Endocrinology Lectures Flashcards
What BMI range is normal?
18.5 - 24.9
What BMI range is overweight?
25.0 - 29.9
What BMI range is obese?
30.0 - 39.9
What BMI range is morbidly obese?
> 40
List 7 risks of obesity.
1) type 2 diabetes
2) hypertension
3) coronary heart disease
4) stroke
5) osteoarthritis
6) obstructive sleep apnoea
7) cancer
List 4 cancers linked to obesity.
1) breast
2) endometrium
3) prostate
4) colon
What is appetite regulation a balance between?
Energy intake and energy expenditure.
List 3 ‘organs’ that release hormones that regulate appetite.
1) brain
2) gastrointestinal tract
3) adipose tissue
What part of the brain is crucial in appetite regulation?
Hypothalamus.
Where is the hunger centre?
Lateral hypothalamus.
Where is the satiety centre?
Ventromedial hypothalamic nucleus.
List 4 hormones that affect appetite.
1) leptin
2) insulin
3) ghrelin
4) PYY
What is the effect of leptin? (2)
1) decreases appetite
2) increases satiety
What is the effect of insulin? (appetite) (2)
1) decreases appetite
2) increases satiety
What is the effect of ghrelin? (2)
1) increases appetite
2) stimulates growth hormone release
What is the effect of PYY? (2)
1) decreases appetite
2) inhibits gastric motility
What is the pituitary gland close to?
Optic chiasm.
How does the anterior pituitary receive blood?
Hypophyseal portal system —> from the hypothalamus.
List the 6 pituitary hormones.
1) GH
2) TSH
3) ACTH
4) LH
5) FSH
6) PRL
List 5 diseases of the pituitary gland.
1) pituitary adenoma - very common —> generally don’t present
2) craniopharygioma
3) traumatic brain injury
4) Sheehan’s syndrome
5) sarcoidosis - pituitary granulomas
What is Sheehan’s syndrome.
Postpartum pituitary gland ischaemic necrosis.
List 3 things pituitary tumours cause.
1) pressure on local structures
2) pressure on normal pituitary gland - hypopituitarism
3) functioning tumour
Give an example of a local structure pressured by a pituitary tumour.
Optic chiasm, causing bitemporal hemianopia.
List 3 conditions caused by a functioning pituitary tumour.
1) prolactinoma
2) acromegaly
3) Cushing’s disease
What is IGF-1?
Insulin-like growth factor 1. Anabolic hormone, carries out peripheral activity of GH.
Where is IGF-1 produced?
Liver.
What is glucose’s effect on GH?
Suppress GH secretion.
List 6 objectives of acromegaly treatment.
1) restore GH and IGF-1 to normal levels
2) relieve symptoms
3) reverse visual changes
4) reverse soft tissue changes
5) prevent further skeletal deformity
6) normalise pituitary function
List 3 therapeutic options for acromegaly.
1) pituitary surgery*
2) medical therapy
3) radiotherapy
List 3 types of medical therapy for acromegaly.
1) dopamine agonists
2) somatostatin analogues
3) GH receptor antagonists
What is cortisol function? (2)
Stress hormone.
1) stimulate gluconeogenesis
2) suppress immune system
What does cortisol circadian rhythm parallel?
Energy levels.
What is the time period of the circadian rhythm?
24.2 hours.
List 2 biochemical features that indicate adrenal insufficiency.
1) hyponatraemia
2) hyperkalaemia
Why are cortisol levels measured at 9:00 am?
Measures cortisol levels when they are at their highest.
What is the pharmaceutical name for cortisol?
Hydrocortisone.
Define adrenal crisis.
Medical emergency caused by severe cortisol insufficiency.
What happens in an adrenal crisis? (3)
1) hypotension
2) decreased organ perfusion
3) death
List 7 signs and symptoms of adrenal crisis.
1) shock
2) hypotension
3) hypoglycaemia
4) hyponatraemia
5) hyperkalaemia
6) fever
7) fatigue
What do you always immediately administer in adrenal crisis?
