Endocrinology passtest Flashcards
What will a deficiency in ApoB-100 molecules cause and why?
Cholesterol build up because when there is a normal amount of ApoB-100 molecule it binds to LDL so the cholesterol doesn’t accumulate.
What is the cause of familial hypercholesterolaemia?
LDL receptor deficiency
What is the 1st line treatment of symptomatic graves?
Propranolol
What is long term treatment of Graves?
Carbimazole
How does carbimazole work?
Inhibits thyroid production
What is a risk to be aware of with carbimazole?
Agranulocytosis
Can carbimazole be used anytime during pregnancy?
Not safe in1st trimester but safe in 2nd and 3rd
What is a risk of propylthiouracil?
Hepatotoxicity
What is the mechanism of action of propylthiouracil?
inhibiting the enzyme thyroid peroxidase, which usually converts iodide to an iodine molecule and incorporates the iodine molecule into amino acid tyrosine.
What is chvostek’s sign?
Ipsilateral facial twitching when facial nerve is stimulated by touching just in front of the ear.
What does chvostek’s sign indicate?
Low calcium level
What is trousseau sign?
Involuntary hand and wrist contraction?
What does trousseau sign indicate?
Low calcium
What happens to calcium and phosphate levels in a total thyroidectomy causing acquired hypoparathyroidism?
It can cause high phosphate and low calcium
What are the calcium and phosphate levels in chronic renal failure?
Low calcium and high phosphate
What are the calcium and phosphate levels in vitamin D deficiency?
Low calcium and low phosphate
When does glucose peak in insulin dependent diabetics?
Peak plasma glucose between 1 and 2 hours
What is the the expected fasting glucose for a insulin dependent diabetic?
Over 7 mmol
How is metabolic syndrome defined?
3 or more of the following:
1. Increased waist circumference
2. BMI over 30
3. Increased triglycerides
4. Decreased HDL
5. Hypertension
6. Increased fasting glucose
What is the differences between primary and secondary hyperparathyroidism?
Primary can be caused by a parathyroid adenoma
Where as secondary is caused by vitamin D deficiency or chronic renal failure
What is the pathophysiology of the mineral levels in primary hyperparathyroidism?
PTH acts on kidneys to increase calcium reabsorption from bones so calcium increases meanwhile more phosphate is excreted.
What else other than PO4- and Calcium is usually elevated in primary hyperparathyroidism? and why?
ALP because PTH increases bone turnover by stimulating osteoclasts. Moreover PTH causes osteoblasts to increase production of RANKL which causes osteoclastic formation and activation which leads to the bone degradation and calcium releases
What are the sodium and potassium levels in Addison’s?
Low sodium and high potassium
How does Conn’s syndrome present?
High BP and Metabolic alkalosis
What is the most common form of thyroid cancer?
Papillary
Are neuropathic ulcers painful?
Usually no
Who do neuropathic ulcer usually present in?
Diabetics
Where do neuropathic ulcers usually present?
Heel and metatarsal head - basically pressure bearing areas
What is the mechanism that causes familial hypocalcuric hypercalcaemia?
Mutation in the calcium sensing receptor gene which then impacts calcium homeostasis - therefore increased calcium in serum and decreased calcium excretion
What is orlistat?
Encourages weight loss by inhibiting pancreatic lipases - so lipase doesn’t break down the triglycerides into free fatty acids for absorption
What is a side effect of orlistat?
Steatorrhea
What’s the pathophysiology of DKA?
There is a lack of insulin, therefore glucose builds up as the glucose can’t be shovelled into the cells. Therefore because there isn’t any glucose in the cells for cells to utilise they begin to break down the fatty acids to create ketones for energy. Therefore ketoacidosis occurs
What is the glucose measurement in DKA?
Same as Over 11
What is the ketone measure in DKA?
3 or ore
What is the pH in DKA?
7.3 or under
What type of breathing may be seen in DKA?
Kussmauls - deep rapid laboured breathing
In what scenarios may euglycemic DKA present
When glycogen stores are exhausted for example in:
1. malnutrition
2. Severe vomiting
3. Alcohol use
4. SGLT2 inhibitors - flozin’s
What is initial treatment of DKA?
Fluid recuss
K+ replacement
Fixed rate insulin infusion
What is the rate of fixed rate insulin used in DKA treatment?
