ENDOCRINE Flashcards
Give 5 parathyroid hormone actions
- Increase Ca2+ reabsorption
- Decrease phosphate reabsorption
- Increase 1 alpha-hydroxylation of 25-OH vit D
- Increase bone remodelling (bone resorption >bone formation)
- Increase Ca2+ absorption because of increase 1,25(OH)2D (no direct effect)
When serum calcium levels are low, what are PTH levels?
PTH levels are high
When serum calcium levels are high, what are PTH levels?
PTH levels are low
What is the effect of hyperparathyroidism on serum calcium levels?
Hyperparathyroidism –> hypercalcaemia
what are the clinical features of hyperparathyroidism?
SYMPTOMS
- BONES – excess bone resorption caused by PTH Pain, fractures, osteopenia, osteomalacia, osteoporosis - STONES – due to excess Ca. Renal colic from renal calculi and biliary stones - GROANS – abdominal pain, malaise, nausea, constipation, polydipsia, polyuria, dehydration, confusion, risk of cardiac arrest - MOANS – depression, anxiety, cognitive dysfunction, insomnia, coma
SIGNS
hypercalcaemia
Give 2 causes of primary hyperparathyroidism
- Parathyroid adenoma
- Hyperplasia
- Parathyroid cancer
what is the the pathophysiology of secondary hyperparathyroidism
Physiological compensatory hypertrophy of all parathyroid resulting in excess PTH due to hypocalcaemia
Often due to CKD and vitamin D deficiency
what is the pathophysiology of tertiary hyperparathyroidism?
Prolonged uncorrected hypertrophy - glands become autonomous producing excess PTH
What blood results would you see in the 3 types of hyperparathyroidism?
PRIMARY =
- PTH = high
- calcium = high
- phosphate = low
- alk phos = high
SECONDARY =
- PTH = high
- calcium = low
- phosphate = high
- alk phos = high
TERTIARY -
- PTH = high
- calcium = high
- phosphate = high
- alk phos = high
Describe the treatment for hyperparathyroidism
- adenoma = surgical removal
- hyperplasia = all 4 glands surgically removed
- calcimimetric = ORAL CINACALET
How does a calcium mimetic work?
Increases sensitivity of parathyroid cells to calcium so less PTH secretion occurs
What is the affect of hypoparathyroidism on serum calcium levels?
Hypoparathyroidism –> hypocalcaemia
what are the clinical features of hypoparathyroidism?
SYMPTOMS:CATs go numb
- convulsions / seizures
- arrhythmias / anxious
- tetany / muscle spasms
- numbness
SIGNS:
- CHVOSTEK’S SIGN - tap over facial nerve and look for spasm of facial nerves
- TROUSSEAU’S SIGN - inflate BP cuff 20 mmHg above systolic for 5 mins = hand spasm - hypocalcaemia
what are the causes of hypoparathyroidism?
- secondary to increased serum phosphate
- severe vitamin D deficiency
- reduced PTH function
- drugs - calcitonin, bisphosphonates
What are blood results for someone with hypoparathyroidism?
Calcium = Low PTH = Low Phosphate = High
What is the treatment for hypoparathyroidism?
Acute = IV calcium Persistant = Vitamin D analogue - ORAL ADCAL
what are the causes of Hypercalcaemia?
Hyperparathyroidism Malignancy Sarcoidosis Thyrotoxicosis Drugs
What is the treatment for hypercalcaemia?
- Treat underlying cause
- increase circulation volume, increase excretion
.- Bisphosphonates, glucocorticoids, gallium, dialysis
Give 2 ECG changes that you might see in someone with hypercalcaemia
- Tall T waves
2. Shortened QT interval
Name 3 causes of hypocalcaemia
Hypoparathyroidism Vitamin D deficiency Hyperventilation Drugs Malignancy Toxic shock
what are the investigations for hypocalcaemia?
Corrected Calcium levels,
ECG (prolonged QT)
Parathyroid function - PTH
what is the treatment for hypocalcaemia?
10ml calcium gluconate/chloride 10% slow IV,
oral calcium and Vit D
Give 2 ECG changes that you might see in hypocalcaemia?
- Small T waves
2. Long QT interval
What does the parathyroid control?
Serum calcium levels
A low serum calcium triggers the release of PTH and a high serum calcium triggers c-cells to release calcitonin
What hormone does the parathyroid secrete and what is its function?
PTH - secreted in response to low serum calcium
What is released by c-cells in the parathyroid in response to high serum calcium?
Calcitonin
What biochemical test might you want to do to establish the cause of hypercalcaemia?
