Endocrinology Flashcards
What are the most likely causes of acromegaly?
GH secreting pituitary adenoma
GH secreting ganglioneuroma, GH-secreting bronchial CA or GH secreting pancreatic CA
What are some signs and symptoms of acromegaly?
sweating
headaches
carpal tunnel syndrome
thick, greasy skin
prominent eyebrow ridge + cheeks, thick lips, broad nose, large tongue, husky voice
enlarged feet
if due to pituitary adenoma -> bitemporal hemianopia
what are the pharmacological management options for patients wtih acromegaly?
subcut somatostatin analogues = octreotide, lanreotide
oral dopamine agonists = cabergoline, bromocriptine
GH antagonists = pegvisomant
what are the common causes of adrenal insufficiency?
iatrogenic (after stopping long term steroid therapy or bilateral adrenalectomy)
in developing worlds -> adrenal TB
in the UK -> primary due to addison’s (autoimmune)
what are RF for adrenal insufficiency?
autoimmune conditions
female
damage or pathology of adrenals
steroid therapy (long term)
what is an adrenal crisis?
an acute adrenal insufficiency attack precipitated by stress (infection, surgery, emotional)
leads to major haemodynamic collapse -> hypotensive shock, tachycardia, pale, cold, oliguria, clammy
A woman presents to the GP with a history of anorexia, weight loss, lethargy + weakness. She has had some dizzy episodes as well as diarrhea + vomiting with abdominal pain.
On examination you notice some increased pigmentation on her gums and hand creases. Her BP drops on standing indicating postural hypotension
what is the likely diagnosis?
adrenal insufficiency
possibly due to Addison’s (autoimmune)
KEY FEATURES: anorexia, weight loss, tired, weak, dizzy, diarrhoea and vomiting, abdo pain, depression, postural hypotension, skin pigmentation
what electrolyte abnormality might be seen on blood results from a patient with adrenal insufficiency?
hyponatraemia
hyperkalaemia
what investigations would you perform to diagnosis adrenal insufficiency?
9am serum cortisol (low)
short-synACTHen test -> no rise in cortisol
long synACTHen test -> just monitor for longer, no rise
bloods - autoantibodies (anti-21 hydroxylase), TFT, U&E
abdo CT, adrenal biopsy
how do you manage an addisonian crisis?
- rapid IV fluid rehydration
- 50mL 50% dextrose
- IV 200mg hydrocortisone - followed by 6hr 100ml bolus till BP is stable
treat underlying cause
how do you manage a patient with adrenal insufficiency in the long term?
replace glucocorticoids with HYDROCORTISONE
replace mineralocorticoids with FLUDROCORTISONE
advise: medic alert, increase dose in acute illness/stress
what is carcinoid syndrome?
where a carcinoid tumour secretes serotonin, histamine and/or bradykinin leading to excess of these hormones. these high levels lead to a cluster of symptoms
what symptoms do patients with carcinoid syndrome commonly experience?
diarrhoea
SOB
flushing
itching
often worse after alcohol and emotional stress
what is a carcinoid crisis?
PC: profound flushing, bronchospasm, tachycardia, fluctuating BP, pyrexial
what causes a carcinoid crisis?
tumour releases an overwhelming amount of the active substances usually due to tumour manipulation (e.g. surgery, biopsy) or in the induction of anaesthesia
What is the most common cause of Cushing’s syndrome?
exogenous corticosteroid exposure (steroid therapies)
ACTH dependent causes of Cushing’s?
cushing’s disease = ACTH secreting pituitary adenoma
ectopic ACTH production (small cell Lung CA or carcinoid tumours)
What are ACTH independent causes of Cushing’s?
adrenal adenoma/cancer
adrenal nodular hyperplasia
iatrogenic (steroid therapy)
carney complex and mccune-albright syndrome [RARE]
what are the features of cushings?
glucose intolerance, dyslipidaemia, weight gain (central obesity), striae, proximal myopathy, facial plethora, moon face
depression, easy bruising, hirsutism, lethargy
what investigations would you order if you suspect cushings?
bloods: glucose, U&Es
late night salivary cortisol (raised)
low dose dexamethasone suppression test
24 hour urinary free cortisol
scans for tumours
what medical therapies may be used to treat cushings?
stop steroids if possible
metyrapone or ketoconazole prevents cortisol synthesis
otherwise surgical intervention to remove tumour or radiotherapy
what is the management for cranial diabetes inspidus?
desmopressin
what is the management for nephrogenic DI?
salt +/- protein restriction
thiazide diuretics
stop any causative medications if possible e.g. lithium
how do you manage DKA?
give bolus insulin then use a sliding scale infusion until ketones are <0.3, pH > 7.3, bicarb >18
fluid resuscitation with saline
potassium replacement and monitoring
close monitoring, broad spec Abx if infection suspected, thromboprophylaxis
what is the pathophysiology of graves disease?
