Endocrinology Flashcards
function of the endocrine system?
coordinate and integrate cellular activity within the whole body regulating cellular and organ function throughout life and maintaining homeostasis.
Hormones are ?? produced by ??. They are released into the ?? and travel to their target. Hormones act by binding to ? receptors. Hormone levels are regulated through ? mechanisms
chemical messengers
endocrine glands
blood stream
specific
feedback
? is the control centre of the release of many hormones in the body. It can detect low or high levels of endocrine hormones in the blood stream and regulates them using ??.
hypothalamus
negative feedback
Low hormone levels -> hypothalamus produces the corresponding ? hormone which acts on the ??. which produces and secretes the corresponding ? hormone which acts on the target organ gland and stimulates hormone production. Once levels have returned to normal this stimulates the hypothalamus and pituitary to stop producing ? and ? hormones
releasing
pituitary gland
stimulating
releasing
stimulating
what is primary endocrine dysfunction?
dysfunction in the secreting gland
in primary endocrine dysfunction
Hormone overproduction is caused by ?? and ???
Hormone underproduction is caused by ?? and ???
autoimmune disease
exocrine gland tumour
autoimmune disease
drug side effects
what is secondary endocrine dysfunction?
failure of hypothalamus-pituitary control
what are the two types of pituitary tumour?
functional adenomas - secretes hormone
non-functional adenomas - can’t secrete hormones but if big enough can put pressure on pituitary glandular tissue preventing secretion of stimulating hormones
how are pituitary tumours removed?
trans-sphenoidal approach through nasal passage and sphenoidal sinus, its minimally invasive and has a fast recovery
what is hypothalamic dysfunction caused by?
brain tumours
brain surgery/radiotherapy
trauma
congenital disorders
what is growth hormone function?
growth and metabolism
growth hormone
Hypothalamus produces ????, anterior pituitary in response produces growth hormone. GH acts on the liver, bones and muscles to produce ????
growth hormone releasing hormone
insulin-like growth factor 1 (IGF-1)
how is growth hormone assessed in blood tests?
measure IGF-1
what does insufficient growth hormone lead to?
Growth failure in children, metabolic changes (increased fat) in adults
what does excessive growth hormone lead to?
Children - gigantism
Adults - acromegaly
what is the most common cause of acromegaly?
benign pituitary tumour
dental implications of acromegaly 5
Ill-fitting dentures due to enlargement of dental alveolar ridge
Class 3 occlusal base -> increased OVD and AOB, occlusal changes, interdental spaces
Hypercementosis - increased size of roots -> difficult XLA
Trigeminal neuralgia
Macroglossia - enlarged tongue
what does the thyroid hormone produce?
T3 and T4
Fall in T3 and T4 if detected by the ?. which produces ???. which stimulate pituitary gland to produce ???. which acts on the ?? to produce more T3 and T4. hypothalamus detects rise in T3 and T4 in the ?? and stops releasing TRH.
hypothalamus
thyrotropin releasing hormone
thyroid stimulating hormone
thyroid gland
blood stream
what is hyperthyroidism?
excess T3/T4 thyroid hormones
what is the causes of primary hyperthyroidism?
graves disease
toxic goitre or adenoma
viral thyroiditis
drugs - amiodarone
graves disease
?? stimulate ? receptors on thyroid gland causing ? of T3/T4 and gland ? (goitre)
auto antibodies
TSH
overproduction
enlargement
what is the cause of secondary hyperthyroidism?
Pituitary tumour - TSH secreting pituitary adenoma
what is this the clinical presentation on?
Heat intolerance, weight loss, goitre, exophthalmos (bulging eyes), increased blood pressure, swelling of legs and scaly skin plaques
hyperthyroidism
in primary hyperthyroidism what would the TSH and T3/T4 levels be?
TSH low
T3/T4 high
in secondary hyperthyroidism what would the TSH and T3/T4 levels be?
TSH high
T3/T4 high
what is the blood test for graves disease?
