Week 14 - Thyroid, Endocrinology Flashcards
Role of oestrogen and progesterone
Oestrogen
xxxx
What does testosterone turn into in females? by what enzyme?
Oestrogen
By aromatase
What does testosterone turn into in men?
xxx
CARDS ON FLOW CHART SLIDE
xxx
On what day does menstrual cycle start?
Day 25
What happens at three months?
Corpus liteum -> placenta
Placenta is now mature and it takes over
What are the actions of oestrogen? (4 categories)
Development
Menstrual
Pregnancy
Cellular
What are the menstrual actions of oestrogen?
Menstrual - Endometrial proliferation, watery cervical mucus, maturation of vaginal epithelium, female sex behaviour
What are the developmental actions of oestrogen?
Development - secondary sex characterstics, breast development, fat distribution, uterine development, bone deposition
What are the pregnancy actions of oestrogen?
Pregnancy - Breast ductal development, fluid retention, increased uterine blood flow
What are the cellular actions of oestrogen?
Cellular - acts via a nuclear receptor, expression of progesterone receptor, decrease plasma cholesterol, hepatic enzyme inducers
What are the actions of progesterone? (3 categories)
Menstrual
Pregnancy
Cellular
Causes of female infertility
Anovulatory - Central and ovarian
Ovulatory
Anorexia nervosa and infertility - outline
Lack of adipose tissue, body can tell you are not storing enough fat through lack of leptin
Central causes of anovulatory female infertility
xx
Ovarian causes of anovulatory female infertility
xxx
Ovulatory causes of female infertility
xxx
Test for female infertility (5)
Karyotype Gonadaotrophins oestradiol Progesterone LHRH test Pelvic ultrasound
What does LH being much higher than FSH indicate?
Ovulatory surge
OUTLINE FSH and INHIBIN
xxx
Luteinising hormone and testosterone
xxx
Testosterone production in women (3)
Ovarian synthesis (granulosa cell) Peripheral conversion of precursor androgen Adrenal synthesis (zon reticularis)
How to measure testosterone
Very unreliable in women
9am fasted sample
Patient in good physical health
Repeated measure (at least 2, 6 weeks apart)
Actions of testosterone
XXXX
Why are men taller?
Later and longer puberty
Heavier bones
Causes of male infertility
Central
Testicular
Post-testicular
Tests for male infertility (4)
Karyotype
Gonadotrophins testosterone
LHRH test
Testicular ultrasound
Describe Cushing’s syndrome
EXCESS of glucocorticoids (cortisol)
Obesity
Facial plethora (redness)
Male pattern hair in female
Describe Addison’s syndrome
SHORTAGE of glucocorticoids (cortisol)
Tiredness, weight loss, postural hypotension
Causes of Addison’s syndrome
Autoimmune Steriod use TB Metastases Infiltration Infection Enzyme defect
Describe 21-hydroxylase deficiency (Classical CAH)
Commonest form of CAH
1:10000 births
Autosomal recessive
HLA linked
Excess sex steroids
No aldosterone, salt-losing crisis
Outline 11B-hydroxylase deficiency (Non-classical)
About 5% of reported 5%
0.5: 100,000 live births
Increased in Moroccan Jews (1:6000)
HLA linked
Salt retention
Excess sex steriods
No aldosterone but HIGH DOC (agonist at NC receptors) - hypertension and hypokalaemia
In what case do you treat with fludocortisone?
21-hydroxylase deficiency to replace absent mineralcorticoid activity
Where is renin produced?
Juxtaglomerular cell
Outline primary and secondary excess of aldosterone
xxx
Outline Conn’s syndrome and treatment
xxx
Outline phaeochromocytoma - what is it? symptoms?
Tumour of the enterochromaffin cells of the adrenal medulla
(can be outside adrenal gland, but is a tumour of the nerve ganglion)
Produces adrenaline (nor adrenaline, dopamine)
Rule of 10% (10% bilateral, malignancy, extra adrenal, inherited)
Causes sweating, anxiety, fever, abdominal pain, headache, angor aminii
Management of phaechromocytoma
Emergency
Alpha blockade - non-competitive alpha antagonist
Beta blockade - non-selective beta blocker
Fluid resuscitation
Surgery
Management of phaechromocytoma
Emergency
Alpha blockade - non-competitive alpha antagonist - FIRST
Beta blockade - non-selective beta blocker - 24 hours after alpha
Fluid resuscitation
Surgery
What is shock?
Reduction of effective blood flow and inadequate tissue perfusion with decreased delivery of oxygen to the capillary exchange beds
What are the common things that change with inadequate O2? (4)
Heart rate
Blood pressure
Respiratory rate
Urine output
What is ABCDE?