PTH measurement
What disease is described as being a ‘disorder of carbohydrate metabolism characterised by hyperglycaemia’?
Diabetes mellitus
what is T1DM?
Autoimmune destruction of pancreatic beta cells leading to complete insulin deficiency.
what is the pathophysiology of T1DM
- autoimmune destruction of beta cells in the Islets of Langerhans by autoantibodies cause insulin deficiency and continued breakdown of liver glycogen
- this causes hyperglycaemia and glycosuria
Is T1DM characterised by a problem with insulin secretion, insulin resistance or both?
Characterised by impaired insulin secretion - severe insulin deficiency
what are the risk factors for developing T1DM?
- Northern European
- Family History:
- HLA DR3-DQ2 or
- HLA-DR4-DQ8 - Other autoimmune diseases:
- Autoimmune thyroid
- Coeliac disease
- Addison’s disease
- Pernicious anaemia
what are the clinical features of T1DM?
Polydipsia - Thirst (fluid and electrolyte losses)
Polyuria (due to osmotic diuresis)
Weight loss
- usually short history of severe symptoms
Describe the epidemiology of T1DM
Onset younger (<30 years) Usually lean More Northern European ancestry
A diagnosis of diabetes can be made by measuring plasma glucose levels. What would a persons fasting plasma glucose be if they were diabetic?
Fasting plasma glucose >7 mmol/L
A diagnosis of diabetes can be made by measuring plasma glucose levels. What would a persons random plasma glucose be if they were diabetic?
Random plasma glucose >11 mmol/L
What might someone’s HbA1c be if they have diabetes?
> 48 mmol/L>6.5%
What happens to C-peptide in T1DM?
C-peptide reduces
How do you treat T1DM?
Education
Glycaemic control through diet (low sugar, low fat, high starch)
Insulin SC
Give 6 complications of Diabetes Mellitus
- Diabetic ketoacidosis
- Diabetic nephropathy
- Diabetic retinopathy
- Diabetic neuropathy
- Hyperosmolar hyperglycaemic coma
- Stroke, ischaemic heart disease, peripheral vascular disease
Give 2 potential consequences of T1DM
- Hyperglycaemia
2. Raised plasma ketones –> ketoacidosis
How is insulin administered in someone with T1DM?
Subcutaneous injections
Other than SC injections, how else can insulin be administered?
Insulin pump
what are the different types of insulin used to treat T1DM?
- short acting - 4-6hrs
- short acting analogues -
- long acting - 12-24hrs
Give 4 potential complications of insulin therapy
- Hyperglycaemia
- Lipohypertrophy at injection site
- Insulin resistance
- Weight gain
- Interference with life style
What is the affect of cortisol on insulin and glucagon?
Inhibits insulin
Activates glucagon
Describe the pathophysiology of diabetic ketoacidosis
Results from a reduced supply of glucose and an increase in fatty acid oxidation.
The increased production of Acetyl-CoA leads to ketone body production that exceeds the ability of peripheral tissues to oxidise them.
Ketone bodies are relatively strong acids (pH 3.5), and their increase lowers the pH of blood
it IMPAIRS THE ABILITY OF HAEMOGLOBIN TO BIND TO OXYGEN
Name 3 ketone bodies
- Acetoacetate
- Acetone
- Beta hydroxybutyrate
Where does ketogenesis occur?
Liver
what are the clinical features of diabetic ketoacidosis?
SIGNS
- Breath smells of pear drops (ketones)
- Kussmaul’s breathing - deep, rapid breathing
- Tachycardia
- Hypotension
- Reduced tissue turgor
SYMPTOMS
- Nausea and vomiting
- Dehydration
- exacerbated by vomiting
- Weight loss
- Drowsy/confused
- Abdominal pain
Give 3 microvascular compilation of DM
- Diabetic retinopathy
- Diabetic nephropathy
- Diabetic peripheral neuropathy
Give 2 macrovascular complications fo DM
CV disease
Stroke
What is the main risk factor for diabetic complications?
Poor glycemic control
What is the treatment for diabetic ketoacidosis?
- ABC
- Replace fluid loss with 0.9% saline IV
- IV insulin
- Restore electrolytes e.g. K+
Give 3 endocrine diseases that can cause diabetes
- Cushing’s
- Acromegaly
- Phaeochromocytoma
What class of drugs can cause diabetes?
Steroids
Thiazides
Anti-psychotics
Is T2DM characterised by problem with insulin secretion, insulin resistance or both?
Characterised by impaired insulin secretion and insulin resistance
what is the aetiology of T2DM?
