Adrenal Flashcards
Zones and hormones of adrenal gland
- Zona glomerulosa - Mineralocorticoid - Aldosterone
- Zona fasciculata - Glucocorticoid - Cortisol
- Zona reticularis - androgen - DHEA
- Medulla - Catecholamines - epi/norepinephrine
What is Cushings syndrome
Excess Cortisol
What is Cushing disease
Excess ACTH - pituitary abn
causing excess cortisol
Causes of Cushing syndrome
- Iatrogenic (steroid intake)
- Cushing disease (pituitary ACTH exces)
- Tumour/adrenal hyperplasia
- Oat cell lung CA - non-endocrine tumour releasing CRH (Corticotropin releasing hormone)
- Ectopic ACTH
C/F of Cushing syndrome (10)
- Central obesity
- Buffaloe hump
- Proximal muscle wasting
- Cushing facies - moon face
- Abdominal striae
- Thin skin
- Hypertension
- Hyperglycemia
- Osteoporosis
- Hirsutism - androgen release excess
- Hypokalemia - mineralocorticoid excess (not clinically significant)
Investigations, gold standard for cushing syndrome
- 24 hr urinary free cortisol - Gold standard
- Dexamethasone suppression test (done 1st)
- Salivary cortisol at 12am (normally low)
Dexamethasone suppression test
1mg dexa given at 11pm
Cortisol levels checked at 8 am
- Come back to normal level on normal pts
*Drugs interacting causing false results-
1. Rifampicin
2. Carbamazepine
3. Phenytoin
*Higher cortisol in stress - anorexia, bulimia, alcohol withdrawal, depression, starvation
Test to distinguish b/w high ACTH due to pituitary adenoma and ectopic ACTH release
High dose Dexa suppression test
Pituitary ACTH - suppressed
Ectopic ACTH - not suppressed
MRI - pituitary gland done continued with inferior petrosal sinus sampling
(or)
CT full body for Ectopic focus
In high cortisol cases, how do you recognise if the cause is adrenal gland
ACTH levels are low (feedback mechanism)
f/b
CT adrenal gland (hyperplasia/CA)
Unresectable adrenal tumour can be treated with which drugs
- Ketoconazole
- Metyrapone
What is Addisons disease
Low Cortisol … low aldosterone
D/t destruction of adrenal gland
Autoimmune mainly
C/F of Addisons disease
- Weakness
- Hypotension
- Hypoglycemia
- Hyperpigmentation of buccal mucosa, hard palate, skin of hand creases
- *Hyperkalemia, Hyponatremia, water loss
What is Cosyntropin
ACTH analogue
Screening test for Addisons disease
Cosyntropin 250 micrograms …
check cortisol after 30-60mins
Still low - Adrenal insufficiency
Primary if ACTH high (adrenal problem)
Secondary if ACTH low (pituitary problem)
Hyperaldosteronism symptoms
Hypokalemia related
Weakness, cramps
Primary and secondary hyperaldosteronism
Primary - adrenal adenoma
Ald high, Renin low (feedback inhibition)
Secondary - dehydration
Renin high … Ald high
Pheochromocytoma Symptoms
Headache
sweating
palpitations
*HTN not reducing with medication
Pheochromocytoma caused due to
Tumour of adrenal medulla (epi/norepinephrine)
Pathology shows which kind of cells in pheochromocytoma
Chromaffin cells
Rule of 10’s in Pheochromocytoma
10% Malignant
10% Bilateral
10% extra adrenal - bladder/Zuckerkandl organ (bifurcation of aorta)
10% Calcify
10% Kids
Diagnosis of Pheochromocytoma
1.Best initial test
↑ free metanephrine level in plasma
- Confirmation: 24-hour urine collection
*↑ vanillyl mandelic acid (breakdown of
norepinephrine and epinephrine)
*↑ metanephrines (more sensitive than
VMA) - Histology
chromaffin cells with enlarged
dysmorphic nuclei - Adrenal CT MRI
- MIGB scan
Rx for HTN in pheochromocytoma
Alpha blockers (prazocine)