Hydrocortisone (if in doubt).
What is the prevalence of thyroid diseases in females compared to males?
5-10 times higher.
List 3 thyroid autoantibodies.
1) thyroid peroxidase
2) thyroglobulin
3) thyroid receptor
What is the main mechanism of thyroid autoimmunity.
Cytotoxic T cell mediated.
List 2 genetic factors increasing risk of thyroid autoimmunity.
1) female
2) HLA-DR3
List 4 environmental factors increasing risk of thyroid autoimmunity.
1) postpartum
2) stress
3) smoking
4) high iodine intake
List 8 autoimmune diseases associated with thyroid autoimmunity.
1) type 1 diabetes
2) Addison’s disease
3) pernicious anaemia
4) vitiligo
5) alopecia areata
6) coeliac disease
7) rheumatoid arthritis
8) myasthenia gravis
What is the cause of thyroid autoimmunity associated ophthalmopathy? (3)
1) extraocular muscle autoantigen identical to thyroid autoantigen
2) thyroid autoantibody reacts with extraocular muscle autoantigen
3) extraocular muscle swelling
Define goitre.
Palpable and visible thyroid enlargement.
List 4 types of goitre.
1) diffuse
2) solitary nodule
3) multinodular
4) dominant nodule
List the 3 mechanisms causing hyperthyroidism.
1) excessive T3/T4 production
2) leakage of preformed T3/T4
3) excessive T3/T4 ingestion
How does iodine 131 work as hyperthyroidism treatment? (4)
1) α particle emission
2) thyroid cells ionise
3) direct damage to DNA and enzymes
4) indirect damage via free radicals
What is the main type of hypothyroidism.
Primary hypothyroidism (99%).
List 3 hormones that affect serum calcium and their effect.
1) PTH —> increase serum calcium
2) calcitriol —> increase serum calcium
3) calcitonin —> decrease serum calcium
List 3 reasons why calcium is important.
1) calcification in ossification (bone formation)
2) nerve functioning
3) muscle functioning
Define corrected calcium.
Measure of serum calcium that accounts for albumin bound calcium.
Corrected calcium formula.
corrected calcium = total serum calcium + 0.02 x (40 - serum albumin)
What is Chvostek’s sign? (3)
1) sign of hypocalcaemia
2) tap facial nerve (near external carotid artery)
3) facial muscle spasm
What is Trousseau’s sign? (3)
1) sign of hypocalcaemia
2) inflate blood pressure cuff 20mmHg above systolic for 5 minutes
3) hand muscle spasm - claw
What is the characteristic sign of pseudohypoparathyroidism?
Short 4th and 5th metacarpals.
List 2 things that can mimic hypercalcaemia.
1) tourniquet on for too long
2) old, haemolysed blood sample
Define puberty.
Physiological, morphological and behavioural changes when gonads develop into adult form.
What is the definitive sign of puberty in females?
Menarche - first menstruation.
What is the definitive sign of puberty in males?
First ejaculation.
Define secondary sexual characteristics.
Features that develop in puberty.
List 4 female secondary sexual characteristics.
1) uterus and vagina growth
2) pubic hair growth
3) breast growth
4) wider hips
List 4 male secondary sexual characteristics.
1) penis grows
2) pubic hair growth
3) larynx and laryngeal muscles enlarge - voice breaks
4) musclier body
What testes size is pre-pubertal? (2)
1) volume < 3ml
2) diameter < 2.5cm
What is the first ‘visible’ female change in puberty.
Breast development - breast bud.
List 3 effects of oestrogen on the breast.
1) ducal proliferation
2) adipose deposition
3) areola and nipple enlargement
List 4 hormones involved in breast development.
1) oestrogen - majority
2) prolactin
3) glucocorticoids - cortisol
4) insulin
Define precocious puberty.
Onset of secondary sexual characteristics before 8 years in females and 9 years in males.