- Decreased insulin secretion and increased insulin resistance
- No immune disturbance
- No HLA disturbance but strong genetic link
- Polygenic
- Associated with obesity, lack of exercise, calorie and alcohol excess
Describe the pathophysiology of T2DM
Insulin binds normally to its receptor – insulin resistance develops post-receptor
Circulating insulin levels are higher than in healthy patients but inadequate to restore glucose homeostasis
Increased glucose production in liver- inadequate suppression of gluconeogenesis and there’s reduced glucose uptake in peripheral tissues
Hyperglycaemia and lipid excess are toxic to beta cells - reduced beta cell mass
Don’t tend to develop ketoacidosis but do get glycosuria
Why is insulin secretion impaired in T2DM
Due to lipid deposition in the pancreatic islets
what are the risk factors for T2DM?
Increase w/ age M > F Ethnicity: African-Carribean, Black African and South Asian Obesity Hypertension
What happens to insulin resistance, insulin secretion and glucose levels in T2DM?
Insulin resistance increase Insulin secretion decreases Fasting and post-prandial glucose increase
Why do you rarely see diabetic ketoacidosis in T2DM?
Insulin secretion is impaired but there are still low levels of plasma insulin
Low levels of insulin prevent muscle catabolism and ketogenesis
By how much has the beta cell mass reduced in T2DM when diagnosis usually occurs?
50% of normal beta cell mass
Describe the epidemiology of T2DM
Onset older (>30)
Usually overweight
More common in African/Asian populations
Males > Females
Describe the treatment pathway for T2DM
- Lifestyle changes - lose weight, exercise, healthy diet and control of contributing conditions
- Monotherapy - Metformin
- dual therapy
- triple therapy
i) metformin
ii) DPP4 inhibitor
iii) SU, gliclazide
iv) SGLT-2 inhibitor
v) pioglitazone
vi) insulin
How does metformin work in treating T2DM?
Increase insulin sensitivity and inhibits glucose production
How does sulfonylurea work in treating T2DM?
Stimulates insulin release
block ATP dependent K+ channels in beta cells -> causes depolarisations and opening of voltage gated Ca2+ channels -> stimulates insulin secretion
what are the side effects of Sulfonylurea?
Hypoglycaemia
weight gain
hyponatraemia
What is hypoglycaemia classified as?
Plasma glucose <3.9 mmol/L and if <3.0 mmol/L it is severe hypoglycaemia
Give 5 symptoms of hypoglycaemia
- Hunger
- Sweating
- Tachycardia
- Anxious
- Shaking
- Confusion
- Weakness
- Vision changes
Why does hypoglycaemia continuously get worse?
Glucagon is not produced so rely only on adrenaline and the threshold for adrenaline release gradually lowers after time
Give 6 consequences of hypoglycaemia
- Seizures
- Comas
- Cognitive dysfunction
- Fear
- Decrease in qualitative life
- Accidents
Briefly describe the treatment of hypoglycaemia
Oral sugar and long acting starch
50% GLUCOSE IV or IM GLUCAGON
If episodes persist, suggest many small high starch meals
Re-educate diabetics on insulin use
Why are patient with diabetes at a particular risk of hypoglycaemia?
In Diabetes there are defects in the physiological defences to hypoglycaemia and there is reduced awareness
What does prevention of hypoglycaemia include?
Eduction
Correct choice of therapy
Adjusting glucose targets in those at high risk
Specialist support from a MDT
Is insulin secretion or insulin resistance the driving force of hyperglycaemia in T2DM?
Hepatic insulin resistance is the driving force
Give a potential consequence of acute hyperglycaemia
Diabetic ketoacidosis and hyperosmolar coma
Give a potential consequence of chronic hyperglycaemia
Mirco/macrovascular tissue complications
A man presents with a history of weight loss, polyuria and nocturia. He is very unwell. The GP performs a capillary blood glucose which is found to be 17.2mmol/l. What is the most likely diagnosis of this mans symptoms?
Type 1 Diabetes Mellitus
Name 5 possible diseases of the pituitary
- Benign pituitary adenoma
- Craniopharygioma
- Trauma
- Apoplexy/Sheehans
- Sarcoid/TB
Give 3 potential consequences of a pituitary tumour
- Pressure on local structures - e.g. optic chasm = bilateral hemianopia
- Pressure on normal pituitary (lack of function) - Hypopituitarism
- Functioning tumours - e.g. Cushing’s, acromegaly, prolactinoma
Describe the growth hormone secretion from the anterior pituitary
It is secreted in a pulsatile fashion and increases during deep sleep
What is acromegaly?
Overgrowth of all organ systems due to excess growth hormone in adults
What is gigantism?