TSH receptor antibodies which stimulate the receptor causing T3 and T4 production
how do you manage acute hypercalcaemia?
IV fluids
avoid exacerbating factors e.g. thiazides or anything dehydrating
what medication can be used to increase parathyroid sensitivity to calcium?
cinacalcet
what order are the pituitary hormones lost?
Usually lost in this order: GH → gonadotrophins (FSH + LH) → ACTH and TSH
what order are the pituitary hormones lost?
Usually lost in this order: GH → gonadotrophins (FSH + LH) → ACTH and TSH
what are the signs of hypothyroidism?
BRADYCARDIC
Bradycardia
Reflexes relax slowly
Ataxia
Dry thin hair/skin
Yawn, drowsy, coma
Cold hands and low temperature
Ascites + non pitting oedema
Round puffy face, double chin, obese
Defeated demeanor (depression)
Immobile + ileus (constipation)
Congestive cardiac failure
what are some causes of hypothyroidism?
autoimmune thyroiditis (hashimoto's disease) thyroidectomy/radiotherapy/iodine therapy for hyperthyroidism
amiodarone or lithium (iatrogenic)
secondary - Sheehan’s, pituitary apoplexy, head trauma
how do you treat hypothyroidism?
levothyroixine sodium to replace T4
if elderly or known heart disease start at a lower starting dose and titre up slowly to prevent exacerbating CVD
how do you treat myxoedema coma?
liothyronine sodium (T3 replacement)
hydrocortisone
correct glucose
fluids
if hypothermic warm slowly
what tumours are associated with MEN1?
parathyroid tumours
pituitary tumours
pancreatic tumours
what tumours are associated with MEN 2a?
parathyroid tumours
medullary thyroid cancer
phaeochromocytoma
what tumours are associated with MEN 2b?
medullary thyroid cancer
phaeochromocytoma
marfanoid appearance
what are the features of a phaechromocytoma?
episodes of sweating, palpitations and headaches
sporadic hypertension
what is osteomalacia?
a disorder of bone matrix mineralisation
what are RF for osteomalacia?
renal phosphate loss (excessive wasting)
vitamin D deficiency
what are the osteoporosis RF?
SHATTERED
Steroid use
Hyperthyroid, hyperparathyroid, hypercalciuria
Alcohol + tobacco
Thin
Testosterone low
Early menopause
Renal or liver failure
Erosive/inflammatory bone disease
Diet (low Ca2+), DM1
what is the origin of cells involved in a phaeochromocytoma?
catecholamine producing chromaffin cells
ADRENAL MEDULLA
what is Conn’s syndrome?
an aldosterone producing adenoma which leads to a primary hyperaldosteronism
what electrolyte imbalance are patients with primary aldosteronism vulnerable to?
hypokalaemia
may become hypernatraemic
what diuretic is appropriate for use in patients with primary aldosteronism?
a potassium sparing diuretic such as spironolactone
what medication is used to manage prolactinomas?
dopamine AGONISTS
e.g. cabergoline or bromocriptine
what is carbemazepine used for?
it is an anti-epileptic and to treat neuropathic pain
what is carbimazole used for?
carbimazole is used to treat hyperthyroidism
it acts by preventing iodination of molecules so reduces the amount of T3 and T4 produced
what is cabergoline used for?
to treat prolactinomas as it is a dopamine agonist
it may also be used to treat excess GH (i.e. acromegaly)
what are the features of SIADH?
inappropriate and excessive ADH
hypotonic hyponatraemia
concentrated urine
euvolaemic state
what are the causes of SIADH
drugs: SSRI, amiodarone, carbamazepine, amitriptyline, NSAIDs, chemo
infections or malignancy
porphyria, alcohol withdrawal
what would results would one expect from investigations for a patient with SIADH?
