Endocrine Flashcards
What hormones are produced by the anterior pituitary
TSH
ACTH
FSH
LH
GH
Prolactin
What hormones are produced by the posterior pituitary
Oxytocin
ADH
Describe hypothalamic pituitary thyroid axis
Hypothalamus - thyrotropin-releasing hormone
Pituitary - Thyroid stimulating hormone
Thyroid - T3 + T4
Negative feed back
Actions of cotrisol
Inhibit immune system
Inhibit bone formation
Raises blood glucose
Increases metabolism
Increases alertness
Actions of growth hormone
Stimulate muscle growth
Increases bone density and strength
Stimulates cell regeneration and reproduction
Stimulates growth of internal organs
Actions of PTH
Increases serum calcium
Increases the activity and number of osteoclasts - causing bone reabsorption
Increases calcium reabsorption in kidneys
Activeates vitamin D in the kidneys - promotes calcium absorption from the small intestine.
Actions of aldosterone
Increases intravascular volume
Increase sodium reabsorption from the distal tubule
Increases potassium secretion from distal
Increase hydrogen secretion from collecting
Define Cushing’s Syndrome
Refers to the signs and aymptoms that develop after prolonged abnormal elevation of cortisol
Define Cushing’s Disease
Refers to specific pituitary adenoma that secretes excess ACTH.
Features of Cushing’s syndrome
Round moon face
Central obesity
Abdominal striae
Buffalo hump
Proximal limb muscle wasting
Hypertension
Cardiac hypertrophy
Hyperglycaemia
Depression
Insomnia
Osteoporosis
East bruising
Common causes of Cushing’s syndrome
Exogenous steroids
Cushing’s disease
Adrenal adenoma
Paraneoplastic - SCLC
Investigations in Cushing’s Syndrome
Overnight dexamethasone suppression test
Define adrenal insufficiency
Where the adrenal glands do not produce enough steroid hormones, particularly cortisol and aldosterone.
Define Addison’s disease
Primary adrenal insufficiency
Autoimmune condition resulting in damage to the adrenal gland.
Define secondary adrenal insufficiency
Inadequate ACTH stimulating the adrenal gland
Pituitary dysfunction removal, infection, loss of blood supply in radiotherapy.
Sheehan’s - Blood loss in child birth causes pituitary necrosis
Define tertiary adrenal insufficiency
Inadequate CRH release by hypothalamus
Long term oral steroids
History of adrenal insufficiency
Fatigue
Nausea
Cramps
Abdominal pain
Reduced libido
Clinical signs of adrenal insufficiency
Bronze hyperpigmentation - ACT stimulates melanocytes, particularly in skin creases
Hypotension - particularly postural
Investigations in adrenal insufficiency
Short synacthen test!
UE - hyponatraemia, hyperkalaemia
Early morning cortisol
ACTH leve
Auto antibodies
CT/MRI
MRI pituitary
Management of adrenal insufficiency
Steroid replacement
Hydrocortisone - glucocorticoid replacing cortisol
Fludrocortisone - mineralocorticoid replacing aldosterone
Define Addisonian crisis
Term used to describe the acute presentation of severe addisons, absence of steroid hormones leads to life threatening presentation
History of Addisonian crisis
Reduced conscious
Hypotension
Hypoglycaemia, hyponatraemia, hyperkalaemia
Very sick
First presentation of Addison’s, or infection, trauma.
Management of Addisonian crisis
Parenteral steroids
IV fluid resuscitation
Correct electrolytes and glucose
Thyroid function test in hyperthyroidis,
TSH - Low
T3+4 - High
Thyroid function test in hypothyroidism
Primary
TSH - High
T3+4 - Low
Secondary
TSH - Low
T3+4 - Low
What antibodies are present in Grave’s disease
anti-TPO Antibodies
Antithyroid perocidase
Define hyperthyroidism
Where there is overproduction of thyroid hormone
Define thyrotoxicosis
Refers to abnormal and excessive quantity of thyroid hormone in the body
Define primary hyperthyroidism
Hyperthyroidism due to thyroid pathology
Define secondary hyperthyroidism
Thyroid producing too much hormone as a result of overstimulation
Pathology in the hypothalamus or pituitary
Most common cause of hyperthyroidism
Graves disease
Define graves disease
Autoimmune condition where TSH receptor antibodies cause primary hyperthyroidism.
