Medicine - Endocrinology Flashcards
What are the criteria for diagnosis of type 2 diabetes?
Either symptoms + 1 pos test result or no symptoms + 2 pos test results Pos test thresholds: - Fasting glucose >7.0 - OGTT >11.1 - Random glucose >11.1 - HbA1c > 6.5%/ 48mmol/L
What are the test ranges for impaired gluose tolerance and impaired fasting glucose?
IGT: OGTT/random = 7.8-11.1; HbA1c = 42-47
IFG = 6.1-7.0
What is the classic triad of symptoms of type 2 diabetes?
Polydipsia
Polyuria
Fatigue
Recall 2 possible consequences of diabetic neuropathy and drugs that can be used to manage each of these possibiities
- Vagal neuropathy –> gastroparesis: domperidone/ metoclopramide
- Neuropathic pain: amitryptiline, duloxetine, gabapentin, pregabalin
Summarise the pathogenesis of diabetic foot
- Peripheral arterial disease reduces O2 delivery –> intermittent claudication
- Neuropathy –> loss of sensation, eventually Charcot’s foot
What is Charcot’s foot?
Rare consequence of T2DM in which foot becomes rocker-bottomed
Recall some ways in which diabetic foot can be screened for, and the frequency with which these tests should be done
Screening should be done annually
Test for ischaemia: palpate the dorsalis pedis and posterior tibial pulse
Test for neuropathy with 10g monofilament test
How should diabetic nephropathy be screened for?
Yearly albumin:creatinine ratio
Microalbuminuria is the first sign of diabetic nephropathy
What is the best management for diabetic nephropathy?
ACE inhibitors
However, these are toxic in AKI so eGFR needs to be monitored
How big a drop in eGFR would warrant stopping an ACE inhibitor in a diabetic patient?
> 20%
Why is an initial drop in eGFR expected when starting patients on an ACE inhibitor?
Dilate the efferent arteriole
Recall 3 things that may cause a falsely high HbA1c
Alcoholism
B12 deficiency
Iron deficiency anaemia
What is the BM target for T1DM patients who are monitoring BMs throughout the day?
Waking target: 5-7mmol/L
Rest of the day: 4-7mmol/L
Recall the names of 2 long-acting insulins
Lantus
Glargine
When are BD mixed regimens of insulin given?
Breakfast and dinner
Name a diabetes prevention programme
DESMOND
Diabetes education + self-management: ongoing and newly diagnosed
Recall some possible risk-factor modifying therapies that can be used in diabetes mellitus
Aspirin 75mg OD
Atorvastatin 20mg OD
Antihypertensives
What is the maximum dose of metformin?
2g/day
Recall 4 important side effects of metformin
Appetite suppression
B12 deficiency (due to reduced absorption)
Lactate acidosis
GI upset
How can you manage GI upset that is due to metformin?
Change immediate release to a modified release mechanism
When should dual therapy be considered in type 2 diabetes?
If HbA1c >58/ 7.5%
What are the options for dual therapy for type 2 diabetes?
Metformin + 1 of:
- Sulphonylurea
- Thiazolidinediones
- Gliptins
- SGLT2 inhibitors
Recall 2 examples of sulphonylureas
Glibenclamide
Gliclazide
Recall an example of a thiazolidinedione
Pioglitazone
Recall an example of a gliptin drug
Sitagliptin
What is the mechanism of action of gliptins?
DPP4 inhibitors
Recall an example of a SGLT2 inhibitor
Empagliflozin
Recall 2 important side effects of sulphonylureas
Weight gain
Hypoglycaemia
What sort of diabetes drug is MODY most sensitive to?
Sulphonylureas
What is the inheritance pattern of MODY?
Autosomal dominant
MODY must be diagnosed before what age?
25
What is the best investigation to confirm the diagnosis of MODY?
C peptides
What is the most common type of MODY, and which gene mutation causes it?
MODY 3
Mutated HNF-1 alpha
What is LADA?
Latent autoimmune diabetes in adults
Late onset T1DM in 20-50yo, no family history
What are the 2 best investigations for confirming the diagnosis of LADA?
GAD Abs C peptide (will be low)
What 3 things are required to diagnosis DKA?