TSH receptor antibodies (TRAb)
what drugs manage hyperthyroidism? 2
Antithyroid drugs block T3/T4
B-blockers control symptoms (tachycardia/tremor)
what surgical treatments are there for hyperthyroidism and graves disease? 3
Thyroidectomy in primary dysfunction
Transnasal transsphenoidal endoscopic surgery to pituitary adenoma for secondary dysfunction
Eye surgery in severe Grave’s disease
how is radioactive iodine used to treat hyperthyroidism? what are the considerations?
Thyroid tissue ablation - removal
Permanent hypothyroidism so need lifelong thyroxine replacement therapy
Contraindicated if pregnant or breastfeeding
what is hypothyroidism?
deficiency of T3/T4 thyroid hormones
what are causes of primary hypothyroidism? 6
Autoimmune (Hashimoto’s) thyroiditis - anti-thyroid peroxidase antibodies
Idiopathic gland atrophy
Radioiodine treatment/thyroidectomy surgery
Iodine deficiency - essential component of thyroid hormone
Drugs for hyperthyroidism can reduce too much thyroid hormone production
Congenital
what are the causes of secondary hypothyroidism?
Hypothalamic dysfunction -> brain tumours, trauma, surgery/radiotherapy, congenital disorders
what is this the clinical presentation of?
Cold intolerance, weight gain, hair loss, bradycardia (slow pulse), macroglossia, eyelid oedema
Hypothyroidism
in blood test for primary hypothyroidism what are the TSH and T4/T4 levels?
TSH high
T3/T4 low
in blood test for secondary hypothyroidism what are the TSH and T3/T4 levels?
TSH low
T3/T4 low
what is the blood test for hashimoto’s thyroiditis?
anti-thyroid peroxidase antibodies (TPOAb)
what is the management of hypothyroidism?
Goal of treatment is to manage symptoms
Replacement with levothyroxine
- TSH monitored to ensure it remains normal
how does thyroid cancer present? 4
Thyroid nodule or swelling
Dysphagia (difficulty swallowing)
Dyspnoea (difficulty breathing)
Hoarse voice due to paralysed vocal cord or recurrent laryngeal nerve
Dental aspects of thyroid disease
Goitre or thyroid lump can be detectable by dentist
Oral effects
- Macroglossia in hypothyroidism
- Burning mouth syndrome in hypothyroidism
Anti-thyroid drug side effects (Carbimozole)
- Neutropenia - increased susceptibility to infection due to decreased neutrophils
- Taste disturbance
Sedation
- Cardiovascular and respiratory depression risk in hypothyroidism
- Reduced effect of LA due to hypermetabolic state of uncontrolled hyperthyroidism increasing drug clearance
LA - uncontrolled hyperthyroidism is a contraindication to the use of adrenaline in LA due to risk of tachycardia/dysrhythmias
where are the adrenals located?
above the kidney
the adrenal glands produce hormones which regulate what? 3
metabolism, blood pressure and bodies response to stress.
in the adrenal cortex there are 3 parts: zona glomerulosa, zona fasciculata, zona reticularis.
what does Zona glomerulosa produce?
mineralocorticoids such as aldosterone
in the adrenal cortex there are 3 parts: zona glomerulosa, zona fasciculata, zona reticularis.
what does zona fasciculata produce?
glucocorticoids such as cortisol and corticosterone
in the adrenal cortex there are 3 parts: zona glomerulosa, zona fasciculata, zona reticularis.
what does zona reticularis produce?
androgens such as dehydroepiandrosterone
what does the medulla of the adrenal gland produce?
adrenaline and noradrenaline
what is the Common precursor to steroid hormones?
cholesterol
Aldosterone is a mineralocorticoid produced by the adrenal cortex
what is its function?
