General Flashcards
What is the mechanism of acromegaly?
Excess growth hormone secondary to a pituitary adenoma in over 95% of cases. A minority of cases are caused by ectopic GHRH or GH production by tumours e.g. pancreatic.
What are the features of acromegaly?
Coarse facial features
Spade like hands
Increase in shoe size
Excessive sweating
Large tongue - interdental space
Pituitary tumour –> Headahce, hypopituitarism
Galactorrhea - prolactin rated in 1/3 of cases
What is acromegaly associated with?
Hypertension
Daibetes
Cardiomyopathy
Colorectal cancer
MEN -1
How should acromegaly be investigated?
IGF-1 (insulin growth factor 1 levels) + serial GH measurements
Oral glucose tolerance test used to confirm diagnosis
MRI may demonstrate pituitary tumour
How can a oral glucose tolerance test be used to diagnose acromegaly?
Normal patients GH is suppressed < 2 with hyperglycaemia
In acromegaly there is no suppression
Management of acromegaly?
Surgery - if possible
If not possible:
1. Somatostatin analogue - directly inhibitors growth hormone
e.g. octreotide
2. Pegvisomant - GH receptor antagonist
3. Dopamine agonists - example bromocriptine
What test can be used to monitor acromegaly treatment?
IGF-1
What are examples of acute phase proteins?
CRP*
procalcitonin
ferritin
fibrinogen
alpha-1 antitrypsin
caeruloplasmin
serum amyloid A
serum amyloid P component**
haptoglobin
complement
In acute phase response what does the liver decrease production of?
albumin
transthyretin (formerly known as prealbumin)
transferrin
retinol binding protein
cortisol binding protein
How does CRP work in acute phase?
binds to phosphocholine in bacterial cells and on those cells undergoing apoptosis. In binding to these cells it is then able to activate the complement system.
What are the features of Addison’s disease?
lethargy, weakness, anorexia, nausea & vomiting, weight loss, ‘salt-craving’
hyperpigmentation (especially palmar creases)*, vitiligo, loss of pubic hair in women, hypotension, hypoglycaemia
hyponatraemia and hyperkalaemia may be seen
crisis: collapse, shock, pyrexia
What are primary causes of hypoadrenalism?
tuberculosis
metastases (e.g. bronchial carcinoma)
meningococcal septicaemia (Waterhouse-Friderichsen syndrome)
HIV
antiphospholipid syndrome
Secondary causes of Addisons disease?
Secondary causes
pituitary disorders (e.g. tumours, irradiation, infiltration)
Exogenous glucocorticoid therapy
How to test for Addisons
- Short synacthen test
- Measure plasma cortisol 30 minutes before and after given 250 micrograms IM of synacthen - Anti -21 hydroxyls may also be demonstrated
What test can be done if a synthacthen test cannot be done? Results?
9 am cortisol level
>500 nmol/L - Addison unlikely
<100 nmol/L - VERY ABNORMAL
100-500 a short synacthen test should be done
What electrolyte / metabolic issues are seen in Addisons?
hyperkalaemia
hyponatraemia
hypoglycaemia
metabolic acidosis
What are causes of Addisons crisis?
- Sepsis or surgery causing an acute exacerbation of chronic
- Insufficiency (Addison’s, Hypopituitarism)
adrenal haemorrhage eg Waterhouse-Friderichsen syndrome (fulminant meningococcemia) - Steroid withdrawal
Management of Addison crisis?
- Hydrocortisone 100 mg IM or IV
- Rehydrate with saline or dextrose if hypoglycaemia
- Continue hydrocortisone 6 hourly
- Begin oral replacement after 24 hours
Causes of ALP rise?
liver: cholestasis, hepatitis, fatty liver, neoplasia
Paget’s
osteomalacia
bone metastases
hyperparathyroidism
renal failure
physiological: pregnancy, growing children, healing fractures
Rasied ALP with raised calcium
Bone metastases
Hyperparathyroidism
Raised ALP and low calcium?
