Endocrinology Flashcards
what are the symptoms of hypercalcaemia?
confusion hallucinations stupor fatigue and easy tiring constipation muscle weakness (from slow muscle contractions) slow or absent reflexes
what feature in a patient’s history may give signs of chronic hypercalcaemia?
a history of kidney stones
what is the most classic sign of hypercalcaemia?
Slow or absent reflexes
how does hypercalcaemia slow muscle contractions and reflexes
sodium channels are stabilised by calcium channels if there is excess calcium in the action potential is harder to reach meaning that neurons are less excitable
what metabolic state does hypercalcaemia predispose to?
metabolic acidosis
what features would you find on ECG of hypercalcaemia?
bradycardia AV block shortened QT interval
how do you diagnose hypercalcaemia?
serum calcium levels > 10.5
what are common causes of hypercalcaemia?
THe CHIMPANZEES
Thyrotoxicosis
Excess Vitamin D + A
C onsumption of calcium H ydration (dehydration) // hyperparathyroid I mmobilisation M yeloma (+leukaemias) P arathyroid cancer/ademoma A drenal insufficiency N eoplasm (Breast and lung + mets prostate) (thia) Z ide diuretics E thanol Excess PTH S arcoidosis
what is the management of hypercalcaemia?
increase urinary excretion by using loop diuretics (frusemide) and increasing fluids + bisphosphonates to prevent bone resorption by inhibiting osteoclastsadj. glucocorticoids (beclamethosone) -> prevent bone resorption
what little rhyme can help you remember the symptoms of hypercalcaemia?
stones bones abdominal moans , thrones and psychic groans
what are common causes of hypocalcaemia?
HPV x2
hypoparathyroidism vitamin D deficiency hypo magnesium hyperventilation Phosphate infusions pancreatitis
what are the uncommon causes of hypocalcaemia?
renal failure burns and sepsis
w patient adjusted calcium comes back at <3mmol, are they likely to be symptomatic?
no
what is the management of the patient who presents with serum calcium of 3-3.5
prompt treatment with fluids and bisphosphonates
what is the management of a patient who presents the serum calcium of >3.5
urgent correction
fluids + diuretics (loop)
consider glucocorticoids
Bisphosphonates
what is pseudo-hypocalcaemia?
hypocalcaemia caused by hypo albuminemia as there is less bound calcium but ionised Calcium is the same
what are the symptoms of hypocalcaemia?
muscle cramps abdominal pain. Oral tingling seizures in extreme cases tetany with involuntary muscle contractions tachycardia brisk reflexes and abnormal ones paraesthesia numbness and tingling as well as poor memory and slowed thinking
what is the effect of hypocalcaemia on action potential?
causes neuronal Destability allowing for easier depolarisation
what abnormal reflexes can be seen in hypocalcaemia?
Chavatekes and Trousseuds
what ECG changes can hypocalcaemia cause
arrhythmias such as atrial fibrillation prolonged ST segment and prolonged QT interval
describe primary hyperparathyroidism
and endocrine disorder in which there is autonomous overproduction of parathyroid hormone resulting in deranged calcium homeostasis
what are the usual causes of primary hyperparathyroidism
parathyroid adenoma - can also be caused by radiation and lithium therapy
does hyperparathyroidism always cause high calcium?
now can also be normal cosmic despite high PTH
as well as the normal symptoms for hypercalcaemia what else can be present in hyperparathyroidism?
bone pain easy fractures and a history of osteoporosis/osteopenia
what bloods should you perform in primary hyperparathyroidism
serum calcium ( norm/+) serum intact PTH (+) serum vitamin D levels norm/low) phostphate (-)
after bloods lead you to suspect hyperparathyroidism what further investigations should you perform?
head CT for underlying adenoma and DEXAscan for bone density
what is the management of primary hyperparathyroidism?
parathyroidectomy with adjuncts of: bisphosphonates vitamin D supplements and Cinacalet (helps reduce serum calcium)
what all the common causes of secondary hyperparathyroidism?
chronic kidney disease malabsorption syndromes low vitamin D and drugs
how does chronic kidney disease caused secondary hyperparathyroidism?