Stimulates sodium reabsorption from the kidneys and which in turn increases water reabsorption which increases blood volume resulting in an increase in blood pressure
aldosterone regulation out-with the hypothalamus and pituitary gland happens through what system?
renin-angiotensin system
what is the renin-angiotensin for aldosterone control used for?
regulate blood pressure
Renin angiotensin system to regulate blood pressure
Decreased blood flow to the kidneys due to reduced ?? or ?. Kidneys release ? which converts ? into ??. Lungs produce ??? which converts angiotensin I to ?. This raises the blood pressure by stimulating the adrenal glands to produce ?. which promotes ? and ? retention, ? of blood vessels and enhances the vasoconstriction effect of ?. Restoring blood pressure to normal
blood pressure
volume
renin
angiotensinogen
angiotensin I
angiotensin converting enzyme ACE
angiotensin II
aldosterone
salt
water
constriction
noradrenaline
inhibiting aldosterone production is used to treat what?
hypertension
what 2 drugs inhibit aldosterone?
ace inhibitors
angiotensin II receptor blockers
how do ACE inhibitors work?
block angiotensin II formation
used to treat hypertension caused by excessive artery constriction
how do angiotensin II receptor blockers work?
Block angiotensin II receptors in smooth muscle and adrenal gland preventing aldosterone secretion
Cortisol is a ? produced by the ??
glucocorticoid
adrenal cortex
what is the function of cortisol?
stress response
cortisol
Controlled by ???? which follows a ? rhythm (? in AM, ? in PM) to prepare the body for the days activities. Additional cortisol can be produced by the ??when its stimulated by the ?? during times of ? or ?
hypothalamic-pituitary-adrenal axis
circadian
high
low
adrenal cortex
pituitary gland
stress
illness
name 4 physiological effects of the steroid cortisol
antagonist to insulin
reduces inflammation and immune response
raises blood pressure
inhibits bone formation
cortisol
? to insulin increases blood ? through ?, ? and ? breakdown and inhibiting ?? by tissues.
antagonist
glucose
gluconeogenesis
fat
protein
glucose uptake
cortisol reduces ? and ? - crucial in preventing ? to minor infection or injuries
inflammation
immune response
overreaction
cortisol Raises ?? -> increases the ? of blood vessels to other ? to ensure adequate ? to vital organs during ?
blood pressure
sensitivity
vasoconstrictors
blood flow
stress
cortisol Inhibits ?? -> decreases the activity of ? (cells responsible for ??) leading to decreased ??over time
bone formation
osteoblasts
bone synthesis
bone density
Regulation of cortisol
Hypothalamus secretes ??? which binds to receptors on pituitary gland increasing production of ??. Binds to receptors on the ??, stimulating the release of cortisol. Increasing cortisol inhibits production of ??? and ??
corticotropin releasing hormone CRH
adrenocorticotropic hormone ACTH
adrenal cortex
corticotropin releasing hormone
adrenocorticotropic hormone
steroid/cortisol is used to treat what? 2
autoimmune disease due to immunosuppression
rheumatoid arthritis and asthma due to decreased inflammatory response
name the side effect of cortisol based on its description
Hypertension - enhanced mineralocorticoid effects
? - increased blood sugar levels
? - inhibits bone formation
? - immunosuppression
Cataracts
? - raised cholesterol levels
hypertension
type 2 diabetes
osteoporosis
increased risk of infections and cancer
atherosclerosis
what diseases are associated with hyperfunction of the adrenal gland?
cushing syndrome
conns syndrome
what is cushing syndrome?
excess glucocorticoid - cortisol
what are the 3 types of cushing syndrome?
ACTH driven cushing syndrome
ACTH independent cushing syndrome
pseudo-cushing syndrome
what is ACTH dependant cushing syndrome caused by?
- Excess ACTH produced by tumour stimulates the adrenal cortex to overproduce cortisol
- Ectopic ACTH secretion - other tumours can cause it, most commonly from non-endocrine malignant tumours such as small cell lung carcinomas
what is ACTH independent cushing syndrome caused by? 3
- Tumours within adrenal gland
- Bilateral adrenal hyperplasia - adrenal glands enlarge stimulating cortisol production
- Iatrogenic Cushing Syndrome - steroid drugs
what is pseudo-cushing syndrome?
Adopt similar clinical features to Cushing syndrome but they don’t necessarily have increased glucocorticoid.
1. Obesity
2. Alcoholism
what are these the clinical features of?
