Endocrine2.txt

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Endocrine2.txt
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  1. What is HONK?
    hyperglycaemic hyperosmolar non ketotic coma
  2. Who gets HONK?
    DM2, it’s a hyperglycaemic emergency
  3. What precipitates HONK?
    • Infection
    • Acute MI
    • Stroke
  4. What is the pathophys of HONK?
    • Decreased insulin activity
    • High serum glucose levels
    • Osmotic diuresis
    • Volume loss
    • Ketogenesis does not occur as endogenous insulin levels are enough to inhibit hepatic ketogenesis. However glucose production by the liver is unrestrained
    • If eat lots of sugary fluids, can lead to really high glucose levels and raised plasma osmolality
  5. How is the diagnosis of HONK made?
    • Raised G
    • Elevated plasma osmolality [2(Na+K) + urea + glucose]
    • hyperNa+
    • identify precipitant
  6. what is the presentation of HONK coma?
    • Dehydrated (secondary to osmotic diuresis and no compensatory polydipsia)
    • Reduced consciousness
    • Plasma osmolality > 340mOsm/kg
    • Focal CNS signs: sensory/motor/seizures, LMN signs
    • Vomit
  7. What are the complications of HONK?
    • Hypovolaemic shock
    • Confusion
    • Coma
    • Thromboelmbolism due to hyperviscosity state
    • Untreated → death
  8. How is HONK treated?
    • ITU, iv access
    • Fluids: 0.9% saline – careful for 2 reasons
    • 1) not too fast as may have cardiac disease – danger of pulmonary oedema – so monitor CVP
    • 2) if too fast give fluids, change from high Na to low Na quickly – affects brain
    • iv soluble insulin infusion pump titrated to plasma glucose
    • K+ replacement titrated
    • Full dose of anticoagulant –because blood is very viscous
  9. How is a pt with HONK monitored?
    • BM
    • ABG, bicarb
    • K+
    • Plasma osmolality
    • Lab glucose
  10. What are the complications of treatment for HONK?
    • Cerebral oedema
    • Pulmonary oedema – too much fluid replacement
    • Central pontine myelinolysis
  11. In a comatosed patients what other things should be checked?
    • Paracetamol OD
    • Salicylate OD
    • Alcohol excess
  12. what are the 2 different types of anaemia that hypothyroid pts can get and why?
    • macrocyctic - assoc. with pernicious anaemia
    • microcytic - blood loss from menorrhagia
  13. What are the symptoms of Conn's?
    • muscle weakness
    • paraesthesia
    • cramps
    • nocturia
    • polyuria
    • thirst
    • hypertension
    • all features of hypoK+
  14. do you get oedema in conns?
    no
  15. what happens to the renin and K levels in conns?
    • K+ low
    • renin low
  16. what are the 2 main causes of primary hyperaldosteronism?
    • Conn's: solitary aldo producing adenoma (2/3)
    • bilateral adrenocortical hyperplasia (1/3)
  17. what is the treatment for Conn's?
    • surgery: laparoscopic adrenalectomy
    • use spironolactone pre-op to control HTN and to treat low K+
  18. what is the treatment for bilateral adrenocortical hyperplasia?
    medical: spironolactone/amiloride/eplerenone (doesn't cause gynaecomastia)
  19. how can you differentiate between the 2 causes of primary hyperaldosteronism?
  20. if a patient has HTN, why would you think it may be due to primary hyperaldosteronism?
    • 1. HTN with low K+
    • 2. refractory HTN not responding to 3 antiHTN drugs
    • 3. HTN before 40yrs
  21. what is a good screening test for Conns?
    • aldosterone/renin ratio increased is HIGH
    • must stop all antiHTN for 2 weeks and spiro for 6 weeks. use alpha blockers to control HTN as they don't affect the test
    • patient has to be sitting up for 2 hrs!
  22. how is conns differentiated from bilateral adrenal hyperplasia?
    • assess the effect of POSTURE
    • maestre renin, aldo and cortisol when lying down then after being upright for 4 hrs
    • renin production increases on standing causing more aldo prod
    • this is exaggerated in BAH but no effect in Conns as aldo production is autonomous
  23. what is secondary hyperaldosteronism caused by?
    • high renin release from reduced renin perfusion
    • eg RAS, accelerated HTN, diuretics, CCF or hepatic failure
  24. Name 4 features of carcinoid syndrome
    • bronchospasm
    • diarrhoea
    • tricuspid stenosis
    • flushing
  25. which cells do phaeochromocytomas arise from?
    sympathetic paraganglia cells which are collections of adrenaline secreting chromaffin cells usually found in adrenal medulla
  26. what is the 10% rule of phaeo?