Diabetes, Ketones, Acidosis
Diabetes - BM >11.1
Ketones - >3
Acidosis - pH <7.3
Recall 4 common causes of DKA
Missed insulin
Trauma
Infection
EtOH
What 3 investigations are most useful for assessing the extent of the damage done by a DKA acutely?
ABG
ECG
U&Es
Recall the 5 main principles of managing DKA acutely
- Fluids
- Insulin
- Potassium (run KCl in NaCL bag)
- 10% dextrose (when BM < 15)
- VTE prophylaxis (very dehydrated)
What dose of insulin should be started in DKA vs HHS?
DKA: 0.1U/kg/hr
HHS: 0.5U/kg/hr
Recall the 3 biochemical criteria used to diagnose HHS
pH >7.3
Osmolarity >320mmol/L
BM >30
Over what time period does HHS develop?
Over a few days
Recall the 3 components of HHS management
- Fluids
- Monitoring (ensure Na+ is not corrected too quickly)
- Insulin
Recall 2 differentials for someone whose TFTs show low TSH and low T4
Secondary hypothyroidism
Sick euthyroid
Recall the Thy classification
Thy 1 = unsatisfactory sample (1c = cyst)
Thy 2 = benign
Thy 3 = atypia of undetermined significance
Thy 4 = Suspicious of malignancy
Thy 5 = malignancy
What classification system is used to classify thyroid nodules?
Thy classification
What are the 4 histological types of thyroid cancer
Anaplastic
Medullary
Papillary
Follicular
Which type of thyroid cancer is associated with a raised calcitonin?
Medullary
Recall 2 differentials for low uptake hyperthyroidism
Sub-acute (De Quervain’s) thyroiditis
Postpartum thyroiditis
Recall 3 differentials for high uptake hyperthyroidism
Grave’s disease
Toxic multinodular goitre
Single toxic adenoma
Recall 7 signs of thyroid eye disease
Mnemonic = NO SPECS No signs or symptoms sometimes OR Only signs (eg upper lid retraction) OR
Signs AND symptoms: Proptosis Extra-ocular muscle pathology Corneal involvement Sight loss due to optic nerve involvement
Why might eye movement be restricted in thyroid eye disease?
Rectus thickening restricts movement
What is the best preventative measure to prevent Grave’s disease?
Stop smoking
Which subtypes of MEN are associated with medullary thyroid cancer?
2A and 2B
Recall the management of Grave’s disease
1st line:
- Propranolol (NOT bisoprolol)
- Anti-thyroid drug eg carbimazole or propylthiouracil OR
- If unlikely to respond to ATDs, radioiodine (I-131)
Recall 2 possible side effects of radioiodine
Hypothyroidism
Thyroid storm
Recall how a patient should be prepared for thyroidectomy
- Need to be euthyroid on medication
- Laryngoscopy to check vocal cords
- Either thionamides or propranolol
Stop thionamides (PTU) 10 days before surgery as it increases vascularity
Recall some symptoms of a thyroid storm
Hyperthermia Tachycardia Jaundice Altered mental state Cardiac (AF/high-output CF)
How should a thyroid storm be managed?
IV propranolol –> Thionamides (PTU)
Hydrocortisone –> iodine
What is the most common cause of primary hypothyroidism in the UK?
Hashimoto’s
What is Riedel’s thyroiditis
Hypothyroidism caused by chronic inflammatory thyroid gland fibrosis
Recall 2 drugs that can cause hypothyroidism
Lithium
Amiodarone
What is the starting dose of levothyroxine?
50-100mcg
How long after starting levothyroxine should the TFTs be checked?
8-12 weeks
Recall 2 medications that interact with levothyroxine
Iron
CaCO3
Recall 4 features of myxoedema coma
Hypothermia
Hyporeflexia
Bradycardia
Seizures
How should myxoedema coma be managed?
IV thyroxine
IV hydrocortisome
IV fluids
What are the most common causes of Addison’s disease?
In the UK: autoimmune adrenal failure
Worldwide: TB
Recall 2 ways that Addison’s/adrenal failure can be investigated for
- 9am cortisol
2. Short synACTHen test
Recall 3 possible cause of an Addisonian crisis (different from Addison’s disease)
- Adrenal haemorrhage (Waterhouse-Friderichson syndrome from meningococcaemia)
- Steroid withdrawal
- Sepsis/ surgery causing an acute exacerbation of chronic insufficiency (autoimmune/ TB)
How should an Addisonian crisis be managed?
