Adrenals Flashcards
Name the sections within the adrenals and what they produce
‘deeper you go, sweeter it gets’
From out (cortex) to in (medulla):
- Glomerulosa = mineralcorticoids (aldosterone)
- Fasciculata = glucocorticoids (cortisol)
- Reticularis = sex steroids
- Medulla = catecholamines (adrenaline, noradrenaline)
Causes of primary hyperaldosteronism
Conn’s syndrome (70% cases, young females)
Bilateral adrenal cortex hyperplasia (30% cases, older males)
Familial hyperaldosteronism
Aldosterone producing adrenal carcinoma (RARE)
What symptoms do you get in hyperaldosteronism and why?
XS aldosterone leads to increased salt and water retention by acting on Na+ channels and Na+/K+ ATPase pump in the collecting duct
Increase blood volume => hypertension
- headache, retinopathy, resistant to medication
Increased K+ secretion => hypokalaemia
- muscle weakness/cramps, polyuria, nocturia, paraesthesia
Ix for primary hyperaldosternoism
Screening:
- plasma K+ levels (low in 20% pts)
- urine K+ (high)
- plasma aldosterone (high)
- plasma aldosterone:renin ratio (high)
Confirmatory:
- salt loading, postural test, CT/MRI
- fludrocortisone suppression test (BMJ best practice; aldo increased, renin decreased)
- bilateral adrenal vein catheritisation (elevated in 1 indicates adenoma laterilised)
Tx of primary hyperaldosteronism
Laprascopic adrenalectomy = Conn’s syndrome
Spironolactone or eplerenone if side effects not tolerated = monitor serum K+, creatinine and BP
What causes Cushing’s syndrome?
Exogenous
- steroid exposure (most common cause)
Endogenous
- ACTH-dependent (80%) => pituitary adenoma, ectopic ACTH
- ACTH-independent (20%) => benign adrenaladenoma, adrenal carcinoma (rare)
Possible signs of Cushing’s
HTN
Facial plethora
Moon face
Interscapular fat pad
Proximal muscle weakness
Central obesity
Pink/purple striae on abdo/breast/thighs
Kyphosis (due to vertebral fracture)
Fractures
Pigmentation in ACTH-dependent cases
Ankle oedema
Ix for Cushing’s
Serum glucose
- high risk glucose
1st line high sensitivity tests
- low dose dexamethasone suppresion test (should suprress but doesn’t)
- late-night salivary cortisol
- overnight dexamethasone suppresion test (+ve is morning >50[unit])
Determine underlying cause
- ACTH- dependent => plasma ACTH, inferior petrosal sinus sampling, high dose dexamethasone suppresion test, pituitary MRI
- ACTH-independent => CT/MRI adrenals, plasma ACTH
Complications of Cushing’s
Diabetes
Osteoporosis
HTN
Pre-disposition to infections
Mx of Cushing’s
Medical
- metyrapone/ketoconazole (use pre-op or if unfit for surgery)
Surgery
- transphenoidal resection of pituitary adenoma
- ectopic ACTH; treatment directed at tumour
- adrenal adenoma/carcinoma; surgery to remove
Radiotherapy
- if persistant post-op cortisol
Complications and prognosis of Cushing’s
Surgical treatment
- CSF leakage, meningitis, sphenoid sinusitis, hypopituitarism
Radiotherapy treatment
- hypopituitarism, radionecrosis, increased risk of 2nd intracranial tumour and stroke
50% survival rate if untreated
Common to become depressed after successful treatment
How may a phaeochromocytoma present?
RARE - young-onset or resistant intractable HTN
Paroyxmal attacks
- P alpitations
- H eadaches
- E pisodic sweating
What are familial causes of phaeochromocytomas?
MEN2a (multiple endocrine neoplasm)
VHL (von-Hippel Lindau syndrome)
NF1 (neurofibromatosis 1)
Signs and sx of a phaechromocytoma
Wt loss, fever, tachycardia, pallor, postural hypotension, HTN
Sweating, headaches, dyspnoea, palpitations, constipation, epigastric, nausea, tremor, anxiety
Ix for phaeochromocytoma
24hr urine collection (sens + spec of 98&)
Plasma free (metabolites of catecholamines present)
Tumour localisation (CT>MRI, i-123 MIBG scintigraphy)
Genetic testing
Types of adrenal insufficiency
Primary => Addison’s disease (acute/insidious onset, autoimmune)
Secondary => pituitary or hypothalamic disease (decreased ACTH secretion)
Causes of adrenal insufficiency
Autoimmune
Infections (meningococcal septicaemia, TB)
Infiltration (lymphoma, amyloidosis, mets)
Inherited (ACTH mutation rec.)
Iatrogenic (after bilateral adrenalectomy, sudden cessation of long-term steroid therapy)
Signs and sx of adrenal insufficiency
Increased pigmentation (buccal mucosa, skin creases, nails, pressure points), postural hypotension, loss of body hair in women (androgen deficiency), associated with AI conditions (vitiligo)
Fatigue, weakness, myalgia, wt loss (anorexia), D&V, abdo pain, depression
Presentation of an Addisonian crisis
Hypotensive shock, tachycardic, pale, cold, clammy
= acute adrenal insufficiency (N&V, abdo pain)
= major haemodynamic collape (SHOCK)
= precipitated by stress (infection, surgery)