Osteomalacia
Renal failure
What is primary amenorrhoea?
defined as the failure to establish menstruation by 15 years of age in girls with normal secondary sexual characteristics (such as breast development), or by 13 years of age in girls with no secondary sexual characteristics
What is secondary amenorrhoea?
cessation of menstruation for 3-6 months in women with previously normal and regular menses, or 6-12 months in women with previous oligomenorrhoea
Causes of primary amenorrhea?
gonadal dysgenesis (e.g. Turner’s syndrome) - the most common causes
testicular feminisation
congenital malformations of the genital tract
functional hypothalamic amenorrhoea (e.g. secondary to anorexia)
congenital adrenal hyperplasia
imperforate hymen
Causes of secondary amenorrhoea?
hypothalamic amenorrhoea (e.g. secondary stress, excessive exercise)
polycystic ovarian syndrome (PCOS)
hyperprolactinaemia
premature ovarian failure
thyrotoxicosis*
Sheehan’s syndrome
Asherman’s syndrome (intrauterine adhesions)
What investigations should be completed for amenorrhea?
- Exclude pregnancy with urinary or serum bHCG
- Coeliac screen
- Thyroid function tests
- Gonadotrophins
- low levels indicate a hypothalamic cause where as raised levels suggest an ovarian problem (e.g. Premature ovarian failure)
- raised if gonadal dysgenesis (e.g. Turner’s syndrome)
prolactin - Androgen levels
- raised levels may be seen in PCOS - Oestradiol
What is the genetics behind androgen insensitivity syndrome
X linked recessive
46 XY male - has a female phenotype
Due to testosterone resistance
What was the other name (old name) for complete androgen insensitivity syndrome?
Testicular feminisation
Features of androgen insensitivity syndrome?
‘primary amenorrhoea’
little or no axillary and pubic hair
undescended testes causing groin swellings
breast development may occur as a result of the conversion of testosterone to oestradiol
How is androgen insensitivity syndrome diagnosed?
Buccal smear - 46 XY
Testosterone levels: High normal range compared to post pubertal boys
What is the management of androgen insensitivity syndrome
bilateral orchidectomy (increased risk of testicular cancer due to undescended testes)
oestrogen therapy
What HLA type is autoimmune polyendocrinopathy syndrome associated with?
HLA DR3 and DR4
What is autoimmune polyendocrinopathy syndrome ?
Addison’s disease (autoimmune hypoadrenalism) is associated with other endocrine deficiencies in approximately 10% of patients. There are two distinct types of autoimmune polyendocrinopathy syndrome
What is autoimmune polyendocrinopathy syndrome type 1?
referred to as Multiple Endocrine Deficiency Autoimmune Candidiasis (MEDAC). It is a very rare autosomal recessive disorder caused by mutation of AIRE1 gene on chromosome 21
chronic mucocutaneous candidiasis (typically first feature as young child)
Addison’s disease
primary hypoparathyroidism
What is the genetics behind bartter’s syndrome?
Autosomal recessive
Defective Na+ K+ 2CL- cotransporter in ascending loop of hence
oop diuretics work by inhibiting NKCC2 - think of Bartter’s syndrome as like taking large doses of furosemide
What are the features of Barter’s syndrome?
usually presents in childhood, e.g. Failure to thrive
polyuria, polydipsia
hypokalaemia
normotension
weakness
How does Barter’s Syndrome differ from other hypokalaemia conditions?
endocrine causes of hypokalaemia such as Conn’s, Cushing’s and Liddle’s syndrome which are associated with hypertension).
What is the mechanism of action of carbimazole?
blocks thyroid peroxidase from coupling and iodinating the tyrosine residues on thyroglobulin → reducing thyroid hormone production
How long should a patient be on carbimazole?
