Summary Book Endocrine Flashcards
Examination steps for hyperthyroidism
Thyroid followed by cardio, then upper limb reflex and confirm proximal myopathy
What are increased beat adrenergic effects
hyperreflexia, bounding pulse, tremor, sweaty palm, tachycardia, atrial fibrillation, flow murmur, high output heart failure
Graves eye signs
proptosis, exophthalmos, ophthalmoplegia
Diffuse goitre with bruit
graves or if hypothyroid then iron deficiency or chronic autoimmune
Nodular goitre ddx
MNG, nodule, cancer
Tender goitre
thyroiditis
Retrosternal goitre examination findings
pembertons sign and dullness to percussion
Cause of hoarseness
Recurrent laryngeal nerve palsy
Signs of hyperthyroidism
If graves = proptosis, exophthalmos, ophthalmoplegia. Goitre. Increased cardiac rate wit possible associated failure. Proximal myopathy, hyperreflexia, tremor, sweaty, hypopigmentation of skin, nail changes (thyroid acropachy = clubbing, swelling, periosteal reaction), accelerated bone remodelling with risk of osteoporosis, pretibial myxoedema
Autoimmune conditions associated with hyperthyroidism
diabetes mellitus, vitiligo, coeliac disease
Aetiology for hyperthyroidism
Autoimmune = graves and Hashimoto. Drug induced = amiodarone (type 1 increases synthesis due to iodine load, type 2 due to thyroid toxicity). Multinodular goitre, toxic nodule, thyroiditis (infectious, ischaemic, lymphocytic), hCG mediated, TSH dependant (TSHoma), iodine induced, paraneoplastic, iatrogenic (thyroxine therapy), factitious
Investigations for hyperthyroidism
Thyroid function tests (TSH secreted by anterior pituitary), T3/4, thyroid antibodies, TSH receptor (graves = activating, Hashimoto = inhibiting), thyroid peroxidase (hashimoto thyroiditis - most common), thyroglobulin. Can also consider ultrasound, radioactive iodine uptake and biopsy.
Management of graves disease.
Symptom control - beta blocker. Reduced thyroid hormone synthesis - thioamides (carbimazole or propylthiouracil), radioactive iodine ablation, thyroidectomy. Adjunctive therapies - corticosteroids (inhibit peripheral conversion and secretion). Management of orbitopathy - smoking cessation, if severe radioactive iodine is contraindicated, corticosteroids, Teprotumumab, Tocilizumab, Rituximab.
Examination for hypothyroidism
Thyroid plus hand, then upper limb reflex
Signs of decreased beta adrenergic effects
slowed mentation, hyporeflexia, bradycardia, pericardial effusion, obesity
Signs of hypothyroidism
goitre, hyporeflexia, slowed mentation, bilateral ptosis, loss of distal eyebrows, tongue swelling, macroglossia, bradycardia, pericardial effusion, proximal myopathy, carpel tunnel syndrome, dry skin and hair thinning, weight gain, ascites, other autoimmune conditions
Aetiology of hypothyroidism
Autoimmune - hashimoto. Thyroid organ failure - atrophy, infiltration, ischaemic, fibrosis, post infectious, amiodarone. Thyroiditis. Iatrogenic - radioactive iodine, thyroidectomy. TSH dependent - pituitary or hypothalamic. Thyroid hormone resistance.
TFT finding differences between primary, secondary and tertiary hypothyroidism
Primary = TSH >10, low T3/4. Secondary = low TSH, low T3/4. Tertiary = low TSH, low T34, low thyroid releasing hormone.
Goals and strategy for management of hypothyroidism
Goals = symptom management, normalise TSH, avoid iatrogenic hyperthyroidism. To normalise TSH titrate levothyroxine (T4).
When should levothyroxine be increased or decreased?
Increase in pregnancy. Decrease in weight loss, aging and androgen therapy.
