Endocrinology Flashcards
T1 and T2 diabetes pathophys
T1 = Autoimmune destruction of pancreatic islet cells cause reduced insulin
T2 = Insulin resistance and hyper secretion of insulin which fails to keep up with inc demand leading to failure of beta cells
C-peptide in diabetes
low in T1
high in T2
Assoc features of diabetes
Retinopathy (cotton wool spots, haemorrhage)
Neuropathy (glove stocking)
Nephropathy
Skin infection/UTI
Pancreatic Islet cell and function
Alpha cells = Glucagon
Beta cells = Insulin
Mechanism of insulin release
Glucose enters beta cells via GLUT2, increased ATP, this closes K+ channels to depolarise cell, opens Ca channels and cellular release of Insulin
Role of insulin
Increase live and muscle uptake of glucose
Suppress: Gluconeogenesis, Lipolysis, Proteolysis, Ketogenesis
T1DM
- Aetiology,
- Presentation,
- Complications
- Genetic predisposition, autoimmune process (env trigger??)
- FH of autoimmune disease (HLA DR3/4)
Polyuria, polydipsia, weight loss, lethargy, DKA (dehydration, ketones, abdominal pain) - DKA
T2DM
- RF
- Presentation
- BMI over 30, low activity, PCOS, metabolic syndrome, FH, South Asian, Gestational diabetes
- Polyuria, polydipsia, lethargy, prolonged/frequent infections (e.g. thrush)
Investigating DM
Urine dip, Oral Glucose tolerance test, Fasting glucose (over 7 is diagnostic)
HbA1c (over 48mmol.mol or 6.5%)
Ix for complications - urine dip (protein), fundoscopy, BP for HTN, fasting lipids (hyperlipidaemia)
when might HbA1c not be accurate?
In anaemic patients, esp haemolytic anaemia
HbA1c treatment goal
below 58mmol/mol of 7.5%
Diabetic Neuropathy
Hyperglycaemia causes oxidative stress and destruction of myelin sheath. Glove and stocking distribution
Diabetic Nephropathy
Hyperglycaemia thickens glomerular BM (sclerosis)
Narrowing efferent artery inc pressure in glomerulus.
The above cause inc gaps between podocytes (more permeable)
Proteinuria and decreased GFR occur due to kidney damage
Diabetic Retinopathy
microvascular occlusion - retinal ischaemia, can see neovascularisation
Pericyte loss - diffuse haemorrhage and oedema
Microaneurysms and haemorrhages
Cotton wool spots from axonal debris build up
number of microaneurysms and quadrants involved determine severity
CVS risks in DM
MI/Stroke
Autonomic dysfunction in DM
Erectile dysfunction, Bladder retention, postural hypotension, tachycardia, diarrhoea
infection in diabetes
due to hyperglycaemia causing reduced phagocytosis
Give pneumococcal vaccine and annual influenza
Diabetic foot
- Incidence
- importance
- Presentation
- Mech
- Chronic features
- 10% diabetics
- most common cause of amputation
- Hot, swollen foot, painless punched out (neuropathic) ulcers
- loss of sensation during damage, ulcer development, bone degeneration, poor healing
- Rockerbottom sole, Charcot foot
Diabetic eye probs presentation and treatment
- Painless reduction in central vision, Haemorrhage (sudden onset dark painless floater)
- optimise BP/glycaemic control/lipid control, Anti-VEGF, Intravitreal steroids (laser photocoagulation)
Emergency referral of diabetic eye
Sudden loss of vision
Red eye
Retinal detachment
Diabetes Tx
lifestyle and diet (6weeks) inform DVLA
- low glucose, dairy, control fats, limit sugar and lose weight.
