Endocrinology Flashcards
Who are the majority of cases of malignant otitis externa seen in?
Diabetes mellitus
What is the HbA1c target for patients on lifestyle + metformin for management of diabetes?
48 mmol/mol
What is the HbA1c target for patients on any drug which may cause hypoglycaemia (e.g. lifestyle + sulfonylurea)?
53 mmol/mol
In patients who are on metformin only for their diabetes, at what threshold should you consider adding a second agent?
58 mmol/mol
What HbA1c level indicates poorly controlled diabetes (and therefore the need for a VRII in peri-operative period)?
≥69 mmol/mol
3rd line therapy options in diabetes?
The following options are possible:
1) metformin + DPP-4 inhibitor + sulfonylurea
2) metformin + pioglitazone + sulfonylurea
3) metformin + (pioglitazone or sulfonylurea or DPP-4 inhibitor) + SGLT-2 if certain NICE criteria are met
4) insulin-based treatment
When is a GLP-1 mimetic (e.g. exanatide) indicated in diabetes?
If triple therapy is not effective or tolerated and have a BMI >35.
What should be used to assess for diabetic neuropathy in feet?
10g monofilament
What are 2 ways of distinguishing between T1DM and T2DM?
1) C-peptide levels
2) Diabetes-specific autoantibodies
How can c-peptide levels be used to distinguish between the two types of diabetes?
T1DM –> low c-peptide
T2DM –> normal c-peptide
What 3 antibodies can be used to distinguish between the two types of diabetes?
1) Antibodies to glutamic acid decarboxylase (anti-GAD)
2) Islet cell antibodies (ICA, against cytoplasmic proteins in the beta cell)
3) Insulin autoantibodies (IAA)
Which type of diabetes do anti-GAD indicate?
Present in around 80% of patients with T1DM
Which type of diabetes do islet cell antibodies indicate?
Present in around 70-80% of patients with T1DM
At what eGFR is metformin contraindicated?
<30 due to risk of lactic acidosis
Features of acromegaly?
1) coarse facial appearance, spade-like hands, increase in shoe size
2) large tongue, prognathism, interdental spaces
3) excessive sweating and oily skin: caused by sweat gland hypertrophy
4) features of pituitary tumour: hypopituitarism, headaches, bitemporal hemianopia
5) raised prolactin in 1/3 of cases → galactorrhoea
What are 95% of cases of acromegaly caused by?
pituitary adenoma
What is serum c-peptide a measure of?
Insulin production (i.e. low in T1D)
What are the 3 types of autoantibodies in T1D?
1) Anti-GAD
2) Anti-insulin
3) Anti-islet cell
Under normal circumstances, what should the rate of potassium infusion not exceed?
Why?
10 mmol/hr
As there is risk of inducing arrhythmia or cardiac arrest.
What should be offered to all adults with T2DM and CKD with an ACR over 30mg/mmol who are taking the highest tolerated dose of ACE inhibitor or ARB?
SGLT-2 inhibitor
What 2 investigations can help to differ between T1DM and T2DM?
1) Serum c-peptide
2) Autoantibodies
What are 2 surgical options in severe T1D?
1) Pancreas transplant
2) Islet cell transplant
Why is the original pancreas left in place in a pancreas transplant?
To continue producing digestive enzymes
Mx of short episodes of hyperglycaemia (once DKA has been excluded)?
Short episodes of hyperglycaemia do not necessarily require treatment.
Insulin injections can take several hours to take effect and repeated doses could lead to hypoglycaemia.
What is the main kidney disease seen in T1DM?
Glomerulosclerosis
To confirm a diagnosis of T2D, when is the HbA1c repeated?
Repeated after 1 month to confirm the diagnosis.
However, if there are symptoms or signs of complications then no repeat is needed.
Infection-related complications of T1D?
(4)
1) Pneumonia
2) UTIs
3) Skin & soft tissue infections
4) Candidiasis (oral and vaginal)
2 key actions of metformin?
1) increases sensitivity to insulin
2) decreases glucose production by liver
Which diabetic drug can potentially lead to a DKA?
SGLT-2 inhibitors
What are the 2 notable side effects of metformin?
1) GI upset
2) Lactic acidosis (e.g. 2ary to AKI)
Mechanism of Pioglitazone?
Same as metformin
Mechanism of SGLT-2 inhibitors?
Increase glucose excreted in urine
Which SGLT-2 inhibitor can increase risk of lower limb amputation?
