Endocrinology Flashcards
DIABETES MELLITUS
What are the three main types of diabetes mellitus and their respective pathophysiologies?
- T1DM = autoimmune destruction of insulin-producing beta cells of the islets of Langerhans in the pancreas leading to absolute insulin deficiency + high glucose
- T2DM = insulin resistance + relative insulin deficiency due to excess adipose tissue
- Pre-diabetes = misses criteria for T2DM but likely to develop over next few years
DIABETES MELLITUS
What are some risk factors for T2DM?
- Obesity + inactivity
- Asian
- FHx
- Gestational diabetes
- PCOS
DIABETES MELLITUS
What is the clinical presentation of…
i) T1DM?
ii) T2DM?
iii) diabetes in general?
i) Polyuria, polydipsia, weight loss, ?DKA in young
ii) Often ASx + incidental, may have polyuria/polydipsia
iii) Visual blurring, candida infections, acanthosis nigricans
DIABETES MELLITUS
How do you diagnose diabetes mellitus?
Asymptomatic and 2x results or symptomatic with 1 result:
- Fasting glucose ≥7.0mmol/L
- Random glucose or OGTT after 2h ≥11.1mmol/L
- HbA1c ≥48mmol/mol (6.5%)
DIABETES MELLITUS
What additional investigations would you consider in T1DM?
- C-peptide (low) + useful if atypical features
- Diabetes-specific Ab (anti-GAD + ICA)
- Monitor for other autoimmune conditions e.g., Addison’s, coeliac, thyroid
DIABETES MELLITUS
When investigating diabetes mellitus, how would you diagnose someone with…
i) impaired fasting glucose?
ii) impaired glucose tolerance?
i) 6.1 ≤ fasting glucose < 7.0mmol/L
ii) Normal fasting glucose but 7.8 ≤ OGTT 2-h value < 11.1mmol/L
DIABETES MELLITUS
What are the HbA1c targets in diabetes mellitus?
How can falsely elevate/reduce HbA1c levels?
- T1DM/T2DM on lifestyle ± metformin = 48mmol/mol
- T2DM on drug which can cause hypoglycaemia = 53mmol/mol
- Lower = reduced RBC life (sickle cell, G6PD, HS)
- Higher = increased RBC life (splenectomy, low vitamin B12 + folate)
DIABETES MELLITUS
What dietary advice is given in diabetes mellitus?
How do you manage pre-diabetes?
- High fibre, low glycaemic index sources of carbs, low salt/fat
- Structured exercise, diet change + weight loss, regular HbA1c testing
DIABETES MELLITUS
What is the management of T1DM?
What are some side effects of this?
- S/c insulin
- Basal bolus preferred (bedtime long-acting + short-acting before each meal) or BD biphasic (mixed rapid + long-acting before breakfast/tea)
- Hypoglycaemia, weight gain, lipodystrophy (rotate sites)
DIABETES MELLITUS
What are the BM targets in T1DM?
What are the sick day rules?
- 5-7mmol/L on waking, 4-7mmol/L before meals, measure QDS
- Continue insulin, check BMs frequently, monitor ketones
DIABETES MELLITUS
What is the first-line management of T2DM?
- Metformin
DIABETES MELLITUS
A woman with a diagnosis of T2DM comes for a review. She currently takes metformin and her HbA1c is 53mmol/mol. What should you do and why?
- Increase metformin dose (if possible) as only add second PO hypoglycaemic agent if HbA1c is ≥58mmol/mol
DIABETES MELLITUS
A woman with a diagnosis of T2DM comes for a review. She currently takes 2 oral hypoglycaemic agents and her HbA1c is 60mmol/mol. What should you do and why?
- Either triple therapy or consider insulin therapy as HbA1c is ≥58mmol/mol
DIABETES MELLITUS
If triple therapy is not effective, tolerated or contraindicated, what would you consider?
What is the criteria?
- Metformin + sulfonylurea + GLP-1 mimetic
- BMI ≥35 + physical or psychological issues associated with obesity
- BMI <35 where insulin has occupational implications or weight loss would benefit other obesity-related comorbidities
DIABETES MELLITUS
What is the criteria for continuing on a GLP-1 mimetic?