diminishes parathyroid hormone effect on kidneys mean there is less calcium absorption
how do malabsorption syndromes lead to secondary hyperparathyroidism?
less calcium absorption in the GI tract means that there will be access parathyroid hormone produced
what things can increase the metabolic requirement of calcium?
bisphosphonate and growing
what drugs increase calcium loss?
loop diuretics
how do you diagnose secondary hyperparathyroidism?
low serum calcium (+) serum intact parathyroid hormone (+) phasphate (+) vitamin D + finding any underlying cause such as doing coeliac testing, U+E, imaging of parathyroid gland
what can help manage secondary hyperparathyroidism?
dietary phosphate restriction and a phosphate binder
what are examples of phosphate binders?
calcium acetate or Sevelamer
what are the causes of low vitamin D?
using SPF avoiding the sun inadequate dietary intake obesity drugs and malabsorption
what drugs cause low vitamin D?
glucocorticoids antiepileptics HAART rifampicin
what does low vitamin D cause in children?
Ricketts
what x-ray findings would you see for Ricketts
widening of endo- epithelial plates of long bones and ragged poor mineralisation
what does low vitamin D causing adults?
can cause osteopenia osteomalacia and osteoporosis however usually it is asymptomatic with some lethargy and possibly proximal muscle weakness
what bloods would you need to perform for vitamin D deficiency?
vitamin D (-) alkaline phosphate (+ in rickets or psteomalacia ) serum calcium (- long standing low vD)
how do you manage vitamin D deficiency?
ergocalciferol sensible UV exposure calcium – calcium carbonate
the patient presents with some lethargy and proximal muscle weakness, you perform a blood test and noticed that vitamin D is low alkaline phosphate is raised and serum calcium is low what does this mean
there is vitamin D deficiency which has been a long-standing causing osteomalacia
what does a raised alkaline phosphate mean in context of low vitamin D?
Ricketts or osteomalacia
what does a low serum calcium mean in context of low vitamin D
long standing low vitamin D
what are the causes of hypoparathyroidism?
post surgical genetic autoimmune
what is meant by postsurgical hypoparathyroidism?
is one of: accidental removal of parathyroid glands vascular compromise transient and hungry bone syndrome
why does transient postsurgical hypoparathyroidism occur?
in hypercalcaemia due to hyperparathyroidism tissues have suppressed and once hyperparathyroidism is corrected and the core is removed it takes a while for the parathyroid tissues to return to normal function
what is hungry bone syndrome?
hypocalcaemia and hypophosphataemia occurring after thyroidectomy or parathyroidectomy
a patient presents with muscle cramps abdominal pain and tingling of the skin they have brisk reflexes so you perform a full blood screen on them you find serum calcium (-) albumin (norm) parathyroid hormone (-) magnesium (slightly +) vitamin D (-) phosphurus (+) - what is the most likely diagnosis?
hypoparathyroidism
described their blood test results that you would find on hyperparathyroidism
calcium (-) albumin (norm) PTH (- or norm) Magnesium (inhibits PTH secretion) vitamin D (-) creatine and phosphurus (+)
what is the management of hypoparathyroidism?
PO/ IV calcium + vitamin D- if not a enough add recombinant PTH - if you notice that calcium is being lost in the urine add thiazide diuretic
what other causes of hypomagnesaemia?
loop and thiazide diuretics long-term PPI use dietary and malabsorption syndromes acutely occurs after an MRI occurs in acute pancreatitis
how does hypomagnesaemia affect potassium and calcium?
potassium: potassium efflux is increased as it is normally inhibited by magnesium calcium: low magnesium causes high calcium as calcium release is normally inhibited by magnesium however low magnesium can also cause hypo para which would cause low calcium
how do you treat hypomagnesaemia
loading dose plus IV infusion of magnesium - make sure to check renal function and stop magnesium inclusion if you notice bradycardia or hypotension
what diseases are associated with posterior pituitary?
lack of vasopressin (cranial diabetes insipidus) resistance to action of vasopressin (nephrogenic diabetes insipidus) too much vasopressin (SIA DH)
if you notice hyponatraemia what is one of the first steps you should do
note serum osmolality and thenthe hydration status as it can indicate the cause of hyponatraemia
what are the three types of hypotonic hyponatraemia
hypovolaemic hypovolaemic ebovulaemic
what are the causes of hypovolaemic hyponatraemia?
