Endocrinology Flashcards
- Sodium-glucose co-transporter-2 inhibitors (SGLT2-i) are now commonly used in the management of T2DM. There is an established association of euglycemic diabetic ketoacidosis with these agents.
Which of the following statements below is incorrect?
A. These agents decrease urinary ketone excretion such that urine ketone testing may be unreliable
B. SGLT2i be ceased at least 24 hours pre-operatively or in other situations of anticipated stress or reduced oral intake
C. Euglycemic DKA is driven by a decline in circulating insulin levels and consequent stimulation of the production of free fatty acids, which are converted to ketone bodies
D. Dextrose, in addition to insulin infusion, is typically needed to drive down ketosis
Answer: B
- Should ceased SGLT2i at least 3 days pre-operatively not 24 hours prior.
- Mechanism of Euglycaemic DKA:
o SGLT2 cause increase urinary glucose excretion which causes reduction in BGL and reduction in insulin.
o This results in increased lipolysis and free fatty acid production leading to ketosis.
o Upregulation of glucagon secretion also likely contributes to increased ketone bodies
- A 38 year old woman has a history of medullary thyroid carcinoma managed with thyroidectomy in her late 20’s is found to have a blood pressure 180/100mmHg. On further history she reports she has been having episodes over the past several months of palpitations, diaphoresis and sweating, often precipitated when she urinates. She has stopped drinking coffee but has found her episodes have continued despite this.
24 hour urine fractionated metanephrines and catecholamines are elevated.
What is her most likely underlying condition?
A. Von-Hippel Lindau disease
B. Familial paraganglioma syndrome
C. Multiple Endocrine Neoplasia type 1 syndrome
D. Multiple Endocrine Neoplasia type 2 syndrome
Answer: D
- Patient has a phaeochromocytoma and a past history of medullary thyroid cancer consistent with MEN2
- MEN2 is due to an underlying RET mutation
- 30-40% of patients with phaeochromocytoma have an underlying genetic disorder and as such all patients should be offered genetic counselling e.g. MEN2, VHL, neurofibromatosis type 2, familial paraganglioma
MEN2: Parathyroid, Pancreatic and Pituitary
MEN 2: 50% chance of developing Phaeo
- An 80 year old man is diagnosed with a somatotroph adenoma of the pituitary gland and declines surgical intervention. HE is managed medically with pegvisomat. Which of the following best measure to monitor his response to medical therapy?
A. Growth hormone
B. IGF-1
C. Prolactin
D. Response to oral glucose tolerance test
Answer: B
- Pegvisomat blocks the peripheral growth hormone binding to receptors and therefore suppresses serum IGF-1. Normalisation of IGF-1 with pegvisomat occurs in up to 70% of patients with acromegaly. However because it acts peripherally it does not target the adenoma, so serum growth hormone will remain high
- A patient with type 1 diabetes is being treated with the following therapy: glargine 30 units at 6pm, Novorapid 10 units with each meal.
Which value is the best estimate of this patients insulin sensitivity factor?
E. 1
F. 1.5
G. 2
H. 2.5
I. 3
Answer: B, Insulin sensitivity factor = 1.67
- Insulin sensitivity factor
o Is how much the blood sugar level will reduce with 1 unit of insulin.
