Endocrinology Flashcards by Callum McCabe

1st line test for Cushing’s

Overnight / low dose dexamethasone suppression test

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Cortisol raised after low-dose dexamethasone suppression test.
Cortisol normal after high-dose dexamethasone suppression test.

Diagnosis + investigation?

Pituitary adenoma

MRI pituitary gland

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Bilateral adrenal disease - drug used to manage hypokalaemia?

Potassium-sparing diuretic e.g. sprinolactone

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Describe Cushing’s DISEASE (different to Cushing’s syndrome)

Cushing’s disease =
- pituitary adenoma
- increased ACTH
- increased cortisol production
(which causes a Cushing’s syndrome)

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Causes of Cushing’s syndrome?

CAPE

Cushing’s disease (pituitary adenoma)
Adrenal adenoma
Paraneoplastic syndrome (small cell lung cancer)
Exogenous steroids

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Tests for adrenal insufficiency

9 am cortisol
U + E
Short synacthen test

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Explain a short synacthen test

Synacthen = synthetic ACTH

(SYNthetic ACTH ENjection = SYNACTHEN)

Stimulates cortisol production.

Cortisol should double. If it doesn’t, there is adrenal insufficiency.

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How to differentiate between primary and secondary adrenal insufficiency ?

ACTH raised = primary adrenal insufficiency (because pituitary gland is producing ACTH with no cortisol no act as a negative feedback)

ACTH low = secondary adrenal insufficiency (because pituitary gland is not producing ACTH)

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All the causes of adrenal insufficiency to be aware of:

Primary adrenal insufficiency (Addison’s disease) can be caused by:

Auto-immune destruction (most common)
Surgical removal of the adrenal glands
Trauma to the adrenal glands
Infectious diseases, such as tuberculosis (more common in developing countries)
Haemorrhage (e.g., Waterhouse-Friderichsen syndrome)
Infarction
Less commonly, neoplasms, sarcoidosis, or amyloidosis

Secondary adrenal insufficiency can occur due to:

Congenital disorders
Fracture of the base of the skull
Pituitary or hypothalamic surgery or Neoplasms in the pituitary or hypothalamus
Infiltration or infection of the brain
Deficiency of corticotropin-releasing hormone (CRH)

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Management of Addisonian Crisis =

Aggressive fluid resuscitation
Administration of intravenous/IM (if no access) steroids STAT
Glucose administration if hypoglycaemia is present

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Basic distinctions between Cushing’s syndrome, Conn’s syndrome, and Addison’s disease

Cushing’s syndrome = too much cortisol

Conn’s syndrome = too much aldosterone

Addison’s disease = not enough cortisol/aldosterone

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Which steroids to give in Addisonian crisis?

IV hydrocortisone

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Patient is on hydrocortisone and fludrocortisone - then gets a severe infection e.g. pneumonia

How to adjust steroid doses?

Double the hydrocortisone

(don’t need to double fludrocortisone as the high-dose hydrocortisone has some mineralocorticoid effects)

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Aldosterone vs cortisol

Which is a glucocorticoid and which is a mineralocorticoid?

Aldosterone = mineralocorticoid

Cortisol = glucocorticoid

AMCOG

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What is Waterhouse-Friedrichsen syndrome?

What is the most common cause?

Bilateral adrenal haemorrhage secondary to infection.

Most commonly, meningococcal septicaemia.

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Visual field defect in pituitary tumour

(how do they first present and what do they become?)

Smaller pituitary tumours = bitemporal superior quadrantanopia

Bigger pituitary tumours = bitemporal hemianopia

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Medication used to shrink pituitary adenoma?

Cabergoline (dopamine agonist)

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What hormones are produced in the anterior pituitary?

The anterior pituitary gland releases:

Thyroid-stimulating hormone (TSH)
Adrenocorticotropic hormone (ACTH)
Follicle-stimulating hormone (FSH) and luteinising hormone (LH)
Growth hormone (GH)
Prolactin

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What hormones are produced in the posterior pituitary?

The posterior pituitary releases:

Oxytocin
Antidiuretic hormone (ADH)

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Explain pretibial myoedema

Specific to Graves’ disease

Deposits of mucin under shin skin
(discoloured, waxy)

Caused by reaction of tissues to TSH receptors antibodies

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Thyrotoxic crisis (thyroid storm)

Acute, severe hyperthyroidism
- pyrexia
- tachycardia
- delirium

Admit + supportive care
- fluid resuscitation
- anti-arrhythmic drugs (if there’s an arrhythmia)
- beta blockers (symptomatic control)

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Treatment for Graves disease

First line = Carbimazole
- normal function after 4 - 8 weeks
- titrate down for maintenance dose / “block and replace” (block all production of thyroid hormone then replace with levothyroxine)
- normally complete remission by 18 months

2nd line =
Propylthiouracil
- small risk of fatal hepatic reactions
or,

Radioactive iodine
- destroys thyroid cells which can cause hypothyroid
(contraindicated in pregnancy, avoid close contact with children and pregnant women for 3 weeks, avoid everyone for 3 days
following the treatment due to radiation)

or,

Surgery
- removes thyroid
- require levothyroxine for life

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What happens to PTH levels in hypercalcaemia?

PTH should be low.

If PTH is normal and calcium is high, PTH is “inappropriately normal”.

This indicates primary hyperthyroidism.

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HbA1C target for patients on gliclazide?

53 mmol/L (to mitigate the risks of hypoglycaemia)

C-peptide levels in T1DM vs T2DM = ?

C-peptide low in T1DM C-peptide normal/high in T2DM

Sore throat when taking carbimazole / propylthiuracil Diagnosis?

Agranulocytosis

Which cells in the pancreas produce glucagon and insulin?

