Endocrinology and clinical biochem Flashcards
What is type I diabetes
Auto-immune desrtruction of beta-cells in the islets of langerhans of the pancreas causing insulin insufficiency and hyperglycaemia
What is the typical presentation of type I diabetes
- polydipsia
- polyuria
- haematuria
- proteinuria
- weight loss
- personal/family history of autoimmune disease
What fasting glucose is indicative of DM
> 7mmol/L
What random glucose is indicative of DM
> 11mmol/L
What HbA1c is indicative of DM
> 48mmol/L
What lifestyle modifications can be advised for T2DM
- weight loss
- ecerxise
- smoking cessation
What is the most widely prescribed drug for T2DM
metformin
What is a serious possible side effect of metformin
lactic acidosis
How does metformin work
It is a type of biguanide and is anti-hyperglycaemic
Does metformin carry a risk of hypoglycaemia
Not if taken alone as it doesn’t increase insulin secretion
Ehat are the names of some sufonylureas
Gliclazide, glipizide
What is a possible side effect of sulfonylureas (eg gliclazide)
hypoglycaemia
What should you look for when examining the skin of a patient who injects subcut insulin
lipohypertrophy
what can you advise the patient to do to prevent lipohypertrophy
Switch injection sites regularly
What happens to insulin levels when a patient continues injecting in a site with lipohypertrophy
The insulin uptake is poorer
What are the two categories of diabetes complications
macrovascular and microvascular
What are the ultra fast-acting subcut insulins
humalog and novorapid
What are the long-acting recombinant human insulin analogues
insuline detemir
insulin glargin
What is first line for long-acting basal insulin therapy
insulin detemir
What are some common insulin regimens
- basal-bolus
- biphasic
- insulin pump
Describe the basal-bolus regimen
One or more separate doses of intermediate- or long-acting insulin with short-acting bolus injections before or right after meals
What should insulin-dependent diabetics remember when they are sick eg with the flu?
- insulin requirement often increases
- maintain calorie intake
- monitor blood glucose and ketonuria
When would you admit a patient who is a insulin-dependent with the flu
if they are vomiting, dehydrated, ketotic, a child or pregnant
What is the target blood pressure for diabetic patients
<135/85mmHg
What are some macrovascular complications of diabetes?
- coronary artery disease
- peripheraly artery disease
- stroke
How should you manage macrovascular risk in diabetes?
- lifestyle advice
- atorvastatin
- manage complications individually
What are some microvascular diabetes complications
- retinopathy
- cataracts
- nephropathy
- neuropathy
- diabetic foot
What are the types of diabetic neuropathy?
- autonomic neuropathy
- painful diabetic neuropathy
- sensory loss
What are some types of autonomic diabetic neuropathy?
- gastroparesis
- bladder emptying issues
- erectile dysfunction
How might diabetes result in the diabetic foor?
diabetic neuropathy and vascular disease
How do you tell the difference between vascular cause of diabetic foot and neuropathic cause
- Vascular may be pulseless
- Neuropathic will have decreased sensation
- Neuropathic may be more likely on pressure points
How do you screen for diabetic retinopathy?
diabetic eye screening programme
How do you treat diabetic nephropathy
ACE-inhibitors or angiotensin II receptor blockers if not tolerated
What is gestational diabetes
Glucose intolerance intolerance that is first recognised during pregnancy
What trimester is most common for diagnosis of gestational diabetes?
Third trimester
What are the risks to the mother of gestational diabetes
- pre-eclampsia
- increased risk of developing T2DM
- increased risk of developing cardiovascular disease
What are the risks to the foetus of gestational diabetes
- miscarriage
- pre-term labour
- congenital malformations
- macrosomia
What is macrosomia
A baby that is much larger than normal
Describe the treatment options for gestational diabetes
- lifestyle changes
- metformin
- insulin
What is secondary diabetes
Diabetes that results as a consequence of another medication, endocrine disease or hereditary disease
Give some examples of diseases that cause of secondary diabetes
- pancreatitis (acute/chronic)
- pancreatic cancer
- other endocrine disorders eg Cushing’s and acromegaly
What is the most common drug cause of secondary diabetes
steroids
What are the two main forms of monogenic diabetes
- neonatal diabetes
* maturity-onset diabetes of the young (MODY)
What is monogenic diabetes
rare forms of diabetes that result from mutations or changes in a single gene
What are the main diabetic emergencies?