HbA1c 3-6monthly and then 6 monthly aim for 48mmol/mol or 6.5%
single drug therapy - Metformin (unless not tolerated) - 6.5% target
dual therapy - metformin + gliptin/sulfonylurea/pioglitazone - target 7% (53mmol/mol
Triple therapy - if still not 58mmolmol/7.5% add third drug or consider insulin
if can’t give metformin then on of the above, add another if not control and then third line is insulin
Diabetes annual review checks
BMI
Complications: Hypos, Hyperosmolar hypoglycaemic state, DKA
CVS assess: BP, pulses, bruits
inspect injection sites (lipodystrophy)
Foot check (neuropathy and pulses)
Urine: protein, nitrites, ketones
Eyes: acuity and ophthalmoscopy
Erectile dysfunction
Bloods: HbA1c
Metformin
- mech
- CI
- SE
Increases sensitivity to insulin
CKD
GI upset: nausea and diarrhoea (20% don’t tolerate)
Gliptin
- mech
- SE
Raised incretin produce more insulin when needed
GI upset, flu-like symptoms
Sulfonylurea
- mech
- CI
- SE
increase pancreatic insulin secretion (S for secretion and Sulfonylurea)
Pregnancy CI
Can cause Hypo (affecting insulin release), weight gain
Pioglitazone
- mech
- CI
- SE
increases insulin sensitivity
osteoporosis, heart failure (due to fluid retention SE)
weight gain, fluid retention, osteoporosis
Insulin Regimes
Once daily
- Long/intermediate acting at bedtime
- only for T2DM
Twice daily
- Pre-breakfast/evening meal
Basal-bolus
- Long/intermediate acting at bedtime with short acting to cover meals
Continuous subcut or insulin pump
- in those with v poor control
NICE Tx T1DM
Basal Bolus regimen
- twice daily insulin deter (long acting)
- Rapid acting insulin analogue (humalog, novorapid) before meals
Nice Tx T2DM
Intermediate acting insulin twice per day: Humulin N or Novolin N
SE of insulin Tx
Hypoglycaemia
- Sweating, confused, aggression, blurred vision
Lipodystrophy
Tx for a Hypo
Conscious:
- 10-20g short acting carb (glass of lucozade, glucogel)
Unconscious:
- IM Glucagon
Inform DVLA
What to do if Diabetic is unwell
4 hourly BG monitoring, monitor ketones
3L fluid every 24 hours
continue oral med, continue insulin with inc monitoring
Stress response = inc cortisol this increases blood sugars and decreases insulin so may need more control
seek help: glucose more than 13mmol/L, DKA signs, BG over 25 and giving more insulin.
DKA precipitants
- Missed insulin
- Infection (corticosteroid risk hyperglycaemia)
- Intoxication (live impairment)
- Ischaemia
- Infarction
Presentation of DKA
Abdominal Pain + Vomiting
Polyuria, polydipsia, dehydration
Kussmaul breathing (deep hyperventilation to correct acidosis)
Acetone breath
Pathophysiology DKA
- Decreased insulin
- Inc protein and fat metabolism
- Ketogenesis from lipolysis
- Acidosis(ketones), hyperglycaemia, Osmotic diuresis, Hypokalaemia (Due to acidosis)
- Dehydration, Acidosis, Coma, Death
ECG Hypokalaemia
PRSTTU
PR prolonged
ST depression
T flat/inverted
Prominent U wave after T
DKA investigation findings
Plasma glucose: over 11
Plasma Ketones: over 3mmol/l
ABG: pH over 7.3
Urine dip: Ketones and glucose high
DKA management
- Fluids
- Hyperglycaemia
- What to watch out for
- Acidaemia
- IV NaCl: 1L in 1st hour, 1L in 2nd hour, 1L in following 2hrs and 1L every 4 hours. When BG below 180mg/mol use 5-10% dextrose
- IV Insulin
- Hypokalaemia (insulin causes K+ to enter cells)
- IV Bicarbonate
Hyperosmolar hyperglycaemic state
- Who gets
- What can be seen on blood tests
T2DM (no DKA as enough insulin to suppress ketogenesis)
Very high blood glucose (over 40) V. high serum osmolality.
over 320mosmol/kg- normal is 285-290
Hypovolaemia
What is osmolality
Osmolarity
concentration expressed as number of solute particles per Kg fluid
Osmolarity is per L fluid
Precipitants to Hyperosmolar hyperglycaemic state
Infection, MI, Dehydration, Thiazides and loop diuretics, poor glucose control.