    • 10% malignant
    • 10% bilateral
    • 10% extra adrenal - paraganliomas
    • 10% familial (MEN2/von Hippel-Lindau)
  27. how would you describe the HTN in phaeo?
    sustained or episodic, not controlled by treatment
  28. what are the symptoms of phaeo?
    • general: sweat, heat intol, pallor, flushing
    • neuro: headache, visual disturbances, seizures
    • CV: palps, tight chest, SOB, faints (postural drop), pulm oedema
    • GI: abdo pain, nausea, constipation
  29. what are the complications of phaeo?
    • persistent HTN
    • heart failure
    • dilated CM
    • arrythmia
    • stroke - cerebral haemorrhage
    • death due to hypertensive crisis
  30. what is the screening test for phaeo?
    3 x 24h urinary free catecholamines test
  31. how is phaeo tumour localised?
    • abdo CT/MRI
    • MIBG chromaffin seeking isotope scan - good for extraadrenal tumours
  32. what is the treatment of phaeo?
    • surgery
    • pre-op: alpha (phenoxybenzamine) and beta block (alpha before beta to avoid crisis from unopposed alpha stimulation
    • post-op: do 24h urine catecholamines 2 wks post op, monitor BP as risk of very LOW
  33. how is a phaeo emergency treated?
    • help!
    • phentolamine: non selective alpha blocker to (vasodilates via alpha1)
    • or labetalol: mixed alpha and beta blocker
    • when BP controlled give phenoxybenzamine (alpha block)
    • also give B1 blocker e.g. atenolol/bisoprolol/metoprolol to control any tachycardia with phenoxybenzamine
    • then surgery after 6wks
  34. what are the SE of phenoxybenzamine?
    • postural hypo,
    • dizzy,
    • tachycardia,
    • nasal congestion,
    • miosis
  35. what is tabes dorsalis? and what causes it?
    • slow degeneration due to demyelination of nerves in dorsal column
    • caused by untreated syphilis
    • one of the symptoms is impotence
  36. what is sick euthyroid syndrome?
    • low T3/T4
    • but feel normal - asymp (due to adaptation?)
  37. what is subclinical hypothyroidism?
    when have symptoms but normal values
  38. which cells does Medullary carcinoma of the thyroid arise from? what do they produce?
    • parafollicular C cells
    • calcitonin
  39. what is the prognosis of follicular carcinoma?
    • 50% excellent
    • 50% if invasive get local recurrence or spread to bone/lung
  40. what are the presenting features of primary ACUTE hypoadrenalism
    • hyoptension
    • hyponatraemia
    • collapse
  41. what are the causes of primary ACUTE hypoadrenalism?
    • rapid withdrawal of long term steroid therapy
    • sepsis/stress in chronic adrenal dysfunction
    • perinatal haemorrhageic necrosis - after prolonged difficult labour because don't have many clotting factors likely to bleed
    • adrenal haemorrhage - heparin/warfarin/DIC
    • post partum infarction
    • warehouse friderichson syndrome: infection N.Meningitidis bacteraemia, low BP shock, DIC, bleed into adrenal gland
    • trauma
  42. what are the clinical features of primary CHRONIC hypoadrenalism?
    • lethargy, depression, anorexia, wt loss
    • hypotension (low aldo)
    • hyperpigmentation: melanocytes stimulated by excess ACTH
  43. what are the Na, K, urea, glucose levels in primary CHRONIC hypoadrenalism?
    • low Na
    • high K
    • high urea
    • low glucose (as low cortisol)
  44. what are the causes of primary CHRONIC hypoadrenalism?
    • autoimmune: destruction of cells = 80%
    • TB, mets, amyloid, haemochromatosis, lymphoma, AIDS = 20%
  45. what are the causes of cushing's syndrome?
    • acth dependent:
    • cushing's disease due to ACTH pituitary tumour,
    • ectopic ACTH (small cell lung cancer, carcinoid tumour) specific features due to LOTS of acth: hyperpigmentation, hypokalaemic met al (inc cortisol acts on MR), wt LOSS, hyperglycaemia. classical cushing's features may be absent.
    • non-acth dependent:
    • iatrogenic - pharmacological doses of steroids (commonest)
    • adrenal adenoma or carcinoma
    • adrenal nodular hyperplasia
  46. what are the first line screening tests for cushing's syndrome?
    • overnight dexamethasone suppression test. give dex at midnight and should cause -ve feedback, less ACTH and less cortisol at 8am
    • 24h urinary free cortisol
  47. when is cortisol highest and lowest and how can this be used as a test?