Clinical signs of Grave’s disease
Exophthalmos - bulging eyes
Pretibial myxoedema
Grave’s eye disease
Diffuse goitre - not nodular
History of hyperthyroidism
Anxiety and irritability
Sweating and heat intolerance
Tachycardia
Weight loss increased appetite
Fatigue
Frequent loose stool
Sexual dysfunction
Unique features of toxic multinodular goitre
Goitre with firm nodules
Over 50
Not graves
Define De Quervain’s thyroiditis
Describes the presentation of a viral infection with fever, neck pain and tenderness, dysphagia and features of hyperthyroidism
Hyperthyroid followed by hypo due to negative feed back.
Management of De Quervain’s thyroiditis
Self limiting
NSAIDs and beta blockers
Presentation fo thyrotoxicosis
Pyrexia
Tachycardia
Deliriu,
Management of thyrotoxicosis
As hyperthyroidism
Fluid resuscitation
Anti-arrhythmics and beta blockers
Management of hyperthyroidism
Carbimazole carful titration to normal levels or to block and replace
Radioactive iodine - taken up by thyroid and radiation destroys it
Levothyroxine replacement
Propranolol for symptoms
Surgery - remove nodules
Common causes of hypothyroidism
Hashimoto’s thyroiditis - anti-TPO antibodies
Iodine deficiency
Iatrogenic
Medication - lithium, amiodarone
Hypopituitarism - tumours, infection, vascular, radiation
Features of hypothyroidism
Weight gain
Appetite reduction
Fatigue
Dry skin
Coarse hair and hair loss
Fluid retention
Heavy or irregular periods
Constipation
Investigations in hypothyroidism
TSH and T3+4
CT
Management of hypothyroidism
Levothyroxine
Define type 1 diabetes mellitus
A disease where the pancreas stops being able to produce insulin. May be genetic, linked to Viruses (coxsackie B + enterovirus).
As a result of no insulin being produced there is a constant state of hyperglycaemia.
Define diabetic ketoacidosis
A state of hyperglycaemia with ketosis and acidosis.
As cells have no fuel they undergo ketogenesis, this leads to acidosis.
So hyperglycaemic that glucoses is excreted in urine, taking with it a lot of water resulting in dehydration.
Insulin drives potassium into cells - common complication of starting treatment
History of DKA
Polyuria
Polydipsia
Nausea and vomiting
Acetone breath - pear drops
Dehydration
Altered consciousness
Diagnosis of DKA
Hyperglycaemia - >11
Ketosis - Blood >3
Acidosis - pH <7.3
Management of DKA
FIG-PICK
Fluids!!!
Insulin
Glucose - monitor and add when below roughly 14
Potassium - monitor and replace
Infection - treat underlying cause
Chart - fluid balance
Ketones
Management of T1DM
Sub cu insulin
Monitoring glucose intake and BMs
History of hypoglycaemia
Tremor
Sweating
Irritable
Dizziness
Pallor
Reduced consciousness
Management of hypoglycaemia
100ml of 20% glucose over 5 minutes
Macrovascular complications of T1DM
Coronary artery disease
Peripheral ischaemia - ulcers
Stroke
HTN
Microvascular complications of T1DM
Peripheral neuropathy
Retinopathy
Kidney disease - glomerulosclerosis
Define type two diabetes mellitus
Repeat exposure to glucose and insulin leads to resistance, requiring progressively more insulin putting strain on the pancreas. This leads to chronic hyperglycaemia
Risk factors for TIIDM
Age
Black, Chinese, south Asian
FH
Obesity
Sedentary lifestyle
High carbohydrate
History of TIIDM
Fatigue
Polydipsia and polyuria
Unintentional weight loss
Opportunistic infection
Slow healing
Glucose in urine
Investigations in TIIDM
OGTT
HbA1c
Random glucose
Fasting glucose
Numbers for diabetes diagnosis on OGTT, HbA1c, Random and fasting glucose
OGTT >11
Random glucose >11
Fasting glucose >7
HbA1c >48 (>42 for prediabetes)
Management of TIIDM
Lifestyle - exercise and weightless
Metformin
Then pioglitazone
Define acromegaly
Clinical manifestation of excessive growth hormone, most often caused by pituitary adenoma.
What visual defect is often seen in acromegaly
Bitemporal hemianopia
History of acromegaly
Headaches + visual field defects - space occupying
Arthritis
Largeness
Sweating
Clinical signs of acromegaly
Frontal bossing - forehead and brow
Large nose
Macroglossia - tongue
Large hands and fee
Prognathism- protruding jaw
Hypertrophic heart
Hypertension
TIIDM
Colorectal cancer
Skin tags
Investigations in acromegaly
Insulin-like growth factor
Oral glucose tollerance test
MRI head
Opthamology
Management of acromegaly
Trans-sphenoidal removal of pituitary tumour
Somatostatin analogues to block GH release,
Define hyperparathyridism
Overproduction of parathyroid hormone.
