Y3 - Endo Flashcards

1
Q

Describe the anatomy of the thyroid gland!

A
  • left and right lobe joined by a central isthmus
  • moves on swallowing
  • supplied by the inferior and superior thyroid arteries
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What do the thyroid hormones do?

A
  • T4 is the main circulating hormone and gets converted peripherally to T3 too
  • thyroid hormones basically increase basal metabolic rate, affecting growth in kids too.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How would hyperthyroidism present?

A
  • AF/ tachycardia/ palpitations
  • increased and loose bowel movements
  • menorrhagia
  • intolerance to heat
  • Insomnia/ irritability
  • weight loss, increased appetite
  • anxious/ sweating/ resting tremor
  • Graves = lid retraction, proptosis, pre-tibial myxoedema, thyroid acropachy on nails
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are some causes of hyperthyroidism? also known as thyrotoxicosis

A
  • Graves = autoimmune most common
  • singular toxic nodule
  • toxic multinodular goitre
  • thyroiditis (inflammatino of thyroid) caused by viral infection/ meds (amiodarone)/ post partum
    • typically followed by a hypothyroid phase
    • this is because inflammation causes follicular cell breakdown so thyroid hormones are released
    • but obviously once the store is released, the breakdown of cells means there is then underproduction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How would you investigate and manage hyperthyroidism?

A
  • T3
  • T4
  • TSH
  • TSH receptor stimulating antibodies = Graves
  • Thyroid peroxidase antibodies (not that specific but indicative of autoimmune)
  • US of thyroid shows nodules
  • Iodine uptake isotope scan shows either localised increased uptake (nodule) or uniform increased uptake (Graves) or absent uptake (thyroiditis)

Management

  • BBlockers for symptoms
  • Carbimozole
    • se = _generalised ras_h. also agranulocytosis so do urgent fbc if unexplained fever/sore throat and stop if neutrophils are low
  • definitive = Radioactive Iodine + Thyroidectomy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How would hypothyroidism present?

A
  • weight gain
  • constipation
  • fatigue
  • intolerance to cold
  • bradycardia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are some causes of hypothyroidism?

A
  • damage from intentional treatment of thyroid disease eg surgical
  • inadvertant damage from eg radiation to head and neck
  • Hashimotos thyroiditis
  • Iodine insufficiency
  • Post partum
  • Medications like amiodarone and lithium
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How would you investigate and manage hypothyroidism?

A
  • T3
  • T4
  • Thyroid peroxidase Antibodies
  • TSH

Managment

Levothyroxine!!!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What hormones are produced by the adrenal glands? What do they do

A

Cortex

  • Glucocorticoids = cortisol
  • Mineralcorticoids = aldosterone
    • distal convoluted tubule to cause K+ loss and Na+ retention
    • is regulated by Renin Angiotensin System (activated by low blood vol, low Na+ or high K+)
  • Androgens

Medulla produces adrenaline and dopamine and their metabolites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How would Primary Adrenal Insufficiency (Addisons disease) present?

A
  • Low Cortisol = fatigue, weight loss, nausea, abdo pain, anorexia, hypoglycaemia, hyperpigmentation from ACTH upregulation
  • Low Aldosterone = postural hypotension, dizziness, Hyponatraemia, Hyperkalaemia
  • Low androgens = loss of axillary and pubic hair, low libido
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Why is there hyperpigmentation in addisons?

A

ACTH excess due to low cortisol.

Acth stimulates melaocyte stimulating hormones which results in hyperpigmentation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How would you investigate and manage Addisons?

A
  • low 9am Cortisol while ACTH is raised
  • Synacthen test for confirmation
  • Hyperkalaemia, Hyponatraemia, Hypoglycaemia, Mild anaemia, Raised urea

Management

  • Hydrocortisone for glucocorticoid replacement
  • Fludrocortisone for mineralcorticoid replacement
  • educate about steroid rules (double glucocorticoid during illness, ensure it is given in surgery/ nausea or vomiting)
  • give steroid emergency card, medical alert jewellry, details of their endo team
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How would you manage secondary adrenal insufficiency (ACTH deficiency)

A
  • only replace Glucocorticoid = Hydrocortisone
  • steroid card etc
  • education etc inform them not to stop steroids suddenly = adrenal crisis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is phaeochromocytoma and paragangliomas?

A

Phaeochromocytomas are catecholamine secreting tumours of the adrenal medulla.

Paraganglionomas are tumours of the extra adrenal chromaffin tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How would phaeochromocytomas present?

A
  • panic attacks and anxiety
  • headache, sweating, pallor, palpitations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How would you investigate and manage phaeochromocytomas?

A
  • 24 hour urinary catecholamines and plasma metanephrines
  • CT/MRI abdo for tumour

Management

  • surgical excision
  • alpha blockade first (as unregulated alpha = hypertensive crisis)
  • then beta blockade to control reflex tachycardia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the 5 axes produced in the pituitary and what do they do?