Immediately:
- IM hydrocortisone 100mg STAT
- IV fluid bolus with glucose
Continuing management:
- IV fluids
- IV/IM hydrocortisone
What is the most common cause of Cushing’s syndrome?
Glucocorticoid therapy
What are some differentials for ACTH-dependent Cushing’s?
Cushing’s disease (80% pituitary tumour)
Ectopic ACTH production
What are the possible causes of pseudo-Cushing’s?
Alcoholism or severe depression
How can Cushing’s and pseudo-Cushing’s be differentiated?
Both will give a positive LDDST and 24hr free urinary cortisol
Can tell the difference between them with insulin stress test
Recall 2 screening tests for Cushing’s
- 11pm salivary cortisol (if low the cause is NOT Cushing’s)
- LDDST
How can the cause of Cushing’s syndrome be confirmed?
Inferior petrosal sinus sampling
Catheter is fed into the jugular vein
What is Nelson’s syndrome?
Possible complication of adrenalectomy
Removal of adrenal gland –> pituitary enlargement and very high ACTH
What is the most common electrolyte disturbance in Conn’s syndrome?
Hypokalaemia
What is the best initial investigation in suspected Conn’ syndrome?
Aldosterone: renin ratio
What are the best tests to determine the cause of hyperaldosteronism?
HR-CT and adrenal vein sampling
What are the possible causes of hyperaldosteronism?
- Conn’s syndrome
2. Renal artery stenosis
What will be the aldosterone: renin ration in Conn’s syndrome vs renal artery stenosis?
Conn’s: high
Renal artery stenosis: normal
What medications can be used to manage hyperaldosteronism?
Spironolactone and epleronone
What test can be used to diagnose diabetes insipidus?
Water deprivation test
Recall 2 possible renal and 2 non-renal causes of hypernatraemia
Renal: osmotic diuresis (T2DM) or diabetes insipidus
Non-renal: GI losses or sweat losses of water
What is the possible complication of correcting hypernatraemia too quickly?
Cerebral oedema
What is the possible complication of correcting hyponatraemia too quickly?
Central pontine myelinolysis
In which patients is a urine sodium measurement not reliable?
Those on diuretics
Recall some drugs that can cause SIADH
SSRIs and TCAs Carbemazapine Sulphonylureas (eg gliclazide) PPIs (omeprazole/ lanzoprazole) Opiates
Recall 2 causes of pseudohyponatraemia
Hyperlipidaemia
Hyperproteinaemia
Recall 2 drugs that can be used to treat SIADH
Demeocycline
Vaptans (eg tolvaptan)
Recall 3 classes of drugs that could cause hyperkalaemia
ARBs
ACE inhibitors
Aldosterone antagonists
Recall one antibiotic that can cause hyperkalaemia
Tacrolimus - it can reduce K+ excretion
Which type of renal tubular acisosis can cause hyperkalaemia
Type 4
Recall the management of hyperkalaemia
10mls 10% calcium gluconate 120mls 20% dextrose Maybe: 10U insulin nebulised salbutamol If really bad: Calcium risonium
For each of the following endocrine conditions, say whether they can cause hypo or hyperkalaemia:
- Addisson’s
- Conn’s
- Cushing’s
Adisson’s: Causes hyperkalaemia
Conn’s: Causes hypokalaemia
Cushing’s: Causes hypokalaemia
Which types of renal tubular acidosis can cause hypokalaemia (rarely)?
Types 1 and 2
Which hormone will likely be high in renal artery stenosis?
Renin
Describe the symptoms of hyper vs hypoclacaemia
Hypercalcaemia: bones, stones, abdominal groans, psychiatric moans
Hypocalcaemia: paraesthesia, muscle cramps, long QT
What is a ‘pepperpot skull?
Radiological sign: Multiple tiny well-defined lucencies in the calvaria (top part of the skull) caused by resorption of trabecular bone in hyperparathyroidism
How should hypercalcaemia be managed?
