Endocrinology Flashcards
What is the most common cause of primary hypothyroidism worldwide?
Iodine deficiency
What is the autoimmune cause of hypothyroidism?
Hashimoto’s thyroiditis
Which drugs can induce hypothyroidism?
Amiodarone
Lithium
Which antibodies are produced in Hashimoto’s thyroiditis?
Antithyroid (TPO) autoantibodies
What surgical causes lead to hypothyroidism?
Thyroidectomy
Radio-iodine treatment
What are the risk factors for hypothyroidism?
- Autoimmune disease e.g. Addison’s
- Turner’s syndrome
- Down’s syndrome
- Cystic fibrosis
- Primary biliary cirrhosis
A myxoedema coma is induced by severe hypothyroidism. What are the symptoms of this?
Hypothermia
Cardiac failure
Hypoglycaemia
Death
How would you treat a myxoedema coma?
IV T3
Glucose infusion
Rewarm patient
What are the symptoms of hypothyroidism?
Menorrhagia Fatigue Cold intolerance Low mood Weight gain Constipation
What are the signs of hypothyroidism? (hint: BRADYCARDIC)
Bradycardia Reflexes slow Ataxia Dry thin hair/skin Yawning Cold hands Ascites Round puffy face Defeated demeanour Immobile Congestive heart failure
How would primary hypothyroidism present on thyroid function tests?
Low T3/T4
High TSH
How would secondary hypothyroidism present on thyroid function tests?
Low T3/T4
Low TSH
How would FBC, sodium and cholesterol present in hypothyroidism?
Macrocytic anaemia
Hyponatraemia
Hypercholesterolaemia
Which drug do you give to treat hypothyroidism?
Levothyroxine (T4)
Which level of vertebrae is the thyroid gland located?
C5-T1
Which hormone stimulates the release of TSH from the pituitary?
TRH = Thyrotropin-releasing hormone from the hypothalamus
Which autoimmune condition causes hyperthyroidism and thyrotoxicosis?
Graves’ disease
Which autoantibodies are produced in Graves’ disease?
Anti-TSH-receptor
They bind to TSH receptors and stimulate production of T3 and T4
Which conditions are associated with Graves’ disease?
T1DM
Addisons
Vitiligo
Apart from Graves’ disease, what are the other causes of hyperthyroidism?
- Toxic multinodular goitre
- Toxic thyroid adenoma
- Iodine excess
- Amiodarone
- Viral infection
- Postpartum thyroiditis
What are the symptoms of hyperthyroidism?
- Tremor
- Diarrhoea
- Weight loss
- Increased appetite
- Sweating
- Heat intolerance
- Palpitations
- Restlessness
- Oligomenorrhoea
What are signs of hyperthyroidism?
- Thin and brittle hair
- Loss of outer third of eyebrow
- Warm and moist skin
- Tachycardia
- Fine tremor
- Brisk reflexes
- Palmar erythema
- Lid lag and retraction
- Goitre
What are signs of Graves’ disease?
- Diplopia
- Exophthalmos
- Chemosis
- Clubbing
- Pretibial myxoedema
- Onycholysis
What is the thyroid function test result for primary hyperthyroidism?
High T3/T4
Low TSH
What is the thyroid function test result for secondary hyperthyroidism?
High T3/T4
High TSH
Which thyroid autoantibodies can you test for?
Anti thyroid peroxidase (anti-TPO)
Anti thyroglobulin
TSH receptor
How would you treat hyperthyroidism?
- Beta blockers
- Block and replace: carbimazole + levothyroxine
- Radioiodine (cannot give in pregnancy or malignancy)
- Thyroidectomy - indicated in malignancy
What are the clinical features of a thyroid storm?
- Palpitations
- Tachycardia
- Tremor
- Nausea and vomiting
- Abdominal pain
- Reduced consciousness
- Confusion
- Seizures
How do you manage. thyroid storm?
- Carbizamole
- Beta blockers
- Potassium iodide
- IV hydrocortisone
What are the complications of thyrotoxicosis?
- AF
- Heart failure
- Angina
- Deterioration of visual acuity
What is Cushing’s syndrome?
Clinical state of excessive cortisol
What is Cushing’s disease?
Cushing’s syndrome caused by a pituitary adenoma secreting inappropriate ACTH
What are the causes of Cushing’s syndrome?
- Oral steroid use
- Adrenal adenoma
- Pituitary adenoma
- Paraneoplastic - small cell lung cancer secreting ACTH
Corticotropin-releasing hormone is secreted from the hypothalamus. CRCh binds to pituitary which then releases ACTH. ACTH stimulates the adrenal cortex to release cortisol. What are the functions of cortisol?
- Increases carbohydrate and protein catabolism
- Increases deposition of fat and glycogen
- Sodium retention
- Increased renal potassium loss
- Gluconeogenesis
- Diminishes host response to infection
- Reduces bone formation
What are the symptoms of Cushing’s syndrome?