Approach to examination in sick patient - must prioritise crucial issues
Airway and oxygenation Breathing and ventilation Circulation and management of shock Disability due to neurological deterioration Exposure and examination
How do you assess breathing / ventilation?
Is the chest clear?
Is ventilation bilateral / equal?
Cyanosis?
SaO2? On room or O2?
What are management options of acute breathing issues?
Oxygen
Treat with nebulisers of wheeze - steriods, magnesium
Decompression for pneumothorax / haemothorax
NIV for hypercapnic respiratory failure
Assessing circulation and management of shock in very sick patient
HR BP Cap refill Temp of limbs Heart sounds Urine output Oedema
Impact of a fluid challenge
Helps improve preload
Heart rate decreases Mean arterial pressure / arterial pulse pressure increase Urine output increases Lactate clearance increases Cardiac output or strike volume increase
Assessment of disability due to neurological deteriotation
GCS
AVPU
Blood glucose
How do you communicate your findings?
S - Situation
B - Background
A - Assessment
R - Recommendation
Total vs free hormone assay
Total - dependent on binding protein levels so NOT always reflective of the free hormone level, cheap
Free - representative of the active hormone fraction, complex and expensive, can have poor reproducibility
Overview of immunoassay
xxx
Thyroid investigations
xxx
Describe release of cortisol
xxx
Investigations of Cushing’s (3 stages)
Screening - urinary free cortisol, diurnal rhythm
Confirmation of diagnosis - Low dose dexamethasone suppression test
Differentiation of the cause - ACTH, high dose dexamthasone suppression, localisation
When best to measure cortisol levels for Cushings diagnosis?
At night (it should be low)
What is dexamethasone?
So similar to cortisol, brain can’t tell difference
BUT won’t come up on assay
Outline the types of dexamethasone suppression test
Low dose - 0.5 six hourly complete suppression in normal subject
High dose - 2mg six-hourly, suppresses cortisol up to 50% in Cushings
DOES NOT suppress in ectopic ADTH or adrenal neoplasia
Outline synacthen tests
xxx
Outline insulin tolerance test
xxx (insulin or glucagon)
Outline oral glucose tolerance test
xxx acromegaly, anorexia nervosa
Describe acromegaly
xxx
Outline syndrome of inappropriate ADH (SIADH)
Too much ADH
Brain infection / injury, lung cancer / infection, pneumonia, metabolic (hypothyroidism / addison’s)
What is diabetes insipidus?
Underproduction of ADH
Can be cranial or nephrogenic
Polyuria, polydipsia
Outline water deprivation test
xxx
If you can do one investigation with neck lump what do you do? and why?
Ultrasound
Can do biopsy at the same time
Identifying benign vs. malignant neck lumps
xxx
Neck lumps in different age groups
xxx
Thyrotoxicosis vs hyperthyroidism
Thyrotoxicosis is excess thyroid hormones in blood due to any reason( outside source).
Hyperthyroidism is excess thyroid hormones only due to increased synthesis from thyroid gland.
Signs of T3 toxicosis
xxx
Describe diagnosis of hyperthyroidism in patient with overt opthalmopathy
xxx
Describe diagnosis of hyperthyroidism in patient without overt opthalmopathy
xxx
Treatment of hyperthyroidism
Antithyroid drug (ATD) B-blockers Glucocorticoids Radioiodine Subtotal thyroidectomy
Outline types of thionomides
Carbimaxole, propythiouracil, methimizole
Which patients are unlikely to undergo remission following hyperthyroidism treatment
Large goitre Positive TSH receptor antibodies Thyroid disease Opthalmopathy Smoking Men
Indications and contraindications of radio-iodine
Safe and appropriate treatment in nearly all types of hyperthyroidism, especially in elderly
Contraindicated in children, pregnancy and women who are breast feeding
Women of childbearing age should wait for 4 months after 131I before becoming pregnant
Should be used with caution in patients with opthalmopathy
Use prophylactic steroids and avoid hypothyroidism
Side effects of radio-iodine (4)
Radiation induced thyroiditis.
Transient worsening of thyrotoxicosis.
Hypothyroidism.
Cancer risk.
Describe thyroid hormone resistance
May present as hypo or hyper - may not require treatment
Developing hyper or hypo when on Amiodrone
Hypo - will likely go away when you stop treatment so you can just treat with T4 in the meanitime
Hyper - two types
Type 1 - XXX
Increase of thyroxine dose during pregnancy
50mcg