High dose for 6 weeks
Patient becomes euthyroid before being reduced
How does propylthiouracil differ from carbimazole?
propylthiouracil has a central and peripheral action by inhibiting 5’-deiodinase which reduces peripheral conversion of T4 to T3
What are the adverse effects of carbimazole?
agranulocytosis
crosses the placenta, but may be used in low doses during pregnancy
HPV virus implicated in cervical cancer?
Human papillomavirus (HPV), particularly serotypes 16,18 & 33
Mechanism of HPV causing cervical cancer?
HPV 16 & 18 produces the oncogenes E6 and E7 genes respectively
E6 inhibits the p53 tumour suppressor gene
E7 inhibits RB suppressor gene
Cervical cancer risk factors?
smoking
human immunodeficiency virus
early first intercourse, many sexual partners
high parity
lower socioeconomic status
combined oral contraceptive pill*
What is congenital adrenal hyperplasia?
Autosomal disorders
Affect adrenal steroid biosynthesis
Results in low cortisol
Pituitary secretes extra ACTH
ACTH stimulated adrenal androgens –> virtualise female infant
Enzyme deficiencies in congenital adrenal hyperplasia?
21-hydroxylase deficiency (90%)
11-beta hydroxylase deficiency (5%)
17-hydroxylase deficiency (very rare)
Features of congenital adrenal hyperplasia - 21 hydroxylase deficiency feature?
virilisation of female genitalia
precocious puberty in males
60-70% of patients have a salt-losing crisis at 1-3 wks of age
Features of congenital adrenal hyperplasia - 11 beta hydroxylase deficiency feature?
virilisation of female genitalia
precocious puberty in males
hypertension
hypokalaemia
Features of congenital adrenal hyperplasia - 17 hydroxylase deficiency feature?
non-virilising in females
inter-sex in boys
hypertension
Steroid with minimal glucocorticoid activity and very high mineralocorticoid activity?
Fludrocortisone
Steroid with high glucocorticoid activity and high mineralocorticoid activity?
Hydrocortisone
Predominant glucocorticoid activity and low mineralocorticoid activity?
Prednisolone
Endocrine side effects of corticosteroids?
endocrine
impaired glucose regulation
increased appetite/weight gain
hirsutism
hyperlipidaemia
Cushing’s syndrome
moon face
buffalo hump
striae
Musculoskeletal side effects of corticosteroids
osteoporosis
proximal myopathy
avascular necrosis of the femoral head
Psychiatric side effects of corticosteroids?
insomnia
mania
depression
psychosis
Gastrointersinal side effects of corticosteroids?
peptic ulceration
acute pancreatitis
Ophthalmic side effects of corticosteroids?
Glaucoma
Cataracts
Side effects of mineralocorticoids?
FLuid retention
Hypertension
Who would be gradual withdrawn from steroids?
- Received more than 40 mg prednisolone daily for more than one week
- Received more than 3 weeks of treatment
- Recurrent repeat courses
Most common cause of Cushings?
Exogenous steroid therapy
What are the types of ACTH dependent Cushings?
- Cushing disease - pituitary tumour secreting ACTH
- Ectopic ACTH production - small cell lung cancer
What are ACTH independent causes of Cushing syndrome?
iatrogenic: steroids
adrenal adenoma (5-10%)
adrenal carcinoma (rare)
Carney complex: syndrome including cardiac myxoma
micronodular adrenal dysplasia (very rare)
What is Pseudo-Cushing’s?
mimics Cushing’s
often due to alcohol excess or severe depression
causes false positive dexamethasone suppression test or 24 hr urinary free cortisol
insulin stress test may be used to differentiate
What are general investigation findings consistent with Cushing’s syndrome?
Hypokalaemmic metabolic alkalosis
Impaired glucose tolerance
Ectopic ACTH secretion - associated with hypokalaemia
How should Cushing’s syndrome be tested?
- Overnight dexamethasone suppression test:
- Most sensitivity
- Patients with Cushing syndrome do not have their morning cortisol spike - 24 hour urinary free cortisol
To test if Cushings is ACTH or ACTH independent, what test should be done?
