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Medicine Y3 TCD 13-24 > 16. Obesity, Cushing's and background science > Flashcards

16. Obesity, Cushing's and background science Flashcards

see adrenal insufficiency

1
Q

What is cushings syndrome

A

the signs and symptoms that develop after prolonged abnormal elevation of cortisol

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2
Q

what is Cushing’s disease

A

refers to the specific conditions where a pituitary adenoma (tumour) secretes excessive ACTH

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3
Q

What are the common features of Cushing’s (imagine a round person in the middle with thin, weak limbs and image the effects of high levels of stress hormone)

A 
Round "moon' face 
central obesity 
abdominal striae (red, purple) 
buffalo hump (fat pad on upper back) 
proximal limb muscle wasting 
Hypertension 
cardiac hypertrophy 
hyperglycaemia (T2DM)
depression 
insomnia 
osteoporosis (protein wasting) 
easy bruising and poor skin healing 
acne 
Hirsutism ( women growing facial hair) 
hypokalaemia
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4
Q

what are some causes of Cushing’s syndrome

A

Exogenous steroids (in patients on long term high dose steroid medications)

Cushing’s Disease (a pituitary adenoma releasing excessive ACTH)

Adrenal Adenoma (a hormone secreting adrenal tumour)

Paraneoplastic Cushing’s

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5
Q

What is paraneoplastic Cushing’s

A

excess ACTH is released from a cancer (not of the pituitary) and stimulates excessive cortisol release
ACTH from somewhere other than the pituitary is called “ectopic ACTH’

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6
Q

what kind of cancer is the most common cause of paraneoplastic Cushing’s

A

small cell lung cancer

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7
Q

what does ACTH stand for and what is its role

A

Adrenocorticotropic hormone (ACTH) is a hormone produced in the anterior pituitary gland in the brain.

The function of ACTH is to regulate levels of the steroid hormone cortisol, which released from the adrenal gland.

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8
Q

how does the dexamethasone suppression test (DST) work

A

take a dose of dexamethasone (synthetic glucocorticoid steroid) at night ie 10pm and their cortisol and ACTH is measured in the morning

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9
Q

if the low dose dexamethasone test is normal what can be excluded

A

Cushings

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10
Q

What dose of dexamethose is used in the low dose DST and what is used in the high hose

A

1mg in low

8mg in high

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11
Q

What is the normal response for the dexamethasone test

A

dex suppresses the release of cortisol by effecting negative feedback of the hypothalamus and pituitary

hypothalamus responds by reducing CRH output

pituitary responds by reducing ACTH output

Lower CRH and ACTH results in low cortisol

when cortisol levels aren’t suppressed, this is abnormal and seen in Cushing’s syndrome

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12
Q

What does the high dose dexamethasone suppression test show in Cushing’s disease (pituitary adenoma)

A

at high dose the pituitary still shows some reponase to negative feedback and so if enough to suppress cortisol

low cortisol

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13
Q

When there is an adrenal adenoma what does the high dose dexamethasone suppression test show

A

cortisol production is independant from the pituitary

therefore cortisone is not surprised however ACTH will be surpassed

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14
Q

When there is an ectopic ACTH (eg from a small cell carcinoma) what does the high dose dex suppressio test show

A

neither cortisol or ACTH will be suppressed as the ACTH production is independant

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15
Q

What can be used as an alternative to dexamethasone suppression test to diagnose Cushing’s syndrome but won’t indicate the underlying cause

A

24 hour urinary free cortisol

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16
Q

what other tests can be used to diagnose Cushing’s depending on the cause

A
  • FBC (raised white cells) and electrolytes (potassium may be low if aldosterone is also secreted by an adrenal adenoma)
  • MRI brain for pituitary adenoma
  • Chest CT for small cell lung cancer
  • Abdominal CT for adrenal tumours
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17
Q

What is the main treatment for Cushing’s

A

main treatment is to remove the underlying cause (surgically remove the tumour)

  • trans-sphenoidal (through the nose) removal of pituitary adenoma
  • surgical removal of adrenal tumour
  • surgical removal of tumour producing ectopic ACTH
  • if adrenal glands are damaged then need to remove them and give life long steroids
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18
Q

what age does Cushing’s disease usually present in

A

25-45 and affects females more

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19
Q

What clinical features are not discriminatory for bushings

A

generalise obesity
oligomenorrhoea
headaches
abnormal GTT

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20
Q

What test can differentiate between pituitary and adrenal Cushing’s

A

ACTH levels

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21
Q

following positive initial screening for Cushing’s, what test would be performed if ACTH is raised

A

pituitary screening

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22
Q

following positive initial screening for Cushing’s, what test would be performed if aCTH is not raised

A

adrenal imaging

23
Q

which test discriminates between a pituitary and Coptic source of excess ACTH

A

inferior petrosal sinus sampling

24
Q

what would be the most useful first line investigation if ectopic ACTH excess was suspected

A

CXR

25
Q

what abnormalities in the patients ions would be seen in Cushing’s in terms of sodium, potassium and bicarbonate

A

high sodium
low potassium
high bicarbonate

26
Q 
In obesity, what BMI would class someone as 
healthy weight 
overweight 
obesity I
obesity II
obesity III
A 
healthy 18.5-24.9
overweight 25-29.9
obesity I 30-34.9
obesity II 35-39.9
obesity III 40 or more
27
Q

in what ethnicities do you use lower BMI thresholds to reduce the risk of conditions such as T2DM

A

black African, African-caribbean and Asian (south asian and Chinese)

28
Q

what are the main illnesses that are linked to obesity

A 
T2DM
fatty liver diease
HTN
gallstones 
GORD
psychological and psychiatric morbidities
29
Q

Under what circumstances would you consider referral to a tier 3 service for obesity

A

o the underlying causes of being overweight or obese need to be assessed
o the person has complex disease states or needs that cannot be managed adequately in tier 2 (for example, the additional support needs of people with learning disabilities)
o conventional treatment has been unsuccessful
o drug treatment is being considered for a person with a BMI of more than 50 kg/m2
o specialist interventions (such as a very-low-calorie diet) may be needed
o surgery is being considered.

