cause
Pancreatitis
Gout
Renal stones
Give a complication of hypothyroidism.
Thyroid lymphoma, generally non-hodgkins
AF, osteoporosis, myxoedema coma (multi organ failure), angina, resistant hypothyroidism
What is first line treatment in hyperthyroidism?
40mg PO propanolol - symptom control then
Carbimazole SE - rash, agranulocytosis
What is Conn’s syndrome?
Syndrome of HTN, severe hypokalaemia and aldosterone hypersecretion with suppression of plasma renin activity. A adrenal adenoma
HTN with LOW renin **
(secondary hyperaldosterone has high renin and Aldos)
What tests would you do in Primary hyperaldosteronism?
Serum K (<3mmol/L) and urinary K (>40mmol/L)
Serum aldosterone and renin levels
Ratio of plasma aldosterone conc:Plasma renin activity (>2PAC:PRA, can get false +ve in renovascular hypotension, diuretics, ACEi, malignant HTN, Cablockers)
Aldosterone suppression test (inability for aldosterone to be suppressed by high Na diet)
CT/MRI adrenals
Adrenal venous sampling
What AI might suggest Addison’s disease?
Autoantibodies to 21-hydroxylase
What is the max amount of Na you can give?
10mmol/L in 24 hours
risk of cerebral oedema
What causes increased levels of growth hormone?
Acromegaly, stress, pregnancy, sleep, puberty
What treatment options are available in acromegaly?
- Trans-sphenoidal surgery - if fails ->
- Somatostatin analogue (octreotide) + domaine agonist (cabergoline) ± radiotherapy
- GH receptor antagonist (pegvisomant)
- Radiotherapy
How might someone with sever hyponatraemia present? (Sr Na <120)
Reduced mental state, confusion, irritability, restlessness, seizures, coma
How can you calculate serum osmolality?
2X (Na) +urea + glucose
What are some causes of SIADH?
Small cell lung cancer
infection - Legionella pneumonia, lung abscess
Meningitis
Head injury or port-op from a major surgery
Stroke, haemorrhage
SSRIs, carbamazepine, thiazide diuretics, NSIADs (mood stabilisers and anti-epileptic)
How could you treat symptomatic hypocalcaemia?
- 10ml of 10% calcium gluconate diluted in N saline or dextrose, (SLOW!) over 10min with cardiac monitoring (giving it fast - arrhythmias)
- Followed by a slow infusion of 100ml 10% Ca gluconate in 1L N saline. ~50ml/hr. Titre dose to maintain Sr Ca at low-normal range. Monitor 2X daily
If Mg low - add 20ml (~40mmol/L) 50% MgSO4 to 230ml N saline and infuse at 50ml/10min then 25ml/hr
What are the treatment options for hyperprolactinaemia?
Bromocriptine or cabergoline - dopamine agonist
What are some causes of hyperkalaemia?
> 6
The body CARED too much for K Cellular movement of IC K to EC in burns and tissue damage Adrenal insufficiency / Addison's Renal failure Excessive K intake Drugs - ACEi, NSAIDs, spironolactone
Tumour lysis syndrome, metabolic acidosis, massive blood transfusion, rhabdomyolysis
What are some symptoms of hyperkalaemia?
MURDER
Muscle weakness
Urine output little to none
Respiratory failure (due to muscle weakness)
Decreased cardiac contractility
Early muscle twitches/ cramps
Rhythm changes - tall peaked T wave, prolonged PR
Cardiac arrhythmia - VF - Fatal
>7 - bradycardia
>9 - Cardiac arrest
What are the ECG changes seen in hyperkalaemia?
Tall peaked T wave
Broad QRS
Flattened or absent P waves
Prolonged PR
How would you manage hyperkalaemia? (K > 6.5?)
Insuline (10U actrapid), dextrose (50ml of 50%) and IV calcium gluconate
Nebulised salbutamol
If renal failure acidotic - sodium bicarbonate
Dialysis is recurrent and severe and renal failure
How might you manage mild hyperkalaemia?
Oral calcium resonium - draws K out of gut and into stool
What are some causes of hypokalaemia?
< 2.5
The body is trying to DITCH the K
Drugs - diuretics, laxatives, hydrocortisone
Inadequate consumption of K
Too much water intake
Cushings or Conn’s (kidneys excrete K)
Heavy fluid loss - vomiting/ diarrhoea**, wound drainage, NG tube suction, intestinal fistula
alkalosis, renal tubular failure, pyloric stenosis
What are some signs and symptoms of hypokalaemia?
7 L's Lethargic Low, shallow respiration .. failure Lethal cardiac dysrhythmias Lots of urine (freq & large volume) Leg cramps Limp muscles Low BP (severe)
What are some causes of hypoglycaemia in non-diabetics?
1st line fir hypoglycaemia testing - short synacthen test
then 72 hour fast
EXPLAIN EXogenous drugs - lithium, beta blockers Pituitary insufficiency/ Addison's Liver failure AI hypoglycaemia Islet cell tumour - insulinoma Non-pancreatic neoplasm Miscellaneous - sepsis, anorexia, starvation
What must you have to get DKA?
Known T1DM or glucose > 11 (1st presentation?)
Acidotic pH <7.3 or bicarb <15 or H > 45
Ketone ++ in urine +/- blood >3mmol/L
What are the first line drugs in T2DM and what comes after?
1st - Metformin or sulphonylurea
2nd - Metformin/SU + SU or SGLT2 inhibitor or DPP-4 inhibitor or Glitazone
3rd - or add GLP-1 agonist
What level is the thyroid at ?
C5-T1 inferior to the thyroid cartilage
Deep to the sternothyroid and sternohyoid
What is Hypopituitarism?