- Reduction of at least 11mmol/mol in HbA1c AND weight loss of at least 3% initial body weight in 6m
DIABETES MELLITUS
What are the 6 types of oral hypoglycaemic agents?
Give an example for each.
- Biguanides e.g., metformin
- Sulfonylureas e.g., gliclazide
- DPP4 inhibitors e.g., sitagliptin
- Thiazolidinediones e.g., pioglitazone
- SGLT-2 inhibitors e.g., empagliflozin
- GLP-1 mimetic e.g., s/c exenatide
DIABETES MELLITUS
Biguanides:
i) mechanism of action?
ii) side effects?
i) Increased insulin sensitivity AND decreased hepatic gluconeogenesis
ii) GI upset (D+V), lactic acidosis
DIABETES MELLITUS
Sulfonylureas:
i) mechanism of action?
ii) side effects?
i) Stimulate pancreatic beta cells to secrete insulin
ii) Hypoglycaemia, weight gain, hyponatraemia
DIABETES MELLITUS
DPP4 inhibitors:
i) mechanism of action?
ii) side effects?
i) Increases incretin levels which inhibit glucagon secretion
ii) Increased pancreatitis risk
DIABETES MELLITUS
Thiazolidinediones:
i) mechanism of action?
ii) side effects?
i) Activate PPAR-gamma receptor in adipocytes to promote adipogenesis + fatty acid uptake to reduce insulin resistance
ii) Fluid retention, weight gain, increased risk of bladder ca
DIABETES MELLITUS
SGLT-2 inhibitors:
i) mechanism of action?
ii) side effects?
i) Reversibly inhibits Sodium-GLucose co-Transporter 2 (SGLT-2) in PCT to reduce glucose reabsorption + increase urinary glucose excretion
ii) Increased UTI risk, Fournier’s gangrene, weight loss, (euglycaemic) DKA
DIABETES MELLITUS
Glucagon like peptide-1 mimetics:
i) mechanism of action?
ii) side effects?
i) Incretin mimetic which inhibits glucagon secretion
ii) N+V, pancreatitis + weight loss
DKA
What is the pathophysiology of diabetic ketoacidosis (DKA)?
- Absence of insulin leads to uncontrollable lipolysis = increased production of FFA which are oxidised in the liver to ketone bodies leading to ketoacidosis
DKA
What is the clinical presentation of DKA?
- Acetone breath (pear drops)
- Vomiting, dehydration + abdo pain
- Hyperventilation due to acidosis = Kussmaul’s breathing
- Drowsiness, coma + hypovolaemic shock
DKA
What are the diagnostic features of DKA?
- Glucose >11mmol/L or known DM
- pH <7.3
- Bicarb <15mmol/L
- Blood ketones >3.0mmol/L or urine ketones ++ on dipstick
DKA
What other investigations would you consider in DKA?
- FBC, U&E, blood cultures + CXR for ?cause (infection)
- ECG = signs of hypokalaemia
DKA
What are some potential complications of DKA?
- Cerebral oedema (especially in paeds)
- VTE
- Hypokalaemia > arrhythmias
- AKI
- Gastric stasis
DKA
What is the most important step in managing DKA?
- Aggressive IV fluid resuscitation
DKA
How do you initially manage IV fluid resuscitation for DKA in paeds?
- Shocked = 1st bolus 0.9% NaCl 20ml/kg, subsequent 10ml/kg over 15m
- Not shocked = 0.9% NaCl 10ml/kg over 1h
DKA
How do you calculate the fluid requirement for DKA in paeds?
What do you give?
- Deficit + maintenance ( – not shocked fluids) over 48h
- 0.9% NaCl with 20mmol KCl in 500ml
DKA
How do you calculate the fluids required to make up the deficit?
How do you quantify the deficit?