High dose dexamethasone test
High dose dex test: Cortisol not suppressed + ACTH suppressed
ACTH independent causes ( e.g. adrenal adenoma)
High dose dex test: Suppressed cortisol + Suppressed ACTH?
Cushing disease (i.e. pituitary adenoma –> acth secretion)
High dose dex test: Cortisol and ACTH not suppressed?
Ectopic ACTH syndrome
e.g. small cell lung cancer
What test is used to differentiate between true Cushing’s disease and pseudo-cushings?
Insulin stress test
Diagnostic criteria for type 2 diabetes?
- 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)
- a HbA1c of greater than or equal to 48 mmol/mol (6.5%) is diagnostic of diabetes mellitus
What may cause a misleading HbA1c result?
Increased red cell turnover
What conditions can HbA1c not be used for a diagnosis of type 2 diabetes mellitus?
haemoglobinopathies
haemolytic anaemia
untreated iron deficiency anaemia
suspected gestational diabetes
children
HIV
chronic kidney disease
people taking medication that may cause hyperglycaemia (for example corticosteroids)
Criteria for impaired oral glucose tolerance?
Glucose less than 7 before test (they fast before)
OGTT 2 hour value: Greater than 7.8 but less than 11.1
Criteria for impaired fasting glucose?
Equal to 6.1 but less than 7.0
Basics of T2DM?
relative deficiency of insulin due to an excess of adipose tissue. In simple terms there isn’t enough insulin to ‘go around’ all the excess fatty tissue, leading to blood glucose creeping up.
Basics of T1DM?
Autoimmune disorder where the insulin-producing beta cells of the islets of Langerhans in the pancreas are destroyed by the immune system
This results in an absolute deficiency of insulin resulting in raised glucose levels
Features of pre diabetes?
term is used for patients who don’t yet meet the criteria for a formal diagnosis of T2DM to be made but are likely to develop the condition over the next few years. They, therefore, require closer monitoring and lifestyle interventions such as weight loss
Basics of gestational diabetes?
Some pregnant develop raised glucose levels during pregnancy. This is important to detect as untreated it may lead to adverse outcomes for the mother and baby
Basics of maturity onset diabetes of the young (MODY) ?
group of inherited genetic disorders affecting the production of insulin. Results in younger patients developing symptoms similar to those with T2DM, i.e. asymptomatic hyperglycaemia with progression to more severe complications such as diabetic ketoacidosis
Basics of latent autoimmune diabetes of adults?
Autoimmune related diabetes presenting as adults
Features of T1DM?
Weight loss
Polydipsia
Polyuria
DKA:
abdominal pain
vomiting
reduced consciousness level
Features of T2DM
Often picked up incidentally on routine blood tests
Polydipsia
Polyuria
How many months does HbA1c represent the average blood glucose?
2-3 months
How is a oral glucose tolerance test (OGTT) completed?
a fasting blood glucose is taken after which a 75g glucose load is taken. After 2 hours a second blood glucose reading is then taken
Diagnosis of T2DM from OGTT? - In symptomatic patient
If the patient is symptomatic:
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)
Diagnosis of T2DM from OGTT - in asymptomatic patient ?
OGTT needs to show diagnostic criteria on two occasions
Side effect of insulin?
Hypoglycaemia
weight gain
Lipodystrophy
Mechanism of metformin?
Increases insulin sensitivity
Decreases hepatic gluconeogenesis
Side effects of metformin?
Gastrointestinal upset
Lactic acidosis
When can metformin not be used?
eGFR < 30
Do not use post heart attack - tissue hypoxia
Mechanism of sulfonylureas?
Stimulate pancreatic beta cells to secrete insulin
Side effects of sulfonylureas?
Hypoglycaemia
Weight gain
Hyponatraemia
Mechanism of thiazolidinediones?
