Endocrinology conditions Flashcards
Whilst type 1 diabetes mellitus is due to relative insulin deficiency, type 2 DM is due to relative insulin….
…resistance
What percentage of those with DM have type 2?
90%
Does type 1 or type 2 DM have a higher twin concordance?
Type 2 (80%) Type 1 (30%)
What test results indicate diabetes?
Venous blood glucose either >7mmol/L fasting or >11mmol/L random.
Oral glucose tolerance test - HbA1c >48mmol/L
What treatments are given in DM?
Control CV risk with ACE-i, statin and low dose aspirin
Type 1: Insulin will always be required
Type 2: 3 main drugs - biguanide (metformin), sulfonylureas, thiazolidendiones. May eventually need insulin. Bariatric surgery can be curative.
What causes hypothyroidism?
Iodine deficiency (presents with goitre)
Hashimoto’s thyroiditis (autoimmune)
Primary atrophic hypothyroidism (common, no goitre)
Iatrogenic
Drugs (amiodarone, lithium, carbimazole)
Subacute thyroiditis
Secondary hypothyroidism (caused by hypopituitarism, very rare)
Symptoms of hypothyroidism?
Fatigue, low mood, cold intolerance, weight gain, constipation, menorrhagia, hoarse voice, reduced memory/cognition, dry skin, loss of outer third of eyebrow, thin hair
SIGNS: pre-tibial myxoedema, bradycardia, delayed tendon reflex relaxation, goitre
What will TFTs show in primary hypothyroidism and primary hyperthyroidism?
Hypo-: High TSH, low T3 and T4
Hyper-: Low TSh, high T3 and T4
What causes hyperthyroidism?
Graves’ disease (most common, autoimmune)
Toxic multinodular goitre (nodules secrete T3+4, seen in elderly and iodine deficient areas)
Toxic thyroid adenoma
Ectopic thyroid tissue
Iodine excess from food contamination/contrast media/drugs
Secondary hyperthyroidism (TSH secreting pituitary adenoma
Gestational thyrotoxicosis (TSH, T3 and T4 all high)
Symptoms of hyperthyroidism?
Diarrhoea, weight loss, increased apetite, over-activity, sweating, heat intolerance, palpitations, tremor, irritability, labile emotions, oligomenorrhoea
SIGNS: palmar erythema, sweaty palms, fine tremor, tachycardia/AF, brisk reflexes, goitre, proximal myopathy, gynaecomastia, lid lag
Graves: exomphthalmous, ophthalmoplegia, pretibial myxoedema, thyroid acropachy, thyroid bruits
How is hyperthyroidism managed?
Anti-thyroid medication (carbimazole)
Radio-iodine (most become hypothyroid)
Surgery - thyroidectomy
Frequency of goitres that may be a sign of thyroid cancer?
1 in 20
What is Cushing’s syndrome?
Clinical state produced by chronic glucorticoid excess and loss of normal feedback mechanisms of the hypothalamo-pituitary-adrenal axis and loss of circadian rhythm of cortisol secretion
What are the ACTH-dependent causes of Cushing’s syndrome?
Cushing’s disease (anterior pituitary adenoma secretes excess ACTH)
Ectopic ACTH production (small cell lung cancer and carcinoid tumours)
Ectopic CRH production (some thyroid and prostate cancer)
What are the ACTH-independent causes of Cushing’s syndrome?
Iatrogenic (most common, prolonged glucocorticoid administration)
Adrenal adenoma/carcinoma
Adrenal nodular hyperplasia
Carney complex
Symptoms of Cushing’s syndrome?
Weight gain, mood change, proximal weakness, gonadal dysfunciton, acne, recurrent Achilles tendon rupture.
Some get skin pigmentation
SIGNS: central obesity, plethoric, moon face, buffalo neck hump, supraclavicular fat distribution, skin and muscle atrophy, bruises, purple abdominal striae, osteoporosis, high BP, high glucose, infection prone, poor healing
What are the 1st line tests for suspected Cushing’s syndrome?
Overnight dexamethasone suppression test
24hr urinary free cortisol
What 3 actions does parathyroid hormone produce?
- Increased osteoclast activity releasing Ca++ and Phosphate from bones
- Increased Ca++ and decreased Phos reabsorption in kidney
- Active 1,25 dihydroxy-vitamin D3 production
Symptoms of hyperparathyroidism?
STONES: renal stones, polyuria, polydipsia
BONES: osteoporosis, osteomalacia, arthritis
MOANS: lethargy, fatigue, weakness, depression, memory loss, psychosis, ataxia, delirium
GROANS: Constipation, indigestion, N+V, peptic ulcers, acute pancreatitis
What is Addison’s disease?
Adrenal insufficiency
Primary - destruction of glands (80% due to autoimmunity)
Secondary - iatrogenic, commonly due to long term steroid use which suppresses pituitary-adrenal axis
Symptoms of Addison’s disease?
Lean, tired, tanned and tearful, weakness, anorexia, dizzy, faints, flu-like myalgia, depression, psychosis, low self-esteem.
How is Addison’s disease managed?
Replace steroids. Daily hydrocortisone PO (glucocorticoid), fludrocortisone (mineralocorticoid)
