human development - endocrinology clinical Flashcards
what is hypothyroidism?
when the thyroid gland does not produce enough thyroid hormone (thyroxine or triiodothyronine)
what is the difference between primary and secondary hypothyroidism?
primary - thyroid gland abnormality; not able to produce TS4 and TS3. most common form of hypothyroidism
secondary - pituitary gland abnormality; not able to produce TSH to stimulate the thyroid gland to produce TS4 and TS3
what is the difference between tertiary and resistance hypothyroidism?
tertiary - hypothalamus abnormality, perhaps due to radiation. unable to produce TRH to stimulate thyrotrophs in the pituitary that produce TSH.
resistance - thyroid hormone receptors aren’t functioning so tissues are resistant to thyroid hormone effects
what is a suprasellar mass?
situated or rising above the sella turcica (saddle shaped depression in the body of the sphenoid bone)
what is the optic chiasm?
- essential for visual pathway
- part of the brain where optic nerves from each eye cross
- located inferior to the hypothalamus but superior to the pituitary
what is hypopituitarism?
when there isn’t enough of one or more of the pituitary hormones (TSH, FSH, LH, GH, PRL, ACTH)
what are the clinical signs for hypopituitarism?
- gaining of weight
- loss of sexual drive (libido)
- loss of menses (periods in women, erections in men)
- fatigue
- loss of hair in the face, skin becomes soft
what causes hypopituitarism?
- tumour compressing optic chiasm and pituitary gland
- this causes interference between the hypothalamus and pituitary gland
- so trophic hormones produced by the hypothalamus can no longer reach the anterior pituitary cells
what are the types of pituitary tumours in terms of size?
- micro adenoma: <10mm
- macro adenoma: >10mm
what are the types of pituitary tumours in terms of function?
- functioning: over secrete hormones; gives rise to endocrine syndromes
- non functioning
what are the functioning macro-adenomas?
- prolactinoma
- Cushing’s (ACTH)
- acromegaly (GH)
(about half of the tumours are non functioning)
what are the different ways pituitary tumours can be treated?
- conservative/surveillance (watch and do nothing) as they can be slow growing tumours
- majority of macro-adenomas are treated surgically (trans-sphenoidal surgery)
- majority of micro-adenomas are treated conservatively or medically
- prolactin secreting tumours are treated medically
- radiotherapy if there is a high likelihood of regrowth after removal
what are the clinical signs for hypothyroidism?
- slowing of metabolic processes
- weight gain
- cold
- tired
- constipation
- bradycardia
- low mood
- thin hair
- dry skin
what causes hypothyroidism?
- iatrogenic: surgery or radio iodine treatment
- chronic autoimmune thyroiditis (most common): atrophic or Hashimoto’s
how can be hypothyroidism be treated?
- levothyroxine
75 - 125 mcg/day
what are the clinical signs for hyperthyroidism/thyrotoxicosis?
- breathlessness
- shaking
- sweating
- palpitations
- restlessness
- diarrhoea
- muscle stiffness and weakness
- lid retraction (eyelid is higher than expected)
- lid lag (eyelid movement lags behind the movement of the eyes)
what are the causes of hyperthyroidism/thyrotoxicosis?
- grave’s disease: thyroid gland is overactive
- toxic thyroid nodule: nodule in the thyroid gland which autonomously produces excessive thyroid hormone
how can hyperthyroidism/thyrotoxicosis be treated?
- 6-12 month course of treatment
. carbimazole (better)
. propylthiouracil - radio iodine (avoid in thyroid eye disease)
- surgery
how can thyroiditis be classed?
- painless (lymphocytic and Hashimoto’s)
- painful (granulomatous and radiation induced)
are thyroid nodules mostly malignant or benign?
benign
what is the main type of thyroid cancer?
papillary thyroid cancer
what is Addison’s disease in terms of the functioning of the adrenal gland?
hypofunction
what are examples of diseases where the adrenal gland is hyper functioning?
- Cushing’s
- Conn’s / hyperaldosteronism
- pheochromocytoma
what is the name of an autoimmune primary hypoadrenalism disease?
Addison’s disease
what are the causes of primary hypoadrenalism?
- abrupt discontinuation of steroids
- autoimmune (addison’s)
- tuberculosis
- haemmorhage / infarction
- surgery
what are the symptoms for primary hypoadrenalism?
- weight loss
- malaise (general feeling of discomfort, illness or fatigue)
- diarrhoea
- nausea / vomiting
- syncope (fainting or passing out due to low BP)
- myalgia (muscle pain)
what are the signs for primary hypoadrenalism?
- pigmentation (new scars, buccal, palmar creases)
- wasting (gradual deterioration)
- dehydration
- loss of body hair
what are the investigations used to detect primary hypoadrenalism?
- random cortisol test
- short synacthen test (synacthen; a synthesised ACTH, is injected into the patient to see whether the adrenal gland responds to it and produces cortisol)
- plasma ACTH test
- urea and electrolytes
- adrenal antibodies
how is adrenal failure treated?
- emergency, life-threatening cases:
ICU care, IV hydrocortisone at high doses, fluids, sodium - maintenance treatment:
glucocorticoids (hydrocortisone, prednisolone)
mineralocorticoids (fludrocortisone)
what is Cushing’s syndrome?
- excess cortisol
- either ACTH dependent or independent
- ACTH dependent: due to pituitary
- ACTH independent: due to adrenal glands
what are the signs for Cushing’s syndrome?
- moon face
- plethora (excess of blood)
- acne
- hirsutism (where women have thick black hair in their face, thighs, tummy, back etc.)
- frontal balding
- thin skin/bruising
- poor wound healing
- pigmentation
- buffalo hump
- striae
what are the dynamic investigations to confirm Cushing’s syndrome diagnosis?
- low does dexamethasone suppression test (normally, after patients take dexamethasone, cortisol will be suppressed to undetectable levels. with Cushing’s syndrome, cortisol can still be detected)
- 24hr urinary cortisol
- loss of diurnal rhythm
how can Cushing’s syndrome be treated?
- laparoscopic adrenalectomy (removal of an adrenal gland)
- replacement hydrocortisone treatment with periodic withdrawal to check if the counteractive adrenal gland is functioning
what is a phaeochromocytoma?
- tumour of the adrenal medulla
- secreting NA or A
what are the clinical features of phaeochromocytoma?
- headaches
- palpitations
- weight loss
- sense of doom
- chest pain
- sweating
what tests can phaeochromocytoma be diagnosed with?
- 24hr urine catecholamines
- 24hr urine or plasma metanephrines (better option)
how is phaeochromocytoma treated?
- pretreated with alpha and beta blockade:
phenoxybenzamine and doxazosin - then surgery
what would a screening blood test show for a patient with primary hyperaldosteronism?
- low renin
- elevated aldosterone
what is conn’s syndrome?
- primary hyperaldosteronism
- independant of RAAS
- hypertension, hypokalaemia, alkalosis
how do you confirm primary hyperaldosteronism diagnosis?
- measurement of renin (suppressed) and aldosterone (elevated) in salt-replete individuals (amount of salt in patient’s body’s is at normal levels)
- selective venous sampling (to determine which adrenal gland is secreting abnormal levels of aldosterone)
how can conn’s syndrome / primary hyperaldosteronism be treated?
- remove the adenoma (laparoscopic)
- drug treatment (spironolactone, eplerenone)
- eplerenone is the preferred drug for men as spironolactone may have negative effects on men