o That is if someone insulin sensitivity factor is 1.5 if you give them 1 unit of insulin their BSL will drop by 1.5mmol/L
o Insulin sensitivity factor = 100/total daily dose = 100/(30+10x3)=1.67
- Insulin: Carbohydrate ratio
o How many grams of carbohydrates 1 unit of insulin will cover
o 500/(total daily dose) = 500/(30+10x3) = 8.3
o That is 1 unit of insulin will cover 8g of carbohydrate. That is if patient has a meal with 40g of carbohydrates they would need 4 units of insulin
5. A 29-year-old woman presents with oligomenorrhoea and a 5kg weight gain over 12 months. Past medical history is unremarkable. She has evidence of hirsutism on examination and a BMI of 27kg/m^2 and early androgenic alopecia. There is no abdominal striae or acanthosis nigricans. Laboratory investigations: Total testosterone 2.3nmol/L (<2.8) DHEAS 7.2 (0-6.7) SHBG 26mmol/L (18-110) 17-hydroxy-progesterone 2.3 nmol/L (<6.6) LH 5.4 (IU/L) FSH 4.6 (IU/L) Oestradiol 360pmol/L ACTH 34ng/L (48) AM cortisol 370nmol/L (180-400) bHCG <1 In light of these findings what is the most appropriate next investigation? A. CT adrenal imaging B. Pelvic USS C. Low and high dose dexamethasone suppression test D. ACTH stimulation test
Answer: A
- Patient has elevated androgens source is either the ovaries or the adrenal gland
- Elevated DHEA-S suggests that the increased androgen production is likely from an adrenal source (e.g. tumour secreting androgen)
- IF the DHEA-S was normal it would most likely by PCOS and as such a pelvic ultrasound would be the answer
- Non-classical CAH (enzyme function is reduced rather than absent) can produce PCOS like features such as oligomenorrhea, acne, infertility, hirsutism. Unlike classical CAH tends to get diagnosed later in life
6. A 40-year-old woman is admitted to hospital with profound lethargy and marked postural hypotension. She was diagnosed with Hashimoto’s hypothyroidism two weeks ago and commenced on thyroxine 100mcg daily. Laboratory results: Sodium: 125 Potassium 6.1 Creatinine 150 Glucose 3.1 Calcium 2.8 Phosphate 1.2 TSH 6.0 Thyroxine: 7.1
After drawing blood for further relevant investigations, the most appropriate management is?
A. Administer a loading dose of thyroxine 300microg PO
B. Administer intravenous pamidronate
C. Administer intravenous normal saline over 4 hours
D. Administer intravenous hydrocortisone
Answer: D
- Biochemistry suggests cortisol deficiency (low Na, high K, low glucose) and volume depletion. Therefore, appropriate management is IV hydrocortisone and aggressive fluid resuscitation
- Administration of thyroxin in untreated adrenalin insufficiency can precipitate adrenal crisis. Therefore always replace hydrocortisone prior to commencing thyroxine
- Significant intercurrent illness is commonly associated with disturbances of thyroid function (non-thyroidal illness)
Which one of the following is least likely to be present in a euthyroid patients with severe illness?
A. Normal thyroid stimulating hormone
B. Raised free triiodothyronine
C. Low thyroid stimulating hormone
D. Normal free thyroxine
Answer: B
- Non-thyroidal illness is also called “sick euthyroid”
o TSH is typically low or low normal,
o T3 is low due to reduction in conversion of T4 to T3
o T4 is low or normal
- A 45 year old man is referred with hypercalcaemia which is known to have been present for at least 6 months, during which time it has been stable. He is asymptomatic and has no past medical history.
Recent investigations are as follows:
Serum calcium 2.7 mmol/L (2.2-2.5)
Serum albumin 41g/L (38.44)
Serum intact parathyroid hormone 4.5 pmol/L (1.0-5.0)
24 hour urine calcium excretion 2.1 mmol/L (3.0-5.0)
24 hour urine creatinine excretion 16 mmol/L (8-18)
Which one of the following investigations is most likely to be diagnostically useful?