0.1units/kg/hr
What tumours are found in MEN1
PPP:
- Pituitary adenoma
- Parathyroid
- Pancreas - look out for a new onset of diabetes
What is C peptide a measurement of?
How much natural insulin a person makes by beta cells
What is giardia?
a tiny parasite (germ) that causes diarrhea. Giardia can spread easily from one person to another or through water, food, surfaces, or objects.
What is the treatment for giardia?
Tinidazole - it’s an a tiny parasite (germ) that causes diarrhea. Giardia can spread easily from one person to another or through water, food, surfaces, or objects.
In a thyroid function, why may thyroid levels be normal but TSH still super high in a non compliant pt ?
They just started taking their tablets a few days just before blood test
Which thyroid cancer is spread through bloodstream?
Follicular
Which thyroid cancers are spread through lymph?
Papillary and medullary
Which thyroid cancer is spread through local invasion?
Anaplastic
What is the classic grave’s symptoms triad?
Pre-tibial myxoedema
Thyroid ophthalmology
Thyroid acropachy (clubbing of fingers and toes) - like they can get super chubby
What is the primary investigation for acromegaly?
IGF1 - it’s used instead of GH as it has a longer half life
What tumours are seen in MEN2?
Parathyroid
Medullary thyroid
Phaeochromocytoma
Remember MEN 2B is associated with marfans
What is pathophysiology of Addison’s?
Automimmune dystruction of adrenal glands so loss of gluco, mineral and corticosteroids
What symptoms present in Addison’s?
Hypotension
Nausea
Abdo pain
In women loss of pubic hair and libido
What is secondary adrenal insufficiency?
There is a decrease in ACRH from pituitary
What is tertiary adrenal insufficiency and what is most common cause?
Decreased in CRH from hypothalamus
Usually caused by overuse of external glucocroticosteroids
What are the mineral levels in a addinsonian crisis? and what other feature may be seen on skin?
Low Sodium
High potassium
Low glucose
Hyperpigmented creases
Why does hyperpigmentation happen in Addinson’s?
caused by the stimulant effect of excess adrenocorticotrophic hormone (ACTH) on the melanocytes to produce melanin. The hyperpigmentation is caused by high levels of circulating ACTH that bind to the melanocortin 1 receptor on the surface of dermal melanocytes.
What actually is short synachten?
Artificial ACTH
What is the short synachten test?
Addison’s - primary adrenal insufficiency. Basically tests how well your adrenal glands can produce cortisol when stimulated by ACTH
How is short synacthen test done?
250MG given. Cortisol is then measured immediatley before, after 30 mins and after 60 mins. Baseline should be over 180-190. After the synachten given in a normal person the cortisol levels should rise to over 500-550.
How is Addison’s treated?
Glucocorticoid replacement with hydrocortisone (15-30mg) and mineral corticoid is replaced with fludrocortisone
What is Addisonian crisis management?
IV hydorocrtisone (100mg) and fluids
What is first line management for type 2 diabetes? If that doesn’t work then what?
Lifestyle changes
Then metformin if Hba1c is still above 48. Then insulin if metformin doesn’t work
What is mechanism of metformin?
Metformin decreases blood glucose levels by decreasing hepatic glucose production (also called gluconeogenesis), decreasing the intestinal absorption of glucose, and increasing insulin sensitivity by increasing peripheral glucose uptake and utilization
What antibodies are present in Hashimoto’s thyroiditis?
Autoantibodies to thyroid peroxidase and thyroglobulin
What’s the difference between kleinfelter’s and reifenstein syndrome?
Kleinfelters: tall and infertile
Reifenstein: Breast development, Erectile dysfunction, normal height - type of partial androgen insufficiency
What is the main symptoms that 17-a hydroxylase deficiency causes?
Hypertension due to an enzyme defect in the mineral corticoid pathway causing it to be overactive
What other condition is acromegaly associated with?
Diabetes and insulin resistance
What percentage of diabetes is type 1?
10%
Can hypothyroidism cause anaemia?
Yes
Why does a high amount of aldosterone = a low potassium?
Because aldosterone acts on collecting ducts to promote excretion of potassium and reabsorption of sodium
What hormone is high in Conn’s?
Primary hyperaldosteronism
What is inheritance pattern for MEN?
Autosomal dominant
Who is affected by X liked recessive?
