Endocrinology Flashcards
Which hormone is elevated in cushing’s syndrome?
cortisol
What are the features of cushing’s syndrome?
Round "moon" face Central obesity Abdominal striae Buffalo hump Proximal limb weakening
What are the causes of cushing’s?
Exogenous steroids
Cushing’s disease
Adrenal adneoma
Paraneoplastic cushing’s
Which test is used to diagnose Cushing’s
Dexamethasone suppression test
What is the result of the low dose dexamethasone suppression test in Cushing’s?
1mg of dexamethasone is given at night. In healthy people this should suppress the early morning spike of cortisol, in cushing’s it does not
What does the different results of the high dose dexamethasone suppression test mean?
8mg of dexamethasone is given.
In cushing’s disease (pituitary adenoma) this is enough to cause negative feedback and suppress the cortisol
In adrenal adenoma the cortisol is not suppressed but the ACTH is suppressed due to negative feedback
Where there is ectopic ACTH (eg SCLC) neither cortisol or ACTH are supressed because the ACTH release is independent of the hypothalamus
What investigations can be done for cushing’s disease?
Dexamethasone suppression test
24 hour urinary free cortisol
FBC
MRI brain, Chest CT, Abdo CT for tumours
What is the management of cushing’s disease?
Trans-sphenoidal removal of pituitary adenoma
Surgical removal of adrenal tumour
Surgical removal od tumour producing ACTH
What is addison’s disease?
Adrenal glands have been damaged which results in a reduction in the secretion of cortisol and aldosterone. This is primary adrenal insufficiency
What is secondary adrenal insufficiency?
There is inadequate ACTH. It is a problem in the pituitary gland
What is tertiary adrenal insufficiency?
Inadequate CRH release by the hypothalamus. Usually the result of patients being on long term oral steroids
What are the features of adrenal insufficiency?
Fatigue nausea Cramps Abdominal pain Bronze hyperpigmentation Hypotension
What is seen on blood tests in adrenal insufficiency?
Hyponatraemia
Hyperkalaemia
ACTH is high in primary and low in secondary
Which autoantibodies are present in adrenal insufficiency?
Adrenal cortex antibodies
21-hydroxylase antibodies
What is the test used to assess for adrenal insufficiency?
The short synacthen test
Give synacthen (synthetic ACTH) which would stimulate healthy adrenal glands to produce ACTH
What is the management of adrenal insufficiency?
Replace the steroids. Hydrocortisone to replace cortisol and fludrocortisone to replace aldosterone
What are the sick day rules for steroid therapy?
Double when ill
What is the presentation of an addisonian crisis?
Reduced consciousness
Hypotension
Hypoglycaemia, hyponatraemia and hyperkalaemia
What is the management of an addisonian crisis?
Intensive monitoring
Steroids
IV fluids
Correct hypoglycaemia
What are TSH and T3/4 levels in hyperthyroidism?
TSH= Low T3/4= high
What are TSH and T3/4 levels in primary hypothyroidism?
TSH= high T3/4= low
What are TSH and T3/4 levels in secondary hypothyroidism?
TSH= low T3/4= low
What antibodies are present in thyroid disease?
Anti- TPO (graves and hashimotos)
Anti-thyroglobulin antibodies (graves and hashimotos)
TSH receptor antibodies (graves)
What can a radioisotope scan show of the thyroid?
Diffuse high uptake= graves
Focal high uptake= toxic multinodular
Cold= cancer
What is plummer’s disease?
Toxic multinodular goitre
What is exophthalmos a sign of?
Grave’s disease
Which antibody causes grave’s disease?
TSH receptor antibodies
What are signs of grave’s disease?
Anxiety and irritability Sweating tachycardia weightloss Fatigue Frequent loose stools Diffuse goitre Exophthalmos Pretibial myxoedema
What is de Quervain’s thyroiditis?
Presents with a viral fever, neck pain, dysphagia and tenderness. There is a hyperthyroid phase and then a hypothyroid phase. It is a self limiting condition which can be managed with NSAIDs for pain and beta blockers for the features of thyroiditis
How does thyroid storm present?
Hyperthyroidism, pyrexia, tachycardia and delierium
How is thyroid storm managed?
Fluid resus
Anti-arrythmic meds
beta blockers
How is hyperthyroidism managed?
Carbimazole (either titration block or block and replace regime)
Propylthiouracil is 2nd line
Radio iodine
Beta-blockers for symptom relief
Surgery is definitive
Which antibodies are associated with hashimotos thyroiditis?