Actions of parathyroid hormone
Raise blood calcium
Increase osteoclast activity - broken down and reabsorbed
Increase absorption in gut
Increase reabsorption
Activate vit D
Presentation of hypercalcaemia
Renal stones, painful bone, abdominal groans and psychiatric moans.
Nausea and vomiting
Fatigue
Depression
Psychosis
Causes of primary hyperparathyroidism
Tumour of the parathyroid gland.
Causes of secondary hyperparathyroidism
Insufficient vit D
Chronic renal failure
Something causing hypocalcaemia - more parathyroid created in feed back
Define Conn’s syndrome
Adrenal adenoma secreting aldosterone
Define primary hyperaldosteronism
Adrenal glands secrete too much aldosterone, also causing low renin
Causes of primary hyperaldosteronism
Bilateral adrenal hyperplasia
Conn’s syndrome
Familial - type 1 and 2
Adrenal carcinoma
Define secondary hyperaldosteronism
Excessive renin stimulates the adrenal glands to produce more aldosterone
Causes of secondary hyperaldosteronism
Renal artery stenosis
Renal artery obstruction
Heart failure
Investigations in hyperaldosteronism
Renin aldosterone ration
Blood pressure
UEs - hypokalaemia
Gas - alkalosis
CT/MRI - tumour
Renal doppler
Management of hyperaldosteronism
Aldosterone antagonists = eplerenone, spironolactone
Remove tumour
Renal artery angioplasty
Define syndrome of inappropriate Anti-Diuretic hormone
A condition where the is inappropriately high amounts of ADH
Action of ADH
Secreted by the posterior pituitary glad and cause reabsorption of water in the collecting ducts - causing increase in blood volume and pressure
History of SIADH
Headache
Fatigue
Muscle aches and cramps
Confusion`
?seizures and reduced consciousness
Causes of SIADH
Posterior pituitary secretes too much
Post operative
Infection - lung abscess and atypical pneumonia
Head injury
Medication - thiazides, carbamazepine, vincristine, cyclophosphamide, antipsychotics, SSRIs, NSAIDs
Malignancy - Small cell lung cancer
Meningitis
Investigations of SIADH
Diagnosis of exclusion
Euvolemic with hyponatraemia
Urine osmolality will be high - lots of salt very concentrated
CXR
CT TAP
MRI head
Negative short synacthen test - rule out adrenal insufficiency
No diuretic use
No diarrhoea
No excessive water intake
No kidney disease or AKI
Management of SIADH
Correct sodium slowly to prevent central pontine myelinolysis
Less than 10mmol/L per 24hours
Define diabetes insipidus
Lack of ADH or response to ADH
Prevents the kidneys from being able to concentrate urine, leading to polyuria and polydipsia.
Define nephrogenic diabetes insipidus
When the collecting ducts do not respond to ADH
Causes of nephrogenic diabetes insipidus
Drugs - lithium
Mutations in AVPR2 gene - X linked
Intrinsic kidney disease
Electrolyte disturbance
Define cranial diabetes insipidus
When the hypothalamus does not produce ADH for the pituitary gland to secrete
Causes of cranial diabetes insipidus
Brain tumours
Head injury
Brain malformation
Brain infections - meningitis, encephalitis, TB
Brain surgery or radiotherapy
History of diabetes insipidus
Polyuria and polydipsia
Dehydration
Postural hypotension
Hyponatraemia
Investigations in diabetes insipidus
Low urine osmolality - low salt concentration high water
High serum osmolality - lots of salt
Water deprivation test - desmopressin
Fluid deprivation test results
No fluids 8 hours urine osmolality, desmopressin then urine osmolality again in 8 hours
Cranial - initialy low osmolality and then high
Nephrogenic - low before and after
Primary polydipsia - high initially
Management of diabetes insipidus
Treat causes
Desmopressin if cranial
Define phaeochromocytoma
A tumour of the chromaffin cells (adrenalin producing cells), that secretes unregulated amounts of adrenaline. Adrenaline is a catecholamine that stimulates the sympathetic nervous system.
Causes of pheochromocytoma
25 % familial and associated with MEN 2
Patterns of tumour
10% bilateral
10% cancerous
10% outside adrenal gland.
Investigations of phaeochromacytoma
24 hour catecholamines
Plasma free metanephrines (breakdown product of adrenaline - longer half life)
History of phaeochromocytoma
Anxiety
Sweating
Headache
Hypertension
Palpitations, tachycardias
Paroxysmal AF
Management of pheochromocytoma
Alpha blockers - phenoxybenzamine
Beta blockers
Adrenalectomy
