Endocrine Diseases Flashcards
What is endocrine disease?
Dysfunction of hormone secreting glands.
What is the difference between primary and secondary endocrine disease?
Primary- gland failure
Secondary- control failure
What is the relationship of the hypothalamus to the pituitary gland?
Hypothalamus produces releasing hormones, which stimulates either the anterior or posterior pituitary produce stimulating hormones, which act directly on tissues to cause effect.
Describe the difference between the anterior and posterior pituitary.
Anterior- releasing hormones from the hypothalamus pass into the anterior pituitary. This stimulates the release of stimulating hormones from the AP into the blood and carried through the body.
Posterior- Both vascular and neurological control can trigger the hormone release.
What hormones are produced in the anterior pituitary?
TSH, ACTH, GH, LH, FSH and prolactin
What hormones are produced in the posterior pituitary?
Antidiuretic hormone
Oxytocin
What is a common cause of pituitary tumours?
Dysfunction from adenomas.
Functional adenomas- produces an active hormone, tumour makes the gland produce more hormone than normal.
Non-functional adenoma- tissue has no secreting ability, mass effects, will compress other tissues.
As pituitary tumours grow, what common structure does it impact?
Optic chiasma
When the tumour grows up and outwards of the sella turcica, it compresses the central area of the optic chiasma .
Patient will have a narrower field of view.
What are the consequences of excess growth hormone?
Giantism in children
Acromegaly in adults
What is the process of excess GH?
GHRH released from the hypothalamus- released at a pulsatile rhythm at night.
Acts on AP- released GH from here.
Acts on the tissues- IGF-1 released from the tissues.
What factor is released to measure GH?
IGF-1
What are the signs and symptoms of acromegaly?
Enlarged supraorbital ridges
Broad nose
Thickened lips and soft tissues
Enlarged hands
Enlarged tongue
Spacing of teeth
“shrunk” dentures
Reverse overjet
T2DM
Cardiovascular disease- cardiac hypertrophy
What is hyperthyroidism?
Excess production of thyroid hormone.
Primary- within the gland, common
Secondary- control failure, issue with he hypothalamus, rare
What is hypothyroidism?
Thyroid hormone deficiency
Primary- common
Secondary- less common
What is the most common cause of Hyperthyroidism?
Grave’s disease- auto-antibodies develop which stimulates the TSH receptor, so the gland produces more thyroid hormone.
What are the other cases of hyperthyroidism?
Toxic multinodular goitre.
Toxic adenoma- tumour within the gland itself, causing an overproduction of thyroid hormone.
What are the signs and symptoms of hyperthyroidism?
Signs- warm moist skin, tachycardia, AF, increased blood pressure, tremor, hyperreflexia, eyelid retraction and lid lag.
Symptoms- hot and excess sweating, weight loss, diarrhoea, palpitations, muscle weakness, irritable, manic, anxious.
What is the most common cause of hypothyroidism?
Hashimoto’s thyroiditis- antibodies attack the gland itself, causes inflammation and gradual fibrosis of the gland and destruction of the thyroid tissue.
What are the other more rare causes of hypothyroidism?
Idiopathic atrophy
Radioiodine treatment/thyroidectomy surgery
Iodine deficiency
Drugs- carimazole, amiodarone, lithium
Congenital
What are the signs and symptoms of hypothyroidism?
Signs- dry course skin, bradycardia, hyperlipidaemia, psychiatric or confusion, goitre, delayed reflexes
Symptoms- tiredness, cold intolerance, weight gain, constipation, hoarse voice, goitre, puffed face, angina, poor memory
What investigations may be required for someone with suspected thyroid disease?
Blood- look for TSH, T3 and T4
Imaging- ultrasound, radioisotop scans
FNA/FNB
In Grave’s disease, what hormone levels would you expect?
Low TSH- caused by negative feedback of the raised T3
Raised T3- caused by the antibodies attacking the gland
In gland failure, what hormone levels would you expect?
High TSH
Low T4
What is the treatment for hyperthyroidism?
