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73 Cards in this Set
- Front
- Back
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Why do you get increased sweating in hyperthyroidism?
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Both because of increased heat production and the increased symp NS action
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What happens to HR in hyperthyroidism?
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- Increased
- Can be irregular = due to supra-ventricular ectopic beats |
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What happens to reflexes in hyperthyroidism?
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HYPER reflexic
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What happens to periods in hyperthyroidism?
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Become lighter
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What happens to skin and hair in hyperthyroidism?
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Skin = warm, moist
Hair = oily |
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What eye features do you see in thyroid diseases? WHY?
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- Lid retraction and lid lag
Due to increased sympathetic activity These are NOT unique to Grave's (unlike proptosis/ exophthalmos) |
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What changes in the vascularity do we see in the thyroid in Grave's?
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Increased vascularity
= why you can hear a bruit |
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Is it true that GOITRE = HYPERthyroidism ?
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No. Can get goitre with hypothyroidism
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What's the most common cause of hypothyroidism in ares where iodine levels are sufficient?
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Hashimoto's
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In which of these are antibodies RESPONSIBLE for the disease process: Grave's, Hashimoto's, MG, Addisons?
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Antibodies responsible in Graves and MG
Not in Hashimoto's or Addison's |
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Do T-cells or antibodies cause Hashimoto's?
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T-cells
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Do T-cells or antibodies cause Grave's?
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Antibodies cause the disease
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What are the antibodies directed against in Hashimoto's? Are they causing the destruction?
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Antibodies against:
- Thyroglobulin - Thyroid peroxidase (TPO) BUT it's the T-cells that are causing the destruction |
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Why might you see increase in THs early in Hashimoto's?
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Get release of all the pre-formed and stored hormones
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Ratio of women:men in Grave's
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10:1
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What antibodies do they have in Grave's?
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Thyroid stimulating immunoglobulins
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What do we see morphologically in Grave's?
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Follicular ep cells are tall and more crowded than normal
The cells project into the lumen/colloid and actively reabsorb the colloid --> pale colloid |
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What are the antibodies directed against in Addison's? Are they responsible for the disease?
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Have antibodies against enzymes involved in steroid biosynthesis
Not responsible for the disease! |
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What are the target antigens in diabetes type I?
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Glutamic acid decarboxylase (GAD)
Tyrosine phosphatase Insulin itself |
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What % of beat cells have to be destroyed before you see hyperglycaemia / ketosis in T1 diabetes?
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90% destroyed
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If we can only do one test to look at thyroid function, what would we test?
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TSH levels
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After a change in thyroid status, how long does it take for TSH levels to reach a new equilibrium?
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4 weeks
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What isotope do we use to scan the thyroid?
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Technetium pertechnetate
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What do we see on a thyroid scan of subacute thyroiditis?
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DECREASED uptake!
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What are the two anti-thyroid drug classes? How do they work?
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- Carbimazoles eg neomercazole
- Proply-thiouracil They both block peroxidase activity (block iodine oxidation, tyrosine iodination and iodo-tyrosine coupling) In addition, PTU inhibits 5' deiodinase --> blocks conversion of T4 to T3 in periphery |
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Name some differences between the two antithyroid drugs
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- PTU acts on 5-deiodinase (as well as peroxidase like carbimazole)
- PTU has shorter half life (2hours) cf carbimazole (8hrs) -> needs to be taken 3x p/day where carb can be once daily - PTU is more protein bound -> less crosses placenta -> safer for first trimester - PTU has more S/Es |
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What's the biggest / most dangerous side effect of the anti-thyroid drugs?
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Agranulocytosis
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Which anti-thyroid drug is preferred in the first trimester of pregnancy?
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Propyl-thiouracil (PTU)
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For how long do we give anti-thyroid therapy in Grave's?
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12-18 months
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What do we give for symptomatic Tx in thyrotoxicosis? Why?
Which is our favourite one? |
Beta-blockers - they block the increased symp NS activity (eg tremor, palpitations and anxiety)
Propanolol - also blocks conversion of T4->T3 |
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How long does it take for radio-iodine treatment to take effect (Tx of thyrotoxicosis)?
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Months - sometimes it's beneficial to render patients euthyroid (with anti-thyroid drugs) before starting
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What meds do patients need after radio-active iodine Tx and after surgery?
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Thyroxine (they will be hypothyroid otherwise)
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Contra-indications for radio-iodine Tx?
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- Really big goitre
- Eye disease |
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When do you do a thyroidectomy as Tx for thyrotoxicosis?
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- They have obstructive symptoms
- Suspect thyroid cancer - Failure or non-compliance with meds - Very large goitre |
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Standard treatment of thyroid carcinoma?
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Thyroidectomy followed by 131-I (in large doses) (wait for them to be hypothyroid before you start the iodine - this will mean you have very high TSH levels - this increases iodine uptake)
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What symptoms do you get in anxiety?
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- Shakiness, trembling
- Flushes, chills - Sweating - Nausea, churning stomach - Palpitations |
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What happens to conc of the following hormones: CRH, ACTH, prolactin, vasopressin, cortisol and adrenaline, during anxiety?