- Weakness
- Facial fullness
- Weight gain
- Low mood
- Decreased libido
- Polydipsia
- Polyuria
- Acne
- Hirsutism
What are the signs of Cushing’s syndrome?
CUSHING Cataracts Ulcers Skin striae Hyperglycaemia + hypertension Increased infection Necrosis Glucosuria
Moon facies
Buffalo hump
Truncal obesity
Oedema
What is pseudo-Cushing’s syndrome caused by?
Excess alcohol
Which investigations can diagnose Cushing’s syndrome?
- 24 hour urinary free cortisol
- Dexamethasone suppression test - failure of dexamethasone to suppress cortisol indicates Cushing’s
- Late night salivary cortisol. Cortisol has diurnal variation, however this is absent in Cushing’s
How do you treat Cushing’s syndrome?
- Reduce steroids
- Resection of tumour
- Mitotane to inhibit glucocorticoid synthesis
What are the complications of Cushing’s syndrome?
- Hypertension
- Diabetes
- Obesity
- Metabolic syndrome
- Osteoporosis
What is acromegaly?
Increased production of growth hormone after the fusion of epiphyseal plates
What are the causes of acromegaly?
- Pituitary adenoma
- Multiple endocrine neoplasia
What does growth hormone stimulate the release of in the liver?
IGF-1
What are the symptoms of acromegaly?
- Sweating
- Headache
- Decreased libido
- Athralgia
- Visual deterioration
- Paraesthesia
What are the signs of acromegaly?
- Skin darkening
- Puffy lips and eyelids
- Big tongue
- Deep voice
- Massive growth of hands, feet and jaw
What investigations would you to do determine acromegaly?
- Oral glucose test - glucose should suppress GH, in acromegaly, this will not occur
- IGF-1 levels
- MRI of pituitary
How would you manage acromegaly?
- Tumour resection
- Somatostatin analogues to inhibit GH
- GH antagonist e.g. pegvisomant
What are the complications of acromegaly?
- Diabetes
- Sleep apnoea
- Hypertension
- IHD
- Arthritis
Which cells are destroyed in T1DM?
Beta cells
What are the risk factors for T1DM?
Enteroviruses
Vitamin D deficiency
Autoimmune disease
What are the symptoms of T1DM?
Thirst Polyuria - glucose draws water into urine by osmosis. Kidneys cannot reabsorb any more glucose as they have reached maximum absorptive capacity Weight loss Fatigue Infections e.g. thrush
What are the signs of DKA?
Tachycardia Hyperventilation Sweating Hypotension Confusion Collapse Vomiting
Which specific investigations can you do for T1DM?
- Autoantibodies against beta cells
- Serum C peptide - absent due to beta cell destruction
What are glucose values for someone with diabetes?
Random venous plasma glucose >11.1 mmol/L
Fasting plasma glucose >7 mmol/L
What is the HbA1c value for someone with diabetes?
HbA1c >48 mmol/mol
What is the treatment for T1DM?
Insulin
What are plasma and urinary ketone levels for someone with DKA?
Plasma ketones >3
Urinary ketones >2
How would you manage DKA?
Fluids
Insulin
Replacement of electrolytes, K+
What are the risk factors for T2DM?
Obesity Alcohol excess High cholesterol Smoking FH CVS disease Hypertension Age
In T2DM, there is insulin resistance. What are the symptoms of this?
Asymptomatic Thirst Polyuria Fatigue Increased hunger
What is the conservative management for someone with T2DM?
Stop smoking Lose weight Exercise Ramipril Statin
Outline the step wise approach to medically treating T2DM.
- Metformin - increases cell sensitivity to insulin
- Sulfonylurea e.g. gliclazide
- DDP4 inhibitor e.g. gliptin
- Isophane insulin
- GLP1-mimetic - incretin analogue
What are the side effects of metformin?
Diarrhoea
Nausea
Weight loss
What are the side effects of gliclazide?
Hypoglycaemia
Weight gain
What are the macrovascular complications of T2DM?
Atherosclerosis
Stroke
MI
Peripheral vascular disease
What are the microvascular complications of T2DM?
Retinopathy
Nephropathy
Neuropathy
What are the features of diabetic retinopathy?
Haemorrhages
Lipid deposits
Macula oedema
What are the features of diabetic nephropathy?
Albumin:creatinine ratio >3
Raised ESR
Normochromic normocytic anaemia
How would you manage diabetic nephropathy?
ACEi
ARB
Dialysis
What are the symptoms of diabetic neuropathy?
Pain Paraesthesia Burning Diarrhoea/constipation Incontinence Erectile dysfunction
What are the signs of diabetic neuropathy?
Ulceration
Infection
Postural hypotension
How would you test for diabetic neuropathy?
- Test sensation using microfilament 10g
- Test vibration perception using tuning fork
- Test ankle reflexes
- Doppler ultrasound
How would you treat diabetic neuropathy?
Avoid weight bearing
Capsaicin