- Fluids (ml) = % deficit x 10 x kg
- 5% = pH 7.2–7.29 or bicarb <15 (mild)
- 7% = pH 7.1–7.19 or bicarb <10 (moderate)
- 10% = pH <7.1 or bicarb <5 (severe)
DKA
How quickly do you give the IV fluids required for DKA in paeds?
Why and what would you do if this happened?
- Rehydrate slowly over 48h
- Risk of cerebral oedema (headache, altered GCS) > CT head, IV mannitol + hypertonic saline
DKA
How do you manage IV fluid resuscitation for DKA in adults?
- 1L 0.9% NaCl over 1h initially
- Consider adding K+ after first bag (>5.5 = nil, 3.5–5.5 = 40mmol, <3.5 = seek ICU help)
- 1L over 2h/2h/4h/4h/8h
DKA
After you’ve sorted IV fluid resuscitation, what is the next step in managing DKA?
What are you aiming for?
What would you do if you don’t achieve this?
- Insulin infusion of Actrapid 50 units in 50ml saline at 0.1unit/kg/h
- Continue long-acting insulin as usual, stop short-acting
- Ketones fall 0.5mmol/h, bicarb rise 3mmol/L/h, glucose fall 3mmol/L/h
- Increase infusion 1 unit/h until reached
DKA
After you’ve sorted IV fluid resuscitation and the insulin infusion, what else would you need to consider when managing DKA?
How does this differ for paeds/adults?
- Prevent hypoglycaemia
- Adult glucose <14mmol/L = 125ml/h 10% glucose alongside saline
- Paeds glucose <14mmol/L = add 5% dex so give 0.9% NaCl + 20mmol KCl + 5% dex in 500ml
DKA
What parameters should be monitored during DKA?
- Capillary glucose + ketones, obs + GCS hourly
- VBG at 2/4/8/12/24h
DKA
When is DKA considered resolved?
What do you do then?
What if it hasn’t resolved?
- pH >7.3 AND blood ketones <0.6mmol/L AND bicarb >15mmol/L
- Stop fixed-rate insulin
- Ketonaemia + acidosis not resolved within 24h = senior endo review
HHS
What is the pathophysiology of hyperosmolar hyperglycaemic state (HHS)?
- Hyperglycaemia results in osmotic diuresis with renal losses of water more than Na + K leading to severe volume depletion > significantly raised serum osmolarity so hyperviscosity of blood
HHS
What are some causes of HHS?
- New T2DM
- Infection
- High dose steroids
- Surgery
- Impaired renal function
HHS
What is the clinical presentation of HHS?
- Confusion/altered GCS
- N+V
- Dehydration
- Fatigue
- Shock
HHS
What is the diagnostic criteria for HHS?
What is the key parameter to monitor?
- Severe hyperglycaemia ≥30mmol/L (but no significant ketonaemia or acidosis), hypotension, hyperosmolality >320mosmol/kg
- Serum osmolarity = 2Na + glucose + urea
HHS
What are some potential complications of HHS?
- Vascular = MI, stroke + peripheral arterial thrombosis
- Central pontine myelinolysis if serum osmolarity declines too quickly
- Fluid overload, cerebral oedema
HHS
What is the most important part of HHS management?
- IV 0.9% NaCl initially as very fluid deplete
- Aim for +ve balance of 3–6L by 12h + remaining within next 12h
- If serum osmolarity not declining, then switch to 0.45% NaCl
- 40mmol KCl added if K 3.5-5.5
HHS
What other aspects should be considered in HHS management?
- Insulin at 0.05units/kg/h only if ketones >1mmol/L or glucose fails to fall
- VTE prophylaxis in most patients
HYPOGLYCAEMIA
What is hypoglycaemia?
What are some causes?
- Blood glucose <4.0mmol/L
- Drugs (insulin, sulfonylureas), sepsis, insulinoma, adrenal insufficiency
HYPOGLYCAEMIA
What is the clinical presentation of hypoglycaemia?
- Sweating/shaking
- Hunger
- Nausea
- Confusion, convulsions, coma
HYPOGLYCAEMIA
What investigations might you consider to work out whether this could be endogenous production or exogenous administration?