GI fluid loss mineralocorticoid deficiency and dehydration
what are the causes of hypovolaemic hyponatraemia?
AKI/CKD CHF cirrhosis nephrotic syndrome
what are the causes of evovulaemic hyponatremia?
SEI ADH high fluid low so you or electrolytes which can occur in marathon running for example medications and adrenal insufficiency beer diets
what medications can cause Evovolumia hyponatremia?
thiazide like diuretics combination diuretics loop diuretics and ACE inhibitors anticonvulsants hormonal analogues such as desmopressin and oxytocin hypnotics such as temazepam recreational drugs such as ecstasy SSRI MAOI
describes the homeostasis of plasma osmolality?
osmolality gets too low thirst is suppressed and vasopressin is suppressed this dilutes your in increasing osmolality there is then negative feedback on the posterior pituitary
describe the renin angiotensin aldosterone system
when blood pressure is too low, or salt (NaCl) or circulating vol decreases the perfusion to the juxtoglomerlular apparatus decreases / this causes an increase on the production of renin by the kidneys/ renin converts angiotensinagen to angiotensin I/ ace is secreted by the surface of the pulmonary and renal endothelium which then converts angiotensin I –> angiotensin II / angiotensin II increases sympathetic activity increases tubular salt reabsorption and potassium excretion as well as water retention it causes the adrenal gland cortex to secrete furthera ldosterone which further propagate this / it causes arteriolar vasoconstriction causing an increase in blood pressure and an increase in the pituitary glands of posterior lobe antidiuretic hormone secretion causing water absorption from the collecting duct of the kidney all of this causes water and salt retention effective circulation volume increase and increases the perfusion of the juxta glomeruli apparatus which then causes negative feedback on the kidneys
what is the presentation of hyponatraemia?
mild cognitive symptoms: confusion headache and balance low in urine output, hypovolaemia and hyponatraemia dizziness fatigue nausea and profuse sweating hyponatraemia predisposes to seizures
what is a consequence of hyponatraemia occurring rapidly less than 48 hours
causes cerebral oedema
what is the presentation of cerebral oedema caused by hyponatraemia?
altered mental status seizures coma
what is the immediate management of cerebral oedema caused by hyponatraemia?
medical emergency requiring hypertonic 3% saline
after assessing volume status what is the next step in finding the cause of hyponatremia
checking urine sodium and urine osmolality
if a patient is hypervolaemic in the urine sodium is less than 20 what is the likely cause
heart failure cirrhosis or nephrotic syndrome
if the patient is hypervolaemic and the urine sodium is over 20 is the most likely cause?
chronic renal failure
the patient is Euvovolumic and the osmolality is high what is the most likely cause?
SIADH + drugs
the patient is Euvovolumic and the osmolality is variable what is the most likely cause?
prolonged exercise or high fluid intake
the patient is Euvovolumic and the osmolality is high what is the most likely cause?
primary polydipsia or potomania
the patient is hypovolumic and urine sodium is less than 20 what is most likely cause
non-renal sodium losses
the patient is hypovolumic and urine sodium is less than 20 what is most likely cause
renal sodium losses
for a patient to be evolaemic what should the urine sodium be like
over 20
if there is hyponatraemia and serum osmolality is high what the most likely causes
hyperglycaemia and hypertonic fluid administration
if there is hyponatraemia and serum osmolality is normal what is the most likely cause
pseudo-hyponatraemia is the most common cause of isotonic hyponatraemia
describes the steps of the investigation of hyponatraemia?
- serum sodium
- serum osmolality IF HYPOtonic
- volume status
- Urine sodium to assess cause
Apart from assessing serum osmolality and urine sodium what other tests should be performed in a person with hyponatraemia? And why?
glucose test – hypoglycaemia associated with low sodium thyroid function test – hypothyroidism needs to be excluded in order to diagnose NSAID H serum cortisol – excludes adrenal insufficiency serum lipids – high lipids means pseudo-hyponatraemia
What is the first step of management of acute hyponatraemia?
