Thyroid 2 Flashcards
What is the AMES risk system?
Age, Metastases, Extend of primary tumour, Size of primary tumour
When would a Thyroid lobectomy with isthmusectomy be used?
Papillary microcarcinoma (less than 1cm in diameter), minimally invasive follicular carcinoma with capsular invasion only, patients in AMES low risk group
When would a sub total or total thyroidectomy be used?
DTC with extra-thyroidal spread, bilateral/multifocal DTC, DTC with distant mets, DTC with nodal involvement
What is done post surgery in sub total/total thyroidectomy patients?
Radioiodine ablation I131, T3 and T4 stopped beforehand to ensure TSH is elevated to produce best result.
What happens if uptake in the thyroid bed following radioiodine ablation is >0.1%?
Thyroid Remnant Ablation
What will patients following TRA be discharged on?
T3 or T4
What should be measured pre-op in suspected thyoid carcinoma patients as it can be a tumour marker?
Anti-thyroglobulin antibodies
What is the commonest cause of hypo/hyperthyroidism?
AI thyroid disease
What laboratory results would you expect in primary overt hypothyroidism?
Raised TSH, decreased fT4, normal or decreased fT3
What laboratory results would you expect in primary subclinical hypothyroidism?
Slightly raised TSH, normal fT4 and fT3
What laboratory results would you expect in secondary hypothyroidism?
Decreased or normal TSH, decreased fT4, decreased or normal fT3
What is myxoedema?
Either refers to severe hypothyroidism e.g. Myx coma, or accumulation of hydrophilic mucopolysaccharide in subcutaneous tissues
What is the cause of Atrophic AI hypothyroidism?
Antithyroid antibodies leading to lymphoid infiltration of the gland and eventual atrophy and fibrosis.
What is the cause of goitrous chronic thyroiditis (Hashimoto’s)
Type of AI hypo, hereditary defects and maternally transmitted causes (antithyroid agents, iodides)
A deficiency of what causes a goitrous hypothyroidism and why?
Iodine deficiency due to borderline hypot leading to TSH stimulation and thyroid enlargement
What are some causes of non-goitrous hypot?
Congenital defect, atrophic thyroiditis, post-ablative (radioiodine, surgery), postradiation
What are some causes for self limiting hypot?
Withdrawal of suppressive thyroid therapy, subacute and chronic thyroiditis with transient hypot, postpartum thyroiditis
Why does Hashimoto’s thyroiditis reduce thyroid hormone production?
AI destruction of thyroid gland
What sex is affected more so by AI hypot?
Females
What is Hashimoto’s characterised by?
Thyroid Peroxidase Antibodies in blood, T-cell infiltrate and inflammation on microscopy
What are the symptoms of hypothyroidism?
Lethargic, decreased mood, cold-intolerance, weight increase, constipation, menorrhagia, hoarse voice, decreased memory/cognition, dementia, myalgia, cramps, weakness
What are the signs of hypothyroidism?
Think BRADYCARDIC- Bradycardic, Reflexes relax slowly, Ataxia, dry thin hair/skin, yawning, cold hands, ascites +-non-pitting oedema +- pericardia/pleural effusion, round puffy face, defeated demeanour, immonile +ileus, CCF. Also neuro/myopathy, goitre
What lab results would you expect in hypothyroidism other than TFTs?
Macrocytyosis typical (rule out B12 deficiency, elevated CK, increased LDL cholesterol, hyponatraemia, hyperprolactinamia
What antibody levels would you expect in AI hypot versus Graves?
Anti-TPO-95% vs70-80, anti-thyroglobulin 60 vs 30-50, TSH receptor antibody 10-20 (blocking) vs 70-100 (stimulating)
What is the management of hypothyroidism?
Normal metabolic rate should be restored gradually. Levothyroxine in young, same in elderly but smaller dose adjusted every 4 weeks. Check after 2/12.
What is myxoedema coma?
