Endo Flashcards
How often is HbA1c checked?
Every 3-6 months until stable
Then 6 monthly
What are the target HbA1cs?
Lifestyle: <48mmol
Lifestyle + metformin: <48mmol
Otherwise: <53mmol
What is the metformin pathway of T2DM management?
- Metformin
- Metformin + gliptin/sulfonylurea/pioglitazone/SGLT2 inhibitor
- 3 of the above OR insulin
- Metformin + sulphonylurea + GLP-1 mimetic
What is the HbA1c threshold for adding another hypoglycaemic agent?
58mmol
What is the level of HbA1c dependent on?
Red blood cell lifespan
Average blood glucose concentration
Which conditions mean HbA1c is lower than expected?
Sickle cell
G6PD deficiency
Hereditary sphreocytosis
Which conditions mean HbA1c is higher than expected?
Vit B12/folic acid def
IDA
Splenectomy
(increased RBC lifespan)
How do you calculate the average plasma glucose from HbA1c?
2x HbA1c - 4.5
What is T2DM is a symptomatic patient?
Fasting glucose >7mmol
Random or post OGTT >11.1
What is T2DM in an asymptomatic patient?
FG>7 or random/post OGTT>11.1
On 2 separate occasions
What is impaired fasting glucose?
Fasting glucose 6.1-7mmol
What is impaired glucose tolerance?
Fasting glucose <7mmol AND
OGTT 2 hour value 7.8-11.1mmol
What can be added in T1DM patients with BMI over 25?
Metformin
Which is the first hormone secreted in response to hypoglycaemia?
Glucagon
What are the characteristics of MODY?
Patients younger than 25 years
Autosomal dominant
Lack of ketosis
Good response to sulfonylurea
What is the most common type of MODY?
MODY 3 - defect in HNF-1 alpha gene
What is MODY 3 associated with?
Increased risk of HCC
What is the pathophysiology of DKA?
Uncontrolled lipolysis which results in an excess of free fatty acids which are converted to ketone bodies
What is the diagnostic criteria of DKA?
Glucose >11mmol or known DM
pH<7.3
Bicarb<15
Ketones>3 or urine ketones +++
What is the management of DKA?
Fluid resuscitation +/- K
IV insulin 0.1IU/kg/hr
Once BM<15 - start 5% dextrose
What should happen with a patient’s normal insulins when in DKA?
Continue long acting insulin
Omit short acting insulin
When should a patient be switched to normal insulins post DKA?
Eating and drinking
After first meal
Name 5 complications of DKA.
Hypokalaemia Cerebral oedema Arrhythmias ARDS AKI
What is the pathophysiology of HHS?
Hyperglycaemia –> osmotic diuresis
Volume depletion –> raised serum osmolality –> hyperviscosity
electrolyte disturbances
What is the diagnostic criteria of HHS?
Hypovolaemia
Hyperglycaemia >30mmol without ketonaemia or acidosis
Raised serum osmolality >320mosmol/kg
What is the treatment of HHS?
IV 0.9% saline
Fixed rate insulin 0.05IU/kg/hr
What are the features of thyroid MALT lymphoma?
Painless goitre
Non-functional thyroid tumour
90% Hashimoto’s thyroiditis patients have which antibody?
anti-TPO
How does subacute De Quervain’s thyroiditis present?
Occurs following a viral infection
Typically presents with hyperthyroidism, painful goitre, raised ESR
How is De Quervain’s thyroiditis diagnosed?
Thyroid scintigraphy - globally reduced uptake of iodine-131
What is the treatment of De Quervain’s thyroiditis?
Self limiting
NSAIDs for pain
What are the biochemical abnormalities in non thyroidal illness?
Low TSH, low thyroxine, low T3
What is the most common type of thyroid cancer?
Papillary
What cell does medullary thyroid cancer originate from?
C cells (parafollicular) which produce calcitonin
Which syndrome is medullary thyroid cancer associated with?
MEN 2a and 2b
What is the treatment of papillary and follicular thyroid cancer?
Total thyroidectomy
Followed by radio-iodine I-131
Yearly thyroglobulin levels
Which antibodies are diagnostic of Graves’ disease?
TSH receptor stimulating antibodies (present in 90%)
What percentage of Graves’ patients have eye problems?
30%
What are other signs of Graves’ disease?
Pretibial myxoedema
Thyroid acropachy, which is a triad of: digital clubbing, soft tissue swelling of hands and feet, periosteal new bone formation
What percentage of Graves’ patients have positive anti-TPO and anti-thyroglobulin antibodies?
Anti-TPO: 75%
Anti-thyroglobulin: 30%
What is the cause of subclinical hyperthyroidism?
Excessive thyroxine
Multinodular goitre
What are risk factors for thyroid eye disease?
Smoking
Radio-iodine
What is the treatment of thyroid eye disease?
Steroids
Topical lubricants
Radiotherapy
What is the treatment of myxoedemic coma?
Hydrocortisone and levothyroxine
Treated as presumed adrenal insufficiency until ruled out
What are the features of MEN type 1?