Canagliflozin
What class of drug is Pioglitazone?
Thiazolidinedione
Which 3 diabetes drugs are associated with weight GAIN?
1) Pioglitazone
2) Sulfonylureas
3) Insulin
What are the notable side effects of Pioglitazone?
(4)
1) Weight gain
2) Increased risk of fractures
3) HF
4) Increased risk of bladder cancer
Which diabetic medication can increase risk of bone fractures?
Pioglitazone
Which diabetic medication can cause HF?
Pioglitazone
Give 2 examples of GLP-1 mimetics?
1) Liraglutide
2) Exenatide
In CKD in patients WITH diabetes, at what albumin-to-creatinine ratio (ACR) are ACEi started?
ACR >3 mg/mmol
What is the role of SGLT-2 in the kidney?
Reabsorb glucose out of the urine and into the blood
In patients with CDK and T2D, what is given when the ACR is >30 mg/mmol (i.e. in addition to the ACEi)?
SGLT-2 inhibitor
What are 2 key side effects of DPP-4 inhibitors?
1) Headache
2) Acute pancreatitis
What class of drug is orlistat?
Pancreatic lipase inhibitor
Role of orlistat?
Can be used in management of obesity.
Orlistat acts by reversibly inhibiting pancreatic lipases. This prevents the hydrolysis of triglycerides, and therefore free fatty acids are not absorbed.
I.e. prevents fat from being absorbed (passed out in poo instead).
Key adverse effects of orlistat?
1) Faecal urgency/incontinence
2) Flatulence
Criteria for using orlistat in obesity?
Either:
1) BMI ≥28 + associated risk factors
2) BMI ≥30
3) Continued weight loss e.g. 5% at 3 months
How long is orlistat usually used for in obesity?
<1 year
What is the 1st line treatment of peripheral neuropathy in diabetes?
Managed as neuropathic pain:
- amitriptyline
- duloxetine
- gabapentin
- pregabalin
What is diabetic neuropathy managed as?
Neuropathic pain
What are the 2 different types of diabetic neuropathy?
1) peripheral
2) autonomic
In CKD in patients WITHOUT diabetes, at what albumin-to-creatinine ratio (ACR) are ACEi started?
≥30
What is the main motor presentation of diabetic neuropathy?
Proximal motor (diabetic amyotrophy):
Severe pain and paraesthesiae in the upper legs, with weakness and muscle wasting of the thigh and pelvic girdle muscles.
What is the step-wise management of obesity?
1) Diet & exercise
2) Medical: orlistat, liraglutide
3) Surgical
Bariatric surgery can be divided into restrictive operations, malabsorptive opertions, and mixed operations.
What is normally the first-line intervention in patients with a BMI of 30-39?
Laparoscopic-adjustable gastric banding (LAGB): this is a primarily restrictive operation.
What is post-obstructive diuresis?
After acute urinary retention, the kidneys may increase diuresis due to the loss of their medullary concentration gradient.
This can lead to volume depletion and worsening of any AKI.
For the DVLA to license an insulin-treated individual with a Group 1 licence, what criteria must they meet? (6)
1) Adequate hypoglycaemia awareness
2) No more than 1 episode of severe hypoglycaemia while awake in the preceding 12 months AND the most recent episode occurred more than 3 months ago
3) Practises appropriate glucose monitoring
4) Not regarded as a likely risk to the public while driving
5) Meets the visual standards for acuity and visual field
6) Under regular review
What CVS complication are patients with RA at risk of developing?
IHD
Mx of post-obstructive diuresis?
Some patients may require IV fluids
In DKA, when should a patient be reviewed by a senior endocrinologist?
if the ketonaemia and acidosis have not been resolved within 24 hours
What is the normal anion gap?
4-12
What metabolic disturbance does renal tubular acidosis lead to?
hyperchloraemic, normal anion gap metabolic acidosis
What medication should patients with T1DM and a BMI >25 be considered for?
Metformin
Metformin works in multiple ways if associated with insulin. It improves insulin sensitivity, stabilises blood glucose and helps weight loss.
What are the 4 most common types of pituitary adenomas?
1) Prolactinoma
2) Non-functioning adenoma (leading to hypopituitarism)
3) ACTH secreting
4) GH secreting
What is the Hba1c target for patients on a drug which may cause hypoglycaemia (eg sulfonylurea)?
<53 mmol/mol
What is Trousseau’s sign a result of?
Hypocalcaemia
1st line medical management of a prolactinoma?