- Measure serum insulin, C-peptide + proinsulin
- All high = endogenous production
- High insulin but low C-peptide + proinsulin = exogenous administration
HYPOGLYCAEMIA
What is the management of hypoglycaemia in a patient who is conscious and able to swallow?
- PO glucose 15–20g liquid, gel or tablet or quick-acting carb like fruit juice
- Repeat after 15m until BM above 4mmol/L
- Follow-up with slow acting carb afterwards e.g., toast, two biscuits
HYPOGLYCAEMIA
What is the management of hypoglycaemia in a patient who is unconscious or unable to swallow?
- 200ml 10% dextrose IV
- 1mg glucagon IM if no IV access
DIABETIC COMPLICATIONS
What are the potential complications of diabetes?
- Neuropathy = peripheral, gastroparesis, autonomic
- Microvascular = nephropathy, retinopathy
- Macrovascular = MI, stroke, PVD
- Diabetic foot disease
DIABETIC COMPLICATIONS
What is the presentation of peripheral neuropathy?
- Sensory not motor loss in a glove + stocking distribution with the lower legs being affected first due to the length of the sensory neurones
- Vibration sensation lost first
DIABETIC COMPLICATIONS
What is the management of peripheral neuropathy?
- First-line = amitriptyline, duloxetine, gabapentin or pregabalin
- Pain management clinics may be useful if resistant problems
DIABETIC COMPLICATIONS
What causes gastroparesis?
How does it present?
- (Vagus) nerve damage to autonomic nervous system
- Delayed gastric emptying, bloating, offensive gas + vomiting
DIABETIC COMPLICATIONS
What is the management of gastroparesis?
- Prokinetics like metoclopramide, domperidone
- Abx like erythromycin to tackle bacterial overgrowth
DIABETIC COMPLICATIONS
What is the presentation of autonomic neuropathy?
What is the conservative management?
What is the medical management?
- Postural hypotension with a fall in BP >20/10mmHg within 3 mins of standing
- Increase dietary salt, raise head of bed, elasticated stockings to overcome venous pooling
- Fludrocortisone or midodrine
DIABETIC COMPLICATIONS
What is diabetic nephropathy?
How is it identified?
- Development of proteinuria + progressive decline in renal function
- ALL patients screened annually using urinary albumin:creatinine ratio (ACR) from early morning specimen where ACR >2.5 = microalbuminuria
DIABETIC COMPLICATIONS
What is the conservative management of diabetic nephropathy?
What is the medical management of diabetic nephropathy?
- Dietary protein restriction, tight glycaemic control, BP <130/80mmHg
- ACEi/ARB if urinary ACR ≥3mg/mmol
DIABETIC COMPLICATIONS
What is the pathophysiology of diabetic retinopathy?
- Poor glycaemic control can lead to vascular occlusion + leakage of the capillaries supplying the retina > retinal ischaemia, new vessel formation + if not managed, loss of sight
DIABETIC COMPLICATIONS
What are the three main types of diabetic retinopathy?
- Non-proliferative diabetic retinopathy (NPDR)
- Proliferative diabetic retinopathy (PDR)
- Diabetic maculopathy
DIABETIC COMPLICATIONS
How is NPDR sub-categorised?
- Mild = ≥1 microaneurysm
- Moderate = microaneurysms, blot haemorrhages, hard exudates + cotton wool spots (soft exudates = retinal infarction)
- Severe = blot haemorrhages + microaneurysms in all 4 quadrants, venous beading in ≥2 quadrants, intraretinal microvascular abnormalities (haemorrhage) in ≥1 quadrant
DIABETIC COMPLICATIONS
What is proliferative diabetic retinopathy?
- Retinal neovascularisation (on retina or optic disc) ± vitreous/pre-retinal haemorrhage
DIABETIC COMPLICATIONS
What is diabetic maculopathy?