Activate PPAR-gamma receptor in adipocytes to promote adipogenesis and fatty acid uptake
Side effect of thiazolidinediones?
weight gain
Fluid retention
Do not use in heart failure
Mechanism of DPP-4 inhibitors? (The gliptans)
Increase incretin levels - inhibit glucagon secretion
Side effect of DPP4 inhibitors?
Pancreatitis
Mechanism of SGLT2 inhibitors ?
Inhibit reabsorption of the glucose in the kidney
Side effect of SGLT2 inhibitors?
Urinary tract infections
Typically cause weight loss
Adverse effects:
urinary and genital infection (secondary to glycosuria). Fournier’s gangrene has also been reported
normoglycaemic ketoacidosis
increased risk of lower-limb amputation: feet should be closely monitored
Mechanism of GLP-1 agonist ( the Tides)?
Incretin mimetic
Inhibits glucagon secretion
Side effect of GLP-1 inhibitors (tide)?
N+V
Pancreatitis
Typically cause weight loss
Treatment algorithm for T2DM?
- Metformin
HbA1c > 58
2. Metformin plus:
- Glipten
- Sulphonyurea
- TZD
- SGLt2
HbA1c > 58
3. Consider a triple agent
OR INSULIN
If triple therapy and BMI > 35
4. Metformin + Suphonylurea + GLP1
When should a GLP-1 agonist be considered?
Triple therapy
BMI > 35
Start:
Metformin + Sulfonylurea + GLP-1 minimetic
T2DM - cannot tolerate metformin?
Try:
Gliptan (DPP4)
Sulfonylurea
Pioglitazone
What does a GLP-1 inhibitor stand for?
Glucagon like peptide 1 mimetic
What does the glucose like peptide do?
Hormone released by small intestine in respond to an oral glucose load
Oral glucose load results in higher release of insulin, compared to IV
This is mediated by GLP-1
How should eventide be given?
Scut injection 60 minutes before morning and evening meal
NOT GIVEN WITH MEAL
What criteria must a patient meet to qualify for repeat prescription of exenatide?
> 11 mmol/mol (1%) reduction in HbA1c and 3% weight loss after 6 months to justify the ongoing prescription of GLP-1 mimetics.
How do DPP4 inhibitors increase GLP1 ?
Decreasing peripheral breakdown
What are the blood glucose targets for T1DM?
5-7 on waking
4-7 before meals or other times
Dietary advice for T2DM?
Increase fibre - low glycemic index
Include low fat dietary products
Discourage use of foods marketed specifically at diabetics
Aim for a weight loss of 5-10 %
HbA1c target for T2DM on lifestyle changes only?
48
HbA1c target for T2DM on lifestyle changes and metformin
48
HbA1c target for T2DM on drugs that may cause hypoglycaemia?
53
What would prompt immediate introduction of SGLt2 inhibitors in T2DM?
Diagnosis of CVD, QRISK score > 10%
What should be done with metformin before adding in other agent?
Increase to maximum dose
Management of T2DM, cannot tolerate metformin, ischaemic heart disease?
SGLT2 mono therapy
Management of T2DM, cannot tolerate metformin, no heat disease?
DPP‑4 inhibitor or pioglitazone or a sulfonylurea
SGLT-2 may be used if certain NICE criteria are met
What blood pressure targets should be used for T2DM < 80?
Clinic: 140/90
Ambulatory /Home blood pressure: 135/85
What blood pressure should be used for T2DM > 80?
Clinic: 150/90
Ambulatory /Home blood pressure: 145/85
Pathophysiology of T1DM?
autoimmune disease
antibodies against beta cells of pancreas
HLA DR4 > HLA DR3
What antibodies are seen in T1DM?
Anti-islet associated antigen
Glutamic acid decarboxylase
Mechanism of diabetic foot disease?
