ENT/thyroid Flashcards
neck lump features during examination
site size consistency edge relationship to: muscles, trachea, hyoid
what nerve lies behind the superior thyroid artery?
external laryngeal nerve
hormones secreted by the posterior pituitary?
oxytocin
ADH
hormone secreted by the anterior pituitary
TSH ACTH FSH & LH GH Prolactin Endorphins
features of hyperthyroidism
heat intolerance, sweating weight loss, diarrhoea, increased appetite tremor, coma tachycardia, HF, dyspnoea eye disease myopathy, periodic paralysis menstrual irregularity gynaecomastia
features of hypothyroidism
cold intolerance dry nails, skin, hair facial oedema pallor non-pitting oedema constipation psychosis, coma, death
examination findings in hyperthyroidism
agitation tachycardia warm clammy hands brisk reflexes eye signs - proptosis, exopthamlos. lid lag, lid retraction opthalmoplegia thyroid acropachy pre-tibial myxoedema goitre
examination findings in hypothyroidism
coarse features
bradycardia
slow relaxing reflexes
goitre
aetiology of hyperthyroidism
grave's disease - 70% multinodular goitre - 20% toxic adenoma - 5% thyroiditis amiodarone/iodine induced (Jod-Basedow phenomenon)
aetiology of hypothyroidism
Grave's disease (toxic diffuse goitre) thyroiditis iatrogenic (surgery, radiotherapy) Drugs - amiodarone, lithium congenital iodine excess or deficiency
thyrotoxic
TSH low
FT4 high
Hypothyroid
TSH high
FT4 low
risk factors for grave’s eye disease
smoking
Male
high initial FT4 >70
anti-thyroid drugs (thyrotoxicosis)
carbimazole, propylthiouracil
inhibit iodination of tyrosine, inhinit FT4 –> FT3 conversion
risks of thyroidectomy
hypocalcaemia
hypo/hyperthyroidism
features of thyroid storm
tachycardia, fever, encephelopathy, fits, stroke, HTN, D&V, circulatory collapse, death
(treat with propylithiouracil, iodine, steroids, beta-blockers, I.V. fluids
treatment of hypothyroidism
L-Thyroxine (100-150mg OD)
tri-iodothyronine
(+ IV fluids and steroids for hypothroid coma)
Normal FT4/FT3
Low TSH
subclinical hyperthyroisism
e.g. recent treatment for hyperthyroidism, drugs (steroids, dopamine), non-thyroidal illness (NTI)
Normal FT4/FT3
High TSH
subclinical hypothyroidism e.g. poor compliance with thyroxine malabsorption of thyroxine drugs (amiadarone) NTI recovery phase TSH resistance
adrenal disease - Cushing’s
illness resulting from chronic exposure to high levels of cortisol
clinical features of cushings
moon face acne, thinnig of skin, striae, bruising hirsuitism, thinning of scalp hair truncal obesity proximal muscle weakness mood disturbances, depression
associated features of cushings
HTN (>50%) impaired glucose tolerance/DM osteopenia & osteoporosis vascular disease coagulopathy susceptibility to infection
endogenous causes of cushings
ACTH-dependent:
Pituitary adenoma, ectopic ACTH syndrome, ectopic CRH secretion
ACTH-independent (adrenal):
adenoma, carcinoma, nodular hyperplasia
DDx for cushings
psuedo-cushings
alcoholism
severe depression
Hypoadrenalism causes:
primary: autoimmune, secondary deposits, TB, HIV
secondary: prolonged exogenous steroids, pituitary lesions
Hypoadrenal/addisonian crisis
causes: severe physical shock, e.g. car crash; severe infection; severe dehydration
Sx of hypoadrenal crisis
extreme weakness confusion drowiness --> coma pronounced dizziness nausea and/or vommiting headache abnormal heart rate low BP feeling v. cold possibly febrile possible abdo tenderness
Addisons is:
detruction of the adrenal cortex leading to cortisol and aldosterone deficiency.
Aldosterone:
essential for Na conservation in the kidney
e.g when dehydrated, increase Na reabsorption to decrease water loss
Cortisol:
released in response to stress and low blood glucose. e.g will prepare the body for activity by freeing up glucose into the blood
renin-angiotensin system
In response to low sodium, or reduced renal blood flow, juxtaglomerular cells secrete renin. this converts angiotensin I into angiotensin II via the enzyme ACE.
angiotensin II triggers aldosterone release by adrenal glands, which act on the kidneys to decrease sodium and therefore water excretion (raise BP)
