Adrenal Disorders Flashcards
What catecholamines are secreted by the the adrenal medulla?
Adrenaline
Noradrenaline
What veins and nerves are found in the adrenal medulla?
Medullary veins
Splanchnic Nerves
What regulates Aldosterone?
Renin-Angiotensin-ALDOSTERONE-System (RAAS)
Plasma Potassium
What are the 6 classes of steroid receptors?
Glucocorticoid Mineralocorticoid Progestin Oestrogen Androgen Vitamin D
What action do glucocortiocoids have on the circulatory/ renal systems?
Increased:
- Cardiac output
- Blood pressure
- renal blood flow
- Glomerular Filtration Rate
What effect do glucocorticoids have on the CNS?
Mood lability
Euphoria/psychosis
Decreased libido
How do Glucocorticoids affect the bone and connective tissue?
Accelerates osteoporosis Decreases: - Serum calcium - collagen formation - wound healing
What are the 3 main uses of corticosteroids in practice?
- Suppress inflammation
- Suppress immune system
- Replacement treatment
Where are the mineralocorticoid receptors found?
Kidneys
Salivary glands
Gut
Sweat glands
What can cause PRIMARY adrenal insufficiency?
- Addison’s disease
- Congenital Adrenal Hyperplasia (CAH)
- Adrenal TB/malignancy
What causes secondary adrenal insufficiency?
- lack of ACTH stimulation
- Iatrogenic (removal of steroid Tx)
- Pituitary/hypothalamic disorders
What is addison’s disease?
Autoimmune destruction of adrenal cortex
Autoantibodies positive in 70%
What percentage of the adrenal cortex is usually destroyed before people experience symptoms in Addison’s disease?
> 90%
What other autoimmune diseases are associated with Addison’s disease?
- Type 1 DM
- autoimmune thyroid disease
- pernicious anaemia
What features of biochemistry would make you suspicious of adrenal insufficiency?
Low Na+
High K+
hypoglycaemia
What treatments are used to manage adrenal insufficiency?
- Hydrocortisone as cortisol replacement
- Fludrocortisone as aldosterone replacement
If people are on treatment for adrenal insufficiency, what should they be educated on?
- ‘sick day rules’ due to needing more steroid when ill
- Cannot stop medication suddenly
- Need to wear identification
What hormones are diminished in secondary adrenal insufficiency?
CRH and ACTH
Where are striae often seen in Cushing’s syndrome and why?
- Around stomach (due to increased central obesity)
- Inside of proximal thighs
What hormone is found in excess in Conn’s syndrome
Aldosterone
Describe what is meant by Primary Aldosteronism?
Autonomous production of aldosterone independent of its regulators (angiotensin II/potassium)
What clinical features normally indicate Primary Aldosteronism?
- Significant hypertension
- Hypokalaemia (in around 30%)
- Alkalosis
What are the main causes of primary aldosteronism?
- Adrenal adenoma (Conn’s)
- Bilateral adrenal hyperplasia (commonest cause)
How is Aldosterone excess confirmed?
- Aldosterone to renin ratio (ARR)
- Saline suppression test
(Failure of plasma aldosterone to suppress by > 50% with 2 litres of normal saline)
How can the type of primary aldosteronism be confirmed?
- Adrenal CT to demonstrate adenoma
- Adrenal vein sampling to confirm adenoma is true source of aldosterone excess
What surgery can be used to treat primary aldosteronism?
- Unilateral laparoscopic adrenalectomy
Only if adrenal adenoma confirmed by vein sampling
What type of treatment can be used in bilateral adrenal hyperplasia?
Use Mineralocorticoid Receptor antagonists (spironolactone or eplerenone)
Aldosterone excess is a common cause of secondary hypertension. TRUE/FALSE?
TRUE
What enzyme is deficient in Congenital Adrenal Hyperplasia
21α hydroxylase
Is Congenital Adrenal Hyperplasia Autosomal Dominant or Recessive?
Autosomal Recessive
What marker is tested for in the suspicion of Congenital Adrenal Hyperplasia
17-OH Progesterone
How does Congenital Adrenal Hyperplasia classically present in males?
- Adrenal insufficiency
- Often around two to three weeks
- Poor weight gain
- Biochemical pattern (Low Na, High K, Hypoglycaemic)
How does Congenital Adrenal Hyperplasia classically present in females?
Genital ambiguity
Describe a “non-classical” presentation of Congenital Adrenal Hyperplasia
Hirsutism Acne Oligomenorrhoea Precocious puberty Infertility or sub-fertility
How are children with CAH usually treated?
- Glucorticoid replacement
- Mineralocorticoid replacement ONLY SOME
- Surgical correction
=> Achieve maximal growth potential
If CAH is not noticed until adulthood, how is it treated at this stage?
- Control androgen excess
- Restore fertility
- Avoid steroid over-replacement
How does Phaeochromocytoma usually present?
- Labile hypertension
- Postural hypotension
- Paroxysmal sweating/headache/pallor/tachycardia
- *sometimes presents with none of these**
What colour are phaechromocytomas and why?
Chromaffin cells reduce chrome salts to metal chromium
=>resulting in a brown colour reaction
In what section of the adrenal gland is a phaechromocytoma found?
Medulla
Why does compression of a phaechromocytoma cause an increase in blood pressure?
Squeezes out noradrenaline and adrenaline
=> sympathetic drive increases BP
What complications of phaeochromocytoma can appear to present as stand alone illness?
Left ventricular failure Myocardial necrosis Stroke Shock Paralytic ileus of bowel
What biochemical abnormalities are often seen in Phaechromocytoma?
- Hyperglycaemia – adrenaline secreting tumours
- low K+ level
- raised Hb conc.
- Mild hypercalcaemia
- Lactic acidosis – in absence of shock
What patients should be investigated on suspicion of phaeochromocytoma?
- Family members with syndromes
- Resistant hypertension
- The young [<50] with hypertension
- Classical symptoms
- Consider with hypertension and hyperglycaemia
How is an excess in catecholamines in phaeochromocytoma confirmed?
Urine – 2x24hour catecholamines or metanephrins
What imaging modalities can be used to identify the source of catecholamine excess?
MRI Scan (Abdomen/Whole body) MIBG – meta-iodobenzylguanidine PET Scan
What medical treatments are used in phaeochromocytoma?
- Phenoxybenzamine (α-blocker)
- Propranolol, atenolol or metoprolol (β-blocker)
A before B
What surgical treatment can be used in phaechromocytoma?
Laparoscopic surgery
Attempt full excision
**chemotherapy can also be used if malignant
=> Radio-labelled MIBG
Phaeochromocytoma is linked to what genetic conditions?
- Multiple Endocrine Neoplasia 2 (MEN2)
- Von-Hippel-Lindau syndrome
- Succinate dehydrogenase mutations (SDH)
- Neurofibromatosis
- Tuberose sclerosis