Pancreatic endocrine tumours
Pituitary tumours
Primary hyperparathyroidism
What are the features of MEN type 2a?
Primary hyperparathyroidism
Phaeochromocytoma
Medullary thyroid cancer
RET oncogene
What are the features of MEN type 2b?
Marfinoid body habitus Neuromas Phaeochromocytoma Medullary thyroid cancer RET oncogene
What is the most common cause of primary hyperaldosteronism?
Bilateral idiopathic adrenal hyperplasia
What are the other causes of primary hyperaldosteronism?
Adrenal adenoma (Conn's) Adrenal carcinoma
What are the features of primary hyperaldosteronism?
Hypokalaemia
Hypertension
High aldosterone, low renin
How is bilateral adrenal hyperplasia differentiated from Conn’s syndrome?
CT abdomen
Adrenal vein sampling
What is the treatment of bilateral adrenocortical hyperplasia?
Spironalactone
What are the features of hypocalcaemia?
Tetany
Perioral paraesthesia
Chronic: depression, cataracts
What are Trousseau’s and Chvostek’s sign in hypocalcaemia?
Trousseau’s: carpal spasm if brachial artery is occluded
Chvostek’s: tapping over parotid causes facial muscles to twitch
What is seen on ECG in hypocalcaemia?
Prolonged QT
When is calcium chloride used in hypocalcaemia?
Haemodynamically unstable or liver failure
Gluconate must be hepatically metabolized before the calcium becomes available
What is the cause of secondary hyperaldosteronism?
High levels of renin
e.g. in nephrotic syndrome, heart failure, liver failure
How can you differentiate the hypertension and hypokalaemia in Cushing’s syndrome, bilateral renal artery stenosis, and Liddle syndrome?
Cushing’s: high aldosterone, low renin
Bilateral renal artery stenosis: high aldosterone, high renin
Liddle syndrome: low aldosterone, low renin
What is the threshold for chronic over acute hyponatraemia?
48 hours
What are the causes of hypovolaemic hyponatraemia?
Dehydration
Diuretic stage of renal failure
Diuretics
Addisonian crisis
What is the cause of euvolaemic hyponatraemia?
SIADH
What is the cause of hypervolaemic hyponatraemia?
Heart failure
Liver failure
Nephrotic syndrome
What is the treatment of chronic hyponatraemia?
Hypovolaemic: isotonic saline
Euvolaemic: fluid restrict 500-1000ml/day, consider demeclocycline/vaptans
Hypervolaemic: fluid restrict 500-1000ml/day, consider loop diuretics/vaptans
What happens if sodium falls after administration of isotonic saline in hyponatraemia?
Suggests SIADH
What is the treatment of acute hyponatraemia with severe symptoms?
3% NaCl
What is a complication of treating hyponatraemia?
Osmotic demyelination syndrome/cerebral pontine myelinolysis
How do vaptans work in hyponatraemia?
Act on V1 and V2 receptors causing vasoconstriction and selective water diuresis
What are the irreversible symptoms of cerebral pontine demyelinosis?
Dyarthria Dysphagia Quadraparesis Seizures Coma
How does demeclocycline work in SIADH?
Inhibits G-protein coupled receptor signalling downstream of ADH binding to the renal vasopressin V2 receptors
Thus inducing nephrogenic diabetes insipidus
What is the management of SIADH?
Mild: fluid restrict
Mod/sev: IV 3% hypertonic saline
Resistant: demeclocycline
What metabolic abnormality is seen in Cushing’s syndrome?
Hypokalaemic metabolic alkalosis
How is Cushing’s syndrome diagnosed?
Overnight dexamethasone suppression test - morning cortisol not suppressed
High 24 urinary free cortisol
In Cushing’s syndrome, how is a non ACTH-dependent cause diagnosed?
Suppressed ACTH in 9am and midnight plasma ACTH and cortisol levels
What are the results of CRH stimulation in pituitary and adrenal/ectopic sources of Cushing’s syndrome?
Pituitary: cortisol rises
Adrenal/ectopic: no change in cortisol
How is ACTH pituitary adenoma diagnosed?
High dose dexamethasone test
Cortisol and ACTH suppressed
Why is eplenerone less likely to cause gynaecomastia than spironalactone?
Eplenerone does not inhibit free testosterone binding to androgen receptors on breast tissue
Why does prednisolone cause neutrophilia?
Demargination of neutrophils via the endovascular lining
Delayed migration of neutrophils into tissue
Releases of immature neutrophils from bone marrow
What are 5 causes of hypoadrenalism?
TB Metastases Waterhouse-Friderichsen syndrome HIV Anti-phospholipid syndrome
What are the features of Addison’s?
N+V, weakness, weight loss Hyperpigmentation Vitiligo Low Na and High K Loss of pubic hair and libido secondary to androgen deficiency Hypotension and hypoglycaemia
How is Cushing’s disease differentiated from pseudo-Cushing’s?
Insulin stress test
In normal pituitary function, GH and cortisol should rise
What is the pathophysiology of PCOS?
Hyperinsulinaema
High levels of LH
How does empty sella syndrome present?
Symptoms of hypopituitarism
Hypokalaemia and normotension are seen in which syndromes?