IV fluids –> bisphosphonates
Recall the progression of multiple myeloma
(1) MGUS
(2) Smouldering myeloma
(3) Multiple myeloma
(4) B cell leukaemia
At what point in the myeloma progression does a patient get the symptoms of CRAB?
Not until it gets to multiple myeloma
What is the limit for monoclonal serum protein in MGUS?
Must be <30g/L
What is the limit for bone marrow plasma cells in MGUS?
<10%
Which type of immunoglobin will be high in myeloma?
IgG or IgA
If Waldenstrom’s - IgM
What is the most useful form of imaging in myeloma?
Whole body low dose CT
Which CD markers are positive in immunotyping in myeloma?
CD38
CD138
CD56/58
What is the pathophysiology of refeeding syndrome?
Refeeding –> rise in insulin –> intracellular shift in phosphate –> hypophosphataemia
What are some symptoms of the refeeding syndrome?
Rhabdomyolysis Low RR Arrhythmia Shock Seizures Coma
What is fibromuscular dysplasia?
Idiopathic, non-atherosclerotic, non-inflammatory disorder of arteries
2 subtypes:
- Renal artery
- Cervical artery
What are the symptoms of fibromuscular dysplasia?
Renal artery FMD: resistant hypertension
Cervical artery FMD: chronic migraines
What is the best investigation for assessing fibromuscular dysplasia?
Catheter angiography
What is the mainstay of management of fibromuscular dysplasia?
Stop smoking
Anti-platelets (clopidogrel)
Anti-hypertension (ACEi or ARB)
Surgery (surgical stenting)
Recall some causes of vitamin B12 deficiency
Autoimmunity
Atrophic gastritis
Gastrectomy
Malnutrition
Recall 2 drugs that can treat vitamin B12 deficiency
Cyanocobalamin IM
Hydroxocobalamin IM
Recall some causes of hypomagnesaemia
Diuretics/ PPIs Diarrhoea TPN EtOH Gitelman's/Barter's Hypokalaemia, hypocalcaemia
What are the symptoms of hypomagnesaemia most similar to?
Hypocalcaemia
What are the ECG features of hypomagnesaemia most similar to?
Hypokalaemia
What is the threshold for giving IV magnesium sulphate as a Mg replacement, rather than just PO tablets?
Mg <0.4mmol/L
How should suspected SIADH be investigated?
- Serum corrected calcium - must exclude hypercalcaemia secondary to hyperPTHism
- Water deprivation test
What is the mechanism of hyponatraemia development in SIADH?
Increased water absorption in the collecting duct
What would be the main abnormality on TFTs in thyrotoxic crisis?
Marked elevation of free T4
What change in vision is caused by a lesion in the optic chiasm?
Bitemporal hemianopia
What change in vision is caused by a lesion in the optic tract?
Homonymous hemianopia
What change in vision is caused by a lesion in the optic radiation?
Superior quandrantopia
Give some examples of causes of metabolic acidosis with increased anion gap
DKA is a big one
Also: lactate acidosis, uraemia secondary to renal failure and salicylate/biguianide poisoning
In DKA, for how long should insulin infusion be continued before switching to SC insulin?
Until blood ketones <0.3mmol/L
How frequently should potassium be monitored in the acute setting of DKA being treated with an insulin infusion?
4 hourly
How should a known type 1 diabetic patient’s insulin be managed when they are in DKA and require an insulin infusion?
Long acting basal insulin should be continued alongside the infusion as this simplifies the change from infusion to SC insulin in due course
Recall 4 side effects of carbimazole
Maculopapular rash
Bone marrow suppression leading to agranulocytosis
Pruritis
Jaundice
How should primary hyperaldosteronism due to BL adrenal hypertrophy be managed?
Spironolactone
What is the first drug to give in phaeochromocytoma?
Phenoxybenzamine
How should once daily insulin regimes be managed pre-operatively?
Reduced dose insulin on the day of the op and the day before
Why might someone get hyponatraemia post-SAH?
SAH can lead to SIADH
What is the best test for diagnosing phaeochromocytoma?
Plasma and serum catecholamines
How can a splenectomy affect blood sugar levels?
Can give a falsely high reading due to the increased life span of RBCs
What is the immediate management of pituitary apoplexy?
IV hydrocortisone
What is the treatment for malignant hyperthermia?
IV dantrolene