30
Q

what is the criteria for bariatric surgery

A

o They have a BMI of 40 kg/m2 or more, or between 35 kg/m2 and 40 kg/m2 and other significant disease (for example, type 2 diabetes or high blood pressure) that could be improved if they lost weight.
o All appropriate non-surgical measures have been tried but the person has not achieved or maintained adequate, clinically beneficial weight loss.
o The person has been receiving or will receive intensive management in a tier 3 service[10].
o The person is generally fit for anaesthesia and surgery.
o The person commits to the need for long-term follow-up.

31
Q

if orlistat does cause at least a ___% body weight loss within 12 weeks of starting, then the treatment must be stopped

A

5%

32
Q

In an adrenal crisis how will the patient present

A

hypotensive and hyponatraemia

33
Q

what would the treatment of an adrenal crisis be

A

o Needs a random serum cortisol and plasma ACTH
o TREAT with high dose, replacement hydrocortisone – 100mg IV every 6 hours
o IV saline- 2/3 L first hour, then 3-4 L per day

34
Q

What important structure is situated immediately anteriorly to the pituitary gland and what can. allege pituitary tumour cause

A

optic chiasm

bitemporal hemianopia

35
Q

Explain the HPA axis

A

hypothalamus releases corticotrophin-releasing hormone (CRH) which acts on the pituitary gland to cause adrenocorticotropic hormone (ACTH) to be released and acts of the adrenal glands to make them release cortisol

36
Q

where are the adrenal glands located and what is their role

A

over the medical aspects of the upper poles of each kidney

role is to secrete steroid and catecholamine hormones

37
Q

arterial supply is via 3 main arteries;

Where does the anterior supra-renal artery arise from

A

inferior phrenic artery

38
Q

arterial supply is via 3 main arteries;

where does the middle supra-renal artery arise from

A

directly from the abdominal aorta

39
Q

arterial supply is via 3 main arteries;

where doe the inferior suprarenal artery arise from

A

renal artery

40
Q

what is the venous drainage of the adrenal gland

A

suprarenal veins
left suprarenal vein drains into the left renal vein
right suprarenal vein drains into the inferior vena cava

41
Q

what is the issue with the adrenal glands having a rich blood supply

A

accounts for frequent metastasis of malignancies such as lung cancer, to the adrenal glands

42
Q

Name the 4 main regions of the adrenal gland from most superficial to deep

A

Zona Glomerulosa
Zona Fasiculata
Zona Reticularis
medulla

43
Q 
which region of the adrenal gland produces minteralcorticoids and give an example of one 
Zona Glomerulosa 
Zona Fasiculata 
Zona Reticularis 
medulla
A

zona glomerulosa

aldosterone

44
Q

which disease affects the Zona Glomerulosa and the production of aldosterone

A

Conns

Excess aldosterone results in electrolyte imbalances and hypertension

45
Q 
which regions of the adrenal gland produces glucocorticoids and give an example 
Zona Glomerulosa 
Zona Fasiculata 
Zona Reticularis 
medulla
A

Zona Fasiculata

cortisol

46
Q

which disease affects the Zona fasculata and affects. glucocorticoid hormone release

A

Cushing’s syndrome

Adrenal tumour resulting in excess glucocorticoid secretion

47
Q 
which region of the adrenal gland produces androgen precursors and give some examples 
Zona Glomerulosa 
Zona Fasiculata 
Zona Reticularis 
medulla
A

zona rectularis

DHEA & androstenedione (converted to testosterone or oestrogen by gonads)

48
Q

what disease Resulting in lack of mineralocorticoids and glucocorticoids and excess of testosterone and its derivatives

A

congenital adrenal hyperplasia

49
Q 
which region of the adrenal gland produces catecholamines and give some examples 
Zona Glomerulosa 
Zona Fasiculata 
Zona Reticularis 
medulla
A

medulla

Adrenaline and noradrenaline

50
Q

which disease is a neuroendocrine tumour of the medulla and results in excess secretion of adrenaline

A

Phaeochromocytoma

51
Q

The drug metyrapone is a glucocorticoid synthesis inhibitor which inhibits 11 beta-hydrolase, therefore inhibiting synthesis of what hormone

A

cortisol

52
Q

what are hte long term side effects of steroid therapy

A 
o	HTN
o	Diabetes mellitus 
o	Fatty liver 
o	Susceptibility to infection 
o	Osteoporosis 
o	Avascular necrosis of bone 
o	Skin sepsis 
o	Electrolyte disturbance; hypokalaemia, metabolic alkalosis
53
Q

what is important to consider if someone is on long term steroids

A

if they become sick they will need a higher dose of treatment and if they are having surgery then they need steroid cover if they are on a dose of 10mg or more of something like prednisolone

54
Q

What patients should receive steroid cover for surgery

A

o Patients on corticosteroids at a dose of 10 mg or more of prednisolone (or equivalent) daily (equivalent to betamethasone 1.6 mg, dexamethasone 1.6 mg, hydrocortisone 40 mg, methylprednisolone 8 mg daily).
o Patients who have received corticosteroids 10 mg daily within the three months preceding surgery.
o Patients on high-dose inhaled corticosteroids (for example, beclomethasone 1.5 mg a day).

Medicine Y3 TCD 13-24 (32 decks)

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