Dopamine agonists e.g. bromocriptine, cabergoline
What is the order of investigations in suspected 1ary hyperaldosteronism?
1) plasma renin:aldosterone
2) high resolution CT abdomen
3) adrenal venous sampling
What will the plasma aldosterone/renin ratio show in 1ary hyperaldosteronism?
Raised aldosterone levels with low renin levels (due to negative feedback du to sodium retention from aldosterone)
What will women with hypothyroidism need to increase their thyroid hormone replacement dose by in pregnancy?
Up to 50%
What imaging is indicated in a pituitary adenoma?
MRI with contrast
What PMH is seen in 90% of those with malignant otitis externa?
Diabetes (90%) or immunosuppression
1st line medical mangement of GH-secreting adenomas?
1) Somatostatins analogues e.g. octreotide
2) GH receptor antagonists (e.g., pegvisomant)
What is the role of somatostatin analogues in the management of a GH-secreting adenoma?
Somatostatin inhibits the release of hormones from the anterior pituitary.
Give the 5 main causes of pruritus
1) Iron deficiency anaemia
2) Polycythaemia
3) Liver disease
4) CKD
5) Lymphoma
What does increased homogenous uptake on a radioactive iodine uptake test suggest?
Grave’s disease
What is subacute thyroiditis (also known as De Quervain’s thyroiditis) thought to occur after?
Viral illness
Give some causes of a lower than expected HbA1c level
Due to a reduced RBC life span:
1) sickle cell anaemia
2) G6PD deficiency
3) hereditary spherocytosis
4) haemodialysis
Which type of thyroid cancer secretes calcitonin?
Medullary
What is the definitive management of a phaeochromocytoma?
Surgery
What must the patient be managed with PRIOR to surgery in a phaeochromocytoma?
Patient must first be stabilised on:
1) Alpha blocker (e.g. phenoxybenzamine) and then
2) Beta blocker (e.g. propanolol)
In type 1 diabetes, when is adding metformin considered on top of insulin therapy?
BMI ≥25
What fasting blood glucose indicates T2D?
≥7 mmol/l
What is a myxoedema coma?
Severe hypothyroidism –> decreased mental status, hypothermia etc
Give some causes of a higher than expected HbA1c level
Due to increased RBC lifespan:
1) vit B12/folic acid deficiency
2) iron deficiency anaemia
3) splenectomy
How does iron deficiency anaemia lead to increased HbA1c level?
RBC production decreases, resulting in an average age of circulating RBCs, and elevated HbA1c levels.
Hashimoto’s thyroiditis is associated with the development of what cancer?
MALT lymphoma
1st line investigation in a phaeochromocytoma?
24 hr urinary collection of metanephrines
NICE CKS have published guidance on the management of patients with SUBCLINICAL hypothyroidism and recommend a ‘watch and wait’ approach in patients over the age of what?
80y
Which 2 tablets can reduce the absorption of levothyroxine?
What can be done to minimise this?
Iron & calcium carbonate tablets
Take them 4 hours apart
What test can be used to distinguish between unilateral adenoma and bilateral hyperplasia in primary hyperaldosteronism?
Adrenal venous sampling
What is the role of adrenal venous sampling?
To determine if excess aldosterone is coming from ONE or BOTH adrenal glands.
High dose dexamethasone suppression test results in Cushing’s disease (i.e. pituitary adenoma secreting ACTH)?
Cortisol and ACTH will be suppressed.
Which class of diabetes medication can cause SIADH?
Sulfonylureas
Which diabetes medication often causes weight gain?
Sulfonylureas & pioglitazone
What test can be used to localise the pathology resulting in Cushing’s syndrome?
High dose dexamethasone suppression test
What is the most important modifiable risk factor for the development of thyroid eye disease?
Smoking
What is the most common site of an extra-adrenal phaeochromocytoma?
organ of Zuckerkandl, adjacent to the bifurcation of the aorta
Nephrogenic diabetes insipidus can occur due to electrolyte imbalances.
Which 2 in particular?
1) Hypokalaemia
2) Hypercalcaemia
What needs to be monitored during treatment of cranial diabetes insipidus with desmopressin?
Sodium levels –> risk of hyponatraemia
Does Grave’s disease cause 1ary or 2ary hyperthyroidism?
1ary - TSH receptor antibodies mimic TSH and stimulate TSH receptors on the thyroid.
Causes of cranial diabetic insipidus?