Define delayed puberty.
Absence of secondary sexual characteristics by 14 years in females and 16 years in males.
List 2 complications of delayed puberty.
1) reduced peak bone mass
2) osteoporosis
Define adrenarche.
Maturation of the adrenal glands resulting in the formation of the zona reticularis.
List 4 features of adrenarche.
1) axillary hair
2) oily skin
3) mild acne
4) body odour
Describe body water distribution. (4)
1) intracellular fluid - 28L
2) extracellular fluid - 14L
3) interstitial fluid - 11L (ECF)
4) intravascular fluid - 3L (ECF)
List 2 responses to low plasma osmolality.
1) decrease thirst
2) decrease ADH secretion
List 2 responses to high plasma osmolality.
1) increase thirst
2) increase ADH secretion
List the 3 ADH receptors, their location and function.
1) V1a - vasculature - vasoconstriction
2) V1b - pituitary gland - ACTH release
3) V2 - renal collecting duct - water reabsorption
List 2 main determinants of osmolality.
1) total body water
2) serum sodium
Formula for calculated osmolality.
calculated osmolality = glucose + urea + 2 x sodium
What is the normal osmolality range?
282 mmol/l - 295 mmol/l
What is the limiting factor of plasma osmolality? (2)
urine osmolality
1) cannot increase beyond 1200mOsmol/kg
2) irrespective of ADH
What is hyponatraemia range?
Serum sodium < 135mmol/l.
What is the severe hyponatraemia range?
Serum sodium < 125mmol/l.
What is the mortality of hyponatraemia and it’s caveat?
1 in 3. Generally due to underlying cause.
List the order of checking SIADH causes. (4)
1) drugs
2) respiratory
3) central nervous system
4) tumours
What is the most common intracranial tumour.
Pituitary adenoma.
What percentage of non-functioning pituitary adenomas are incidenalomas?
50%
List 3 reasons why testing pituitary function is complex.
1) many hormones
2) may have borderline deficiencies
3) pulsatile and affected circadian rhythm
What should diabetes mellitus be thought of as?
A vascular disease.
Which form of diabetes mellitus has a higher genetic component? (2)
Type 2.
1) type 1 - 30% concordance in twins
2) type 2 - 80% concordance in twins
2 out which 3 features indicate type 1 diabetes mellitus and immediate insulin treatment? (3)
1) weight loss
2) high ketones (blood or urine)
3) short history of hyperglycaemic symptoms (week)
List 3 reasons differentiating type 1 and type 2 diabetes mellitus is hard.
1) type 1 patients can be obese
2) type 2 patients can be young
3) uncontrolled type 2 can present with weight loss and ketouria
What geographical parameter increases risk of type 1 diabetes mellitus?
Distance from equator.
List 4 antibodies associated with type 1 diabetes.
1) pancreatic islet cell
2) islet antigen 2
3) zinc transporter 8
4) glutamic acid decarboxylase
Describe the onset of diabetic ketoacidosis. (8)
1) decreased insulin secretion / decreased insulin efficacy
2) decreased cellular glucose uptake
3) hyperglycaemia
4) increased lipolysis
5) increased free fatty acids
6) increased hepatic fatty acid metabolism
7) increased plasma ketone bodies
8) decreased plasma pH
List the 3 main features of diabetic ketoacidosis.
1) hyperglycaemia
2) ketones
3) acidosis
List 2 things type 1 diabetes mellitus patients should aware of during insulin treatment.
1) carbohydrate intake
2) exercise
List the 5 stages of hypoglycaemia.
1) 4.6mM - inhibition of insulin secretion
2) 3.8mM - glucagon and adrenaline secretion
3) 3.8-2.8mM - autonomic symptoms
4) < 2.8mM - neuroglycopenic symptoms
5) < 1.5mM - severe neuroglycopenic
List 3 autonomic symptoms of hypoglycaemia.
1) sweating
2) tremor
3) palpitations
List 5 neuroglycopenic symptoms of hypoglycaemia.
