Thyroid Clinical Flashcards
What causes hypothyroid
Usually primary but can be 2
Hashiomoto’s = most common
Iodine deficiency
Lithium
What can cause hypo and hyperthyroid
Subacute thyroiditis
Post-partum thyroiditis - usually transient but presence of Ab makes it more likely to persist
Amiadarone
What causes hyperthyroid
Grave’s
Toxic multi nodular goitre
TSH and T4 levels primary hypothyroid
TSH =.high as trying to stimulate
T4 = low
Secondary hypothyroid
TSH = low T4 = low
Subclinical hypothyroid
TSH = High - to maintain hormone T4 = normal but will become love
Poor compliance with thyroxine
TSH high
T4 normal
Grave’s / hyperthyroid
TSH low
T4 high
What are symptoms of hyperthyroid
Increased BMR + heat production - Weight loss - Heat intolerance Increased protein catabolism - Muscle weakness Increased CVS - Tachycardia - Palpitations - HF due to increased CO / angina - AF Hyper-reflexia Autonomic Sx Increased appetite Bone resorption / osteoporosis Anxiety Irritable Oligomenorrhoea Sexual dysfunction Goitre Thyroid eye disease
What affect does Thyroid hormone have on CVS
Permissive to epinephrine
What are autonomic Sx
Sweating
Tremor
Diarrhoea
What are symptoms of hypothyroid
Decreased BMR + heat - Weight gain - Cold Disrupted protein - Thick skin - Dry skin - Dry coarse scalp hair - Hair loss - Brittle nails Dereased CVS - Brady - Oedema Fluid retention = oedema, ascites, effusion Slow reflexes Carpal tunne Depression Aching joints Lethargy Constipation Menorrhagia Giotre
What does severe hypothyroid cause
Puffy face Large tongue Hoarse voice Coma Pleural effusion + oedema
What causes thyroid eye disease
Hypo or hyper
What are RF
Smoking
RAI
What are features
What are signs from least to most severe
Proptosis / exompthalos = same but used for Grave’s
Extra-ocular - opthamoplegia = paralysis
Corneal involvement
Sight loss
- Optic disc swelling
How do you Rx
Topical lubricant
Steroid
RT
Surgery
When do you get urgent ophthalmology review
Unexplained deterioration in vision Change in colour vision Hx eye popping out (globe subluxation) Corneal opacity Cornea visible when eye closed Disc swelling
What causes primary hypothyroid
Congenital Autoimmune -Hashiomoto's Iatrogenic Chronic iodine deficiency Post subacute thyroiditis 'De Quervain's Somatostatin Glucocorticoids
What are iatrogenic causes
Post thyroidectomy for hyperthyroid RAI Anti-thyroid drugs External RT Lithium Amiadarone
Congenital causes
Type 4
Maternal iodine deficiency
What is Hashimoto’s
Autoimmune destruction of thyroid gland
Cytotoxic T cells/ cytokines
Causes diffuse enlargement of gland / goitre to compensate
Can initially be hyperthyroid
What is associated with Hashimoto / Grave’s
DM
Addison’s
Pernicious anaemia
What Ab
Ab to thyroglobulin and thyroid peroxidase (TPO)
What causes secondary hypothyroid due to pituitary damage
Tumour
Craniopharyngioma
Post surgical Sheehan’s
Isolated TRH deficiency
What is subclinical hypothyroid
Mild symptoms but normal thyroid
Raised TSH to maintain at normal level
When do you consider treatment (don’t need to Rx )
If TSH >10
If TSH >5 with Ab present
Pregnancy
Symptomatic
What would overRx lead to
Osteoporosis
AF
as causes hyperthyroid
How do you investigate
TFT
Ab
Blood
What do you look for in blood of person with hypothyroid
Macrocytic anaemia Hyponatraemia due to SIADH if tumour Hyper-Cholesterol Hyper-Prolactin Increased muscle enzymes
How do you Rx
Levothyroxine (T4)
Titrate until stable
If TSH low then T4 dose too high
What do you do if change dose
Check levels after 8-12 weeks of TSH
What are SE and what drugs affect absorption
Hyperthyroid
Reduced BMD
Worsening angina
AF
Iron affect absorption / food so take 30 mins before
What are special situations
If IHD start at lower dose as may precipitate angina by increasing HR
If pregnant may need increased dose
What causes primary hyperthyroid
Grave's disease = most common Toxic mulinodular goitre - 2nd most Thyroid adenoma / solitary nodule De-Quervains following viral infection Drugs - amiadarone
What are causes of secondary hyperthyroid
Pituitary adenoma secreting TSH = rare
What causes thyrotoxicosis without hyperthyroid
Destruction as release hormones
- Amiadarone
- Post partum
Excessive levothyroxine
What is Grave;s disease
Ab produced that mimics TSH and activates thyroid
TSH receptor Ab = 90%
Anti-thyroid peroxidase