Weight gain in the middle of the body, face, neck (buffalo hump)
Muscle wasting and weakness
Osteopenia - risk of bone fractures
Hypertension
T2 diabetes
Increased infection risk
cushing syndrome - excess glucocorticoid - cortisol
what blood tests are used to investigate cushing syndrome?
cortisol, glucose, ACTH
investigations for cushing syndrome
Blood tests -> cortisol, glucose, ACTH
Urinary cortisol levels
Imaging - CT/MRI
treatment for cushing syndrome? 4
Transsphenoidal surgery if pituitary cause
Adrenalectomy
Surgery for ectopic tumour that is ACTH producing
Medication to block cortisol synthesis
what is conns syndrome?
excess mineralocorticoid aldosterone
what are the causes of conns syndrome? 2
adrenal adenoma
bilateral adrenal hyperplasia
what are these clinical features of?
Hypertension
Polyuria - dilute urine
Muscle weakness
conns syndrome
polyuria is a bit confusing as aldosterone increases water retention but also causes loss of K which causes diabetes insipidus leading to increased frequency of peeing.
what are the blood tests to investigate conns syndrome?
Renal function - high Na low k
Renin and aldosterone levels
investigations for conns syndrome
Blood tests
- Renal function - high Na low k
- Renin and aldosterone levels
Imaging CT
what is the management for conns syndrome? 2
Surgery
Spironolactone treatment with potassium sparing diuretic drug
what disease is caused by Hypofunction of adrenal gland - adrenal insufficiency
addison’s syndrome
what is addison’s syndrome?
not enough cortisol and aldosterone produced
what is addison’s syndrome caused by?
Destruction of the adrenal cortex by autoantibodies
what are these the clinical features of?
Fatigue, weight loss, muscle weakness
Hypotension
Hyperkalaemia
Hyperpigmentation
addisons syndrome - hypofunction of adrenal gland - too little cortisol and aldosterone
explain the following clinical features of addison’s syndrome
Fatigue, weight loss, muscle weakness
Hypotension?
Hyperkalaemia?
Hyperpigmentation - brown/black dots on oral mucosa ?
Hypotension - drop in blood pressure during postural change as less water and sodium
increased potassium
hyperpigmentation - high ACTH levels stimulate the production of melanocytes
what are the blood tests for addisons syndrome? 4
Hormone levels - ACTH, cortisol, aldosterone
Synacthen test
Renal function
glucose
in addisons syndrome caused by pituitary failure what are blood test levels for ACTH and cortisol
low ACTH and low cortisol
in addisons syndrome caused by adrenal gland dysfunction what are the blood test levels for ACTH and cortisol?
high ACTH
low cortisol
what is synacthen test?
used for addisons syndrome
Pt given ACTH then a blood test for cortisol
in synacthen test Pt given ACTH then a blood test for cortisol.
what does a positive response mean?
pituitary failure
in synacthen test Pt given ACTH then a blood test for cortisol.
what does a negative response mean?
adrenal gland dysfunction
what is tested in the blood to investigate renal function?
sodium and potassium levels
what is the medical emergency associated with addisons syndrome - adrenal hypofunction?
adrenal crisis
what is the management for addisons syndrome? 4
hormone replacement therapy
regular monitoring
emergency preparedness - hydrocortisone injection and medical alert bracelet
lifestyle adjustments - diet, stress, hydrated
adrenal crisis is caused by sudden and severe ? in adrenal hormones (? and ?) that are crucial in maintaining ??, ?? and ??. This leads to severe ?, ?? and sharp decline in ??.
decrease
cortisol
aldosterone
blood sugar
blood pressure
electrolyte balance
dehydration
electrolyte imbalances
blood pressure
what are the triggers for adrenal crisis? 4
Concurrent illness
surgery
failure to take medications
dental treatment
what is this the clinical presentation of?
Pain in lower back, abdomen or legs
GI: abdominal pain, vomiting, diarrhoea
Hypoglycaemia
CVS: dehydration, hypotension, hypovolaemic shock
Fever
Confusion
adrenal crisis
what is the management of adrenal crisis?
999
Lie patient flat
Give O2
Pt hydrocortisone injection
Transfer patient to hospital
Normal insulin function
Insulin is produced by ?? in the ??? in the ?
Eat food, blood glucose ?, islets of Langerhan’s secrete ?, this stimulates the ? of glucose into the cells, the cells use glucose for energy and the blood glucose returns to normal (?mM). Any remaining glucose not used by cells is converted into ? and is stored in the ? for later use.