Gitelman’s
Bartter’s
What are 6 causes of raised prolactin?
Pregnancy Prolactinoma Physiological PCOS Primary hypothyroidism Phenothiazines, metoclopramide, domperidone
What are the causes of hypertriglyceridaemia?
DM Obesity Alcohol CKD Thiazides, BB, unopposed oestrogen Liver disease
What are the causes of hypercholesterolaemia?
Nephrotic syndrome
Cholestasis
Hypothyroidism
What is the inheritance of androgen insensitivity syndrome?
X-linked recessive
What is the pathophysiology of androgen insensitivity syndrome?
End-organ resistance to testosterone
Genotypically male children have a female phenotype
What are the features of androgen insensitivity syndrome?
Primary amenorrhoea
Undescended testes
Breast development may occur as a result of conversion of testosterone to oestradiol
How is phaeochromocytoma diagnosed?
24h urinary metanephrinesW
What are the causes of primary hyperparathyroidism?
80% solitary adenoma
15% hyperplasia
4% multiple adenoma
1% carcinoma
Why does peptic ulceration and hypertension occur in primary hyperparathyroidism?
Hypercalcaemia
Ca stimulates gastrin release
Ca causes vasoconstriction
What are the biochemical results seen in primary hyperparathyroidism?
High Ca
High-normal PTH
Low PO4
When is surgery indicated in primary hyperparathyroidism?
Symptomatic
Calcium>2.85
End organ disease
What are the causes of secondary hyperparathyroidism?
CKD - lack of vit D hydroxylation by kidneys
Vit D deficiency
What are the biochemical abnormalities seen in secondary hyperparathyroidism?
Low-normal Ca
High PTH
High PO4
Low Vit D
What is the treatment of secondary hyperparathyroidism?
Phosphate binders
Calcium/vit D supplementation
What are the manifestations of renal bone disease?
Osteitis fibrosa cystica
Osteomalacia
Osteoporosis
What are the biochemical abnormalities seen in tertiary hyperparathyroidism?
High-normal Ca High PTH Low-normal PO4 Low-normal Vit D High ALP
What is the treatment of tertiary hyperparathyroidism?
Parathyroidectomy
How is benign familial hypocalciuric hypercalcaemia diagnosed?
Urine calcium: creatinine clearance ratio <0.01
Where is growth hormone secreted?
Somatotroph cells of anterior pituitary
What stimulates and inhibits secretion of growth hormone?
Stimulated: GnRH pulses from hypothalamus, sleep, exercise
Inhibits: glucose, somatostatin
How is acromegaly diagnosed?
Serum IGF-1 with serial GH measurements
OGTT confirms diagnosis if IGF-1 raised
What is the management of acromegaly?
Trans-sphenoidal surgery
Somatostatin analogue octreotide or SC pegvisomant (GH receptor antagonist)
What are 4 complications of acromegaly?
HTN
Diabetes
Cardiomyopathy
Colorectal Ca
What are the features of insulinoma?
Hypoglycaemia
Weight gain
How is insulinoma diagnosed?
High insulin
Raised proinsulin:insulin ratio
High C peptide
72 hour fast
When is metformin contraindicated?
eGFR<45
What are the side effects of metformin?
Diarrhoea
Lactic acidosis
Which class of hypoglycaemics are used for patients with an erratic lifestyle?
Meglitinides
How do sulfonylureas lower blood glucose?
Bind to beta cell receptors
(Close K channel –> depolarises cell –> opens VG Ca channels –> increases intracellular Ca)
Leads to insulin secretion
Also stimulates glycolytic pathway
What are the side effects of sulfonyureas?
Weight gain Severe hypos Teratogenic SIADH Bone marrow suppression
How do meglitinides such as repaglinide work?
Increase pancreatic insulin secretion by blocking K channel of beta cells
Which diabetes drug is an agonist to the PPAR-gamma receptor (controls adipocyte differentiation and function) therefore reduces peripheral insulin resistance?
Pioglitazone
What are the side effects of pioglitazone?
Weight gain Increased fracture risk Fluid retention liver impairment Bladder Ca
What is the mechanism of action of DPP-4 inhibitors such as sitagliptin?
Increases insulin, lowers glucagon
Reduce the peripheral breakdown of incretins such as GLP-1
Which DPP-4 inhibitor is linked with ischaemic heart disease?
Saxagliptin
What is GLP-1?
A hormone released by small intestine in response to PO glucose load
How do GLP-1 mimetics work?
Activate GLP-1 receptor to increase insulin, lower glucagon, slow gastric emptying
What is a favourable feature of GLP-1 mimetics and SGLT-2 inhibitors?
Prevent weight gain/lose weight
What are the side effects of GLP-1 mimetics such as exenatide?
GI disturbance
Acute pancreatitis
How do SGLT-2 inhibitors work?
Reduce glucose reabsorption in PCT by reversibly inhibiting sodium-glucose co-transporter 2
What are the side effects of canagliflozin?
Genital thrush –> Fournier’s gangrene
Increased risk of euglycaemic ketoacidosis
Increased risk of lower limb amputation