55 Endocrine investigations Flashcards
What does low TSH and low thyroxine (T4) indicate?
Pituitary failure.
What does high TSH and low thyroxine (T4) indicate?
Unresponsive thyroid.
What does low TSH and high thyroxine (T4) indicate?
Thyroid gland overproduction.
What does high TSH and high thyroxine (T4) indicate?
Pituitary gland overproduction/feedback failure.
What are the features of Cushing’s syndrome? (7).
Central obesity (moon face). Thin skin with purple striae. Hypertension. Glucose intolerance. Thin limbs. Osteoporotic back pain. Depression + psychoses.
What is Cushing’s syndrome due to?
Excess cortisol.
What are the features of Addison’s disease? (6).
Tiredness. Weight loss. Pigmentation. Hypoglycaemia. Abdominal pain. Hypovolaemic collapse.
What is Addison’s disease due to?
Insufficient cortisol.
Which test is used in suspected Cushing’s?
Dexamethasone supression test.
Which test is used in suspected Addison’s?
Synacthen stimulatory test.
Why is it futile to test thyroid function in hospital patients?
Thyroid markers rise and then fall in non thyroidal illness.
Which binding proteins does thyroxine bind to? (3).
TBG.
Albumin.
TBPA.
Which binding protein do sex hormones bind to? (2).
Albumin.
SHBG.
What does IGF-1 bind to in the blood?
IGFbp.
What is sick euthyroid?
Unusual levels of T3/4 but thyroid is normally functioning. Adaptation of hypothalamic-thyroid-pituitary axis.