- DKA
- hypoglycaemia
- HHS
What does HHS stand for
Hyperosmolar hyperglycaemic state
What is diabetic ketoacidosis
A consequence of insulin deficiency where there is breakdown of free fatty acids into ketone bodies which causes acidosis
What are ketones?
An energy substrate made in starvation or insulin deficiency
What is the classic presentation of diabetic ketoacidosis
- polyuria
- polydipsia
- Kussmaul breathing
- sweet smelling breath
- reduced GCS
What is Kussmaul breathing? What is it indicative of?
Deep rapid breathing indicative of patient trying to ‘blow off’ CO2 in acidosis
What investigations should be undertaken in an unwell diabetic?
- blood glucose
- venous blood gas
- blood ketones
- urine dipstick
What blood results (including VBG) would indicate ketosis?
- glucose >11mmol/L
- ketones >3mmol/L
- VBG signs of metabolic acidosis
How is DKA managed?
- Fluids!
- IV insulin infusion
- eventually give glucose in fluids
Why would you start giving glucose in fluids in DKA?
because the insulin reduces the ketones but can cause hypoglycaemia at the same time
What is HHS?
Hyperosmolar hyperglycaemic state is a hyperglycaemic state of hypovolaemia
What is the predominant problem in HHS
dehydration
What is the pathogenesis of HHS
Patients with T2DM may have enough insulin to stop ketone body production, but glucose still accumulates in the blood, leading to an osmotic diuresis
What is the onset period for HHS compared to DKA
Can be over many days, whereas DKA is a few hours or days
What is the management of HHS like
- fluid replacement
* insulin infusion, although lower rates than in DKA
When do symptoms of hypoglycaemia start to appear? What glucose level?
<3.4mmol/L
What are some symptoms of hypoglycaemia?
- hunger
- pallor
- sweating
- palpitations
What severe symptoms of hypoglycaemia might a patient present with?
- seizures
- unconsciousness
- death
What treatment should unconscious patients with hypoglycaemia receive?
- IM glucagon or IV glucose infusion
What are some primary causes of hypothyroidism
- iodine deficiency
- hashimoto’s thyroiditis
- surgery or medication
What are some symptoms of hypothyroidism?
- cold sensitivity
- weight gain
- lethargy
- constipation
- menstrual disturbances
What is the emergency that hypothyroidism might result in
myxoedema coma
What is the metabolically active form of thyroxin
T3
What are the bloods like in primary hypothyroidism
- high TSH
* low T3/T4`
How is hypothyroidism treated
levothyroxine (T4)
What are symptoms of hyperthyroidism
- palpitations
- sweating
- heat intolerance
- weight loss
- anxiety
- diarrhoea
- a goitre
What are some complications of hyperthyroidism?
- heart failure
- atrial fibrillation
- Graves’ ophthalmopathy
- thyrotoxicosis
What is the main cause of primary hyperparathyroidism
Graves’ disease
What blood results indicate hyperthyroidism
Low TSH
Elevated T3/T4
What drug therapy can be given for hyperthyroidism
- caribomazole
* thyroxine may be required
What non-pharmacological therapy can be given for hyperthyroidism
- surgery
* radioactive iodine
Why would radioactive iodine be contraindicated
in patients with Graves’ ophthalmopathy it makes it worse
What is a possible complication of thyroid surgery
- hypothyroidism
- hypoparathyroidism
- bleeding
What is a toxic thyroid goitre?
A goitre associated with hyperthyroidism
How are thyroid goitres treated
- treat underlying pathology
* surgery
What may be found on examination of a goitre in Graves’? Why?
a bruit may be heard because the goitre becomes very vascular
What would a diffusely enlarged and smooth goitre without bruit indicate?
Iodine deficiency
Does a thyroid goitre need to be investigated in pregnancy if there are no symptoms?
