Clinical Aspects of Adrenal Disorders Flashcards
What does each layer of the adrenal glands secrete?
Zone Glomerulosa- Aldosterone
Zone Faticulata- Cortisol
Zona Reticularis- Androgens
What can hypofunction of the adrenal glands be caused by?
- Primary adrenal insufficiency
- Addison’s disease
- Immune destruction
- Invasion
- Infiltration
- Infection
- Infarction
- Iatrogenic
- Adrenal enzyme defect
- Congenital adrenal hyperplasia (most commonly 21-hydroxylase deficiency)
- Addison’s disease
What enzyme most commonly causes adrenal enzyme defect?
21-hydrolase deficiency
What does adrenal enzyme defect cause?
Congenital adrenal hyperplasia
State the common autoantibodies responsible for Addisions disease
Positive adrenal autoantibodies to 21-hydroxylase
How is the adrenal cortex involved in Addison’s disease?
Lymphatic infiltrate of adrenal cortex
Addison’s disease is often associated with other autoimmune disease, what are some examples?
Thyroid disease
Type 1 diabetes mellitus
Premature ovarian failure
What are some common symptoms of primary adrenal failure?
What are some clues to a diagnosis of adrenal failure?
- Disproportion between severity of illness and circulatory collapse/hypotension/dehydration
- Unexplained hypoglycaemia
- Other endocrine features (hypothyroidism, body hair loss, amenorrhoea)
- Previous depression or weight loss
Investigations for Adrenal Insufficiency
Synacthen test (and basal ACTH)- synthetic ACTH given- +ve if cortisol does not increase
Routine bloods (U and Es, glucose, FBC)
Random cortisol (<450nmol/L)
MRI/CT for Adrenal/Pituitary tumours
Treatment for Primary Adrenal Insuffiency
Glucocorticoid replacement (replace cortisol):
- Hydrocortisone 20-30mg
- Prednisolone 7.5mg
- Dexamethasone 0.75mg
Minerocorticoid Replacement (aldosterone):
- Fludocrtisone 50-300mg
What are 3 important self-care rules for patients on steroids?
- Never miss steroid dose
- Double the hydrocortisone dose in the event on intercurrent illness (such as flu or UTI)
- If severe vomiting or diarrhoea call for help without delay
What are some causes of hypersecretion of adrenal glands?
- Cortex
-
Cushing’s syndrome (cortisol, androgens)
- Adenoma, carcinoma or bilateral hyperplasia
-
Conn’s syndrome (aldosterone)
- Adenoma or bilateral hyperplasia
-
Cushing’s syndrome (cortisol, androgens)
- Medulla
- Phaeochromocytoma
What does Cushing’s syndrome cause hypersecretion of?
Cortisol, androgens
What does Conn’s syndrome cause hypersecretion of?
Aldosterone
What are some causes of primary Cushing’s syndrome?
Pituitary Adenoma, carcinoma or bilateral hyperplasia
What are some causes of primary Conn’s syndrome?
Adenoma or bilateral hyperplasia
What is the clinical presentation of Cushing’s syndrome?
What are some ACTH dependent causes of Cushing’s syndrome?
- Pituitary tumour (Cushing’s disease)
- 75% of cases
- Ectopic ACTH secretion (such as lung carcinoid)
- 5% of cases
What are some ACTH indendent causes of Cushing’s syndrome?
Adrenal Tumour
Investigations for Cushings
1) 24hr Urinary free cortisol (12-135nmol/day)
2) Low Dose Dex test
3) High Dose Dex test (if low dose comes back abnormal)
Investigations for Conns Syndrome
- 1st Line: Aldosterone to renin ratio (Plasma Aldosterone:Plasma Renin Activity Ratio PA:PRA)
- 24Hr Urinary aldosterone (12 ug/day)
- CT MRI
- Serum Electrolytes (High Na, Low K)
- Blood gas- alkalosis
What does low PA low PRA potentially indicate
Congenital Adrenal Hyperplasia
What does high PA low PRA potentially indicate
Conns Syndrome
What does high PA high PRA potentially indicate
Seconday Hyperaldosteronism (renal problems)
What is phaeochromocytoma?
Rare tumour of adrenal gland tissue that causes release of epinephrine and norepinephrine
What is the clinical presentation of phaeochromocytoma?
- Hypertension
- Paroxysmal attacks
- Headache
- Sweating
- Palpitations
- Tremor
- Pallor
- Anxiety
What percentage of phaemchromocytoma cases are due to inherited causes and state 2 common ones
30% of the time
MEN 2 & Von Hippel- Landau
Investgations for Phaechomocytoma
1) Clinical suspicion
2) Endocrine workout
- Free metanephrine in plasma or urine
- ALD/PRA ratio
3) Imaging work up
- CT
- Chemical shift MRI
Pathophysiology of congenital adrenal hyperplasia
21-hydroxylase deficiency (90%)
Complications of congenital adrenal hyperplasia
Neonatal salt crises
Ambiguous genitalia (girls)
Pseudo-precocious puberty (boys)
Hirturism (women)
Complications of Addisions Disease (Addisonian Crisis)
Hyperkalemia
Hyponatreamia
Hypoglycaemia
Hypotension
Reduced Consciousness
Management of an Addisionian Crisis
Paraenteral Steriods
IV Fluid Resus
Correct Hypoglycaemia
Electrolyte Correction
Complications of Cushings Syndrome
Tissue breakdown causes:
- Muscle wasting
- Bone weakness
- Skin Weakness
Insulin is anatogonised by cortisol:
- Diabetes
Immune supression
Hypertension & Cardiac Hypertrophy due to Na++++
Management of Cushings
Reduce Steriods
Surgery
Meds to detroy adrenal cortico cells:
- Mitotane
Radiotherapy
Management of Conns Syndrome
Surgey
Aldosterone Antagonists:
- Epilerenone
- Spironolactone
1 Complication of Conns
Secondary Hypertension due to Na+++++
Phaechromocytoma is the 10% tumour
10%
- Bilateral
- Tumour
- Malignant
- Outside adrenal gland
- Hyperglycaemia