Females can only be the carriers but can pass the condition on to 50% of their sons
What can distinguish between primary hyperparathyroidism and squamous cell lung cancer?
Parathyroid RELATED hormone is released in SCLC not PTH so PTH won’t be raised but calcium will still be high and phosphate will be low.
In patients from 40-45 with menopausal symptoms what hormones can be used to test for menopause?
FSH will be high as there is a drop in progesterone production therefore oestrogen acts uninhibited and raises FSH. If FSH is greater than 30 then diagnose menopause.
When should a serum FSH be measured to diagnose menopause?
Day 3 menstrual cycle
Who is at risk population for De Quervain’s thyroiditis?
Females after a viral URTI.
What is the thyroid status in de quervain’s thyroiditis?
inflammation of the thyroid characterised by a triphasic course of transient thyrotoxicosis, followed by hypothyroidism, followed by a return to euthyroidism
What is treatment of phaechromocytoma?
Laparoscopic adrenalectomy and manage hypertension with a-adrenoreceptor antagonists
Which a-adrenoreceptor antagonist can be used to manage hypertension?
Phenoxybenzamine
What are some side effects of phenoxybenzamine?
Reflex tachycardia
Dizzy
Droswy
Nausea/ vomit
Congestion
Fatigue
Which hormone inhibits release of growth hormone?
Somatostatin
What is somatomedin C? and where is it produced?
Produced in liver from GH and promotes growth in cartilage and bone
When does GH conc peak?
During sleep - secreted in a pulsatile manner
What does GH do to insulin?
Anti-insulin effects - it promotes gluconeogenesis
Does IGF1 have proinsulin or anti-insulin effects?
Pro-insulin effects
What molecules does lipoprotein lipase hydrolyse ?
Chylomicrons & VDL. Therefore a reduction in lipoprotein lipase results in a build of chylomicrons and VDLS
What receptors are decreased in familial hypercholesterolaemia?
Decreased LDL receptors so increase in LDL.
What hormone stimulates contraction of uterus muscles during labour?
Oxytocin - production of oxytocin then further enhances release of prostaglandins.
What is seen on histopathology in papillary thyroid cancer?
Opthalmic nuceli and psamomma bodies, orphan annie cells
What are psamomma bodies?
round, microscopic calcifications found in certain cancers,
What is the incretin effect?
Oral intake of glucose leads to a higher insulin secretion that if it’s parenteral glucose infusion.
What’s the physiology behind incretin effect?
When glucose is consumed orally, the body releases incretin hormones, such as glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), which stimulate the pancreas to produce insulin. This results in a higher insulin response than if the glucose were administered intravenously.
Other than GH what other substance does somatostatin inhibit release of?
Gastric acid
What is the role of glucagon?
Increase glucose production in liver
What does increasing glucagon levels do to GH, cortisol and C peptide?
Increase them
What drug diabetes drug is contraindicated in renal failure and low eGFR?
Metformin because it can lead to lactic acidosis
Which medications can renal failure diabetics use?
DPP4 inhibitors - linagliptin - the liptins.
How do DPP4 inhibitors work?
Blocking the degradation of GLP-1 therefore sustaining insulin release consequently reducing blood sugar.
What level of plasma osmolality triggers ADH release?
280, thirst starts to be felt at 290
What does ADH release cause?
More water to be reabsorbed in kidneys which leads to hyponatraemia as the sodium in the serum can get diluted. Urine osmolality increases whilst serum osmolality decreases.
What can cause SIADH?
Strokes
Subarachnoid haemorrhage
Trauma to head
Psychosis
Small cell lung cancer - ectopic release of ADH (vasopressin)
Infection
Carbamazepine
Cyclophosphamide
What is 2hr plasma glucose in diabetics?
11.1 or more
What is HbA1c in diabetics?
48 mmol or more
What would be a random plasma glucose in a diabetic?
More than 11.1
What happens to macrophage and neutrophil function in badly controlled glycaemic control in diabetics?
It’s impaired. Chemotaxis, phagocytosis and intracellular killing is impaired.
What would be the presenting symptoms of a somatostatinoma?
Diarrhoea
Weight loss
Gallstones
DM
inhibit pancreatic hormones and gastrointestinal hormones. Thus, somatostatinomas are associated with mild diabetes mellitus, steatorrhoea and gallstones, and achlorhydria.