1) confusion
2) drowsiness
3) altered behaviour
4) speech difficulty
5) incoordination
List 2 severe neuroglycopenic symptoms of hypoglycaemia.
1) convulsions
2) coma
What is dilemma for type 1 diabetes mellitus patients?
Balancing hypoglycaemia symptoms against diabetic complications.
List 4 factors making type 1 diabetes mellitus self-management hard.
1) difficulty
2) hypoglycaemia
3) lifestyle interference
4) lack of training
List 4 other causes of diabetes mellitus.
1) monogenic
2) exocrine pancreas pathology
3) endocrine pathology
4) drug induced
List 3 mechanisms by which diabetes mellitus causes morbidity and mortality.
1) acute hyperglycaemia —> diabetic ketoacidosis and hyperosmolar coma
2) chronic hyperglycaemia —> tissue complications
3) hypoglycaemia (treatment side effects)
List 3 clinical consequences of diabetic neuropathy.
1) pain, e.g. burning and paraesthesia
2) autonomic pathology, e.g. incontinence or erectile dysfunction
3) insensitivity - numbness
What is the pattern of sensory loss in diabetic neuropathy?
Glove and stocking.
List the 2 causes of a diabetic foot amputation.
1) neuropathy —> decreased sensation
2) vascular disease —> decreased perfusion
List 4 signs of diabetic vascular disease.
1) decreased/absent pedal pulse
2) cold feet and toes
3) poor skin and nails
4) absence of hair on feet and legs
List 5 ways to decrease diabetic amputation.
1) screening
2) education
3) orthotic shoes
4) MDT feet clinics
5) revascularisation
What is the most common cause of end stage renal disease?
Diabetic nephropathy.
List 4 modifiable risk factors for diabetes mellitus complications.
1) blood glucose
2) blood pressure
3) smoking
4) high cholesterol
Where does ingested glucose go? (2)
1) peripheries (e.g. muscles) - 60%
2) liver - 40%
List 5 effects of insulin.
1) decreased hepatic glycogenolysis
2) decreased hepatic gluconeogenesis
3) increased glucose uptake in insulin sensitive tissues (fat and muscle)
4) decreased lipolysis
5) decreased muscle breakdown
List 5 effects of glucagon.
1) increased hepatic glycogenolysis
2) increased hepatic gluconeogenesis
3) decreased glucose uptake in peripheries
4) increased lipolysis
5) increased muscle breakdown
At a cellular level when is the clinical onset of type 1 diabetes mellitus?
10% of β cells remain.
Why doesn’t type 2 diabetes mellitus generally lead to diabetic ketoacidosis?
Low insulin levels prevent ketogenesis.
What are the hypoglycaemia classifications? (3)
1) level 1 - no symptoms alert value, plasma glucose < 3.9mM
2) level 2 - mild symptoms, plasma glucose < 3.0mM
3) level 3 - severe symptoms, plasma glucose < 3.0mM
What is the distinction between mild and severe hypoglycaemia? (2)
1) mild hypoglycaemia - self-treatable
2) severe hypoglycaemia - require help
What is the average number of severe hypoglycaemic episode for a patient in a year?
1.
List 6 risk factors for severe hypoglycaemia in type 1 diabetes mellitus patients.
1) HbA1c < 48mmol/mol
2) history of severe episodes
3) long duration
4) extreme ages
5) renal impairment
6) impaired awareness of hypoglycaemia
List 6 risk factors for severe hypoglycaemia in type 2 diabetes mellitus patients.
1) aggressive treatment
2) long duration of insulin therapy
3) old age
4) cognitive impairment
5) renal impairment
6) impaired awareness of hypoglycaemia
How do you treat hypoglycaemia? (6)
1) recognise symptoms
2) check blood glucose (alert value < 3.9mM)
3) 15g fast-acting carbohydrate - relieve symptoms
4) recheck blood glucose (> 4.0mM)
5) 15g fast-acting carbohydrate - if < 4.0mM
6) long acting carbohydrate - prevent recurrence of symptoms
List 4 ways medications for type 2 diabetes mellitus work.