A. Measurement of serum 1,25(OH)2 vitamin D
B. Measurement of serum parathyroid hormone related peptide (PTHrP)
C. Bone scintigraphy with radiographs of areas of increased uptake
D. Serum calcium measurement in first degree relatives
E. Ultrasound of the neck
Answer: D
- Patient likely has familial hypocalciuric hypercalcaemia
o Despite elevated serum calcium patient has an inappropriately low urine calcium excretion
o Autosomal dominant therefore should check serum calcium measurement in first degree relatives
o Familial hypocalciuric hypercalcaemia is usually benign, asymptomatic, autosomal dominant, and due to a defect in CaSR
- Serum 1,25(OH)2 vitamin D would be measured if suspecting sarcoid
- PTHrP would be measured if suspecting malignancy
- Bone scintigraphy with radiographs of areas of increased uptake would be if suspecting Pagets disease
- Ultrasound of neck would be performed if suspecting PTH adenoma
- Hypercalcaemia:
o ?PTH dependent or independent
IF PTH mediated:
• Primary hyperparathyroidism: PTH adenoma
• Tertiary hyperparathyroidism: renal
• Familial hypocalciuric hypercalcaemia
PTH independent:
• Malignancy: bone metastases, multiple myeloma, or PTHrP
• Granulomatous disease (e.g. Sarcoidosis/tuberculosis), lymphoma (excess activated vitamin D)
• Excess vitamin D, exogenous calcium etc.
- A 55-year-old woman presents to her GP with a history of recurrent headaches. Her GP requests a CT brain which demonstrates a 6mm round pituitary mass. There are no abnormalities on neurological and general examination.
What is the hormone that this mass is most likely to be secreting?
A. Corticotrophin
B. Gonadotrophin
C. Prolactin
D. Thyrotropin
E. Somatotrophin
Answer: E
- Microadenoma is <1cm. A microadenomas in and of themselves do not cause a headache as they are not large enough to cause mass effect so if headache is present it is more likely related to IGF-1/GH excess
- Prolactinoma is the most common secreting pituitary microadenoma
- Growth-hormone secreting adenomas (somatotrophinomas) are generally small, but IGF-1 excess can present with headaches
10. Which of the following agents is NOT effective in the treatment of adrenal Cushing’s syndrome? A. Ketoconazole B. Mitotane C. Pasireotide D. Etomidate
Answer: C
- Answer is Pasireotide as it is a somatostatin analogue and works in the pituitary it will have no effect on adrenal Cushing syndrome
o Somatostatin analogue: somatostatin is an inhibitory hormone and predominantly inhibits growth hormone but also blocks the release of ACTH from the corticotrophs in the pituitary
- Ketoconazole, mitotane, etomidrate are used in adrenal Cushing syndrome
- Treatment of Cushings disease
o Cushings disease refers to cushing syndrome caused by an ACTH secreting pituitary adenoma
o Firstline treatment is transsphenoidal adenomectomy which has a longterm cure rate of 80-90%. Following surgery patient will be transiently glucorticoid deficient and will require glucocortioicd replacement until recovery which typically takes months and up to a year.
o Alternative to surgery is radiatiotherapy
o Medical therapy does not treat the underlying tumour, nor restore normal diurnal pattern of cortisol secretion. Only use if failure of surgery or surgery is inappropriate
- Treatment of ectopic and Adrenal cushings syndrome:
o Firstline treatment is surgical removal of the adrenal adenoma or carcinoma, or of ACTH-secreting tumour (small cell lung cancer, bronchial carcinoid, thymic carcinoid, medullary cancer of thyroid, phaechromocytoma, islet cell tumour)
11. A 25 year old pregnant woman presents to the emergency department 12 weeks into her pregnancy with nausea vomiting, a fine tremor and a heart rate of 115. She remains tachycardic despite intravenous fluid resuscitation. There was not goitre or ophthalmopathy T3: 6 [1-3] T4: 50 [ 10-20] TSH <0.01 [0.5-6] TSH receptor antibody: negative Anti-TPO antibody negative What is the appropriate treatment for this patient? A. Supportive care B. Propylthiouracil C. Carbimazole D. Propranolol E. thyroxine
Answer: B
- Most common cause of hyperthyroidism in a pregnant lady is gestational thyrotoxicosis. This is due to beta-HCG having molecular similarity to TSH and can stimulate thyroxine production. Typically causes a subclinical hyperthyroidism in the first half of gestation. Management of this is supportive care
- However, in this patient they have overt severe hyperthyroidism given a markedly elevated T4, fully suppressed TSH and they are symptomatic. For this reason, they should be treated for Grave’s disease
o In gestational thyrotoxicosis get a T4 just above the upper limit of normal, typically 20-30
o Note antibody testing during pregnancy can be negative because pregnancy is a state of immunosuppression. Often will become antibody positive post-partum
o Symptomatic: nausea, vomiting, tremor and tachycardia. These may be due to pregnancy/hyperemesis gravidarum however given tachycardia not fluid responsive this is less likely.