What is plasma aldosterone: renin ratio in Conn’s?
It’s increased
What class of drugs can be used to treat acromegaly?
Somatostatin analogues
What other conditions can somatostatin analogues treat?
Carcinoid syndrome, VIPomas
What are some examples of somatostatin analogues?
Octreotide
Lareotide
What is triad of symptoms in a VIPoma?
- Achloridyha
- Watery diarrhea
- Hypokalaemia
How does psychogenic polydipsia present?
Water seeking behaviour and excessive water drinking sometimes accompanied by hyponatraemia and water intoxication
What does DI do to sodium levels?
Increases sodium because of water loss from a deficiency in ADH or renal insensitivity of the hormone
What test can be used to diagnose diabetes insipidus?
Water deprivation test (desmopressin stimulation test)
The patient avoids all fluids for up to 8 hours before the test (water deprivation). After water deprivation, urine osmolality is measured. If the urine osmolality is low, synthetic ADH (desmopressin) is given. Urine osmolality is measured over the 2-4 hours following desmopressin.
In primary polydipsia, water deprivation will cause urine osmolality to be high. Desmopressin does not need to be given. A high urine osmolality after water deprivation rules out diabetes insipidus.
In cranial diabetes insipidus, the patient lacks ADH. The kidneys are still capable of responding to ADH. Initially, the urine osmolality remains low as it continues to be diluted by the excessive water lost in the urine. After desmopressin is given, the kidneys respond by reabsorbing water and concentrating the urine. The urine osmolality will be high.
In nephrogenic diabetes insipidus, the patient is unable to respond to ADH. The urine osmolality will be low both before and after the desmopressin is given.
What hormone in high levels in men can cause infertility?
Testosterone, esp exogenous supply. It suppresses GnRH and so FSH and LH drop causing a decrease in spermatogenesis
Where is the left adrenal gland positioned in relation to the crus of diaphragm?
Left adrenal gland is posterior and left of left crus of diaphragm
What medications can be used in overactive thyroid?
Propylthiouracil or carbimazole
What are the risk associated with carbimazole?
Agranulocytosis
Angioedema
Lymphadenopathy
Acute pancreatitis
How long should a women wait before becoming pregnant after radioactive iodine treatment? and men?
At least 6 months and men at least 4
If there is a super high testosterone level in females what must be done as next management steps?
Referral via cancer pathway to rule out a androgen secreting tumour
Except from, potassium, fluids and fixed rate insulin what else should DKA patients be given?
LMWH due to VTE risk
Which hormone decreases appetite? Which hormone increases appetite?
Leptin
Ghrelin
What is adiponectin?
Adiponectin is a hormone your adipose (fat) tissue releases that helps with insulin sensitivity and inflammation. Low levels of adiponectin are associated with several conditions, including obesity, Type 2 diabetes and atherosclerosis.
What may be a niche sign in a child that there is type one diabetes?
Previously bed trained child may start wetting bed again
In cushing’s disease which hormone is high?
Cortisol due to high ACTH - dexamethasone suppression would work to lower these levels.
When DKA patient glucose levels drop below 12mmol on there fixed rate insulin what fluid should be swapped instead of saline?
Instead of saline swap to 5% dextrose to avoid hypoglycaemia caused by the fixed rate insulin
1st line investigation or phaeochromocytoma is?
24 urine collection of catecholamines
What symptoms may present with osteomalacia?
Bone and joint pain
Muscle weakness
Fractures
What causes osteomalacia?
Abnormal bone mineralization of osteoid due to vitamin D deficiency
What defect is responsible for congenital adrenal hyperplasia?
21-Hydorxylase deficiency
What are the symptoms of congenital adrenal hyperplasia?
Increased ACTH leads to increased sex hormones and mineral corticoids, therefore, female babies may have ambiguous genitalia and male babies may have penile enlargement and hyperpigmentation. Also K+ will be high and sodium will be low.
What are the symptoms of a thyroid storm?
High temp
Tachycardic
Agitated
What is 1st line treatment of a thyroid storm?
Carbimazole
When is carbimazole contraindicated?
neutropenia and agranulocytosis
What 3 medications can be given during a thyroid storm and what is there purpose?
- Propylthiouracil + iodine = blocks synthesis of thyroid hormones
- Hydrocortisone = prevents conversion of t4 to t3
- Propranolol =decreases BP
Which cell’s secrete glucagon?
alpha islet cells
Why can carbamazepine cause SIADH?
