Thyroid Flashcards
Causes of hyperthryoidism
Graves's disease - Ab against TSH receptor causing stimulation. 5:1 F:M. ~ 40 to 60 Toxic nodular goitre - not autoimmune and solitary. F/M. Later life. Uncommon Subacute thyroiditits Hashimoto's thyroiditis Amiodarone therapy Iodine- induced Rare TSH secreting pituitary tumour.
Presentation of hyperthyroidism
Classic triad features
Goitre - Hyperthyroidism - viscerally enlarge thyroid
Exopthalmos - infiltrative ophathalmopathy - proliferation of tissue so not reverse
Dermopathy- pre tibial myxedema (minority)
Clinical presentation
Increase sympathetic activations
Younger patients - anxiety, hyperactivity and tremor
Older patient - more CV symptoms - Dyspnoea, AF, weight loss
Symptoms of Hyperthyroidism
Weight loss Diarrhoea Osteoporosis Myopathy anxiety hair loss Heat intolerance palpitations Amenorrhagia Polyphagia - increase appetite Increase swelling Irritability Exertion dyspnoea
Hx questions for Hyperthyroidism
History of thyroid problems?
FmHx of thyrotoxicosis or vitiligo, addison’s disease, pernicious anaemia, type 1 DM, Myasthenia graves and premature ovarian failure.
Amiodarone or thyroxine?
Recent exposure to iodine eg iodinated X-ray contrast materials.
Palpitations? Red flag for AF causing HF.
Insomnia, irritability or hyperactivity?
Loss of Wt, diarrhoea or ↑stool frequency, ↑ sweating or heat intolerance?
Muscle weakness? problems getting out of chair
Eye problems eg double vision, grittiness, redness or pain. Watery eyes, photophobia?
Signs of Hyperthyroidism
GI - Anxious, Exophthalmos - staring appearance, weight loss, thyroid facies, psychosis, Hair loss
Vitals: tachycardia ST, AF or collapsing character, BP-hypertension, RR +/-, temp, BMI- decrease, BSL- decrease
Hands - I - tremor, onycholysis, acropathy, warm, moist palms, palmer erythema,
P - proximal myopathy, Bicep reflex - hyperreflexia
Face - I -sweaty and oily,
Eyes : exophthalmos - lid retraction, protrusion, Lid lag, proptosis, conjunctival and periorbital oedema.
Complications of proptosis: chemosis, conjunctivitis, corneal ulcers, ocular motility, Optic atrophy.
Vision acuity, field, confrontation test, pupillary and fundiscopy examination (disc swelling, or atrophy)
Neck -I – visible enlargements (diffuse, smooth and firm = grave’s, one nodule = solitary toxic adenoma, Multiple nodules = MNG, firm and tender gland = De Quervain’s.
I Dilated veins, pemberton’s signs, lymph nodes, stridor on open mouth inspiration, Scars
Cup of water and inspect for movement: movement up pause than down (Goitre), Cancer wont move.
Thyroglossal will move up when tongue in protruded.
Look for inferior border.
P - From back while swallowing, lymph nodes +thrills. Partially flexed
Characterise any swelling seen/ felt and comment on:
Size (feel for lower border as absence suggests retrosternal extension)
Shape (may feel nodules in MNG)
Consistency (soft normally, rubbery hard in Hashimoto’s, stony hard in carcinoma and fibrosis
Tenderness (feature of thyroiditis)
Mobility (carcinoma may tether gland)
Thrill (palpable over gland, when gland is unusually metabolically active as in hyperthyroid)
Front - palpate again, Tracheal displacement, carotid pulse, stridor on inspiration
P - front of sternum across chest for retrosternal extension.
A - bruits over thyroid and carotids
Extra - pemberton’s signs
Chest - Gynaecomastia, Pericarditis, signs of CCF and systolic flow murmurs, Hyper apex beat, S3
Resp - Pleural oedema
Abdo-
Legs - Proximal myopathy (ask to squat), pretibial myxoedema (bilateral firm, elevated dermal nodules and plaques), hyper reflexes
Cx of Hyperthyroidism
Thyroid storm - Sudden severe hyperthyroidism: fever, tachycardia, AF, Arrhythmia
Psycosis
Cardiac dysrhythmiase eg AF -> embolic stroke. Need anticoagulation and cardio version once euthyroid.