o Note neonate would need to be monitored for neonatal Graves disease
- Carbimazole:
o Firstline after first trimester (approx 16 weeks) as teratogenic in first trimester
Teratogenic: associated bith defects including aplasic cutis and carbimazole embryopathy characterised by choanal atresia or oseophageal atresia
o Inhibits thyroid peroxidase enzymes, inhibits thyroid hormones synthesis
o Firstline as it has a faster onset of action (takes 3-4 weeks to work) and less hepatotoxicity
o Side effects: agranulocytosis, rash, hepatoxicity (has been associated with cholestatic jaundice rarely)
- Propylthiouracil
o Inhibits thyroid peroxidase enzyme
o Typically second line
o Firstline in first trimester
o s/effects: serious hepatotoxicity (hepatocellular hepatitis immune mediated, occurs in 0.1% of patients however 10% develop liver failure and require transplant), agranulocytosis
- A 65 year old man with metastatic melanoma, who has been commenced on ipilimumab 2 months earlier presents with marked fatigue and dizziness. Patient has a mild hyperkalaemia 5.1 and serum sodium is 131 (compared to 140nmol/L 2 weeks prior).
What is the most helpful initial investigation?
A. Morning cortisol level
B. Thyroid function tests
C. Gonadotrophins and total testosterone
D. Synacthen test
Answer: D
- Immunotherapy have been associated with inflammation of the pituitary (hypophysitis), thyroid or adrenal gland.
- Patient presents with dizziness and low serum sodium hence need to consider if this patient is cortisol deficient
- Most helpful initial investigation would be to perform both the morning cortisol and synacthen test. However question makes you choose between the two. Synacethen test likely most helpful as it tells you whether this is secondary adrenal or pituitary
- Thyroiditis should also be considered as a differential diagnosis
- Synacthen test: typically performed in AM, firstly get baseline cortisol level, then give 1mg of synacthen (synthetic ACTH), if adrenal problem present the cortisol will not augment, if pituitary cause will get a rise in cortisol post synacthen.
- A 16 year old girl presents with polyuria and polydipsia. Her 24 hour urine volume is 7.2L. She has a normal blood glucose and calcium level. A water deprivation test is performed.
Time DDAVP given: 2mcg IV given at 11:00AM
Which of the following is the most likely diagnosis? A. Central diabetes insipidus B. Primary polydipsia C. Diuretic abuse D. Lithium toxicity E. Ectopic ADH production
Answer: A
- Central diabetes insipidus is characterised by decreased release of ADH resulting in a variable degree of polyuria.
- Water deprivation test:
o Water deprivation test is stopped when achieve 5% loss of body weight, serum sodium is 150 or above or serum osmolality is >300.
o DDAVP is then administered. uOSm should increase by 50% or to >800 uOsm if it is central diabetes insipidus. Nephrogenic DI does not respond to DDAVP (as problem is in the tubules).
- In this patient after 2 hours the urine osmolality has increased by more than 50%, hence they have responded appropriately to DDAVP suggesting a central cause
- Diuretic abuse / lithium treatment would have a nephrogenic diabetes insipidus.
- A 52 year old man with a 3 year history of hypertension is referred for further evaluation of refractory hypertension. Current medications include: perindopril 10mg daily, prazosin 2mg BD and verapamil SR 180mg daily.
The following investigations are obtained:
Creatinine 68 (<60)
K: 3.1
Renin 16 mU/L (5-50)
Aldosterone 1100 pmol/L (80-1000)
Aldosterone renin ratio 69 pmol/mU (<70)
Which of the following statements if FALSE?