GI Alpha cells = glucagon Beta cells = insulin

Treatments of primary, secondary, and tertiary hyperparathyroidism?

Primary - surgical removal Secondary - treat underlying cause Tertiary - surgical removal

Hypercalcaemia management ?

IV fluids then bisphosphonates

Hashimoto's thyroiditis - what cancer is patient at risk of developing?

MALT lymphoma

Nuclear scintigraphy results in toxic multinodular goitre ?

Patchy uptake (Graves/subacute thyroiditis = diffuse uptake)

Dexamethasone suppression test results

Pituitary is high (above the adrenals) - suppressed by HIGH dex Adrenals are low (beLOW pituitary) - suppressed by LOW dex Lung cancer is the worst - not suppressed at all

What class are gliptins?

DPP-4 inhibitors (they increase levels of incretins)

IV in place, hypoglycaemia and reduced consciousness - what to give?

IV glucose

Management of DKA

IV saline + fixed-rate insulin infusion (continue regular long-acting insulin, stop regular short-acting insulin)

Black, T2DM, hypertension = which medication ?

ARB e.g. candesartan

High QRISK score + metformin contraindicated = which diabetes drug(s)?

SGLT2 (e.g. dapagliflozin) monotherapy (QRISK = CVD risk score)

First line insulin regimen in children with T1DM

Multiple daily injection basal-bolus insulin regimen This combines: - long-acting insulin (to provide a basal level of insulin throughout the day) - short-acting insulin (to cover mealtimes) (this accommodates the various needs of children throughout the day)

Parathyroid hormone effect on phosphate?

Low PTH = high phosphate PTH decreases renal reabsorption and therefore increases urinary excretion of phosphate

How does PTH act on bones to increase serum calcium levels

Binds to osteoblasts (which inhibits them). This stimulates osteoclast activity (which increases calcium reabsorption from bone)

Symptoms of hypoparathyroidism but elevated PTH levels?

Pseudohypoparathyroidism

What does urine osmolality refer to?

How concentrated the urine is i.e. high urine osmolality = more concentrated urine

Where is ADH produced and from where is it secreted?

Produced in the hypothalamus. Secreted by the anterior pituitary. (also produced ectopically by small cell lung cancer)

Too much ADH = ?

Increased water reabsorption. Leads to hyponatraemia + more concentrated urine

Which diabetes drugs increase the risk of hypoglycaemia?

Sulfonylureas e.g. gliclazide, glimepiride

Pituitary swelling in acromegaly - first and second line treatments?

1st = transsphenoidal surgery if surgery is contraindicated... 2nd = octreotide (a somatostatin receptor ligand)

1st, 2nd, 3rd trimesters of pregnancy - which drug for hyperthyroidism?

1st = propylthiouracil (lower risk of foetal malformations) 2nd + 3rd = carbimazole (lower risk of hepatotoxicity)

Painful goitre + globally REDUCED uptake on radioisotope scan ?

De Quervain's thyroiditis (De QuerPAIN)

Hypercalcaemia - constipation or diarrhoea ?

Constipation

Diabetes drug which causes lactic acidosis?

Metformin - acidosis - high lactate

Gestational diabetes - uncontrolled on diet, exercise, and metformin.

Insulin

Which diabetes drug increases risk of UTIs?

SGLT2 inhibitors (gliflozins)

Hashimoto's thyroiditis key features

hypothyroidism + goitre + anti-TPO

Cushing's syndrome blood gas results?

Hypokalaemic metabolic alkalosis - same as vomiting

HbA1C > 48 + type 2 diabetes symptoms ?

Diagnose type 2 diabetes - no further tests needed

Side effects of thiazide diuretics

HyperGLUC (GLUC GLUC GLUC) - hyperGlycemia - hyperLipidemia - hyperUricemia - hyperCalcemia

Extreme hypothyroidism leading to myxoedemic coma - management ?

Thyroxine + hydrocortisone

Hypocalcaemia signs

Chvostek's sign = tapping facial nerve causes twitching Trosseau's sign = arm spasms due to blood pressure cuff

Liraglutide drug class

GLP-1 mimetic

most common complication of thyroid eye disease?

Exposure keratopathy - proptosis causes inability to close eye - causes corneas to become dry and irritated

Difference between cranial DI and nephrogenic DI ?

Cranial DI = a lack of ADH Nephrogenic DI = a lack of response to ADH

Water deprivation (desmopressin stimulation) test results for cranial and nephrogenic DI

Cranial = low - high Nephrogenic = low - low (because nephrogenic doesn't respond to ADH)

What is desmopressin?

Synthetic ADH

What to give in Addisonian crisis?

IV hydrocortisone

Subclinical hypothyroidism in the elderly - management?

Watch and wait - repeat TFTs in 3-6 months

-gliflozins Where do they act?

Flo (urine flow) - they act on SGLT2 receptors - in the kidneys

Pioglitazone side effects ?

Fat Bastards Won’t Feel Lighter – Fractures, Bladder cancer, Weight gain, Fluid (contra in HF), Liver impairment

Toxic multinodular goitre treatment = ?

Radioactive iodine therapy

T2DM - patient cannot tolerate triple therapy and they have a BMI greater than 35

Prescribe a GLP-1 mimetic e.g. exenatide, semaglutide (Ozempic)

Basic diabetes prescribing rule

Metformin + DSS Metformin + DPP-4 (gliptins) / sulfonylureas / SGLT2 inhibitors (depending on individual clinical scenario) If triple therapy doesn't work, try insulin. If BMI high, don't prescribe insulin - prescribe a GLP-1 mimetic e.g. semaglutide (Ozempic)

Double vision + thyroid problems =

Exophthalmos causes strained eye muscles causes double vision (Graves')