Adrenal Gland Flashcards
Cushing’s is…
Excess cortisol
What are the causes of Cushing’s syndrome?
- 65% = pituitary
- 25% = adrenals
- 10% = ectopic source (small cell lung ca), non-pituitary, ACTH producing tumour
Cushing’s Symptoms?
SWEDISH
Differentials of Cushings:
- Chronic severe anxiety and/or depression
- Prolonged excess alcohol consumption
- Obesity
- Poorly controlled diabetes
- HIV infection
How is Cushing’s diagnosed?
- Perform at least two first-line biochemical tests to obtain the diagnosis:
- Urine free cortisol (UFC) (at least two measurements)
- 1-mg overnight Dexamethasone Suppression Test (ODST)
- Longer low-dose Dexamethasone Suppression Test (LDDST) (2 mg/d for 48 h).
- CT/MRI of Pituitary and Adrenal
Treatment of Cushings:
• Metyrapone, ketoconazole, and mitotane can all be used to lower cortisol by directly inhibiting synthesis and secretion in the adrenal gland.
What are the complications of Cushings?
Premature death in untreated Cushing’s syndrome are caused by vascular disease (MI/CVA), uncontrolled DM and infections.
Secondary vs Primary adrenal insufficiency:
Can also be caused by:
- TB (most common worldwide)
- Infections – AIDS, fungal
- Adrenal haemorrhage (caused by sepsis, meningitis)
- Metastatic spread to adrenals
- Amyloidosis
- Adrenalectomy
- Genetic/congenital defects
What is Addison’s Disease?
Addison’s Disease refers to the specific condition where the adrenal glands have been damaged, resulting in a reduction in the secretion of cortisol and aldosterone. This is also called Primary Adrenal Insufficiency. The most common cause is autoimmune.
Primary Auto-immune Addison’s:
- True Addison’s:
- Affects 1 in 10000 in UK – rare
- Common presentation between 30 and 50
- Affects women more
- 70-90% have autoimmune basis – cytotoxic T cells
- Clinical and biochemical insufficiency only occurs once >90% of the gland is destroyed.
Symptoms and signs of Addisons and adrenal insufficiency:
Hyperpigmentation
Weight loss
Low BP
Nausea and GI problems
What are the symptoms of Adrenal crisis?
- Fever
- Syncope
- Severe vomitting and diarrhoea
- Convulsions
- Hypoglycemia
- Hyponatremia
Investigations of Adrenal insufficiency:
Blood tests:
- Low Na, low cortisol
- Low aldosterone causing high K
- High adrenocorticotrophic hormone (ACTH)
- Low glucose
- CXR and CT/MRI of adrenals
Why is a chest xray done in cases of adrenal insufficiency?
To check for TB.
Causes of adrenal insufficiency?
Auto-immune destruction
TB (most common worldwide)
Infections – AIDS, fungal
Adrenal haemorrhage (caused by sepsis, meningitis)
Metastatic spread to adrenals
Amyloidosis
Adrenalectomy
Genetic/congenital defects
Amyloidosis
Abnormal protein, called amyloid, builds up in your organs and interferes with their normal function.
Treatment of adrenal insufficiency
Treat cause.
Replace steroids.
Symptoms of an Addisonian Crisis:
Treatment of Addisonian crisis
- Medical emergency
- Bloods, large bore cannula
- Seek help if you suspect
- Iv Hydrocortisone
- Iv fluids
- Iv glucose if needed
Mineralcorticoid =
= Aldosterone produced by zona glomerulosa
What are the actions of Aldosterone?
- Sodium retention.
- Excretion of Potassium
- Increase blood volume and pressure.
- H+ excretion.
Aldosterone acts where?
On the DCT (distal convuluted tubule)
What are the primary causes of hyperaldosteronism?
- Idiopathic most common.
- Conn syndrome - Adenoma secretes to much aldosterone.
- Familial - where aldosterone is produced in repsonse to ACTH aswell as angiotensinogen 2.
What are the secondary causes of hyperaldosteronism?
Usually due to excess renin - can result from chronic low blood pressure in cases of congestive heart failure / cirrhosis.
- Decreased renal perfusion (arteriolar nephrosclerosis, renal artery stenosis)
- Arterial hypovolemia and edema (congestive heart failure, cirrhosis, nephrotic syndrome)
- Pregnancy (due to estrogen-induced increases in plasma renin substrate)
Metabolic profile of hyperaldosteronism:
High Na+
Low K+
Alkalosis due to H+ loss.
Symptoms of Hyperaldosteronism:
Raised blood pressure.
Resistant raised BP big sign.
How is hyperaldosteronism diagnosed?
Measuring levels of renin and aldosterone.
Plasma:
- Hypokalemia
- Aldosterone:renin ratio (ARR): Plasma renin/aldosterone
Urine :
• Increase urinary potassium
Imaging :
- CT/ MRI
- Adrenal vein sampling
- Functional imaging
How is hyperaldosteronism treated?
Spironolactone (potassium sparing diuretic).
- spironolactone competitively binds to aldosterone receptors on the principal and intercalated cells of the DCT - blocks aldosterone.
Removal of tumour in Conn’s syndrome.
Management of congestive heart failure and cirrhosis.