A. Renovascular hypertension is the most likely diagnosis
B. Primary hyperaldosteronism cannot be excluded
C. These tests should be repeated after a 6 week washout period of perindopril
D. Prazosin and verapamil do not affect the ARR
E. Potassium should be replaced prior to measuring ARR
Answer: A
- High ARR suggests primary hyperaldosteronism (low renin, high aldosterone)
- Normal ARR suggests a renal abnormality e.g. renovascular hypertension (high renin, high aldosterone)
- This patient may have a falsely normal ARR due to being on an ACEi. Increased renin levels are usually seen with ACEi treatment and renovascular hypertension. In this patient the renin is more or less on the lower end of normal despite ACEi treatment making renovascular hypertension unlikely.
- Ideally perindopril should be stopped prior to performing ARR
- Medications that do not affect screening:
o Prazosin, moxonidine, verapamil, hydralazine
- ARR can be falsely normal in hypokalaemia
- Which of the following people with diabetes would be at the highest risk of a severe hypoglycaemic episode in the next 24 hours?
A. A type 1 diabetic patient being changed from twice daily protamine to glargine
B. A type 1 diabetic patient who has just been treated for a severe hypoglycaemic episode
C. A type 1 diabetic patient with nocturnal hypoglycaemic episodes twice per week
D. A person with post pancreatectomy diabetes
E. A type 1 diabetic with co-existent Addisons disease
Answer = B
- Hypoglycaemic unawareness: reduced sympathoadrenal responses resulting in absent or reduced neurogenic symptoms upon which to act. Occurs via decreased SNS output from the CNS.
- If recent hypoglycaemic event get defective response to hypoglycaemia. No increase in glucagon during hypoglycaemia. Shift in the glycaemic threshold for sympathoadrenal response to a lower glucose level.
- Recovery can occur in as little as 2-3 weeks of avoid hypoglycaemia
- A 77 year old frail woman with a history of early dementia, well controlled hypertension (Average 130/80mmHg), osteoarthritis and previous cholecystectomy presents with self-limiting abdominal pain. Medications include verapamil vitamin D and paracetamol. CT abdomen shows a 1.8 cm adrenal lesion. Attenuation was minus 10 Hounsfield units.
Investigations:
-Normal plasma free metanephrines,
-serum cortisol of 20nmol/L following administration of 1mg dexamethasone the evening prior
-potassium 3.9
-plasma renin activity 3ng/mL/hour (0.6-4.3)
-Serum aldosterone 152pmol/L (110-580)
A. Repeat CT and hormonal studies in 6-12 months
B. No further follow up required
C. Repeat CT in 6-12 months and repeat hormonal studies only if changes in clinical picture
D. Change verapamil to low dose prazosin and repeat renin/aldosterone in 4 weeks
Answer = B
- Investigation of an adrenal adenoma:
o Exclude functional adenoma:
Cortisol: 24 hour urinary cortisol if features of cushing’s syndrome. Or 1mg dexamethasone suppression test if asymptomatic
Adrenal androgens (DHEAS)
Plasma renin aldosterone ratio
24 hour urinary metanephrine/normetanephrine or plasma metanephrine/normetanephrine
o CT appearance:
Pre-contrast Hounsfield units <10 = benign
95% of malignant lesions are >4cm
- Given patient has a non-functioning adrenal adenoma that is <10HU and <4cm no further follow up required (Fassnacht et al, European journal of endocrinology 2016)
- A 48-year-old man presents with difficult to control diabetes diagnosed 1 year ago HbA1c at diagnosis was 8.1%, and BMI 26kg/m2. Despite weight loss (3kg) and treatment with metformin and sulfonylurea, HbA1c has increased to 9%. He is otherwise well and his only other medication is thyroxine for hypothyroidism.
What is the most appropriate next step?
