Endocrine 2 Flashcards
Thyroid
involves in hypothalamus
Anterior pituatory
Hypothyroidism
Goitre, weight gain, cold intolerance, myxedema
Could be a problem with thyroid or hypotholamus
TSH (Important diagnostic feature)
primary high and secondary Low
Thyroid drugs
Levothyroxine - T4
Liothyronine - T3
Levothyroxine ( cost effective )
Oral 50- 100u/day
Half life by binding into TBG
It is a prodrug
T4 converted to T3 in the cell to act on a nuclear receptor
Liothyronine
Intravenous injection
It is an emergency
Thyroid hormone receptor, how does thyroxine work?
thyroxine does not work on cytoplasm or in cell membrane but it works only in nucleus.
Levothyroxine ( Pharmacological effects)
Increased O2 consumption and heat production
inc cardiac muscle contracitility
Adverse effects of hypo drugs are
diarrhoea, sweating, nervousness, tachycardia, increased appettite, loss of weight
also leads to hyperthyroidism
Hyperthyroidism
Exoptholamus
Weight loss
Heat intolerance
CVS ?
TSH
Primary
Secondary
Thyroid hormone : Synthesis
Thyroperoxise
Inhibitors of thyroperoxidase
Mechanism : Competitive inhibitors for substrate binding site on thyroperoxide
Carbimazole
oral prodrug , rapid inhibition of enzyme (12hr).
Effect takes between 2-4 weeks ( depletion of thyroid and plasma stores of T4 required.
Propylthiouracil
Reduces the deiodination of t4 and t3 in the peripheral tissues that may work more quickly.
AD effects are Neutropenia and agranulocytosis
symptoms are sore throat, blood count , rash, headache, joint pain
Important point to remember
hyper and hypo both can be treated by throxine
Permissive Hormone Action
T3 and the heart ( B adrenoreceptor)
Hypothalamic pituatory axis
Adrenals (CRH AND ACTH) ADRENAL CORTEX
Adrenaline Medulla
blood vessels, heart, bronchial smooth muscle
Epinephrine
Cardiac arrest
anaphylaxis - angioedema- acute hypersensitivity(epipen)
Glucocorticoid - cortisol
Mineralocorticoid - aldosterone
5 major steroids
Replacement therapy
Adrenal Cortex
Cortisol (glucocorticoid + weak mineralocoticoid)
Aldosterone (mineralocotticoid)
Addison’s Disease
Glucocorticoids : Anti-inflammatory effect
Immunosuppression
Mediator effect - decreased expression , COX-2, IL-1 to IL-8, TNF alpha, complement, NO and histamine, IgG.
Glucocoticoid Drugs
Hydrocortisone is cortisol
Cortisone is a prodrug which is converted to hydrocortisone.
Therefore, hydrocortisone preffered to cotisone.
The ration is 1/1
Glucocorticoids in Asthma
Step 2 Inhaler (fluticasolone)
Step 5 Oral (prednisolone)
Glucocorticoids therapeutic use
Skin
Lung
GI
Musculoskeletal
Eye
CNS
Renal
Infectious Diseases
Haematology
Malignant
Glucocorticoids adverse effects
diabetes
osteoporosis
muscle wasting
peptic ulcer
cushing syndrome moon face
straie
acne
Adrenal suppression - withdrawal
Abrupt withdrawal
Acute adrenal insufficiency leads to hypotention, death possible.
Fever, weight loss, inflammation .
If corticosteroid is given for more than 3 weeks, treatment should not be stopped abruptly.
Magnitude or speed withdrawal
It is slower when down to physiological dose ( prednisolone 7.5mg daily)
Corticosteriods and covid
DEXAMETHASONE reduced all the causes of mortillity at 28days compared with usual care alone
offer dexamethasone or hydrocortisone to people with severe
Gonadotrophins and Posterior pituatory
Gonads
Combined oral contraceptives
inhibit ovulation - the combination of an oestrogen and a progestin is the most potent method known to supress GnRH, FSH and LH to release inhibiting follicular development and thereby preventing ovulation
HPA - Posterior pituatory
oxytocin ADH
Anti-diuretic hormone (ADH)
Diabetes insipidus
Vasopressin (Water retention )
1. Desmopressin (V2) ORAL AND NASAL spray
- Carbamizole (Anti-epileptic)
- Thiazides (diuretic)
Vasoconstriction (V1)
terlipressin - variceal bleeding secondary to portal hypertention
felypressin - added to local anaesthetic injection
Syndrome of Inappriate ADH secretion
Hyponatremia (more than 134mEq)
headache
vomiting
confusion
Summary
- thyroid hormones
- Adrenal Steroids (Glucocorticoids)
- Hypothalamic/pituatory axis (HPA)
- Posterior Pituatory (Oxytocin, ADH)
Kahoot quiz followed by
A patient with supraventricular tachycardia is prescribed a dose of verapamil 120mg to be taken 3 times a day .
How many tablets should be taken at each dose ?
120/3 = 40
Anterior pituItory hormone ?
ACTH
Posterior pituitory hormone?
antidieuretic hormone
Which drug would be the most effective in the maintanence therapy of hypothyroidism?
Levothyroxine
why does it take 1-2 weeks for carbamizole to reduce thyroxine levels in hyperthyroid disease?
Depletion of thyroxine stores
which drug would be the most effective at treating cardiac arrythmias due to hyperthyroidism?
proponolol
Most likely drug to contributing to these symptoms?
26 yrs old woman presents to her GP with tachycardia, weight loss and night time walking in a stressful state. Her medication list is shown bleow?
Levothyroxine
First test to check for patients with a sore throat on carbimazole?
A 44 year old female patient is prescribed carbimazole by her GP as a part of a block and replacement regimen for the treatment of thyrotoxicosis. Gp advised her to report any sore throat immediately.
Neutrophil count
Select the most appropriate treatment option,
29 years old with hasimotos thyroiditis has increasing anxiety, difficulty in sleeping and loose stools culture negative. Together with levothyroxine 200mcg daily. She is prescribed lopermide and lorazepem. Her next thyroid function test gives a TSH
Decrease the dose of thyroxine to 150 mcg daily
Which drug is an oral steroid used to treat severe forms of asthma and exacerbations of COPD?
Prednisolone
Select the most appropriate peice of information to communicate to the patient
An 80 year old woman presents to her GP with general lethargy and pain around her shpoulders and pelvis. Her ESR is elevated at 70mm/hr and she struggle to lift her arms over head. A diagnosis of polymyalgia
Select the most appropriate piece of information to communicate to the patient
Bisphosphonate should be added to reduce osteoporosis risk
select the most appropriate information to communicate to the patient
A 25 years old male is seen for follow up of his ulcerative collitis for which he takes mesalazine. He has now complained of increasing stool frequency with occasional blood and mucus. It is felt he is having a midl flare of his colitis and is commenced on oral prednisolone 30mg once daily
never stop prolonged courses of steroids suddenly
What is the major target site of action for the combined oral contraceptive?
hypothalamus
which drug mechanism might be useful in the prevention of premature labour ?
oxytocin antagonist
what volume of midazolam solution should be administered answer in millilitres?
An 8 month old boy weighing 9kg requires a dose of midazolam 2.5mg to be administered bucally for febrile convulsions. Buccal midazolam liquid is available
25ml