A

Growth hormone (GH)

  • secreted pulsatile
  • acts on liver to produce IGF-1
  • -ve feedback from somatostatin

ACTH

  • secreted circadian rhythm
  • stimulates cortisol release

Gonadal (FSH/LH)

  • FSH and LH are inhibited by prolactin

Thyroid (TSH)

  • stimulates T4 and T3

Prolactin

  • causes lactation
  • inhibits gonadal hormones
  • itself is inhibited by dopamine
18
Q

How would you assess the pituitary gland?

A
  • MRI of pituitary for microadenomas (<1cm) or macroadenomas
  • Synacthen test
  • Insulin Tolerance Test for GH and ACTH reserve (not in ischaemic heart disease or epilepsy)
  • Prolactin and TSH can be measured at any time
  • FSH and LH in women measured in first 5 days of menstrual cycle
  • FSH and LH and Testosterone in men measured at fasting 0900
  • Measure GH and IGF-1
  • Basal Cortisol at 0900
19
Q

How would you investigate hyperprolactinaemia?

A
  • MRI for microadenoma (<1cm) or macroadenoma
  • rule out pregnancy
  • medications review (dopamine antagonists like antipsychotics or antiemetics)
  • prolactin levels typically >5000 in secreting prolactinoma

Microadenoma

  • menstrual disturbance, galactorrhoea, infertility
  • unlikely to be PCOS if no pituitary lesions on MRI, also prolactin is usually <1000

Macroadenoma

  • prolactin typically >5000miU
20
Q

How would you manage hyperprolactinaemia?

A
  • give dopamine agonists like bromocriptine or cabergoline
  • SE = nausea, postural hypotension, psychiatric disturbance
  • They can cause the tumour to shrink really fast and cause CSF leak = meningitis risk
21
Q

How would acromegaly present?

A
  • large hands and feet
  • puffy hands = carpal tunnel syndrome
  • coarse facial features
  • frontal bossing of forehead
  • protrusion of chin
  • wide spaced teeth
  • Enlarged soft tissue = large soft palate and tongue
  • Snoring and sleep apnoea
  • Sweating, headaches, HTN
  • Risk of CVS, bowel cancer, DM
22
Q

How would you investigate and manage acromegaly?

A
  • GH and IGF-1
  • Oral Glucose Tolerance Test
  • Pituitary MRI to show tumour

Management

  • Surgical excision
    • repeat OGTT and follow up with GH/IGF-1 monitoring
  • Stereotactic radiotherapy if it is away from optic chiasm
  • somatostatin analogues can help
  • Monitor for sleep apnoea, bowel cancer, CVS, DM
23
Q

How would you manage hypopituitarism?

A

ACTH = hydrocortisone

GH = daily growth hormone subcut injections

FSH/LH = COCP/HRT in females or testosterone injections for males

Thyroid = levothyroxine

24
Q

How would Cushings disease present?

A

Pituitary adenoma resulting in excess cortisol.