A. Add a SGLT2 inhibitor
B. Conduct genetic testing for mature onset diabetes of the young
C. Measure coeliac serology
D. Measure glutamic acid decarboxylase antibodies
Answer: D
- Differentials for this patient include latent adult onset diabetes and type 1 diabetes hence important to measure anti-GAD
- LADA:
o autoimmune diabetes associated with GAD antibodies
o Slow progression beta-cell failure and therefore not insulin requiring at least during the first 6 months after diagnosis
o Presents of GAD antibodies can help to identify these patients who were thought to have type 2 diabetes
- A 65 year old man presents with sudden onset of a severe headache. He appears generally unwell and has a blood pressure of 90/60mmHg. There are no focal neurological signs and visual field testing is normal. A non-contrast T1 weighted MRI scan shows the following:
Which of the following is the most appropriate first step in management? A. Glucocorticoid administration B. Emergency transsphenoidal surgery C. Pituitary radiotherapy D. Dopamine agonist therapy E. Somatostatin analogue therapy
Answer = A
- Pituitary tumour apoplexy is sudden haemorrhage into the pituitary gland.
- Haemorrhage often occurs due to a pituitary adenoma
- In most dramatic presentation causes sudden onset headache, diplopia and hypopituitarism.
- All pituitary hormonal deficiencies can occur, but the sudden onset of ACTH and therefore cortisol deficiency is the most serious because it can be life threatening
- A 34 year old woman reports reduced libido and mild depression. Her GP tests her prolactin level which is 960mlU/L (normal <500). A repeat test is at a similar level. Her thyroid function is normal. She has regular periods and no history of galactorrhoea. Beta-HCG is negative.
How should this patient be further investigated?
A. Pituitary MRI
B. LH and FSH measurement
C. Measurement of prolactin at 1:100 dilution
D. Macroprolactin assessment
Answer = D
- Macroprolactin has no clinic significance, but can be misdiagnosed as prolactin hypersecretion
- Macroprolactin is native prolactin that is bound to IgG and is much larger in size than monomeric prolactin. Macroprolactin causes hyperprolactinaemia through decreased prolactin clearance
- Patients are asymptomatic and no further treatment is required
21. Compared with medical or surgical therapy for the treatment of Graves’ disease, radioiodine ablation is associated with which of the following complications? A. Agranulocytosis B. Permanent hypothyroidism C. Recurrent laryngeal nerve injury D. Worsening of Graves ophthalmopathy
Answer = D
- Radioactive iodine is preferred treatment in nonpregnant patients. Exception to this is moderate to severe Graves ophthalmopathy as it can exacerbate the eye disease. If mild Graves’ disease may still undergo radioactive iodine but with prednisolone prophylaxis.
- Following oral administration radioactive iodine is transported into thyroid follicular cells resulting in cell necrosis over weeks to months.
- 10% develop radiation thyroiditis with transient worsening of thyrotoxicosis and painful thyroid inflammation. Hence antithyroid medication is typically given prior to radioactive iodine to achieve euthryoidism especially if older, or comorbidities
- A 56-year-old male presents with ongoing hypertension following angioplasty for acute cardiac chest pain. He is on labetalol. He has a history of paroxysmal sweating and headaches. Appropriate next management step would be:
A. A CT scan of his abdomen is required to confirm phaeochromocytoma
B. He requires genetic testing for SDHB mutation
C. 24-hour urinary catecholamines is the best way to screen for a phaeochromocytoma
D. Labetalol may not provide adequate control in this setting and should be stopped
E. Alpha blockade should be added pending further investigation
Answer: E
- Question is wanting you to consider phaeochromocytoma as the leading differential
- Initial evaluation includes 24-hour urinary fractionated catecholamines and metanephrines and plasma free metanephrines. Following biochemical confirmation of the diagnosis CT abdomen should be performed to assess for adrenal lesions
- 30-40% of patients have the disease as art of a familial disorder and as such all patients should be offered genetic counselling e.g. MEN2, VHL, neurofibromatosis type 2, familial paraganglioma. SDHB is associated with familial paraganglioma, which is an autosomal dominant disorder. Would only perform genetic testing once diagnosis confirmed.