Carbimazole- prevents uptake of iodine in the thyroid gland, preventing production of T3 and T4.
beta-blockers
Radioiodine
Partial thyroidectomy
What is the treatment for hypothyroidism?
T4 tablets
What is a goitre?
Diffuse enlargement of the thyroid gland- often the patient is iodine deficient
Describe the hormones that produced from the Zona glomerulosa zone fasicularis and the zona reticularis.
Glomerulosa- aldosterone
Fasicularis- Cortisol
Reticularis- Adrenal androgens
Describe the adrenal regulation pathway.
CRH is produced from the hypothalamus.
Stimulates the pituitary to produce ACTH.
ACTH stimulates the adrenal gland to produce aldosterone, cortisol and adrenal androgens.
This then produces negative feedback to the pituitary and hypothalamus to stop producing CRH and ACTH.
What is aldosterone?
Hormone responsible for salt and water regulation- enhances sodium reabsorption (and subsequently water) and potassium loss.
Renin converts angiotensinogen to angiotensin 1.
Angiotensin 1 is converted to angiotensin 2 by ACE.
Angiotensin 2 stimulated secretion of aldosterone.
What is cortisol?
Natural glucocorticoid- released in response to ACTH, inhibits it’s own release.
What are the physiological effe ts of cortisol?
Increases blood pressure
Lowers the immune reactivity
inhibit stone synthesis
Antagonist to insulin
Give examples of therapeutic steroids?
Hydrocortisone
Prednisolone
Dexamethasone
Betamethasone
What effect do glucocorticoids have?
Immunosuppression
Reduced inflammatory response
What effect do mineralocorticoids have?
Salt and water retention
Hypertension
Describe some of the adverse effects of therapeutic steroids?
Hypertension
T2DM
Osteoporosis
Increased infection risk
Peptic ulceration
Easy bruising
Hyperlipidaemia
Cataracts and glaucoma
What disease causes adrenal hyper function?
Cushing’s disease
What is Cushing’s disease?
Tumour present within the pituitary, which causes excessive ACTH to be produced.
What are the signs and symptoms of Cushing’s syndrome?
Signs- centripetal obesity, moon face, buffalo hump, hypertension, muscle weakness, osteoporotic changes.
Symptoms- DM features, poor resistance to infections, back pain, psychiatric disorders, hirsutism, skin and mucosal pigmentation (generalised patchy brown pigment).
Why do Cushing’s patients get mucosal pigmentation?
Within the gene coding for ACTH, there is also alpha-MSH.
When ACTH is produced, it will also stimulate pigment cells.
What disease causes adrenal hypo function?
Addison’s disease.
What is Addison’s disease?
Autoimmune condition, whereby antibodies attack the adrenal glands and cause destruction to them.
90% of the gland must be lost to start to see an effect.
What are the signs and symptoms of Addison’s disease?
Signs- postural hypotension, weight loss and lethargy, hyperpigmentation, vitiligo.
Symptoms- weakness, anorexia, loss of body hair.
What is Addisonian crisis?
Occurs if no treatment given for Addison’s.
Patient experiences, hypotension, vomiting, eventual coma.
What is the management of Addison’s disease?
Hormone replacement- cortisol and fludrocortisone
Cortisol dose varies with environment- increased by physical/psychological stress, increased by infection.
Under what circumstances would someone with adrenal insufficiency need prophylactic steroid cover?
Minor dental procedure (scale and polish, replacement filling)- extra oral dose 60 minutes prior to procedure and then an extra dose post-treatment if symptoms should arise.
Minor dental surgery (RCT)- double oral dose 60 minutes prior to surgery (put to 20mg hydrocortisone) and then double the oral dose for 24 hours after treatment.
Major dental surgery (XLA)- 100mg hydrocortisone IM 60 minutes prior to the procedure. Then double the oral dose for 24 hours post-treatment.
What guidelines would you refer to for steroid prophylaxis in adrenal insufficiency patients?
Addison’s self help group- dental guidelines.
Also contact the patient’s endocrinologist to ask about cover.