Anti-TPO and antithyroglobulin antibodies
Which medications can cause hypothyroidism?
Lithium
Amiodarone
Whats is the presentation of hypothyroid disease?
Weight gain Fatigue Dry skin Coarse hair and hair loss Fluid retention heavy or irregular periods Constipation
What is the management of hypothyroid disease?
levothyroxine
What is the ideal concentration of glucose in the blood?
Between 4.4 and 6.1mmol/l
What are the 3 main problems in DKA?
Ketoacidosis Dehydration Potassium imbalance (serum potassium high, whole body potassium low)
What is a possible adverse effect of insulin therapy in DKA?
severe hypokalaemia leading to arrythmias
How does diabetic ketoacidosis present?
Polyuria Polydipsia N&V Acetone smell to breath Dehydration and hypotension Altered consciousness
How is DKA diagnosed?
Hyperglycaemia
Ketosis
Acidosis
How is DKA managed?
FIG-PICK F-fluids I-insulin (actrapid 0.1 unit/kg/hour) G-glucose P-potassium I-infection C-chart fluid balance K-ketone monitoring
What is the general rule regarding potassium infusion?
Dont infuse at a rate of >10mmol/hour
Why should diabetic patients cycle their injection sites?
Injecting into the same spot can cause lipodystrophy where the subcutaneous fat hardens and the patients cannot absorb insulin properly
What are the typical symptoms of hypoglycaemia?
Tremor, sweating, irritabilty, dizziness and pallor
What are the management options for hypoglycaemia?
If mild, rapid acting glucose such as lucozade and slower acting carbohydrates
If severe, IV dextrose and intramuscular glucagon
How often should HbA1c be measured?
every 3-6 months
When should type 1 diabetics measure their blood sugar?
Waking, at each meal and before bed
What is the pathophysiology (simplified) of type 2 diabetes?
Repeated exposure to glucose and insulin makes cells resistant to the effects of insulin. Beta cells become damaged by producing so much insulin that they start to produce less. This leads to chronic. hyperglycaemia
How is an oral glucose tolerance test undertaken?
Take a fasting plasma glucose level, give 75g glucose drink then measure the plasma glucose 2 hours later
What is the HbA1c range for pre-diabetes?
42-47mmol/mol
What is the impaired fasting glucose range for pre-diabetes?
6.1-6.9 mmol/l
What is the HbA1c level for a diabetes diagnosis?
> 48mmol/mol
What is the random glucose level for a diagnosis of diabetes?
> 11mmol/l
What is the fasting glucose level for a diagnosis of diabetes?
> 7mmol/l
What is the OGTT level for a diagnosis of diabetes?
> 11mmol/l
What is the HbA1c target for a new type 2 diabetic?
48mmol/mol
What is the HbA1c target for diabetics who are beyond metformin treatment?
53mmol/mol
What is the first line treatment for diabetes?
Metformin titrated from 500mg OD as tolerated
What is the second line treatment for diabetes?
Metformin +
Sulfonylurea, pioglitazone, DPP-4 inhibitor and SGLT-2 inhibitor
What is third line treatment for diabetes?
Triple therapy with metformin or metformin and insulin
What type of drug is metformin?
Biguanide
What effect does metformin have on weight?
It is considered to be a weight neutral drug so does not effect a patient’s weight
What are the notable side effects of metformin?
Diarrhoea and abdo pain
Lactic acidosis
What kind of drug is pioglitazone?
Thiazolidinedione
What are the notable side effects of pioglitaozne?
Weight gain Fluid retention Anaemia Heart failure Extended use may increase the risk of bladder cancer
What is the most common sulfonylurea?
Gliclazide
What are the notable side effects of sulfonylureas?
Weight gain
Hypoglycaemia
Increased risk of CVD and MI
What is the most common DPP-4 inhibitor?
Sitagliptin
What are the notable side effects of DPP-4 inhibitors
GI upset
Symptoms of upper respiratory tract infection
Pancreatitis
What is a common GLP-1 mimetic?
Exanatide
What are the notable side effects of GLP-1 mimetics?
GI tract upset
Weight loss
dizziness
Hypoglycaemia
What is a common SGLT-2 inhibitor?
Empagliflozin
What are notable side effects of SGLT-2 inhibitors?
Glucoseruria
Weight loss
DKA
Lower limb amputation
Name 3 rapid acting insulins
Novorapid
Humalog
Apidra
Name 3 short acting insulins
Actrapid
Humalin S
Insuman Rapid
Name 3 long acting insulins
Lantus
Levemir
Degludec
Name 3 combination glucose
Humalong 25
Humalog 50
Novomix 30
What causes acromegaly?