1) Idiopathic
2) Brain surgery
3) Brain tumour
4) Brain infections e.g. meningitis, encephalitis
What 4 conditions are seen in Wolfram syndrome?
1) Cranial diabetes insipidus
2) Optic atrophy
3) Deafness
4) Diabetes
What are 2 key side effects of carbimazole?
1) Acute pancreatitis –> look out for a patient on carbimazole presenting with symptoms of pancreatitis (e.g., severe epigastric pain radiating to the back).
2) Agranulocytosis
following treatment with radioactive iodine, how long must women not get pregnant?
6 months
2nd line drug used in hyperthyroidism?
Propylthiouracil
following treatment with radioactive iodine, how long must men not father children?
4 months
Why is carbimazole preferred to propylthiouracil in hyperthyroidsim?
Propylthiouracil carries risk of severe liver reactions
What 2 antibodies are seen in Hashimoto’s?
Anti-TPO & Anti-Tg (thyroglobulin)
What are 2 key side effects of propylthiouracil?
1) severe liver reactions
2) agranulocytosis
Mechanism of carbimazole?
Anti-thryoid agent –> inhibits thyroid peroxidase (TPO)
Which drug can cause hyperthyroidism?
Amiodarone
Where levothyroxine is not tolerated, what can be used instead?
Liothyronine sodium (a synthetic version of T3)
Is carpal tunnel syndrome seen in hypo- or hyperthyroidism?
Hypothyroidism
What 2 drugs can cause hypothyroidism?
1) lithium
2) amiodarone
What triad of symptoms can be seen in a thyroid storm?
1) Tachycardia
2) Fever
3) Delirium
Which 2 causes of hypothyrodism can cause a goitre?
1) Iodine deficiency
2) Hashimoto’s –> can initially cause a goitre, after which there is atrophy (wasting) of the thyroid gland.
How is the levothyroxine dose titrated?
Based on TSH level
Mx of a thyroid storm?
1) Symptomatic mx e.g. paracetamol
2) Treatment of underlying precipitating event
3) Beta blockers e.g. propanolol
4) Anti-thyroid drugs e.g. methimazole or propylthiouracil
5) Lugol’s iodine
6) Dexamethasone / hydrocortisone
Role of dexamethasone / hydrocortisone in mx of a thyroid storm?
blocks the conversion of T4 to T3
Patients with poor compliance with levothyroxine may have increased TSH levels and normal T4 levels on TFTs.
Why?
The normal T4 indicates that they have been taking thyroxine on the days prior to the blood test
However the TSH remaining raised indicates that the T4 level has been low for some time prior to this period - therefore indicating that compliance has overall been poor.
When should mx of subclinical hypothyroidism be considered?
If patient is <65 y/o and TSH level of >5.5
Bone profile results in osteomalacia?
- low calcium
- low phosphate
- high PTH
- high ALP
What is the strongest risk factor for developing a Bell’s palsy?
Pregnancy
What is the best test to diagnose Cushing’s syndrome?
Low dose (overnight) dexamethasone suppression test
Results of low dose (overnight) dexamethasone suppression test in Cushing’s syndrome?
Patients with Cushing’s syndrome do NOT have their morning cortisol spike suppressed
How can nephrotic syndrome affect thyroid levels?
Can cause low total thyroxine levels (due to urinary loss of thyroid-binding globulins, leading to a low total T4 level).
How is diabetes usually diagnosed in children?
Random blood glucose (at that time) + symptoms
What is HbA1c target in children?
<48 mmol/mol
What is the definition of hypoglycaemia in a child with diabetes?
Blood glucose <4 mmol/L
Rate of fluid correction in DKA in chilrren?
Over 48 hours
Hereditary haemochromatosis can what what type of diabetes insipidus?
Cranial
What is the max metformin dose that can be given per day?
500mg TDS
What type of diabetes insipidus can haemochromatosis cause?
Cranial
Driving post MI:
a) private vehicles
b) bus or lorry drivers (group 2 vehicles)
a) no need to inform DVLA, don’t drive for 4 weeks
b) inform DVLA and they will assess, stay off work for 6 weeks
How can pre-eclampsia affect amniotic fluid?
Is a cause of oligohydramnios
Blood glucose targets for patients with T1D:
a) in morning after waking
b) at any other points (i.e. before meals)
a) 5-7 mmol/l
b) 4-7 mmol/l
Does hypo or hypercalcaemia predispose to cataracts?
Hypocalcaemia