Hyperosmolar hyperglycaemic state Pathogenesis
Hyperglycaemia, osmotic diuresis, hyperosmolarity gives fluid shift into intravascular compartment = severe dehydration
No ketogenesis as some residual pancreatic function surpasses ketogenesis
Hyperosmolar hyperglycaemic state Presentation
Extreme dehydration and altered mental state
± seizures
± delirium
Investigation findings Hyperosmolar hyperglycaemic state
Urinalysis - glycosuria and sometimes ketonuria (mild)
Blood glucose - over 30
Serum osmolality - over 320mmol/L
U&E - shows AKI (high creatinine+urea)
ABG - normal
Hyperosmolar hyperglycaemic state Tx
Treat cause (e.g. infection, dehydration)
replace fluid and electrolytes to normalise osmolality (NaCl, positive balance of 3-6 L by 12 hours)
Insulin if glucose not falling with other medications.
Hyperosmolar hyperglycaemic state complications
Seizures
Cerebral oedema (if glucose drop too quick)
Pontine myelinosis
Pathogenesis of Cerebral Oedema in DKA and Hyperosmolar hyperglycaemic state
Sudden drop in blood glucose and decrease in osmolality
Brain traps osmotially active particles
Conc gradient means fluid moves from intravasc to brain parenchyma
Metabolic syndrome criteria for Dx
Truncal obesity or BMI over 30 BP systolic over 130 or prev HTN High triglycerides Reduced HDL fasting glucose over 6.1mmol/l (prediabetes)
Metabolic Syndrome complications
Atherosclerosis (CVD), Diabetes, PCOS, NAFLD
Cause of metabolic syndrome
Obesity epidemic - Overnutrition, atherogenic diet, sedentary lifestyle
BMI Levels
under 18.5 = under 18.5 - 24.9 = Optimal 25-29.9 = Over 30-34.9 = Obese I 35-39.9 = Obese II Over 40 = Obese III
Medication causes of Obesity
Glitazone, Sulfonylurea Anticonvulsants Antidepressants: tricyclics, mirtazapine Lithium Progesterone only contraception BB Corticosteroids
Conditions that cause obesity
PCOS Hypothyroidism Cushing's Hypogonadism Prader-Willi
When to consider surgery in Obesity
Obese II (BMI 35-39.9) Always try lifestyle (diet & exercise) and drug (e.g. Orlistat)
How does Orlistat work
Inhibits lipase
Gynaecomastia pathophysiology
balance between oestrogen (stimulate) and androgens (inhibit).
Conditions raising oestrogen, dropping testosterone or increase in conversation androgen to oestrogen (aromatisation by inc fats)
Physiological causes of gynaecomastia
in early teenage assoc with delayed testosterone.
Unilateral and tender
Also seen with ageing (dec in testosterone)
Pathological causes gynaecomastia
Low testosterone:
- Androgen resistance, Klinefeltners, Viral Orchitis (mumps), renal disease
High Oestrogen
- HCG secreting neoplasms (seminoma), ectopic BCG (lung, renal, adrenal tumours), CAH, Liver disease, Obesity, Hyperthyroid, Prolactinoma
Medications causing Gynaecomastia
DISCO:
- Digoxin
- Isoniazid
- Spironalactone
- Cimetide
- Oestrogen
Anabolic steroids (inc androgens = inc conversion to oestrogen)
Prolactin - antipsychotics, TCA, Metoclopramide
LH and testosterone in gynaecomastia
LH high Testosterone low = testicular failure
LH low Testosterone low = inc oestrogen
LH high Testo high = Androgen resistance or neoplasm
Investigations in Gynaecomastia
Hormones: Estradiol, testosterone, Prolactin, bHCG, AFP, LH,
LFT, TFT
Imaging - USS/mammography or needle core biopsy if suspicious.
Thyroid-Hypothalamic-Pituitary axis
TRH from Hypothalamus to Pituitary
TSH from pituitary to Thyroid follicular cella
Thyroid secrets Active T3 and also T4
(peripheral conversion to T3 also occurs). T3 both free (active) and also bound to TBG/Albumin.
Negative feedback of T3/4 to Pituitary and Hypothalamus
How is Thyroid hormone excreted
Liver conjugation/Excretion
Renal excretion
Which is active form of thyroxine.