Examination for cushings syndrome
Skin with blood pressure and proximal myopathy
Pathophysiology of cushings syndrome
high cortisol
Signs of cushings syndrome
cognitive dysfunction / psychosis, increased facial width, dorsal fat pad, skin pigmentation, hypertension, decreased limb fat, thin skin / bruising, osteoporosis, insulin resistance, increased abdominal fat, abdominal striae, hypogonadism, hypercoagulable state and increased infection risk
Organ and ddx of primary cushings syndrome
Adrenal. DDX: adenoma, carcinoma, bilateral macronodular adrenal hyperplasia, primary pigmented nodular adrenocortical disease.
Organ and ddx of secondary cushings syndrome
Anterior Pituitary = Cushings Disease. DDX: ACTH -secreting pituitary adenoma.
Organ and ddx of tertiary cushings
Hypothalamic. DDX: CRH secreting lesion.
Most common and oncological causes of cushings
Most common is endogenous with steroid use. Paraneoplastic causes of cushings are SCLC, pancreatic and thyroid.
Investigations for suspected cushings
- Exclude steroids. 2. Demonstrate hypercortisolism with either 24hr urinary cortisol, midnight salivary cortisol or low dose dexamethasone suppression test. 3. Also serum ACTH (<1.1 = ACTH independence, >4.4 ACTH/CRH dependence). 4. If low ACTH can use high dose dexamethasone suppression test = if cortisol <5 microg/dL then pituitary cause, if no suppression then ectopic. 5. CRH stimulation test -> ACTH response = pituitary, no response = ectopic.
Tests for suspected primary cushings
CT of adrenals +/- MRI, and petrosal sinus sampling of microadenoma
How to screen for complications of cushings syndrome
HbA1c, fasting blood sugar, urinalysis, ECG, ECHO, sleep study, colorectal cancer screening, DEXA, vit D, dyslipidaemia
Management of primary cushings
laparoscopic adrenalectomy
Management of secondary cushings
Transsphenoidal pituitary resection, stereotactic radiotherapy for persistent or recurrent disease, bilateral adrenalectomy (require lifelong supplementation, may cause nelsons syndrome - enlarged pituitary gland / abnormal hormones / invasive adenomas)
Medical therapy to lower cortisol
Adrenal enzyme inhibitor (ketoconazole), adrenolytic agent, dopamine agonist (cabergoline), somatostatin analogue (pasirotide), glucocorticoid antagonists (mifepristone)
Pathophysiology of addisons
low cortisol
3 key findings of addisons
- hyperpigmentation. 2. postural BP. 3. electrolyte derangement (low sodium / BLS, high K)
Causes of addisons
autoimmune adrenal disease (80%), TB, histoplasmosis, amyloid/sarcoid, bilateral adrenal haemorrhage
Diagnosis of addisons
short synacthen test - no increase in plasma cortisol level with ACTH
Management of addisons crisis
glucocorticoid stress dosing
Examination of acromegaly
hands + cardio + visual fields + thyroid palpate + abdo palpate
Signs of acromegaly
enlarged head circumference, hypopituitarism, bilateral hemianopia, macroglossia, obstructed sleep apnea, prominent jaw, gaps between teeth, thyroid nodules, left ventricular hypertrophy, cardiomyopathy, aortic or mitral regurgitation, hypertension, osteoarthrtis, carpel tunnel syndrome, spade like hands, diabetes mellitus, organomegaly, BPH, colonic polyposis, hypogonadism, osteoporosis, peripheral neuropathy
Pathophysiology of acromegaly
excessive secretion of growth hormone and thus insulin life growth factor 1.
Causes of acromegaly
> 95% are due to somatotroph pituitary adenoma
Mortality of acromegaly
> 60% cardiovascular and 25% cancer
Diagnosis of acromegaly
serum IGF-1 (high sensitivity), glucose suppression test (growth hormone >1mg/ml 2 post 75g oral glucose), MRI of pituitary
Investigations of acromegaly
Reduced cortisol / TSH / T4 / FSH / LH / testosterone. elevated prolactin 25%. Also HbA1c, blood glucose, urinalysis, ECG, ECHO, sleep study, colorectal cancer screening, DEXA, vit D, calcium, dyslipidaemia.