Endocrinology Flashcards
what is addison’s disease
autoimmune destruction of the adrenal glands resulting in primary hypoadrenalism
results in low cortisol and low aldosterone
what are the symptoms of addison’s disease
- symptoms:
- lethargy
- weakness
- anorexia
- nausea & vomiting
- weight loss,
what are the signs of addison’s disease
- hyperpigmentation (especially palmar creases)
- note that secondary adrenal insufficiency does not cause hyperpigmentation
- vitiligo
- loss of pubic hair in women
- hypotension
- hypoglycaemia
- hyperkalaemia
- hyponatraemia
- addisonian crisis;
- shock
- collapse
non-autoimmune causes of hypoadrenalism
- Primary causes
- tuberculosis
- metastases (e.g. bronchial carcinoma)
- meningococcal septicaemia (Waterhouse-Friderichsen syndrome)
- HIV
- antiphospholipid syndrome
- Secondary causes
pituitary disorders (e.g. tumours, irradiation, infiltration)
management of addison’s disease
- need glucocorticoid and mineralocorticoid therapy
- hydrocortisone: usually 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
patient education in addison’s
- emphasise importance of not missing dose of glucocorticoid
- give injections of hydrocortisone to be administered in the case of crisis
- if there is intercurrent illness:
- double the glucocorticoid dose
- keep fludrocortisone dose the same
what is the definitive diagnostic investigation for addison’s
ACTH stimulation test (short Synacthen test). Plasma cortisol is measured before and 30 minutes after giving Synacthen
what addison’s investigations can you do if the synacthen test is unavailable
- Adrenal autoantibodies such as anti-21-hydroxylase
- 9am serum cortisol
- > 500 nmol/l makes Addison’s very unlikely
- < 100 nmol/l is definitely abnormal
- 100-500 nmol/l should prompt a ACTH stimulation test to be performed
what are the associated electrolyte abnormalities of addison’s
- hyperkalaemia
- hyponatraemia
- hypoglycaemia
- metabolic acidosis
causes of addisonian crisis
- sepsis or surgery causing an acute exacerbation of chronic insufficiency (Addison’s, Hypopituitarism)
- Waterhouse-Friderichsen syndrome (fulminant meningococcemia)
- steroid withdrawal
what is the management of addisonian crisis?
- hydrocortisone 100 mg im or iv
- 1 litre normal saline infused over 30-60 mins or with dextrose if hypoglycaemic
- continue hydrocortisone 6 hourly until the patient is stable. No fludrocortisone is required because high cortisol exerts weak mineralocorticoid action
- oral replacement may begin after 24 hours and be reduced to maintenance over 3-4 days
what is waterhouse-friderichsen syndrome
Patients with meningococcal meningitis are at risk of Waterhouse-Friderichsen syndrome (adrenal insufficiency secondary to adrenal haemorrhage).
what is the most common cause of cushing’s sydnrome
steroid therapy
causes of cushing’s syndrome
- ACTH dependent causes
- cushing’s disease (80%) - ACTH secreting pituitary tumour causes adrenal hyperplasia
- ectopic ACTH production (5-10%): e.g. small cell lung cancer is the most common causes
- ACTH independent causes
- steroid therapy
- adrenal adenoma
what is pseudo cushings
- 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 test for cushing’s syndrome
- overnight dexamethasone suppression test
- if a patient has cushing’s syndrome they will not have their morning cortisol spike suppressed
how do you find out if the cause of cushings is ACTH dependent or independent
9am and midnight plasma ACTH (and cortisol) levels. If ACTH is suppressed then a non-ACTH dependent cause is likely such as an adrenal adenoma
what is MODY
maturity onset diabetes of the young
A group of inherited disorders that result in relatively young patients developing symptoms similar to T2DM
i.e. asymptomatic hyperglycaemia with progression to more severe complications such as diabetic ketoacidosis
what is LADA
Latent autoimmune diabetes of adults
patients often diagnosed as having type two diabetes
what are the diagnostic criteria for diabetes as they relate to fasting blood glucose and HbaA1c
How does metformin work, what are he main side effects and what are the contraindications
- how does it work?
- increases insulin sensitivity
- decreases hepatic gluconeogenesis
- what are the main side effects?
- lactic acidosis
- GI upset
- what are the contraindications?