Dysfunction of the hypothalamus, pituitary stalk or pituitary gland that causes a reduction in the anterior pituitary hormone release.
Can be due to trauma, inflammation, ischaemia or infection
GH affected first, ACTH last
Give some examples of causes of hypopituitarism.
Hypothalamis - Kallmann’s syndrome, tumour, ischaemia, infections - TB, meningitis, inflammation
Pituitary stalk - Carotid artery aneurysm, meningioma, trauma, surgery
Pituitary gland - Infiltration (HH, amyloidosis, mets), ishcaemia (Sheehan’s syndrome, pituitary apoplexy), tumour, irradiation, inflammation
What are some signs of hypothyroidism?
BRADYCARDIC Bradycardia Reflexes relax slowly Ataxia Dry skin Yawning - tiredness and fatigued Cold hands Ascites Round puffy face Defeated demeans Immobile CCF
What does GH do and what Sx would show a deficiency of it?
Stimulates IGF-1 in the liver and controls metabolism, growth, sleep, food intake and memory. It increases muscles mass and reduces body fat.
Sx -
Central obesity, short height, low blood sugar, reduced muscle mass and exercise tolerance, reduced strength, atherosclerosis, dry, wrinkled skin
What affect would gonadotrophin deficiency have on males?
FSH-Spermatogenesis via ABP from sertoli
LH- stimulates testosterone by leydig
Reduced secondary sex characteristic, reduced libido, reduced muscle bulk, erectile dysfunction, small testes
What affect would gonadotrophin deficiency have on females?
FSH - development of the ovarian follicle
LH - maturation of follicle, formation of corpus lute, ovulation
Reduced libido, reduced fertility, breast atrophy, osteoporosis, oligo/amenorrhoea
What might cause unexplained abdominal pain and vomiting?
Addiosns - primary adrenal insufficiency
What affect would corticotrophin deficiency have?
Cortisol - released during stress, regulates metabolism, anti-inflammatory, glucose met
fatigue, myalgia, low mood, loss of appetite, increased thirst, N&V, dizziness
NO hyperpigmentation
Give an example of a cause of iatrogenic hypothyroidism.
Post-thyroidectomy, post radioactive iodine, amiodarone
Lithium: Block the TSH from binding to its receptor
Before starting they should get a neck exam and TFTs checked. 6 monthly TFTs
What is sick euthyroid syndrome?
Abnormal TFTs in the presence of systemic disease e.g. critical illness, starvation. Switches the body into a catabolic state. T4/T3 low TSH - low or normal
Gland is functioning normally but there is less deiodinase and dysregualtion of thyrotrophic feedback control (reduced TSH, TRH) - due to catabolic state (immune cells produce cytokines (IL-6/TNF-alpha) which act directly on hypothalamus and pituitary)
What antibodies are seen in hashimotos thryoiditis?
Anti-thyroglobulin*, anti-thyroid peroxidase, anti-TSH receptor
Destruction of follicular cells - release of T3/T4 = transient hyperthryoid phase, but long term low T3/4
In Hashimotos thyroiditis, how might a goitre form?
Chronic inflammation leads to
Build up of connective tissue
Infiltration of immune cells
Less functional thryoid tissue
What do thyroid hormones do?
Increase the bodys basal metabolic rate and heat production.
Increases SNS - Increases CO, RR, mental awareness
Inc long bone growth, brain development, hair follicle growth
Inc sebaceous and sweat gland secretion, increases glucose metabolism
What are the types of AI thyroiditis in hypothyroidism?
Hashimotos - In areas with water/salt fortified with iodine. Goitre formation
Primary myxoedema/atrophic - similar to above but NO goitre
Reidels thyroiditis - IgG4 mediated. Dense fibrous tissue replaces thyroid- Fibrosis extends beyond thyroids fibrous capsule - goitre (Associated with RETROPERITONEAL FIBROSIS)
What is subclinical hypothyroidism?
A state of thyroid function where thyroid hormones are normal level but TSH is raised.
TH may be in range but a FALL from a previous level
More common to progress to overt hypo if:
Higher TSH, especially >10mU/L–> give Levothyroxine
Anti-thyroid peroxidase
Sheehans syndrom is a cause of secondary hypothyroidism, what is it?
Post partam pituitary necrosis caused by ishcaemic necrosis due to blood loss/ hypovolaemia during child birth
What is the most common cause of hypothyroidism in the UK and worldwide?
UK - Hashimotots
World wide - iodine deficiency - hypertrophy of the gland causing a goitre
List some causes of secondary hypothyroidism?
Pituitary tumour - bitemporal hemianopia
Sheehans syndrome
Sick euthyroid syndrome
Head trauma
What investigations would you do to investigate thyroid dysfunction?
US
FNA
Thyroid uptake scan
MRI head
What is a goitre?
A symmetrical swelling at the front of the neck that moves on swallowing
What causes the clinical features in graves disease?
Triad - thyrotoxicosis, goitre, eye signs
Fibroblasts are stimulated by TSH receptor antibodies which causes deposition of glycosaminoglycans which causes fluid retention
Exopthalmos - inflammation, hypertrophy and swelling of retro orbital structures push eye forward. - this causes limited eye movement - Ophthamoplegia
Depositions in the skin causes non-pitting oedema and skin thickening - pretibial myxoedema
Why is there lid lag and retraction in Graves?
Overactivity of SNS? and so over activity of the lelevator palpebral superiors
Corneal ulceration - more prone to dry eyes
What is the most common cause of hyperthyroidism in iodine deficient areas?
Toxic multi nodular goitre (plummers disease)
Toxic - nodules autonomously secrete excess TH