- Management:
o Surgical resection
o Pre-operative alpha-receptor blockade (phenoxybenzamine) for 10 to 14 days before surgery is essential to prevent hypertensive crisis during surgery, up titrated to achieve a BP of 130/80mmHg,
o If possible, beta blockade must not be started in patients with phaeochromocytoma until alpha blockade has been established. Can cause dramatically elevated blood pressure due to unopposed alpha adrenoceptor stimulation
23. Which of the following is a marker of bone resorption? A. Alkaline phosphatase B. Urine N-telopeptide (NTX) C. Osteocalcin D. Procollagen C-terminal propeptide E. Procollagen N-terminal propeptide
Answer: B
- Markers of bone resorption
o Urinary n-telopeptide crosslink (NTX)
o Serum C-telopeptide crosslink (CTX)
- A 45 year old man presents to outpatients for review of treatment refractory hypertension. Investigations include potassium 3.9, aldosterone 450 pmol/L (60-980), renin (direct) 4 (7-50), aldosterone:renin ratio 112.5. 2L of 0.9% sodium chloride is infused over 4 hours. Aldosterone level is 200pmol/L (<165) post this infusion. A CT adrenal scan showed a 12mm lipid rich adenoma on the left side. Adrenal vein sampling showed no evidence of lateralisation of aldosterone production.
What is the most appropriate treatment strategy?
A. Laparoscopic left adrenalectomy
B. Bilateral adrenalectomy
C. Commencement of spironolactone 50mg daily
D. Commencement of Prazosin 1mg Bd
Answer: C
- Patient has primary hyperaldosteronism given positive normal saline suppression test.
- Even though a lesion is identified on CT, adrenal vein sampling suggested there was no adrenal lateralisation hence the adrenal lesion is likely incidental.
- Patient most likely has bilateral adrenal hyperplasia rather than an aldosterone producing adrenaloma.
- Treatment of unilateral adrenal hyperplasia is surgical, however bilateral is treated with medical therapy and first line would be a mineralocorticoid receptor antagonist
- A 67 year old female with a history of rheumatoid arthritis presents to your clinic. She has been taking prednisolone 5mg daily for the past 6 weeks. She recently suffered non-displaced fracture of her left radius due to minimal trauma. What is the most appropriate next step in diagnosis and management of this patient?
A. Perform a bone mineral density scan and commence anti-resorptive therapy if T score = -2.5
B. Perform a bone mineral density scan and commence anti-resorptive therapy if T score = -1.5
C. Initiate bisphosphonate
D. Initiate oestrogen replacement therapy
Answer:
- Osteoporosis is diagnosed when BMD T-score is -2.5 or below, a T-score of -1 to - 2.5 is considered osteopaenic
- If patient is on bisphosphonate long term (>7.5mg/day for 3 months) can commence bisphosphonate if patient is osteopaenic, that is t-score
- Which of the following people has the greatest risk of developing type 1 diabetes?
A. Personal history of coeliac disease
B. Sibling of a patient with type 1 diabetes
C. Father with type 1 diabetes
D. Dizygotic twin with type 1 diabetes
E. HLA DR3/DR4 haplotype
Answer = B
- Lifetime risk of developing T1DM:
o Sibling 8%
o Father 5%
o Mother 3%
o Mono twin: 50% concordance
o Dizygotic twin: 10% concordance
- Highest risk haplotype: DR3 and DR4-DQ8
o 80-90% of type 1 patients have 1 of these haplotypes
o 30-50% of type 1 patients have both (DR3/DR4)
o Present in 2.4% of the general population
- A 41-year-old female is being investigated for repeated episodes of diaphoresis, slurred speech and tremulousness that resolve with meals. During one of these episodes a blood sugar level was measured as 1.9mmol/L and improved with intravenous glucose administration. She was referred for a 24 hour fst and she became diaphoretic and confused. Blood tests at the time are shown:
What is the most likely diagnosis?
