Endocrinology Flashcards
T1DM Ix?
- Urine = glucose and ketones
- Bloods = fasting glucose, random glucose, HbA1c, C-peptide, Diabetes-specific antibodies
*C-peptide is a byproduct of insulin production. When the pancreas produces insulin, it splits proinsulin into insulin and C-peptide. Measuring C-peptide can provide an indirect assessment of endogenous (self-produced) insulin levels.
T1DM Antibodies?
- anti-GAD (80%)
- anti-ICA (70%)
- IAA (insulin autoantibodies)
- Insulinoma-associated-2 autoantibodies (IA-2A)
Insulin autoantibodies (IAA) mushkies?
Presence in T1DM correlates strongly with age, found in over 90% of young children with T1DM but only 60% of older patients
T1DM diagnostic criteria?
- Fasting glucose greater than or equal to 7.0 mmol/l
- Random glucose greater than or equal to 11.1 mmol/l (or after 75g oral glucose tolerance test)
- (If the patient is asymptomatic the above criteria apply but must be demonstrated on two separate occasions)
When is polydipsia seen?
Fasting plasma glucose >16.6mmol/L
How often should HbA1c be checked in T2DM?
Every 3-6 months until stable, then 6 monthly
HbA1c targets in T2DM for lifestyle/single drug treatment?
- Lifestyle = 48mmol/L (6.5%)
- Lifestyle + metformin = 48mmol/mol (6.5%)
- Includes any drug which may cause hypoglycaemia e.g. sulfonylurea = 53mmol/mol (7.0%)
HbA1c targets in T2DM for patient already on one drug, but HbA1c has risen to 58mmol/L (7.5%)?
53 mmol/mol
First-line management of T2DM?
- Assess cardiovascular risk –> high risk of CVD or established CVD or chronic HF?
- No –> Metformin
- Yes –> Metformin –> Once established at SGLT2 inhibitor
If metformin not tolerated due to GI s/e?
Switch to modified release metformin
If metformin is C/I and pt has high risk of CVD or established CVD or chronic HF?
SGLT2 monotherapy
If metformin is C/I and pt is at low risk of CVD or established CVD or chronic HF
- DPP4 inhibitor OR Pioglitazone OR Sulfonylurea
- SGLT2 may be used if certain NICE criteria are met
2nd line Rx of T2DM?
Add one of: DPP4i/Pioglitazone/Sulfonylurea/SGLT2i
3rd line Rx of T2DM?
- Add another one of: DPP4i/Pioglitazone/Sulfonylurea/SGLT2i OR
- Start insulin-based treatment
Further therapy of T2DM?
If triple therapy is not effective or tolerated consider switching one of the drugs for a GLP-1 mimetic if BMI >35 or insulin would have occupational implications (GLP-1 mimetics should only be added to insulin under specialist care)
At what HbA1c level is further treatment indicated for T2DM?
58mmol/mol (7.5%)
Starting insulin recommendation?
- Start with human NPH insulin (isophane, intermediate-acting) taken at bed-time or twice daily according to need
Thiazolidinediones MOA?
PPAR-gamma receptor agonists, reduce peripheral insulin resistance (glitazones, e.g. pioglitazone)
Thiazolidinedione s/e?
- Weight gain
- Liver impairment (monitor LFTs)
- Fluid retention (therefore C/I in HF)
- Fractures
- Bladder cancer
When is thyroxine starting dose 25mcg?
- Cardiac disease
- Severe hypothyroidism
- > 50 y/o
Change in thyroxine dose TFT check time?
8-12 weeks later
Hypothyroid women become pregnant dose increase?
By at least 25-50mcg
Levothyroxine s/e?
- Hyperthyroidism
- Reduced bone mineral density
- Worsening of angina
- AF
Levothyroxine interactions?
Iron and calcium carbonate (absorption of levothyroxine reduced, give at least 4 hours apart)
Subclinical hypothyroidism bloods?
TSH raised but normal T3/T4
Significance of subclinical hypothyroidism?
- Risk of progressing to overt hypothyroidism 2-5% per year (higher in men)
- Risk increased by the presence of thyroid autoantibodies
Subclinical hypothyroidism Rx classification?
- TSH 4-10 and normal thyroxine
- TSH >10 and normal thyroxine
TSH 4-10 and normal thyroxine Rx?
- < 65 y/o with symptoms suggestive of hypothyroidism –> give a trial of levothyroxine, if no improvement then stop
- > 80 y/o = watch and wait
- If asymptomatic observe and repeat TFTs in 6m
TSH >10 and normal thyroxine Rx?
- < 70 y/o = start treatment even if asymptomatic
- > 80 y/o = watch and wait
HHS or DKA has higher mortality?
HHS
HHS pathophysiology?