Excessive growth hormone most commonly due to unregulated hormone secretion by a pituitary adenoma
Which visual field defect can occur in acromegaly?
Bitemporal hemianopia
What are the presenting features of acromegaly?
Prominent forehead and brow Large nose, tongue, hands and feet Arthritis HTN Hypertrophic heart Type 2 diabetes Colorectal cancer
Which investigations should be done for acromegaly?
Insulin like growth factor
OGTT
MRI brain
What is the management for acromegaly which is caused by a pituitary adenoma?
Trans-sphenoidal surgical removal
Which medications can be used to block growth hormone?
Pegvisomant
Somatostatin analouges
Dopamine agonists
Which cells produce parathyroid hormone?
Chief cells
How does parathyroid hormone raise blood calcium levels?
Increases osteoclast activity
Increases calcium absorption from the gut
Increases calcium
Increasing vitamin D activity
What are the symptoms of hypercalcaemia?
Renal stones
Painful bones
Abdominal groans (N+V. constipation)
Psychiatric moans (depression, psychosis and fatigue)
What causes primary hyperparathyroidism?
Uncontrolled parathyroid hormone
PTH=high
Calcium= high
What causes secondary hyperparathyroidism?
Insufficient vitamin D, chronic renal failure which causes hyperplasia of the parathyroid glands
PTH=high
Calcium= low
What is the role of aldosterone?
It is a mineralcorticoid
Increases sodium reabsorption for the distal tubule
Increases potassium secretion from the distal tubule
Increases hydrogen secretion from the collecting ducts
What is conn’s syndrome?
Primary hyperaldosteronism. Adrenal glands produce too much aldosterone which causes low serum renin
What causes secondary hyperaldosteronism?
Excessive renin stimulates the adrenal gland to produce more aldosterone
What is the main cause for excessive renin production
The BP in the kidneys is significantly lower than in the rest of the body. Usually due to renal artery stenosis
What are the investigations for hyperaldosteronism?
Renin/aldosterone ratio:
High aldosterone, low renin= primary
High aldosterone, high renin= secondary
Hypokalaemia and alkalosis on bloods
What is the management of hyperaldosteronism?
Aldosterone antagonists: eplerenone and spironolactone
Treat the underlying cause (surgical removal of adenoma or renal artery angioplasty)
What is the role of ADH?
Stimulates water reabsorption from the collecting ducts of the kidneys
what electrolytes changes are caused by SIADH?
euvolaemic hyponatraemia
What are the symptoms of SIADH?
Headache Fatigue Muscle aches and cramps Confusion Severe hyponatraemia
What are some causes of SIADH?
Post op
Infection
Head injury
Malignancy (SCLC)
How is SIADH diagnosed?
It is a diagnosis of exclusion
How is SIADH managed?
Correct sodium slowly to prevent central pontine myelinolysis
Fluid restriction
Tolvaptan (ADH receptor blockers)
What causes diabetes insipidus?
Lack of ADH, lack of response to ADH
Can be nephrogenic or cranial
What are causes of nephrogenic diabetes insipidus?
Drugs (lithium)
Intrinsic kidney disease
Electrolyte disturbances
What are causes of cranial diabetes insipidus?
Hypothalamus does not produce ADH
Brain tumours
head injury
brain infections
brain surgery or radiotherapy
What is the presentation of diabetes insipidus?
Polyuria
Polydipsia
Hypernatraemia
What investigation results would be indicative for diabetes insipidus?
Low urine osmolality
High serum osmolality
water deprivation test
How does the water deprivation test diagnose diabetes insipidus
Patient is deprived of water for 8 hours, urine osmolality is measures. Synthetic ADH is provided and urine osmolality is measured again after 8 hours
Cranial= low after deprivation, high after ADH
Nephrogenic= low and low
Primary polydipsia= high and high
How is diabetes insipidus managed?
Desmopressin
What is a phaeochromocytoma?
A tumour of the chromaffin cells which secretes unregulated and excessive amounts of adrenaline
How is phaeochromocytoma diagnosed?
24 hour urine catecholamines
Plasma free metanephrines (breakdown product of adrenaline
What are the symptoms of phaeochromocytoma?
Anxiety Sweating Headache HTN Palpitations
What is the management of phaeochromocytoma?
Alpha blockers
Beta blockers
Adrenalectomy