- Neuropathy
- Peripheral arterial disease
Presentation of diabetic foot disease?
neuropathy: loss of sensation
ischaemia: absent foot pulses, reduced ankle-brachial pressure index (ABPI), intermittent claudication
complications: calluses, ulceration, Charcot’s arthropathy, cellulitis, osteomyelitis, gangrene
Risk stratification of diabetic foot disease?
Low risk: No risk factors, except callus
Moderate risk: Deformity or Neuropathy or non-critical limb ischaemia
High risk: Previous significant disease or combination of vascular and neuropathy
High risk - should be monitored at diabetic foot centre
What is the pathophysiology of Diabetic Ketoacidosis?
DKA is caused by uncontrolled lipolysis (not proteolysis) which results in an excess of free fatty acids that are ultimately converted to ketone bodies
Biochemical diagnosis of DKA?
glucose > 11 mmol/l or known diabetes mellitus
pH < 7.3
bicarbonate < 15 mmol/l
ketones > 3 mmol/l or urine ketones ++ on dipstick
Features of DKA?
abdominal pain
polyuria, polydipsia, dehydration
Kussmaul respiration (deep hyperventilation)
Acetone-smelling breath (‘pear drops’ smell)
Management of DKA?
- Fluids replacement with isotonic saline - normally deplete 5-8 litres
- Insulin 0.1 unit per kg PER HOUR
- Once BM < 15 - COMMENCE DEXTROSE FLUIDS
- Serum potassium is often high on admission, falls quickly, Potassium will lower potassium. Therefore add potassium
- Continue long act insulin
Describe the fluid choice over first 6 hours
0.9% sodium chloride 1L 1000ml over 1st hour
0.9% sodium chloride 1L with potassium chloride 1000ml over next 2 hours
0.9% sodium chloride 1L with potassium chloride 1000ml over next 2 hours
0.9% sodium chloride 1L with potassium chloride 1000ml over next 4 hours
0.9% sodium chloride 1L with potassium chloride 1000ml over next 4 hours
0.9% sodium chloride 1L with potassium chloride 1000ml over next 6 hours
Guidance of potassium in fluids for DKA?
Over 5.5 Nil
3.5-5.5 40
Below 3.5 Senior review as additional potassium needs to be given
What is biochemical resolution of DKA?
pH >7.3 and
blood ketones < 0.6 mmol/L and
bicarbonate > 15.0mmol/L
IF EATING - can then switch to subcutaneous insulin
Complications of DKA?
gastric stasis
thromboembolism
arrhythmias secondary to hyperkalaemia/iatrogenic hypokalaemia
iatrogenic due to incorrect fluid therapy: cerebral oedema*, hypokalaemia, hypoglycaemia
acute respiratory distress syndrome
acute kidney injury
Features of androgen insensitivity syndrome?
46 XY
X linked recessive
Defect in androgen receptor
Resistance to testosterone
Phenotypically female
Rudimentary vagina and testes present
Testosterone - elevated
Oestrogen - elevated
LH - elevated
Features of 5 alpha reductase deficiency ?
46 XY
Auotsomal recessive
Males unable to convert testosterone to dihydrotestosterone
Ambiguous genitalia
Hyposadias
Virilisation at puberty
What is male pseudohermaphroditism?
46XY
Individual has testes but external genitalia are female or ambiguous. may be secondary to androgen insensitivity syndrome
What is female pseudohermaphroditism?
46 XX
Individual has ovaries but external genitalia are male (virilized) or ambiguous. May be secondary to congenital adrenal hyperplasia
True hermaphroditism?
46 XX or 47 XXY
Very rare, both ovarian and testicular tissue are present
Sex hormone is primary hypogonadism (klinefelters) ?
LH - high
Testosterone - low
Sex hormone in hypogonadtrophic hypogonadism ( Kallman’s)
LH low
Testoestone low
Androgens insensitivity syndrome sex hormones?
High LH
High Testosterone
Testosterone secretin tumour sex hormones?
Low LH
High testosterone
What does LH do in males?
Makes testosterone from testes