serum sodium < 135 (low)
serum osmolality < 280 {low}
urine osmolality > 100 and urine sodium > 40 if euvolaemic
What are other causes of hyponatraemia that must be ruled out prior a diagnosis of SIADH?
hypovolaemia
oedema
renal failure
adrenal insufficiency
hypothyroidism
what is the management of SIADH?
if severe hyponatraemia (<125) give hypertonic saline but only to stop seizures not to normalise sodium
fluid restriction
furosemide
vasopressin receptor antagonist (talvaptan)
what are the types of thyroid cancer?
papillary
follicular
anaplastic
medullar
what is the most common type of thyroid cancer?
papillary
where does a papillary thyroid cancer usually spread?
lymph nodes
how does a follicular thyroid cancer spread?
haematologically
what is the tumour marker for papillary and follicular thyroid cancer?
thyroglobulin
what is thyroglobulin a marker for?
follicular and papillary thyroid cancer
what is the marker for medullary thyroid cancer?
calcitonin
what is calcitonin a marker of?
medullary thyroid cancer
what are drugs that commonly cause drug-induced thyroiditis?
amiodarone, lithium and interferons
what is riedel’s thyroiditis?
chronic thyroiditis where normal thyroid tissue is replaced with fibrotic tissue
what are the complications of diabetes?
microvascular = retinopathy, neuropathy, nephropathy
macrovascular = MI, stroke, PVD
metabolic = DKA, HHS, hypoglycaemia
What drug is used to treat prolactinoma?
cabergoline
zones of adrenal + hormones produced
zone glomerulosa → aldosterone
zona fasciculata → cortisol
zone reticularis → sex steroid hormones
medullar → catecholamines (e.g. NA)
zones of adrenal + hormones produced
zone glomerulosa → aldosterone
zona fasciculata → cortisol
zone reticularis → sex steroid hormones
medullar → catecholamines (e.g. NA)
acromegaly - definition + causes
excess GH in adults leading to overgrowth of all organs, bones and soft tissue
causes:
- pituitary adenoma
- ectopic GH (rare)
- ectopic GnRH (rare, ganglioneuroma, bronchia CA, pancreatic CA
key features of acromegaly presentation
- headaches
- sweating
- carpal tunnel syndrome
- visual disturbance - bitemporal hemianopia
- thick greasy skin
- prominent eyebrow ridge, broad nose bridge, prognathism
- enlarged hands + feet
investigations for acromegaly
- bedside
- BP, ECG (LVH), CN/visual fields
- bloods
- IGF-1 (screening)
- oral glucose tolerance test (diagnostic)
- pituitary status - TFTs, LH + FSH, Test/Oes, prolactin
- CoD screen - HbA1c/glucose, lipids, bone profile
- imaging
- MRI pituitary
- CT chest - assess for CA ectopic cause
- ECHO - LVH + cardiomegaly
complications of acromegaly
structural are usually irreversible so early treatment ESSENTIAL
- HTN, cardiomyopathy (LVH)
- OSA
- colon + thyroid cancer
- raised calcium, phosphate
- raised lipids
- DM/glucose intolerance
- renal stones
treatment of acromegaly
-
transphenoidal hypophysectomy
- CoM: nasoseptal perf, hypopituitarism, recurrence, infection. CSF leak
- medical Mx
- SC somatostatin analogue (octreotide)
- PO DA agonist (bromocriptine, cabergoline)
- GH antagonist (Pegvisoman)
- screening - monitor for DM/cardiac, colonoscopy if > 40 and every 5 years
definition and causes of adrenal insufficiency
inadequate production of cortisol + mineralocorticoids from adrenal cortex
primary - Addison’s disease (AI destruction of cortex)
secondary
- infection - TB, post-meningococcal sepsis (Waterhouse-Friederichesen syndrome)
- infiltration - mets, amyloidosis, lymphoma
- infarction
- inherited - ACTH receptor mutation
- iatrogenic - bilateral adrenalectomy, long term steroid use
investigations for adrenal insufficiency
- bloods
- 9am cortisol - < 100nmol/L essential Ddx, 100-500 more tests, > 500 unlikely
- autoAb - anti 21-hydroxylase, adrenal cortex Ab
- U&Es, glucose
- imaging
- CT adrenals + contrast - infection/infiltration
- specialist
- short synACTH, < 550nmol at 30 = adrenal failure
- adrenal biopsy
electrolyte abnormality in adrenal insufficiency
hyponatraemia
hyperkalaemia