Because it stimulates V2 vaspopressin receptors - protein complex G
What glucose amount suggest hyperosmolar hyperglycaemic state (HHS)?
Glucose 30 or over
What is pH is HHS?
Greater than 7.3
What is the pathophysiology of HHS?
Decrease in insulin and increase in counter regulatory hormones : cortisol, GW, Glucagon. So glucose increases and this leads to osmotic diuresis
What is blood pressure like in HHS?
It’s low
What can trigger HHS?
Infection, stroke ,MI, Vomiting, High dose steroids
How is HHS managed?
Fluidrecuss, insulin ONLY if there is ketonemia(more than 1mmol). Replace Potassium . If there is ketonemia then used fixed rate insulin at 0.5/kg/hr
What are the complications of HHS and how are they then prevented?
- DVT/PE : LMWH
- Cerebral oedema: may occur due to the rapid correction of hyperglycaemia therefore resulting in a lower plasma osmolality due to to fluid recuss: rehydrate slowly
What is the treatment of reifenstien?
The man has XY but is resistant to androgens so they may have both parts. Therefore treat with androgens as it increases chances of fertility
What are most cases of acromegaly due to vs. what’s a the small minority due to?
95 % = pituitary adenoma
5% = ectopic release of GH from a carcinoid tumour
When is a prolactinoma suspected?
If prolactin is above 250 ng/ml
What is preferred imaging for a Prolactinoma?
MRI
What’s the most common cause of hyperthyroidism?
Graves
What’s the most common form of secondary hypertension?
Primary hyperaldosteronism
What signalling pathway does GH use?
Tyrosine kinase receptor that uses the JAK/STAT pathway
If sodium is high what happens to renin?
It goes low
What’s important to remember in Conn’s when looking at the electrolytes?
K+ may be normal instead of low so don’t just focus on that for diagnosis
What can be used to decrease secretion of prolactin?
Bromocriptine - dopamine agonist
What’s the treatment for hyponatraemia in SIADH?
800ml fluid restriction over 24 hours
Desmopressin is artificial?
ADH- vasopressin
What is 2nd line diabetic medication if there is poor tolerance or SE from metformin?
Gliclazide
What is pseudohypoparathyroidism?
Failure of target cells to respond to PTH so PTH increases, Calcium decreases and phosphate increases
What are the ACTH levels in adrenocortical tumours?
Low/ undetectable due to negative feedback from super high cortisol concentrations
When should SIADH not be diagnosed?
Presence of:
- Hypovolaemia
- Hypotension
- Addison’s
Fluid overload
Hypothyroid
Why must you always give an alpha blocker before a beta blocker?
It can cause hypertensive crisis if beta blocker isgiven first
What type of capillaries are in endocrine organs?
Fenestrated capillaries
What is kallman’s syndrome?
Hypogonadotropic hypogonadism due to defect in GnRH action and release due to failure of GnRH secreting neurones to migrate from nose during embryonic development
What would be the hormone results in kallman’s?
Low: GnRH, Low LH, Low FSH, Low oestrgoen
What are the features of kallman’s?
Anosmia
Absent/delayed puberty
Unilateral kidney agenesis
Bimanual synkinesis
Cleft lip
What is renin levels in addison’s and why?
They are high. Because low aldosterone causes high renin
In what condition is doing a renin: aldosterone ratio useful and what would you expect?
Conn’s as renin would be low due to high aldosterone
What is peutz jeghers?
A genetic disorder causing polyps and perioral freckling
What is a side effect of GLP-1 agonists like exenatide?
Delayed gastric emptying - don’t give this medication if pt have a problem with diabetic gastroparesis
What are some rare side effects of statins?
Raised creatinine kinase
Hair loss
What are some causes of raised creatinine kinase?
Steroid use
Hypothyroid
Alcohol excess
Rhabdomyolysis
What is regarded as impaired fasting glucose?
6.1-6.9
What is regarded as impaired glucose tolerance ?
7.8 -11.1, 2 hours post 75g oral glucose
What is sheehans syndrome?
postpartum pituitary gland necrosis, occurs when the pituitary gland is damaged due to significant blood loss and hypovolemic shock or stroke, originally described during or after childbirth l
Is aldosterone dependent on pituitary function?
NO