- eGFR <30
How do sulfonylureas work?
they stimulate the pancreatic beta cells to produce more insulin
what is an example of a sulfonylurea
glipizide
gliclazide
glimepiride
what are the side effects of sulfonylureas
hypoglycaemia
weight gain
hyponatraemia
how do Thiazolidinediones work
they are for treatment of diabetes
they promote adipogenesis and fatty acid uptake
e.g. pioglitazone
what is an example of a thiazolindinedione
pioglitazone is the only one available
what are the side effects of pioglitazone
Weight gain
Fluid retention
how do DPP-4 inhibitors work
they increase incretin levels which inhibit glucagon secretion
what do DPP-4 inhibitor drugs end in
-gliptin
what is an example of a dpp-4 inhibitor
sitagliptin
how do SGLT-2 inhibitors work
Inhibits reabsorption of glucose in the kidney
what are the main side effects of SGLT-2 inhibitors
urinary tract infections and weight loss
what do the drug names of SGLT2 inhibitors end in
-gliflozin
what is an example of an SGLT2 inhibitor
Dapagliflozin
Canagliflozin
how do GLP-1 antagonists work?
they are incretin mimetics and therefore they inhibit glucagon
what do GLP-1 antagonist drugs end in
-tide
what is an example of a GLP-1 antagonist
Dulaglutide
Exenatide
what are the side effects of GLP-1 antagonists
- subcut injections so side effects of sc injection
- nausea
- vomiting
- pancreatitis
draw the flow chart of T2DM drug treatment
which antibodies may be present in T1DM
- Anti-GAD
- present in 80% T1DM patients
- Islet cell antibodies (ICA)
- presentin 70-80% T1DM patients
- Insulin auto antibodies
- found in over 90% of young children with T1DM but only 60% of older patients
what are the diagnostic criteria for T1DM
- 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 THEN THIS NEEDS TO BE DEMONSTRATED ON TWO SEPARATE OCCASIONS
If there is ambiguity over whether it is T1DM or T2DM then what could you do
test fo c peptide and/or diabetes specific auto-antibodies
how often should HbA1c be monitored in patients with T1DM and what should the target be
- should be monitored every 3-6 months
- adults should have a target of HbA1c level of 48 mmol/mol (6.5%) or lower
what is the recommended blood glucose monitoring for T1DM
- recommend testing at least 4 times a day, including before each meal and before bed
- more frequent monitoring is recommended if frequency of hypoglycaemic episodes increases; during periods of illness; before, during and after sport; when planning pregnancy, during pregnancy and while breastfeeding
what are the blood glucose targets for T1DM
- 5-7 mmol/l on waking and
- 4-7 mmol/l before meals at other times of the day
when should you add metformin in T1DM
If BMI >25
what are the different types of insulin and what are their onset, peak and duration?
two examples of rapid acting insulin
- insulin aspart: NovoRapid
- insulin lispro: Humalog
two examples of short acting insulin
Actrapid
Humulin S
two examples of long-acting insulin
- insulin determir (Levemir): given once or twice daily
- insulin glargine (Lantus): given once daily
why is it important to rotate injection sites when adnministering insulin
to prevent lipodystrophy
how do insulin pumps work
they deliver a continuous basal infusion and a patient-activated bolus dose at meal times.
what are the key sick day rules
- increase blood glucose monitoring to four hourly
- if struggling to eat then try sugary drinks
- if taking oral hypoglycaemics then continue them even if you’re not eating much
- the exception is metformin which should be stopped if the patient becomes dehydrated → renal function
- keep a mobile phone by you
- try and drink 3L of water per day
what are the most common precipitating factors in DKA
MI
Infection
Missed insulin doses
diagnostic criteria for 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
management of DKA
- Fluid replacement
- normal saline
- once blood glucose <15 start infusion of 5% dextrose
- Insulin 0.1 unit/kg/hr
- their short acting insulin should be stopped
- their long acting insulin should be continued
- Electrolyte correction
- if the rate of potassium infusion is greater than 20 mmol/hour then cardiac monitoring may be required
how do you decide what concentration of potassium to give patients when they need replacement in DKA
what is the amount of fluid that patients in DKA typically need and how fast would you give this
patients in DKA are usually deplete around 5-8 litres
see picture for how fast to replace this
note that younger adults may need slower infusions as they are at greater risk of cerebral oedema