Excess GH production in children before fusion of the epiphyses of the long bones
what are the clinical features of acromegaly?
SYMPTOMS: large hands, box jaw, thick skin, arthritis, sight problems weight gain
SIGNS: hypertension, insulin resistance, bitemporal hemiopia large tongue
what is the pathophysiology of acromegaly?
GH exerts activity indirectly through IGF-1 or directly on tissue
Excessive IGF- levels mediate most of the skeletal and soft tissue growth like features of acromegaly
What can cause acromegaly?
- A benign pituitary adenoma producing excess GH
- rarely due to hyperplasia
Describe the epidemiology of acromegaly
Average age is 40 years
male = female
Reduces life expectancy by 10 years
What complications are associated with acromegaly?
type 2 diabetes
sleep aponea
heart disease
arthritis
What are the investigations for acromegaly?
1st line = IGF-1
2nd line = oral glucose tolerance test
3rd line = pituitary function tests
4th line = MRI
also investigate for complications
What is the gold standard diagnostic test for acromegaly?
Oral glucose tolerance test - failure of glucose to suppress serum GH
what is the management for acromegaly?
1st line = trans sphenoidal surgery
2nd line = OCTREOTIDE (somatostatin analogue) +/- CABERGOLINE (dopamine agonist) if GH secretions persist
3rd line = PEGVISOMANT (GH receptor antagonist)
4th line = radiotherapy
Give 3 potential complications of transsphenoidal surgical resection for the treatment of acromegaly
- Hypopituitarism
- Diabetes insidious
- Haemorrhage
- CNS injury
- Meningitis
What types of medical therapy can be used to treat acromegaly?
somatostatin analogue = octreotide
dopamine agonist = cabergoline
GH receptor antagonist = pegvisomant
Give 3 advantages of using dopamine agonists in the treatment of acromegaly
- No hypopituitarism
- Oral administration
- Rapid onset
Give 2 disadvantages of dopamine agonists in the treatment of acromegaly
- Can be ineffective
2. Risk of side effects
Name a dopamine agonist that can be used as a treatment for acromegaly
Cabergoline
Why can somatostatin analogues be used in the treatment of acromegaly?
They inhibit GH release
Why can GH receptor antagonists be used in the treatment of acromegaly?
They suppresses IGF-1
What is prolactinoma?
Lactotroph cell tumour of the pituitary
Prolactin secreting tumour
Name the 2 types of prolactinoma
- Microprolactinoma = most common, >90%
2. Macroprolactinoma = >10mm
what are the causes of prolactinoma?
- Pituitary adenoma
- Anti-dopaminergic drugs
- Head injury - compression of the pituitary stalk
what are the clinical features of prolactinoma
SYMPTOMS: amenorrhea, galactorrhoea, gynaecomastia, low libido, possible cerebral symptoms
SIGNS:
low testosterone,
infertility
Briefly describe the pathophysiology of Prolactinoma
Increased release of prolactin can cause galactorrhoea and can inhibit FSH and LH
Compression of the pituitary stalk
Prevents secretion of dopamine from hypothalamus - stops inhibition of prolactin
what are the investigations for prolactinoma?
Serum prolactin levels - HIGH
CT head
What is the treatment for prolactinoma?
Dopamine agonists - cabergoline - inhibits prolactin release
Occasionally transsphenoidal pituitary resection
What is Cushing’s Syndrome?
Chronic, excessive and inappropriate elevated levels of circulating plasma glucocorticoids (cortisol)
What is Cushing’s Disease?
When Cushing’s syndrome is caused by a pituitary tumour so excess glucocorticoids due to inappropriate ACTH secretion
what is the clinical presentation of Cushing’s disease?
Central obesity Plethoric complexion Moon face Mood change Proximal muscle weakness Purple abdominal striae Gastric ulcers Osteoporosis Hirsutism
what are the causes of excess cortisol?And are they ACTH dependent or independent?
ACTH dependent:
- Cushing’s disease
- Ectopic ACTH production
- ACTH treatment
ACTH independent
- adrenal adenoma
- iatrogenic
What is a differential diagnosis of Cushing’s syndrome?
Pseudo-Cushing’s = excessive alcohol consumption can mimic the clinical and biochemical signs but resolved on alcohol recession
Describe the epidemiology of Cushing’s syndrome
women > men
majority diagnosed 20-50y/o
most common cause is oral steroids
what are the investigations for Cushing’s syndrome?
- drug history - oral steroids
- random plasma cortisol - high
- overnight dexamethasone suppression test and urinary free cortisol (24hr) - positive (no suppression = cushings)
- test plasma ACTH
How does a dexamethasone suppression test work?