Not neccessarily, because the thyroid may enlarge for increased demand and then will receed after pregnancy
What investigation should be done for a nodular goitre?
fine needle aspiration and TFTs
What are causes of thyroid lumps?
- thyroid cysts
- follicular adenoma
- malignancy
- nodule of multinodular goitre
What is multinodular goitre
enlarged thyroid that contains many nodules of varying sizes
How is thyroid carcinoma treated?
- radioactive iodine
- radiotherapy
- chemotherapy
- surgery
What causes PTH release?
Low calcium levels
What does PTH do
- triggers bone resorption
- causes kidney reabsorption of Ca
- causes kidney production of calcitriol
What does calcitriol do
increases GI absorption of calcium
What elecrolyte abnormalities are found in hyperparathyroidism
hypercalcaemia
hypophosphataemia
What are symptoms of hyperparathyroidism
- painful and fragile bones
- kidney stones
- cardiac arrhythmias
- confusion
- muscle weakness
- dehydration
What is the most common cause of hyperparathyroidism
parathyroid gland adenoma
What are malignant tumours of the parathyroid gland often associated with?
MEN (multiple endocrine neoplasia)
How is hyperparathyroidism investigated
- PTH levels
- serum calcium and phosphate
- U&Es
- x ray
What LFT might be elevated in hyperparathyroidism
Alk Phos
What medications may cause hypercalcaemia
- lithium
* thiazide diuretics
What treatment can be given for primary hyperparathyroidism
- surgery
* bisphosphonates, calcitonin, cinacalcet
What medical therapy can be used for primary hyperparathyroidism
- calcitonin
- cinacalcet
- bisphosphonates
What are complications of surgical removal of parathyroid glands
- hypocalcaemia
- recurrent laryngeal nerve injury
- bleeding
What causes secondary hyperparathyroidism
conditions that cause hypocalcaemia will result in increased PTH secretion, which if prolonged can cause the glands to enlarge
Give an example of a condition that causes hyperparathyroidism
- vitamin D deficiency or malabsorption
* renal failure
What is tertiary hyperparathyroidism
If secondary hyperparathyroidism persists, the level of calcium required to inhibit PTH production is reset to a higher level which causes autonomous parathyroid gland activity
What is treatment of tertiary hyperparathyroidism
surgery
What condition often causes tertiary hyperparathyroidism
chronic kidney failure
What are the main causes of hypoparathyroidism
- surgery
- congenital deficiency - digeorge syndrome
- idiopathic hypoparathyroidism
What are the symptoms of hypoparathyroidism
- hand and feet parasthesia
- muscle cramps
- depression
- cardiac arrhythmias
What is Trousseau’s sign? What condition causes it?
Blood pressure cuff on arm causes carpopedal spasm due to tetany of muscles in hands
Hypocalcaemia/hypoparathyroidism
What would the elecrolytes show in hypoparathyroidism
hypocalcaemia
hyperphosphataemia
What are some causes of hypocalcaemia you should investigate
Hypoparathyroidism Acute pancreatitis Renal failure Vitamin D3 deficiency Alkalosis Rhabdomyolysis Drugs (eg bisphosphonates)
Does adrenal cortex insufficiency usually affect a specific layer?
It tends to affect the whole adrenal cortex rather than specific layers
What causes increased skin pigmentation in adrenal insufficiency?
increased ACTH levels
What effect does cortisol have on glucose
increases blood glucose levels
What triggers cortisol release
ACTH from the pituitary
What triggers aldosterone release
renin
What effect does aldosterone have
- increases sodium
- decreases potassium
- increases blood pressure
What does loss of aldosterone cause
- hyponatraemia
- hyperkalaemia
- hypovolaemia
- low blood pressure
- metabolic acidosis
What drugs are given in primary adrenal insufficiency?