Severe hypothyroidism presenting with confusion or coma, often in elderly women with untreated hypot
What findings would you expect in myxoedema coma?
ECG-bradycardia, low voltage complexes, varying heart block, T wave inversion, prolongation of QT interval, type 2 resp failure, hypoxia, hypercarbia, resp acidosis, co-existing adrenal failure in 10%
How would you treat Myxoedema coma?
ABCDE. Rewarm, cardiac monitoring, monitor bp, cvp ,oxygen, urine output, BM, fluids, electrolyte balance, broad spectrum antibiotics, caution with thyroxine (low doses) and hydrocortisone
What are the symptoms of hyperthyroidism?
Diarrhoea, weight decrease, appetite increase, overactive, sweats, heat intolerance, palpitations, tremor, irritability, labile emotions, oligomenorrhoea +-infertility
What are some signs of hyperthyroidism?
Fast/irregular pulse (AF or SVT), warm moist skin, fine tremor, palmar erythema, thin hair, lid lag, lid retraction, goitre, thyroid nodules or bruit depending on case
What are signs of Graves disease?
Eye disease, pretibial myxoedema:oedematous swelling above lateral malleoli, thyroid acropachy:extreme with clubbing, painful finger and toe swelling, periosteal reaction in limb bones
How is Graves disease caused?
Serum IgG antibodies bind to TSH receptors in the thyroid, stimulating thyroid hormone production, they behave like TSH. These antibodies are specific for Graves.
What test results will you find for Graves?
High T3/4, low TSH. Antibody +ve (TRAbs), smooth symmetrical goitre (scintigraphy)
What will happen by 18 months in Graves patients?
50% will have burnt out, 50 will relapse
What opthalmopathys can be present in Graves?
Lid retraction/lag, chemosis, proptosis, visual loss, diplopia
What is the treatment for opthalmopathys in Graves?
Lubricants, decompression surgery, radiotherapy, corrective surgery, stop smoking
What are the defining features of Toxic multinodular goitre?
Older patients, more insidious onset, gland may feel nodular
What test results would you expect on TMG?
High T3/4, low TSH, antibody -ve (TRAbs), assymetrical goitre on scintigraphy
What are the features of thyroid storm?
Emergency-severe hyperthyroidism, resp/cardiac collapse, hyperthermia, exaggerated reflexes, maybe associated underlying infection
What is the treatment of thyroid storm?
Lugols iodine, glucocorticoids, PTU, b-blockers, fluids, monitoring, may require ventilation
What is the treatment of hyperthyroidism?
Carbimazole, propylthiouracil (preferred in pregnancy). To treat symptoms rapidly use b-blocker-propranolol. Risk of agranulocytosis
What is the 2nd line treatment of hyperthyroidism?
Radio-iodine
What are some precautions in taking radio-iodine for hyperthyroidism?
Most become hypothyroid post treatment. Avoid pregancy, don’t share a bed for x days, ensure not pregnant. Risk of thyroid storm
What is the 3rd line treatment for hyperthyroidism?
Surgery-thyroidectomy
What are some types of thyroiditis?
Graves, hashimotos, De Quervains/subacute (viral), post-partum, drug induced and radiation, acute/suppurative (bacterial)
What is the cause of de Quervains?
Acute inflammatory process-likely viral origin.
What may be associated with de Quervains?
Sore throat/fever, other viral symptoms
How will de Quervains progress?
Usually self limiting (over few months)
What test results will you see in de Quervains?
T4-high in early stage, low in late then normal, TSH- low in early, high in late, normal. Scintigraphy-low uptake
What drug can often induce thyroid dysfunction-both hypo/hyper?
Amiodarone
What pattern exists in amiodarone patients developing hyper or hypothyroidism?
In low iodine intake area thyrotoxicosis more likely, in high area hypothyroidism more likely
Why does amiodarone cause adverse effects on the thyroid?
It’s high iodine content
