Thyroid! Flashcards
Thyrotoxicosis
↑T4 - gland hyperfunction
Thyrotoxicosis symptoms
Diarrhoea Increased appetite/wt loss Sweats, heat intolerance Palpitations, AF Tremor Manic/irritability/anxiety Oligomenorrhoea/infertility
Thyrotoxicosis signs
Fast/irregular pulse Fine tremor Palmer erythema Thin hair Lid lag/retraction Goitre Nodules
Causes of thyrotoxicosis
Graves disease
Toxic multinodular goitre
Drugs (amiodarone)
Thyrotoxicosis investigations
Low TSH
Increased T4 &T3
Increased calcium & LFTs
What is Graves disease?
autoimmune over activation of thyroid
anti-TSH antibodies
T1DM, vitiligo, addisons
Graves specific signs!
Diffuse goitre
Exophthalmos
Pre-tibial myxoedema (lesions)
Thyroid acropachy (clubbing/thick)
Hyperthyroidism treatment
Propanolol - 4 symptoms like tremor Carbimazole - blocks thyroid peroxidase/hormone synth reduce gradually SE: agranulocytosis If relapse - radioiodine treatment
Thyroid treatment in pregnancy
hyper = propylthiouracil hypo = increase dose up to 50%
Thyroid synthesis
Hypothalamus –> TRH - thyrotropin releasing hormone
Ant pit –> TSH - thyroid stimulating hormone
Thyroid:
T4 = Thyroxine
T3 = Triiodothyronine
regulate energy source use, protein synth, bodies sensitivity to other hormones
Hypothyroidism types?
Primary - gland problem /autoimmune d
Secondary - pituitary disorder/compression
Congenital
Hypothyroidism symptoms
Weight gain Lethargy Cold intolerance Dry anhidrosis, cold, yellow skin Non-pitting oedema - hands, face Dry, coarse scalp hair Loss of lateral aspect of eyebrows Constipation Menorrhagia Decreased deep tendon reflexes Carpal tunnel syndrome
Hashimoto’s thyroiditis
Autoimmune hypothyroidism
TPO +ve
Goitre
can have transient thyrotoxicosis in acute phase
De Quervains
Subacute thyroiditis
painful goitre
post viral URTI
raised ESR
Causes of hypothyroidism
Hashimotos De Quervains Iodine deficiency Post partum Drugs - carbimazole, lithium, amiodarone *Atrophic thyroiditis (UK)
Atrophic Thyroiditis
anti-TPO, anti-TSH +ve
No goitre
Pernicious anaemia, vitiligo
Hypothyroidism investigations?
high TSH low T3/T4 increased MCV, normochromic anaemia increased triglyceride, cholesterol hyponatraemia (SIADH) TPO, TSH antibodies
Hypothyroidism management?
Levothyroxine
thyroid storm
acute, life-threatening
excessive thyroid hormones
treat: beta blockers, propylthiouracil and hydrocortisone
myxoedema coma
severe hypothyroidism!
Hypothermia, hypoglycaemia
Heart failure: bradycardia, low bp, coma, seizures
Simple goitre
Diffuse painless Dysphagia Stridor SVC obstruction Usually euthyroid Iodine deficiency
Papillary thyroid malignancy
Follicular cells Tg tumour marker Lateral aberrant thyroid Total thyroidectomy, node excision, radioiodine T4 to suppress TSH
Parathyroid hormone
Low Calcium => PTH secretion - Increases osteoclast activity - Increases Ca2+ - Decreases PO4 resorption in kidney Kapow! - Increases a-hydroxylation of 25OH-vitD3
Primary hyperparathyroidism
Solitary adenoma Hyperplasia of gland Ca2+ increased inappropriately - normal PTH - increased ALP - decreased PO4
Primary hyperparathyroidism investigation
ECG - decreased QTc, Brady cardia, 1st d HB
X ray - osteitis fibrosa cystica –> phalangeal erosions
DEXA - osteoporosis
Parathyroid hormone
Low Calcium => PTH secretion - Increases osteoclast activity - Increases Ca2+ - Decreases PO4 resorption in kidney Kapow! - Increases a-hydroxylation of 25OH-vitD3
Primary hyperparathyroidism
Solitary adenoma Hyperplasia of gland Ca2+ increased inappropriately - normal PTH - increased ALP - decreased PO4
Primary hyperparathyroidism investigation
ECG - decreased QTc, Brady cardia, 1st d HB
X ray - osteitis fibrosa cystica –> phalangeal erosions
DEXA - osteoporosis
Primary hyperparathyroidism mgmt?
Increase fluid intake
Avoid dietary Ca2+ and thiazides (increase serum Ca)
Surgical excision of adenoma
Secondary hyperparathyroidism causes?
Vitamin D deficiency
Chronic renal failure
- bone disease, osteitis fibrosa cystica
- soft tissue calcifications
Secondary hyperparathyroidism mgmt?
Phosphate binders - With Ca - calcichew - Without - sevelamer, lanthanum Vitamin D - calcitrol = active - cholecalciferol = inactive
Tertiary hyperparathyroidism causes
Prolonged secondary HPT –> autonomous PTH secretion
Tertiary hyperparathyroidism
v high PTH, high Ca,
always w CKD
Tertiary hyperparathyroidism mgmt?
if not resolved
remove affected gland or
total parathyroidectomy
symptoms of low calcium? hypoHPT
Spasms - Trousseau’s sign Perioral paraesthesia Anxious, irritable Seizures Muscle tone increase - colic, wheeze, dysphagia Orientation - confusion Dermatitis Impetigo herpetiformis Chovsteks, cardiomyopathy (↑ QTc → TdP)
Causes of Hypoparathyroidism
Autoimmune
Congenital - DiGeorge
Hypoparathyroidism mgmt?
Ca supplements
Calcitriol
Hypoparathyroidism
Decreased PTH due to gland failure so low calcium!!!! low Ca high PO4 lowPTH normal ALP