Ix for Hyperthyroidism
TFT
TSH - decreased
T4 - increased
T3 - increased or normal
Antithyroid Ab - increased or normal
Thyroid receptor Ab - increased or normal
Nuclear scans - to Dx causes - iodine uptake scan
Technecium scan - Less radiation, Cost less
CT for unilateral eye signs to exclude tumour
Mx of hyperthyroidism
Antithyroid drugs - 1st line
carbimazole, propylthiouracil: Inhibits thyroperoxidase
Radioactive iodine
Slow to act > 3 months
Commonly causes hypothyroidism
Contraindicated in children, nursing mothers and pregnant women or soon to be pregnant
AE - thyroiditis like AE acutely and slightly increase risk of cancer.
Surgery
Indication - Large goats or respond poorly to other modalities of tx.
Complication - recurrent laryngeal nerve palsy, permanent hypoparathyroidism and hypothyroidis, Thyroid crisis during surgery if poor control prior. relapse.
Eyes - artificial tears, sunglasses, and diuretics for severe oedema. Sleeping with raised head of the bed. If severe then high-dose steroids, azathioprine, surgical decompression and or radiotherapy.
Symptom control
Beta blockers - stop tremor and palpitation. Used as sole treatment in transient mild hyperthyroidism postpartum, subacute thyroiditiss and when antithyroid drugs are contraindicated
Prognosis
Good. Eventually become hypothyriodism
AE of antithyroid Medication
Agranulocytosis Aplastic anaemia Hepatotoxicity Hair loss, lupus like syndrome Myopathy, vasculitis, nepritis Taste disturbances Neuritis, oedema, skin pigment Sialadenopathy, lymphadenopathy Jaundice
Causes of hypothyroidism
autoimmune - Hashimotos’ Autoimmune destruction of thyroiditis = hypothyroidism. Most common primary.
post radioactive iodine - Most common
Post surgery - Most common
secondary to pituitary failure - uncommon
Iodine deficiency - Commonest in first world.
Dyshormonogenesis
viral thyroiditis
Amiodarone
Lithium
Epidemiology and common comorbidities of Hypothyroidism
Commonest cause of non endemic goitre Age - 45-65 yr Female - 10-20:1 females develop antibodies faster. can be any age, sex, even children
Common comorbidity other autoimmune disorders Diabetes M Pernicous Anaemia Vitilago B cell lymphoma Papillary carcinoma
Symptoms of Hypothyroidism
Classic features on legs thick firm sub cut tissue Non pitting oedema - pre tibial - due to accumulation of protein in sub cut Dermatitis Commonly no palpable goitre Rarer is a period of hyperthyroidism
Symptoms Weight gain apathy, low concentration Depression - K 10 Constipation weakness Deafness Diminished sweating Menorrhagia Prone to hypothermia memory loss missing of the outer 1/3 of eyebrow carpal and tarsal tunnel Hoarse voice Lethargy swelling of eyelids Coarse skin Orange - hypercarotenaemia
Signs of Hypothyroidism
GI - psychosis, dry hair, loss of outer third of eyebrow, Myxoedemic face , typical complexion, gruff voice, Orange, loss of sweating, Hoarseness of voice.
Vital - bradicardia, Increase BMI, small volume pulse
Hands - carpal tunnel syndrome, muscle weakness, Delayed reflexes, cyanosis(reduced CO) swelling of the skin, cool and dry, palmer crease pallor (anaemia of ACD, VITB12 def, IDA - menorah), Xanthomata
Face - hearing test, swelling, dry hair, yellow skin but not sclera, skin thickened, +/- alopecia or vitiligo
Eye - 1/3 eye brow missing, periorbital oedema, Xanthelasmata
Mouth - swollen tongue, coarse voice
Neck - I - Goitre - non tender, diffuse, rubber
Chest - IHD sign, Pericardial effusion?
Resp - Pleural effusion
Abdo - Ascites
Legs - dry cold skin
Non pitting oedema - due to accumulation of proteins in sub cut
Muscle weakness - squat
Relayed reflexes
Cx of hypothyroidism
Myxoedema coma Medical emergency usually in elderly people Signs are coma and hypothermia Prognosis - 50% fatal Mx Intensive nursing care NGT suction Cautious fluid therapy passive rearming Corticosteroid therapy IV T3 Treatment of underlying disease Oral levothyroxine - caution if hypopituitarism or hypo adrenal then delay T3/4 therapy by several day.
IX of hypothyroidism
ECG changes - IHD TFT TSH - increased T4 - decreased T3 - decreased or normal Antithyroid AB - increased or normal Thyroid receptor Ab - increase or normal only further imaging if pressure symptoms or suspicious feeling nodule then do aspiration cytology and USS. Lipids LFT