  • dorso cervical fat pad
  • facial roundness and plethora
  • thin skin, striae, easy bruising
  • osteoporosis of limbs
  • central obesity
  • HTN, DM
25
How would you investigate and manage Cushings disease?
* Screen for alcoholism and depression * Elevated **24 hour urinary Cortisol** * **Overnight dexamethasone suppression test** * failure to suppress cortisol \<50nmol/L after overnight Dexamethasone Suppression test * Elevated **late night salivary cortisol levels** * Hypokalaemic, Metabolic alkalosis * MRI of pituitary Management * **Metyrapone** and ketoconazole * Radiotherapy * **Transphenoidal removal of pituitary adenoma** * If it is adrenal = lap adrenalectomy
26
What are some symptoms of hyponatraemia?
* headache * nausea, vomiting * general malaise * confusion, agitation, drowsiness later
27
How would you investigate hyponatraemia?
* Urine Osmolality * Urine Sodium * \<30mmol/L = low effective arterial vol * \>30mmol/L and euvolaemic = SIADH once ACTH def is excluded * \>30mmol/L and dehdyrated = Addisons/ vomiting/ DI
28
How would you diagnose and manage SIADH?
* Diagnosis of exclusion as there isn't really a test... * Rule out other causes eg. adrenal insufficiency\*\*\* (-ve short synacthen), rule out diuretics, excess fluid intake, ckd, aki, etc. * clinical examination shows euvolaemia * low serum osmolality \<275momol/kg * high urine osmolality \>100mosmol/kg * urine Na \>30mmol/l Ensure to rule out _ACTH deficiency_ as it also causes excretion of free water (cortisol deficiency causes increased vasopressin activity).\*\*\* Also look for any underlying malignancy eg. small cell lung cancer. Management (the goal is to correct sodium slowly to prevent central pontine myelinolysis) * **fluid restriction** * **tolvaptan** (adh receptor blocker) * monitor as it can cause rapid sodium increase * demeclocycline (tetracycline antibiotic that inhibits adh)
29
How would you diagnose cranial/nephrogenic diabetes insipidus?
* \>3L urine in 24 hours * high serum osmolality \>295mosmol/kg * low urine osmolality \<300mosmol/kg * do water deprivation test (they should have unacceptable thirst and significant weight loss due to water loss. stop if symptoms get too severe!) * then give a synthetic vasopressin like desmopressin. * Cranial will get better, Nephrogenic no response Management * Desmopressin for cranial DI * Nephrogenic = less salt, protein, nsaids, diuretics
30
How would you investigate hypercalcaemia?
* high PTH * high PTH is usually **primary hyperPTH due to a single parathyroid adenoma** * Parathyroid hyperplasia in more than one gland = Multiple Endocrine Neoplasia * Very high _calcium \>3.5_ could be **parathyroid cancer** (associated with jaw tumours) * suppressed PTH * malignancy unless proven otherwise!!! * usually **squamous cell carcinoma** * also could be benign granulomatous disease like **tb/ sarcoidosis** * Parathyroid ultrasound for adenoma
31
How would hypercalcaemia present?
* renal stones * abdominal pain, GI upset, constipation * Depression, fatigue, psychiatric symptoms * Bony aches and pains * polydypsia and polyuria
32
How would you manage hypercalcaemia?
* Surgery if Ca\>2.85 * **parathyroidectomy** * **Calcimimetics like cinacalcet** for primary hyperparathyroidism
33
How would hypocalcaemia present?
* seizures * tetany * qt prolongation on ecg * **Chvosteks sign +ve** = facial spasm when cheek is tapped gently with finger * **Trousseaus sign** = carpo-pedal spasm induced after inflation of sphygmomanoometer
34
What are some causes of hypocalcaemia? Ca\<1.9
* Vit D deficiency = will have a low phosphate * Hypomagnesaemia = GI loss, alcohol/drugs, PPIs * Parathyroid gland damage from surgery etc.
35
How would you manage hypocalcaemia?
* Calcium replacement * vitamin d supplements * bisphospohonates * stop offensive meds for hypomagnesaemia and give IV MgSO4 24mmol/24 hours
36
How would Conns present? | (primary hyperaldosteronism)
* Hypernatraemia, hypokalaemia * polyuria, polydipsia * HTN * metabolic alkalosis
37
How would you investigate Conns?
* **Aldosterone:Renin ratio \>800** confirms diagnosis * false +ve with BBlockers * False -ves with ACEI, ARBs, CCB * ECG = hypokalaemia * CT/MRI for adrenal mass/hyperplasia * **Lying and standing aldosterone:renin** * adrenal hyperplasia = aldosterone \>30% after standing over 4 hours * adrenal adenoma = no change
38
How would you manage Conns?
adrenal adenoma (Conns) * **surgial removal** of adenoma * **Spironolactone** (aldosterone antagonist) Bilateral adrenal hyperplasia * **spironolactone** * SE = gynaecomastia and ED as also blocks testosterone receptors * **Amiloride** * K+ sparing diuretic weaker than spironolactone * **Eplerenone** * aldosterone antagonist that does not block testosterone receptors
39
What is the pathophysiology of SIADH?
* ADH is produced in the hypothalamus and secreted by the **posterior pituitary** * ADH stimulates water reabsorption from collecting ducts in kidneys * SIADH is when ADH is secreted excessively * either due to posterior pituitary secreting too much * or ADH coming from somewhere else like a **Small cell lung cancer** * Results in excessive water, diluting sodium in the blood = **hyponatraemia** * but the water is not significant enough to cause fluid overload = **euvolaemic hyponatraemia** * Urine becomes more concentrated as water is retained = high urine osmolality and high urine sodium
40
What is central pontine myelinolysis? (also known as osmotic demyelination syndrome)
a complication of rapidly correcting severe hyponatraemia (\>10mmol/L increase in over 24 hours) * as blood sodium falls, water moves from the level of low solute conc (blood) to high solute conc (brain) * this causes the brain to swell * the brain reduces its solutes so that water moves back down through the blood brain barrier and reduces oedema in the brain * this adaptation takes a few days and so in people who have a chronically low sodium, their brain cells will have adapted to have a low osmolality. * Therefore when we correct that low sodium rapidly, water rapidly shifts out of the brain cells into the blood. Early First phase Presentation * electrolyte imbalance = encephalopathic and confusion * nausea, vomiting, headache Second phase presentation * Later on the demyelination of neurones starts, particularly in the pons * **spastic quadriparesis** * **pseudobulbar palsy** * **cognitive and behavioural changes** Management = supportive