    • highest: 8am
    • lowest: midnight
    • check cortisol at midnight, if raised its cushing's syndrome
  48. how can you localise the lesion in cushing's syndrome i.e. pituitary/adrenal/ectopic?
    • 1. measure plasma ACTH - if undetectable then ADRENAL tumour likely then CT the glands.
    • if ACTH is detectable then distinguish pituitary from ectopic ACTH production:
    • 2. HIGH dose dex sup test: if cortisol levels are suppressed after 2days then its cushing's disease (i.e. pituitary cause) as pit retains SOME feedback
    • 3. if not suppressed then it is ectopic ACTH - CT neck, thorax, abdomen for small cell lung cancer and carcinoid tumours
  49. What is MODY?
    • maturity onset diabetes of the young
    • rare autosomal dominant form of DM2 affecting young people with a positive family history
  50. what are the drug causes of DM?
    • steroids
    • thiazides
  51. what are the other causes of DM?
    • pancreatic: pancreatitis, surgery (removal of pancreas), haemochromatosis, cystic fibrosis, pancreastic cancer
    • endocrine: cushing's, acromegaly, phaeochromacytoma, thyrotoxicosis, glucagonoma
  52. what is the definition of impaired glucose tolerance?
    • fasting plasma glucose can be high but < 7.0mmol/l
    • OGTT 2h glucose 7.8 - 11.1
    • manage with exercise and diet
    • RF for DM
  53. what is impaired fasting glucose?
    • fasting plasma glucose: 6.1-6.9
    • manage with exercise and diet
    • RF for DM
  54. which test is used to diagnose addisons disease?
    • short synACTHen stimulation test
    • give ACTH but cortisol stays low due to adrenal insufficiency
  55. what is CAH?
    • lack of an enzyme involved in cortisol steroid synthesis
    • therefore -ve feedback to pituitary as low cortisol
    • more ACTH is released and get adrenal hyperplasia
    • but the steroid production pathway is diverted to ANDROGENS --> virilisation
  56. what are the 2 types of CAH and features?
    • 21 hydroxyls deficiency: salt wasting due to low ado, virilisation of females (cliteromegaly, labial fusion), at birth vomit, dehydrate, collapse, low Na, high K
    • 11B hydroxyls deficiency: salt sparing as still produce corticosterone which has mineralocorticoid activity. may get HTN in adulthood, also features of high androgens
  57. which cranial nerves go through the cavernous sinus?
    3, 4, 6, V1, V2
  58. which are the most common pituitary tumours?
    prolactinoma > GH > PRL & GH, ACTH
  59. what are the local pressure symptoms due to pituitary tumours?
    • headache
    • visual field defect: bitemporal hemianopia due to optic chiasm compression
    • palsy of CN 3, 4, 6 if pressure to cav sin
    • DI if stalk affected (ADH is made in hypothal and stored in post pit)
  60. what is pituitary apoplexy?
    rapid pituitary enlargement due to haemorrhage into a tumour causing SUDDEN mass effects
  61. what is a craniopharyngioma?
    • from rathke's pouch (origin of ant pit)
    • rare, most common in children
  62. what are the features of craniopharyngioma?
    • hypopituitarism
    • growth failure, amenorrhoea, loss of libido
    • hyopthal features: DI, hyperphagia so get obese, sleep disturbance
    • tumour mass effect: headache, visual field defect
  63. what is kallmanns syndrome caused by?
    GnRH deficiency
  64. what are the features of kallmanns?
    • hypogonadotrophic hypogonadism
    • fails to get proper erection
    • anosmia
    • cleft palate
    • renal abnormalities
    • cerebral abnormalities e.g. colour blindness
  65. what is the inheritance pattern of kallmanns?
    x-linked
  66. if surgery is CI, which drug can be used to treat cushing's syndrome?
    metyrapone: blocks cortisol synthesis
  67. is proximal myopathy a feature of hypo/hyperthyroid?
    hyperthyroid due to muscle wasting
  68. what is the difference between primary and secondary hypogonadism?
    • primary: problem with the testes
    • secondary: due to low gonadotrophins
  69. what are the causes of primary hypogonadism?
    • local trauma, radio, chemo, torsion
    • orchitis - mumps, HIV
    • renal failure
    • cirrhosis
    • alcohol excess (toxic to leydig cells)
    • chromosomal: Klinefelters 47 XXY: delayed sexual development, small tests, gynaecomastia
  70. what are the causes of secondary hypogonadism?
    • hypopituitary
    • kallmanns: isolated GnRH deficiency, anosmia, colour blindness
    • prader-willi syndrome
  71. what are the 3 features of kallmann's syndrome?
    • GnRH deficiency - hypogonadism
    • anosmia
    • colour blindness

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