- Hyperglycaemia results in osmotic diuresis with associated loss of sodium and potassium
- Severe volume depletion results in a significant raised serum osmolarity (typically > than 320 mosmol/kg), resulting in hyperviscosity of blood.
- Despite these severe electrolyte losses and total body volume depletion, the typical patient with HHS, may not look as dehydrated as they are, because hypertonicity leads to preservation of intravascular volume.
HHS Dx?
- Hypovolaemia
- Marked hyperglycaemia (>30mmol/L) without significant ketonaemia or acidosis
- Serum osmolality > 320 mosmol/kg
HHS management goals?
- Normalise the osmolality gradually (the key parameter)
- Replace fluid and electrolyte losses
- Normalise blood glucose gradually
Serum osmolality estimation?
2Na + Glucose + Urea
Fluid losses in HHS estimation?
100-220ml/kg (10-22 litres in an individual weighing 100kg)
HHS If the serum osmolarity is not declining despite positive balance with 0.9% sodium chloride?
Switch to 0.45% NaCl which is more hypotonic relative to HHS patient serum osmolality
HHS fluid replacement goals?
Aim for a positive balance of 3-6 litres by 12 hours and the remaining replacement of estimated fluid losses within the next 12 hours (aim of treatment should be to replace approximately 50% of estimated fluid loss within the first 12 hours and the remainder in the following 12 hours)
When is rising serum Na+ a concern during HHS fluid replacement?
Only a concern if the osmalility is not declining concurrently
Plasma glucose fall rate during HHS fluid replacement?
4-6mmol/hr, rate of fall should not exceed 10mmol/L in 24 hours
Target blood glucose during HHS treatment?
10-15mmol/L
Mixed HHS/DKA picture insulin treatment?
(I.e. if significant ketonaemia is present) –> 0.05 units/kg/hr fixed rate
Two conditions accounting for 90% of cases of hypercalcaemia?
- Primary hyperparathyroidism = commonest cause in non-hospitalised patients
- Malignancy = most common cause in hospitalised patients
Mechanisms by which malignancy can cause hypercalcaemia?
- PTHrP from tumour e.g. SCLC
- Bone metastases
- Myeloma = due primarily to increased osteoclastic bone resorption caused by local cytokines (e.g. IL-1, tumour necrosis factor) released by the myeloma cells
Diuretic causing hypercalcaemia?
Thiazides
How to assess for diabetic neuropathy in the feet?
10g monofilament
Diabetic foot screening?
Annually
1. Ischaemia = palpating dorsalis pedis and posterior tibial artery
2. Neuropathy = 10g monofilament on various parts of the sole of the foot
Risk stratification of diabetic feet?
- Low = no risk factors except callus alone
- Moderate = deformity/neuropathy/non-critical limb ischaemia
- High = previous ulceration/amputation, on renal replacement therapy, neuropathy + non-critical limb ischaemia, neuropathy + callus/deformity, non-critical limb ischaemia + callus/deformity
Who should be followed up by local diabetic foot centre?
All moderate and high risk patients
Most common cause of thyrotoxicosis in UK?
Graces
Thyrotoxicosis causes?
- Graves’ disease
- Toxic nodule goitre
- Acute phase = subacute, post-partum, Hashimoto’s thyroiditis
- Amiodarone
- Contrast
DKA pathophysiology?
Uncontrolled lipolysis (not proteolysis) which results in an excess of free fatty acids that are ultimately converted to ketone bodies
Most common causes of DKA?
- Infection
- Missed insulin doses
- MI
DKA diagnosis?
- BM > 11
- pH < 7.3
- Bicarb < 15
- Ketones >3 or ++
DKA Rx?
- Fluid replacement (1h, 2h, 2h, 4h, 4h, 5h)
- 0.1 units/kg/hr fixed rate
- Once BM <15mmol/l, start 5% dextrose infusion
- Continue long acting insulin, stop short acting insulin
DKA potassium replacement?
- Over 5.5 = Nil
- 3.5-5.5 = 40mmol/L
- <3.5 = senior review as additional potassium needs to be given
DKA resolution?
- pH > 7.3
- Ketones < 0.6
- Bicarb > 15
If ketonaemia and acidosis hasnt resolved within 24 hours DKA?
Senior review from endocrinologist
Suspicion of cerebral oedema during fluid resuscitation in DKA?
CT head and senior review
Most common cause of hypothyroidism?
Hashimoto’s (autoimmune) thyroiditis
Hashimoto’s thyroiditis features?
- 10F:1M
- Goitre: firm, non-tender
- Anti-TPO (thyroid peroxidase) and anti-thyroglobulin (anti-Tg) antibodies
What lymphoma is associated with Hashimoto’s?
MALT lymphoma
Addison’s disease management?
- Hydrocortisone = given in 2 or 3 divided doses, patients typically require 20-30 mg per day, with the majority given in the first half of the day
- Fludrocortisone