- Macular oedema (+ hard exudates) caused by leakage of vessels close to macula which can significantly threaten vision + needs urgent treatment
DIABETIC COMPLICATIONS
What is the management of…
i) NPDR?
ii) PDR?
iii) maculopathy?
i) Regular eye tests, ?laser photocoagulation
ii) Laser photocoagulation, intravitreal VEGF inhibitors e.g., ranibizumab, vitreoretinal surgery in severe disease
iii) Change in visual acuity > VEGFi (ranibizumab)
HYPERTHYROIDISM
What are the causes of hyperthyroidism?
- Most common = Graves’ disease (autoimmune)
- Toxic multinodular goitre or toxic adenoma secreting excess hormones
- Subacute (De Quervain’s thyroiditis)
- Exogenous iodine excess (food, drugs like amiodarone, thyroxine)
HYPERTHYROIDISM
What generic symptoms would you expect in hyperthyroidism?
- General = weight loss, increased appetite, diarrhoea, heat intolerance
- Psych = anxious, irritable, ?psychotic
- Sympathetic = sweating, palpitations, tremor
- Gynae = oligomenorrhoea, usually seen in women aged 30–50
HYPERTHYROIDISM
What are some generic signs in hyperthyroidism?
- Nodules on thyroid gland
- Irregular pulse (AF)
- Thin hair
- Warm skin
HYPERTHYROIDISM
What are some Graves’ disease specific signs?
- Thyroid eye disease (exophthalmos, ophthalmoplegia, lid lag + retraction)
- Diffuse goitre without nodules
- Thyroid acropachy
- Pretibial myxoedema
HYPERTHYROIDISM
What is…
i) thyroid acropachy?
ii) pretibial myxoedema?
i) Triad of: digital clubbing, soft tissue swelling of hands + feet & periosteal new bone formation
ii) Mucin deposits under pretibial skin giving discoloured appearance due to reaction to TRAb
HYPERTHYROIDISM
What is the clinical presentation of De Quervain’s thyroiditis?
- Post-viral infection where initially hyperthyroid with painful goitre + raised ESR
- Euthyroid > hypothyroid (longer phase than hyper)
- Eventually thyroid structure + function normalises
HYPERTHYROIDISM
What are some important investigations in suspected hyperthyroidism?
- Thyroid function tests
- Thyroid autoantibodies (TSH receptor stimulating antibody TRAb IgG + anti thyroid peroxidase in Graves’)
- Thyroid scintigraphy (isotope scan)
- ?Investigate for other autoimmune conditions such as Addison’s, coeliac, T1DM
HYPERTHYROIDISM
What patterns of hyperthyroidism might you see on TFTs?
- Primary = low TSH, high T3/4
- Secondary = high TSH, high T3/4 (hypothalamus or pituitary pathology)
- Subclinical = low TSH, normal T3/4
HYPERTHYROIDISM
What patterns of hyperthyroidism might you see on thyroid scintigraphy?
- Patchy uptake = toxic multinodular goitre
- Globally reduce uptake = De Quervain’s
- Homogenous uptake = Grave’s disease
HYPERTHYROIDISM
What is an important complication in hyperthyroidism and what can cause it?
How does it present?
- Thyroid storm/thyrotoxicosis
- Thyroid/non-thyroidal surgery, trauma, infection or acute iodine load (e.g., CT contrast)
- Fever, tachycardia, HTN, confusion, heart failure, N+V
HYPERTHYROIDISM
What is the management of thyrotoxicosis?
- IV propranolol (digoxin if fails or C/I e.g., asthma)
- Propylthiouracil NG followed by Lugol’s iodine 6h later
- High dose corticosteroids
HYPERTHYROIDISM
What are the main management options for hyperthyroidism?
- Symptomatic relief with non-selective beta-blocker propranolol
- Anti-thyroid drugs by either titration or block & replace
- Radioiodine (131) therapy to radiate + destroy thyroid cells
- Surgical thyroidectomy either total or removal of nodules
HYPERTHYROIDISM
What is the first-line anti thyroid drug? What are some side effects?
What other anti thyroid drug is there and why is it not first line?
- Carbimazole – agranulocytosis + not used in first trimester
- Propylthiouracil – small risk of severe hepatic reactions