Function of Thyroid hormones
T3 (Tri-iodothyronine)
Must be unbound (free
Control metabolic rate of tissues
Target for Thyroxine
THRa and THRb
What is
TRH
TSH
Thyrotropin releasing hormone
Thyroid stimulating hormone
Where does T4 get converted to T3
80% Liver
20% Thyroid
Cause of goitre:
- Diffuse goitre
- Nodular goitre
- Painful goitre
- Physiological, Graves, Hashimoto’s (autoimmune)
- Mulitnodular goitre, Adenoma, adenocarcinoma
- De Quervain’s (sub-acute hypothyroiditis)
Hypothyroidism
- Most common cause and what other assoc diseases
Hashimoto’s Thyroiditis
Other autoimmune conditions: T1DM, Addisons, pernicious anaemia
Causes of Hypothyroidism
Atrophic hypothyroidism Subacute hypothyroidism (De Quervain's - painful and raised ESR) Riedels Post partum Iatrogenic - surgery and radio iodine Tx
Secondary causes of hypothyroidism
TSH deficiency, Hypopituitary disorders (Neoplasm, Radiotherapy, infection) Hypothalamic disorders (Neoplasm, Trauma)
Hypothyroidism Signs
Bradycardia Delayed tendon reflex Ataxia (cerebellar) Dry thin skin/hair Puffy face/hands/feet (myxoedema) Obesity Carpal tunnel Megacolon
Hypothyroidism symptoms
Tired & Lethargic Cold intolerance Slow intellectually (poor memory, difficult concentrate) Constipation Weight gain + low appetite Deep/Hoarse voice Monorrhagia Reduced libido Depression
Acute presentation of severe Hypothyroid & Tx
Features of hypothyroidism + seizures + decreased consciousness + hypoventilation
Tx- IV levothyroxine + IV hydrocortisones + Resp support
Hashimotos:
- Goitre
- Autoimmune Ab’s
Painless, diffuse, varying size, rubbery, irregular surface
Anti-thyroid peroxidase
Antithyroglobulin (90-95%)
De Quervains
- pathophysiology
- Tx
viral infection then local symptoms of pain and nodularity
Initially thyrotoxic and then hypothyroid
Aspirin and prednisolone can be given although most cases self resolving
Investigation of hypothyroidism
- TFTs (TSH, T3 and T4) shows primary or secondary
- Antibodies: antiTPO, anti Tg
if worry neoplasm - USS
is secondary cause - MRI pituitary and check visual fields
Diagnosis of primary or secondary thyroid disease
high TSH and low T3/4 = primary
low TSH, low T3/4 = secondary
Clinical management of hypothyroidism
- What
- Follow up
- Risks of medication
T4 - Levothyroxine for life
check TFT every 3-4 weeks. Annual TFT once stable
Osteoporosis, Arrhythmia
for subacute treat if TSH below 10
Hyperthyroidism Causes
Grave’s disease (75%)
Toxic mutinodular goitre (high iodine diet or amiodarone)
Toxic nodule/ adenoma
Subacute/De Quervain’s (transient toxicosis, pain, raised ESR)
Drugs: amiodarone, exogenous thyroids hormone treatment excess
Ectopic thyroid tissue: metastatic follicular carcinoma, ovarian teratoma
Secondary - pituitary adenoma
Hyperthyroidism symptoms
weight loss, inc appetite irritable and weak sweating tremor Diarrhoea Anxiety and psychosis Heat intolerance loss of libido Oligomenorrhea
Hyperthyroidism signs
Sweaty/Warm palms Fine tremor Tachycardia ± AF Hair thinning Goitre Proximal myopathy (wasting and weakness) Gynaecomastia Brisk reflexes Pruritus Pretibial myxoedema Eye disease (lid lag, ophthalmoplegia, exophthalmos)
Graves disease
- Pathology
- AAb
Anti-TSH receptor Abs
(may also react with orbital antigens to give thyroid eye disease)
Hyperplasia of follicular cells = diffuse goitre
anti TSHR (99%), anti-thyroglobulin, anti-TPO
Thyroid eye disease
lid lag, lid retraction, ophthalmoplegia, exophthalmos, gritty eyes, diplopia, loss of colour vision, conjunctival oedema, papilloedema.
Investigations hyperthyroidism
TFT: TSH low, T3/4 high in primary
Imaging: USS to look for cancer/adenoma
Radioisotope uptake scale hot = overactivity. (if not hot then could be De Quervain’s)
ESR raised in De Quervain’s
Of suspect secondary (pituitary adenoma) then MRI head + check visual fields