Adrenal Disorders Flashcards
This deck covers the main adrenal disorders:
- Cushing’s Syndrome
- Addison’s Disease
- Conn’s Syndrome
- Pheochromocytoma
2 types of primary adrenocortical insufficiency
Acute and chronic adrenocortical insufficiency
Adrenal enzyme defects (CAH)
What is Addison’s Disease? [2]
Insufficiency adrenal cortex [1] causing insufficient glucocorticoids and mineralocorticoids [1]
What causes Addison’s? Primary vs Secondary
Mainly Autoimmune
Primary causes
* tuberculosis
* metastases (e.g. bronchial carcinoma)
* meningococcal septicaemia (Waterhouse-Friderichsen syndrome)
* HIV
* antiphospholipid syndrome
Secondary causes
* pituitary disorders (e.g. tumours, irradiation, infiltration)
Exogenous glucocorticoid therapy
*Primary Addison’s is associated with hyperpigmentation whereas secondary adrenal insufficiency is not
How does Addison’s Present?
State 7 clinical feature with the most likely at the top
In decreasing order of likelihood:
- Weakness, fatigue, weight loss & anorexia
- Skin pigmentation or vitiligo (loss of pigment)
- Hypotension
- Unexplained hypoglycaemia
- Salt Craving
- Postural Symptoms
- N&V + Diarrhoea
What tests do you do if you suspect Addison’s? [5]
- Routine bloods
- Random Cortisol
- Synacthen Test and cortisol levels half hourly
- Plasma ACTH
- Adrenal Auto-antibodies
What does a random cortisol test tell you about addison’s and why is it first line investigation?
If they’re cortisol is >700nmol/l then it’s not Addison’s
First line investigation as high negative predictive value
What does a synacthen test tell you about Addison’s?
Give ACTH to see how much their cortisol goes up
In addison’s they should produce very little cortisol
Why test plasma ACTH in Addison’s? [2]
If its elevated it confirms Primary Adrenal Insufficiency (due to negative feedback)
If its suppressed however the source is secondary (cause is pituitary or hypothalamic dysfunction)
Rx Addison’s disease? [2]
State dose
Glucocorticoid replacement e.g. Hydrocortisone 20-30mg
Mineralocorticoid replacement e.g. Fludrocortisone 50-300 mcg daily
Sick day rules for steroid replacement
Why are glucocorticoid replacements given in divided doses? Give an example of what this may mean
During stressful stimuli they need an increased dose, as their own production is suppressed. But as stress abates, reduce by 50% per day until back on usual dose
Double dose on minor or intercurrent illness
Divided doses: eg
HC 20mg at 9h then 10mg at 18h
Why? To mimic diurnal variation, avoid at bedtime as can cause insomnia
What other conditions are associated with Addison’s [3]
Other autoimmune conditions like:
- Type 1 DM
- Thyroid disease
- Premature ovarian failure
How does Cushing’s Disease present?
- Moon face & pendulous breasts/abdomen, edema
- Proximal myopathy
- Thin skin > ulcers
- Spontaneous purpura
- DM
- Cardiac failure due to muscle atrophy
- Hirsutism
Types of Cushing’s? [6]
ACTH dependant
- Pituitary Tumour - 75% (cushings disease)
- Ectopic ACTH - 5% (lung cancer)
ACTH independant:
- Adrenal adenoma or carcinoma -20%
- CCS therapy
Investigations: Cushing’s Disease
What are the 2 tests used for screening Cushing’s Disease?
What screening test is reliable for Cushing’s syndrome?
Screening
Overnight dex suppression test
24 hour urine cortisol
Late night salivary cortisol - Cushing’s syndrome
Paired morning/midnight cortisol/ACTH test to check ACTH dependency
If ACTH dependent do a High dose Dex test to identify source of ACTH
Localise with MRI/CT/CT chest as appropriate