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Flashcards

Adrenal Disease

Ellie Britt Endocrinology English 32 cards

hypothalamo-adrenal axis

Cards in this deck (32)

  1. 1adrenal gland anatomy and functioncapsule
    Adrenal Cortex
    Glomerulosa :Aldosterone --> salt
    Fasciculata: Cortisol --> sugar
    Reticularis: Androgens --> sex
    Adrenal Medulla
    Chromograffin cells: catecholamines
  2. 2regulation of the RASRenin major regulator of aldosterone production
    Activated in response to low blood pressure
    Leads to production of Ang II which causes direct (vasoconstriction) and indirect (aldosterone) methods of BP elevation
  3. 3action of aldosteroneAldosteron binds to MR and:
    - upregulates ENaC in collecting duct and colon, mor eNa+ absorption
    - Cl- is reabosrbed
    - upregulates basolateral Na+/K+ pumps
    - secretion of K+ into tubular lumen
  4. 4hypothalamo-adrenal axishypothalamo-adrenal axis
  5. 5When is a secondary cause for hypertension more likely?- young
    - resistant/severe hypertension
    - clinical suspicion
  6. 6hallmarks of primary aldosteronism best screening tool?hypertension and hypokalaemia
    low renin
    best screening tool is increased ARR (>35 is suspicious)
  7. 7causes of primary aldosteronism40% adenoma; 60% bilateral hyperplasia
  8. 8What BP medications to stop in aldosterone excess? Alternatives?Definitely stop β blockers and MR antagonists (they increase ARR)
    Alternative drugs include
    α-blockers/verapamil/hydralazine
  9. 9Saline suppression test2L saline over 4 hours
    4h aldosterone >270 pmol/l highly suspicious
  10. 10Management of primary aldosteronismSurgical
    - Unilateral laparoscopic adrenalectomy
    - Only if adrenal adenoma !!!!!!!!
    - Cure of hypokalaemia
    - Cures hypertension in 30-70% cases
    Medical
    - Use MR antagonists (spironolactone or eplerenone)
    - Or amiloride (blocks Na reabsorption by kidney)
  11. 11clinical features of Cushings syndromeweight gain
    hirsutism
    psychiatric
    proximal myopathy
    obesity (truncal or generalised)
    plethora
    moon facies
    hypertension
    bruising
    striae
  12. 12screening for Cushings syndromePerform 2 of the following:
    Urinary free cortisol
    - X 3 cortisol:creat ratio or 24 hr urine collection for cortisol
    Dexamethasone suppression test
    - Either overnight or low dose test over 48 hours
    - Plasma cortisol should be undetectable in normal circumstances
    Late night salivary cortisol
    - Should be undetectable or very low in normals
  13. 13HPA axishypothalamus (CRH) --> anterior pituitary (ACTH) --> adrenal cortex (CORT)
  14. 14causes of Cushing's syndrome - ACTH dependent - ACTH independentACTH dependent
    - Pituitary adenoma (68%) Cushing’s Disease
    - Ectopic ACTH 12%
    - Ectopic CRH <1%
    ACTH independent
    - Adrenal adenoma 10%
    - Adrenal carcinoma 8%
    - Nodular hyperplasia 1%
  15. 15Localisation of cortisol sourcePlasma ACTH
    - If low then adrenal source
    High dose dexamethasone suppression test
    - If *pituitary*, cortisol will lower to <50%
    - No response in ectopic ACTH
    CRH test
    - exaggerated response in pituitary disease!!!
    - No response in ectopic ACTH
    Imaging
    - Adrenal CT or MRI
    - Pituitary MRI only detects 50% of ACTH producing pituitary tumours
    - Optimal imaging for ectopic tumours unclear (CT/PET/MRI)
  16. 16medication following adrenalectomyshort term hydrocortisone replacement therapy
  17. 17Congential adrenal hyperplasia - inheritance - most common geneAutosomal recessive disorder
    Range of genetic disorders relating to defects in steroidogenic genes
    Most common
    CYP21 (21α hydroxylase) --> no aldosterone or cortisol, DHEA made instead (zona reticularis)
  18. 18congenital adrenal hyperplasia in boys and in girlsFemale
    - ambiguous genitalia
    Boys
    - Adrenal crisis (Hypotension, hyponatraemia)
    - Early virilisation
  19. 19Treatment of congenital adrenal hyperplasiamineralocorticoid and glucocorticoid replacement
  20. 20Why short height in CAH?accelerate bone maturation
  21. 21What is a paraganglioma?neoplasm of extra-adrenal neural crest cells eg sympathetic ganglia
  22. 22What is phaeochromocytoma?neoplasm of adrenal medulla
    Rare, 2-8/million cases per year
  23. 23symptoms and signs of phaeochromocytoma- Hypertension (intermittent in 50%)
    - Episodes of headache, palpitations, pallor and sweating
    - Also tremor, anxiety, nausea, vomiting, chest or abdo pain
    Crises last 15 minutes
    Often well in between crises
  24. 24diagnosis of phaeochromocytoma24 hour urinary catecholamines
    (At least twice)
    Imaging
    - CT abdomen
    - MIBG scan
  25. 25What does an MIBG scan use to find phaeochromocytomas?chromaffin seeking analogue
  26. 26effect of no aldosterone on electrolyte balancehyponatraemia
    hyperkalaemia
  27. 27genetic conditions and phaeochromocytomaUp to 25% of cases associated with genetic condition
    - MEN
    >50% lifetime risk, usually non-malignant
    - VHL
    15% lifetime risk
    - SDHB & SDHD mutations
    - Neurofibromatosis
    15-20% malignant (5yr survival <50%)
    80-85% benign
  28. 28pre-operative treatment of phaeochromocytomaAlpha-blockade initially
    - vasodilation
    - Phenoxybenzamine or doxazosin
    - Aim for SBP< 120 mm/Hg if possible
    - Postural drop
    Then beta blocker if tachycardic
    - Labetolol or bisoprolol
    Encourage salt intake
  29. 29Adrenal insufficiency - what - clinical featuresInadequate ADRENOCORTICAL function
    Primary insufficiency
    - Addison’s disease
    - Autoimmune destruction
    Clinical features
    - Anorexia, weight loss
    - Fatigue/lethargy
    - Dizziness and low BP
    - Abdominal pain, vomiting, diarrhoea
    - Skin pigmentation
  30. 30Diagnosis of adrenal insufficiency‘Suspicious biochemistry’
    decreased Na+, increased K+
    hypoglycaemia
    SHORT SYN*ACTH*EN TEST
    - Measure plasma cortisol before and 30 minutes after iv ACTH injection
    - Normal: baseline >250nmol/L, post ACTH >480
    ACTH levels
    Should be increased (causes skin pigmentation)
    Renin/aldosterone levels
    - increased renin and decreased aldosterone
    Adrenal autoantibodies
  31. 31Management of adrenal insufficiencyDo not delay treatment to confirm diagnosis
    Hydrocortisone as cortisol replacement
    - If unwell, give intravenously first
    - Usually 15-30mg daily in divided doses
    - Try to mimic DIURNAL RHYTHM
    Fludrocortisone as aldosterone replacement
    - Careful monitoring of BP and K
    Need education
    - ‘sick day rules’
    - Cannot stop suddenly
    - Need to wear identification
  32. 32primary vs secondary adrenal insufficencyPrimary adrenal insufficiency (cortisol/aldosterone)
    Secondary adrenal insufficiency (cortisol only)

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Endocrinology Flashcards on Adrenal Disease, created by Ellie Britt on 22/01/2018.
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