hydrocortisone and fludrocortisone
What hormoen does fludrocortisone replace
aldosterone
What hormone triggers ACTH release
corticotrophin releasing hormone from the hypothalamus (CRH)
What are causes of primary adrenal insufficiency
- autoimmune (addisons)
- TB
- malignancy
What are symptoms of primary adrenal insufficiency
- fatigue
- confusion
- postural hypotension
- abdominal pain
- nausea and vomiting
- skin hyperpigmentation (especially around joints)
What are symptoms of an addisonian crisis
- back/abdo/leg pain
- vomiting and diarrhoea
- dehydration
- loss of consciousness
- hypotension
- hypoglycaemia
What is an addisonian crisis
When a trigger (often illness) causes chronic adrenal insufficiency to become acute
How is primary adrenal insufficiency diagnosed
- synthetic ACTH
* cortisol levels monitored do not increase with ACTH
What would be the issue if synthetic ACTH did trigger appropriate cortisol levels were observed?
secondary adrenocortical insufficiency
What is the most common cause of hypopituitarism
treatment for hyperpituitarism
What are some causes of hypopituitarism
- compression
- infarct
- haemorrhage
- tumour
What is treatment for hypopituitarism
hormone replacement with careful monitoring
What investigations are required for hypopituitarism
- cranial nerve exam (for any focal deficits caused by compression)
- CT/MRI head
- hormone levels
- stimulation tests
What is the most common cause of Cushing’s disease (if not taking cortisol)
pituitary adenoma
What are the possible causes of Cushing’s (if not on exogenous cortisol)
- pituitary adenoma
- paraneoplastic syndrome
- adrenal tumour
What investigations should be undertaken for Cushing’s
- CT/MRI head for pituitary adenoma
- PET-scan for other malignancies
- dexamethasone suppression test
What would results from a dexamethasone suppression test tell you?
- reduced ACTH indicates adrenal tumour
* elevated ACTH = pituitary adenoma or paraneoplastic syndrome and requires imaging
How is Cushing’s disease treated
surgery
What is a complication of surgery for Cushing’s disease pituitary adenoma?
panhypopituitarism
What is acromegaly
excessive growth after skeletal epiphyseal closure due to increased growth hormone
What usually causes acromegaly
benign pituitary adenoma
What causes morbidity and mortality in untreated acromegaly
- cardiovascular disease
- cerebrovascular disease
- malignancy
What are some symptoms of acromegaly
- sweating
- headache
- clothes fit tightly
- amenorrhoea or impotence
- deep voice and slow speech
What is the most common functioning adenoma of the anterior pituitary gland
prolactinoma
How do prolactinomas present in females
- oligomenorrhoea
- amenorrhoea
- infertility
- galactorrhoea
How do prolactinomas present in males
- headache
- visual field defect
- erectile dysfunction
Why would prolactinomas cause visual field defects?
compression of optic chiasm
What can be given as a test to suppress GH secretion
oral glucose
What is PCOS
a condition of hyperandrogenism, oligo-/an-ovulation, and polycystic ovaries
What causes PCOS
raised LH levels
What are symptoms of PCOS
- oligo/amenorrhoea
- hirsutism or male pattern baldness
- infertility
- obesity
- insulin resistance
What dermatological finding is associated with PCOS
acanothosis nigricans
What tests and results are diagnostic of PCOS
- increased LH:FSH ratio
- increased androstenedione levels
- 5 cysts found on ultrasound of ovaries
What are causes of gonadal failure in males
- Klinefelter
- cryptorchidism
- testicular torsion
What are causes of gonadal failure in females
- Turners
* autoimmune ovarian failure
What is Klinefelter’s?
46XXY
What is a phaeochromocytoma?
a rare cathecholamine-producing tumour of the adrenal medulla
What do phaeochromocytomas do?
secrete adrenaline and noradrenaline causing headaches and high blood pressure
Apart from the adrenal medulla, where might phaeochromocytomas occur?
the sympathetic ganglia beside the abdominal aorta
What is Conn’s syndrome
An adenoma causing hyperaldosteronism
What are the effects of hyperaldosteronism?
- hypernatraemia
- hypokalaemia
- fluid retention
- alkalosis
- hypertension
What triad of symptoms should make you suspicious of Conn’s?
- hypokalaemia
- hypertension
- alkalosis
What would be different in blood tests between hyperaldosteronism and renal artery stenosis?
renin would be raised in renal artery stenosis but low in hyperaldosteronism