IV hypertonic saline line over 20 minutes regularly check sodium and repeat IV infusions of 3% hypotonia say line over 20 minutes until there is a 5mm/L increase in sodium
after you have managed to get sodium to increase by 5mmol/l what is the next step in the management of hyponatraemia?
stop infusion and start an IV line of not .9% say line on minimum volume find and manage the underlying cause
at what rate should sodium levels increase during the first 24-hour is after initial stabilisation? And what about after the first 24 hours?
increased to 10mmol/l and then an increase of 8mmol/lUNTIL 130mmol/l
how often should you check sodium whilst the stabilising hyponatraemia?
initially check after every IV infusion once initial stabilisation has occurred checked every six , 12 hours and then daily
what are the risks associated of to too rapid an increase in sodium in the management of hyponatraemia?
predisposes to central pontine myelinosis and cerebral oedema (causing osmotic demylination)
what is central pontine myelinosis
brain damage caused by pseudo-bulbar and pons demyelination in the cortico spinal and cortico bulbar tracts
what is the presentation of central pontine myelinosis
spastic quadriplegic confusion horizontal gaze paralysis mutism this is called locked in syndrome occurring over 48 – 72 hours
apart from medical management causing central pontine myelinosis what else can cause this?
beer potomania the rapid and consecutive drinking of bacon drop sodium very low leading to locked-in syndrome
what is SIADH?
syndrome of inappropriate antidiuretic hormone - too much antidiuretic hormone is secreted this impairs urinary excretion leading to fluid retention
where does antidiuretic hormone target in the kidneys?
the distal convoluted tubule and the collecting ducts is where there is the actual antidiuretic hormone causing fluid retention
what type of hyponatraemia does SIADH cause?
evolumic hypotonic hyponatraemia
what is another name for antidiuretic hormone
vasopressin
what are causes of SIADH?
malignancy including SCLC GI pulmonary infections CNS disorders such as infections MS GBS drugs such as SSRI amitriptyline amiodarone carbamazepine
if you suspect SIA DH what blood test must you perform in order to get the diagnosis?
after finding out the type of hyponatraemia by using serum osmolality and urine sodium check diode function and serum cortisol as SIA DH is a diagnosis of exclusion
how do you manage S IAD H
treat hyponatraemia with acute treatment and chronic management
what is a chronic management of hyponatraemia
loop diuretics if caused by chronic heart failure own erotic syndrome Spironolactone caused by cirrhosis vasopressin receptor agonists are usually used second line
what is the definition of hyprenatraemia
serum sodium concentration of over 145 mmol /l
what other three types of causes of hypernatraemia
free water loss deficit in water losses sodium losses
what is the most common cause of hypernatraemia
dehydration
what is meant by free water loss causes of hypernatreamia
GI losses insensible losses and sweat renal concentrating defects osmotic diuresis diabetes insipidus
what is meant by deficit in water losses causes of hypernatraemia?
inability to drink water impaired thirst mechanism from brain tumours general lack of drinking
what is meant by sodium losses causes of hypernatraemia
hypertonic fluids excess sodium ingestion mineralocorticoid excess in Cushing’s or primary aldosteronism
in severe hypernatremia what is a consequence of its
acute cerebral shrinking
what is the presentation of hypernatremia
feelings of thirst weakness nausea and loss of appetite if more severe muscle twitching confusion + intracranial haemorrhage
which individuals most at risk of developing hypernatremia
patient of older age especially if living in a care home as they tend to get hypovolaemic
what investigation should you perform in hypernatremia?
U+E -? Renal impairment urine osmolality serum osmolality urine electrolytes and outputs
if urineosmolality is High Street higher than plasma osmolality what is the most likely aetiology
pure volume depletion from GI or insensible losses
if urine osmolality is the same as plasma osmolality what is the most likely cause
renal concentration defects such as renal failure osmotic diuresis or use of diuretics
what is the management of hypernatremia
give IV fluids loop diuretics if caused by yet eugenic causes or mineralocorticoid excess this is usually the case if the patient is hyper volumic
what is diabetes insipidus
metabolic disorder characterised by the inability to concentrate urine
what is the classic triad associated with diabetes insipidus
inapropiately dilute urine polyuria polydipsia
what are the two types of diabetes insipidus
central and nephrogenic