At night or during fasting blood glucose levels ? (hypoglycaemia), stimulates the ? cells in the pancreas to produce the hormone ?, this stimulates the liver to undergo ? (glycogen broken down to glucose) and ? (synthesis of glucose from non-carbohydrate precursors)
B cells
islets of langerhans
pancreas
increases
insulin
uptake
4-6mM
glycogen
liver
drop
alpha
glucagon
glycogenolysis
gluconeogenesis
what is type 1 diabetes mellitus
Absolute insulin deficiency
what is type 1 diabetes mellitus caused by?
Autoimmune destruction of the beta cells of the islets of Langerhan’s in the pancreas that produce insulin. Lack of insulin leads to hyperglycaemia (high blood glucose).
what autoantibodies are associated with type 1 diabetes mellitus?
GAD glutamic acid decarboxylase
ICA islet cell antibodies
IAA insulin autoantibodies
remember for type 1 diabetes by the time the disease presents there is a lots of islet cell destruction so will require insulin from diagnosis
what is ketoacidosis?
Body cells cant access glucose for metabolism so they start to metabolise fat which results in ketones as an end product
is ketoacidosis more common in type 1 or type 2 diabetes mellitus?
type 1 as there is not insulin production
also more common in children
what is this the clinical presentation of?
Excessive thirst and hunger
Unexplained weight loss
Blurred vision
Poor wound healing
Increased risk of infections
Fatigue
Frequent urination
type 1 diabetes
Type 1 diabetes causes frequent urination
presence of ? in the ? raises the ?? reducing water ? in the kidneys increasing ??
Urinary glucose can be monitored with dipstick urine analysis
glucose
urine
osmotic pressure
reabsorption
water volume
what is type 2 diabetes mellitus?
defective or delayed insulin synthesis due to B cell dysfunction
impaired response to insulin by tissues - insulin resistance - less glucose taken into cells
pt are unable to maintain glucose homeostasis leading to hyperglycaemia
what medication can lead to medication-induced diabetes?
corticosteroidsw
what is this the clinical presentation of?
Commonly asymptomatic and picked up on routine screening
Weight gain
muscle atrophy
digestive problems
bone fracture risk
risk of skin infections
neuropathic damage (sensory issues)
cardiovascular disease
nephropathies (renal function deteriorates)
type 2 diabetes
what is the blood glucose of someone with diabetes?
≥11.1mmol/l
what is the fasting blood glucose of someone with diabetes?
(fasting for at least 8hrs)
≥7mmol/l
what are the glucose levels in a glucose tolerance test for someone with diabetes?
(2hrs after 75g oral glucose)
≥11.1mmol/l
what is the HbA1c for someone with diabetes?
degree of hyperglycaemia over the preceding 3 months. Can be used to monitor glycaemic control
≥48mmol/l
(≥6..5%)
what is impaired glucose tolerance?
glucose levels above normal but not high enough for diabetes diagnosis
what are the macrovascular long term complications of diabetes?
atherosclerotic plaque formation in large blood vessels
what are the microvascular long term complications of diabetes?
damage to small blood vessels (retinopathy, nephropathy, neuropathy)
what is diabetic foot?
peripheral blood vessel to foot is damaged
neuropathy means foot is numb so wont feel injury
poor wound healing leads to infection and necrosis due to compromised blood supply
tissue death can occur leading to amputation of toes, foot, leg
erectile dysfunction is a complication of diabetes due to compromised blood supply
remember diabetes has an increased susceptibility to infection
what are the dental implications of diabetes?
increased perio and ginigivitis risk
recurrent bacterial/fungal infections
poor wound healing
dry socket
reduced salivary function - dry mouth - caries risk
dysaesthesia - burning/tingling feeling
sialosis - enlargement of salivary gland
dental management in diabetic patients on day of treatment? 7
see first in the morning
diabetic control?
ensure pt eaten and taken medication
check blood glucose if type 1 or poorly controlled
warning signs before hypoglycaemia?
prevent and treat infections ASAP
good OH and preventative care