A. Insulin administration (factitious hypoglycaemia)
B. Insulinoma
C. Insulin like growth factor excess
D. Non-insulinoma pancreatogenous hypoglycaemic syndrome-NIPHS (islet hypertrophy and nesidioblastosis)
Answer = B
- This patient most likely has an insulinoma symptomatic hypoglycaemia, low BSL and relief of symptoms with glucose administration
- Elevated pro-insulin and c-peptide confirm that this insulin is endogenous
- Non-insulinoma pancreatogenous hypoglycaemic syndrome causes hypoglycaemia post-prandially, typically 2-4 hours post meal. Fasting hypoglycaemia is rare
28. During pregnancy, which maternal condition confers the highest risk of foetal thyrotoxicosis? E. Gestational thyrotoxicosis F. Toxic multinodular goitre G. Graves disease H. Subacute thyroiditis
Answer = C
- Can get transplacental transfer of antibodies which can stimulate the foetal thyroid gland, just as they do the mothers gland
- What is the primary mechanism of corticosteroid induced osteoporosis?
A. Increased apoptosis of osteoblasts
B. Increased intestinal calcium absorption
C. Increased PTH activity
D. Decreased activity of osteoprotegrin
E. Decreased urinary calcium excretion
Answer: A
- Corticosteroid induced apoptosis
o Main mechanism of action is increased apoptosis of osteoblasts
o BMD is related to cumulative not daily dose
o Reversible on stopping Rx
o Trabecular loss >cortical bone
o Higher fracture risk for same BMD compared to postmenopausal osteoporosis
- A 36 year old man presents with intermittent lethargy, sexual dysfunction and reduced libido gradually developing over the last 6 months. On examination no specific abnormality is detected. He is taking no medications investigations are as follows:
Which of the following is the MOST appropriate investigation? A. CT of the brain B. Ultrasound of the testes C. MRI of the pituitary D. Penile doppler E. CT of the abdomen
Answer: C
- Patient has secondary hypogonadism given LH/FSH and testosterone is low. The underlying cause is likely due to a prolactinoma
- MRI is standard for the evaluation of pituitary tumours
- Which statement about pituitary hormone testing is correct?
A. Insulin tolerance test can be used to assess prolactin function
B. Insulin tolerance test can be used to assess growth hormone deficiency
C. Testosterone level can be measure randomly to determine male hypogonadism
D. Water deprivation test is indicated in diagnosis of SIADH
E. Morning cortisol is used to confirm Cushing’s Syndrome
Answer: C
- Insulin tolerance test is used to assess growth hormone deficiency. Low blood sugar level causes increased production of growth hormone.
- Testosterone level is usually highest in the morning and hence should be measured prior to 10AM
- Water deprivation test is used for diabetes insipidus
- Cortisol is typically highest in the morning and lowest at night. Morning cortisol is used for cortisol deficiency not excess.
- Cushings syndrome diagnosis: (elevated cortisol) need 2 abnormal tests
o Late night salivary cortisol
o 24 hour urine free cortisol
o Overnight dexamethasone suppression test (1mg)
- Which of the following statements is true for Cushing’s syndrome?
A. Cushing’s disease is the most common cause of ACTH independent Cushing’s syndrome
B. Buffalo hump is specific for Cushing’s syndrome
C. Combined oral contraceptive pill can falsely elevated cortisol levels
D. 24 hour urinary cortisol is effective at excluding pseudo-Cushing’s syndrome
E. Dexamethasone can interfere with the cortisol assay
Answer: C
- Cushing’s disease is the most common ACTH dependent not independent form of Cushing’s syndrome
- Buffalo hump is not specific
- OCP can cause falsely high levels of cortisol due to oestradiol
- 24 hour urinary cortisol is not effective at excluding pseudo-Cushing’s, it just picks up excess cortisol
- Dexamethasone does not interfere with the cortisol assay.