1) replace - insulin injections
2) secrete - increase insulin secretion
3) sensitise - increase response to insulin
4) excrete - decrease renal reabsorption of glucose
List 3 type 2 diabetes mellitus drugs that work by increasing insulin secretion.
1) sulphonylurea
2) DDP-4 inhibitors
3) GLP-1 receptor agonists
List 2 type 2 diabetes drugs that work by increasing response to insulin.
1) metformin
2) pioglitazone
What type 2 diabetes mellitus drugs works by decreasing renal reabsorption of glucose?
SGLT2 inhibitors.
What is the first drug prescribed for type 2 diabetes mellitus?
Metformin.
What fasting blood glucose does basal insulin aim to achieve?
5mM - 7mM.
What type of basal insulin is better and why? (2)
1) synthetic basal analogues are better than human basal analogues
2) steady insulin action - no peak
What is the best insulin treatment for type 1 diabetes mellitus?
Basal-bolus insulin therapy.
Describe management progression of type 2 diabetes mellitus. (5)
1) lifestyle changes
2) metformin
3) add one of pioglitazone, suphonylurea, DPP-4 inhibitor, GLP-1 receptor agonist, SGLT2 inhibitor
4) add another one of pioglitazone, suphonylurea, DPP-4 inhibitor, GLP-1 receptor agonist, SGLT2 inhibitor
5) insulin therapy
What effect does metformin have on weight?
Weight loss.
What effect does sulphonylurea have on weight?
Weight gain.
What effect do DPP4 inhibitors have on weight?
No effect.
What effect does plioglitazone have on weight?
Weight gain.
What age does pseudoparathyroidism generally present in?
Childhood.
What condition is associated with Albright hereditary osteodystrophy?
Pseudoparathyroidism.
List 3 features of Albright’s hereditary osteodystrophy.
1) short 4th and 5th metacarpals
2) round face
3) short stature
What percent of hypercalcaemia is caused by either malignancy or primary hyperparathyroidism
90%.
List 5 causes of hypocalcaemia with elevated serum phosphates.
1) chronic renal failure
2) hypoparathyroidism
3) pseudoparathyroidism
4) parathyroidectomy
5) thyroidectomy
List 3 causes of hypocalcaemia with low serum phosphate.
1) acute pancreatitis
2) vitamin D deficiency
3) osteomalacia
How do NSAIDs treat nephrogenic diabetes insipidus? (4)
1) NSAIDs inhibit prostaglandin synthase
2) decreased prostaglandin inhibition of ADH action
3) increased water retention
4) decreased urine production
List 2 common places to develop hypernatraemia.
1) hospital
2) care home
What is the HbA1c target range for type 1 diabetes mellitus?
48-55.
What is the myocardial infarction risk increase for diabetics?
X4.
What is the stroke risk increase for diabetics?
X2.
List the 2 methods of antithyroid drug administration.
1) block and replace
2) titrate
What method of antithyroid drug administration is preferred and why?
Block and replace, less likely to progress to hypothyroidism.
What is the difference between hyperthyroidism and thyrotoxicosis? (2)
1) hyperthyroidism —> excess thyroid stimulation
2) thyrotoxicosis —> excess T3/T4 in blood
What term is used to describe sever hypothyroidism?
Myxoedema coma.
List 5 features of a myxoedema coma.
1) hypothermia
2) hypoventilation
3) hyponatraemia
4) hypoglycaemia
5) heart failure
List 7 features of a thyroid storm.
1) hyperpyrexia
2) tachycardia
3) jaundice
4) diarrhoea
5) vomiting
6) confusion
7) coma
List the 4 stages of diabetic retinopathy.
1) preproliferative retinopathy
2) proliferative retinopathy
3) maculopathy
4) cataracts