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They're all INCREASED
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What drugs can we used in Tx of anxiety?
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- Benzos
- SSRIs (need higher doses cf for depression, they're anxiogenic for the first little while) - Azapirones (serotonin R agonists) |
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What are the three catecholamines of importance?
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Adrenaline
Noradrenaline Dopamine |
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Where is dopamine secreted from?
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The extra pyramidal mesocortical and mesolimbic pathways
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What are all catecholamines synthesised from?
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Tyrosine
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Describe the synthesis of catecholamines
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Come from tyrosine originally
It's converted to DOPA by the enzyme tyrosine hydroxylase then to DA/ Nor/ Adr |
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What does activation of beta Rs on teh heart do?
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Increased force of contraction
Faster AV node conduction |
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What does activation of beta Rs on the juxtaglomerular cells of the kidney do?
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Increase renin secretion
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What does activation of beta Rs on smooth muscle do?
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Relaxation of smooth muscle
--> relaxation of BVs, bronchi, gut and genitourinary systems |
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What does activation of beta Rs in adipose tissue do?
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Activates lipolysis
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What happens in the cell when adrenaline binds to a beta R?
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G-protein activated
-> AC stimulated --> cAMP increased |
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What happens in the cell when alpha adreno Rs are activated?
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Inhibition of AC --> decreased cAMP --> activation of phospholipase C --> increased intracellular Ca2+
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What is phaeochromocytoma?
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A relatively rare tumour
In 90% of cases, it arises in the adrenal medulla -> increased secretion of adrenaline / noradrenaline |
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What is basal metabolic rate?
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Energy expended by humans when they're completely at rest but not asleep, in the absence of muscle movement and without any symp NS arousal
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What's teh difference between resting metabolic rate (RMR) and basal MR?
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Basal -> no muscle movement at all, no symp NS arousal. Very difficult to achieve
-> We measure RMR. Resting MR is usually about 10-15% higher than BMR |
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What are the two ways we can measure RMR?
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- Indirect calorimetry (measure gaseous exchange in fasted state using ventilated hood / mask technique)
- Direct calorimetry (in a metabolic chamber) |
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What's the metabolically active tissue in humans?
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Lean body mass (fat free mass)
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What's the relationship between size of a person and their BMR?
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Larger the person -> higher the BMR
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What's the difference in BMR between obese and lean people?
What about when you adjust for their lean body mass? |
- Obese -> increased BMR (because they have more lean body mass to support the fat)
When you adjust for lean body mass, will be the SAME |
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What happens to BMR in hypothyroidism?
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Decreased
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What's the grading system of goitres?
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0 = no goitre visible or palpable
1a = can palpate it when neck extended, can't see it when neck extended 1b = can see and palpate when neck fully extended 2 = goitre is visible with neck in normal position 3 = very large goitre recognisable from a considerable distance |
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What's the most common cause of non-toxic diffuse / non-toxic multinodular goitres?
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Dietary iodine deficiency
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What's the most common cause of toxic diffuse gotire?
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Grave's disease
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What's the most common type of thyroid cancer?
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Follicular cell cancer
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What cell types can thyroid cancers originate from?
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Follicular cells
C-cells Thyroid lymphocytes |
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What are the boundaries for the anterior neck triangle?
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SCM muscle
sternal notch and medial line Mandible |
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What are the boundaries of the posterior neck triangle?
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SCM
Clavicle Anterior border of trapezius muscle |
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What LNs could you feel in the posterior neck triangle?
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- Supraclavicular nodes
- Along the accessory nerve - In the occipital region |
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What lumps can you feel in the middle of the anterior neck triangle?
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Submental LNs
Thyroglossal duct cysts Nodules in isthmus of the thyroid |
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Where does the thyroid originate from embryologically?
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The foramen caecum at the base of the tongue
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What's the thyroglossal tract?
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The remnant of the descent of the thyroid (From the foramen caecum at base of the tongue, down around the hyoid bone then in front of the thyroid cartilage)
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What lumps can you feel more laterally in the anterior triangle of the neck (Middle lumps covered in a different card)
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Nodules in the thyroid gland
Enlarged submandibular salivary glands Enlarged LNs in jugular chain Branchial cysts Carotid body tumours |
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Where in the neck would you feel carotid body tumours?
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In the lateral parts of the anterior triangle
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What are branchial cysts?
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They arise from vestigial branchial clefts
They protrude beneath the anterior border of the upper 1/3 of the SCM |
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What could a single thyroid nodule be due to?
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- simple thyroid cyst
- colloid nodule - dominant nodule in a multi-nodular goitre - benign adenoma - thyroid cancer - localised area of thryoiditis |
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What could cause an enlarged salivary gland?
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Inflammation
Tumour (submandibular gland can be intermittently enlarged due to obstruction of the submandibular duct by a calculus) |
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Metastatic involvement of LN in the neck region -> where could the cancer have come from?
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Mucosal squamous cancer in the oropharynx, nasopharynx or larynx
Thyroid cnacer Skin cancer of face / scalp |