Give synthetic steroids that suppress pituitary and adrenals and then measure the cortisol
In Cushing’s there is no suppression of cortisol
What is the treatment for Cushing’s syndrome?
Tumours = surgical removal
- pituitary adenoma = transsphenoidal surgical resection
- adrenal adenoma = adrenalectomy
Drugs to inhibit cortisol synthesis - metyrapone, ketoconazole
What are some complications associated with Cushing’s Syndrome?
cardiovascular disease
hypertension
diabetes mellitus
osteoporosis
What is the circadian system?
Body clock that regulates your body
Clear rhythm of cortisol production follows circadian rhythm
When do cortisol levels peak?
At around 8:30 am
What’s the primary cue that synchronises an organism’s biological rhythms?
Light
What is adrenal insufficiency?
Adrenocortical insufficiency resulting in a reduction of mineralocorticoids, glucocorticoids and androgens
what is Addison’s disease?
Destruction of entire adrenal cortex resulting in mineralocorticoid (aldosterone), glucocorticoid and androgen deficiency
what are the causes of Addison’s disease?
- autoimmune destruction (21-hydroxylase present in 60-90%) - most common in developed countries
- TB - most common in developing countries
- adrenal metastases- long term steroid use
what are the clinical features of Addison’s disease?
SYMPTOMS
Fatigue
Weakness
Weight loss
SIGNS Hyperpigmentation Postural hypotension Hypoglycaemia Other signs of autoimmunity
What is the treatment for adrenal insufficiency?
Hormone replacement - any steroids
ORAL HHYDROCORTISONE
ORAL FLUDROCORTISONE
What is the pathophysiology of Addison’s disease?
Destruction of the adrenal cortex results in decreased production of the hormones
All steroids reduced
Reduced cortisol levels = increased CRH and ACTH production through feedback
What are the investigations for Addison’s disease?
- SynACTHen test = giving synthetic ACTH does not increase cortisol levels
- Serum electrolytes = low Sodium, high Potassium
- FBC: Anaemia and eosinophilia
- Morning serum cortisol = Reduced
- Adrenal CT or MRI
What investigations would you do to determine whether Adrenal insufficiency is primary or secondary?
Primary = adrenal antibodies, very long chain fatty acids, imaging and genetics Secondary = any steroids?, imaging and genetics
what are the features of addisonian crisis?
Vomiting abdominal pain profound weakness hypoglycaemia hypovolemic shock
What is the management of adrenal crisis?
Immediate IV Hydrocortisone
Fluid resuscitation - saline (IV)
What would sodium and potassium levels be in someone with adrenal insufficiency?
Hyponatraemia = low sodium
Hyperkalaemia = high potassium
Lack of aldosterone and so less sodium reabsorbed and less potassium excreted
Why is it important to take a drug history when speaking to someone with potential Cushing’s?
To exclude steroid use as a potential cause
Briefly describe the mechanism of thyroid destruction
Cytotoxic (CD8+) T cell mediated thyroglobulin and Thyroid peroxidase (TPO) antibodies may cause secondary damage (alone have no effect)
Antibodies against the TSH receptor may block the effect of TSH (uncommon)
What are the main 3 types of cells that cause thyroid destruction?
- Cytotoxic T cells
- Thyroglobulin
- TPO antibodies
Briefly describe the pathophysiology of Grave’s disease
Specific serum IgG (TSH receptor stimulating antibodies) bind to TSH receptors in thyroid
Behave like TSH – stimulate T3 and T4 production
This results in excess secretion and hyperplasia of thyroid follicular cells – causing hyperthyroidism and graves ophthalmopathy
what is the clinical presentation of Grave’s opthlmopathy?
SYMPTOMS Eye discomfort Grittiness increased tear production Photophobia Diplopia reduced acuity
SIGNS Exophthalmos – protruding eye Proptosis – eye protrudes beyond orbit Conjunctival oedema Corneal ulceration Ophthalmoplegia – paralysis of eye muscles
what is the clinical presentation of grave’s dermopathy?
Pretibial myxoedema – raised, purple red symmetrical skin lesions over anterolateral aspects of shin
Thyroid acropachy – clubbing, swollen fingers and periosteal bone formation
what is the treatment for Grave’s ophthalmology?
Conservative treatment – smoking cessation and sunglasses
IV METHYLPREDNISOLONE and surgical decompression/eyelid surgery
Name 5 risk factors for Graves disease
- Female
- Genetic association
- E.coli
- Smoking
- Stress
- High iodine intake
- Autoimmune diseases
Name 5 autoimmune diseases associated with thyroid autoimmunity
- T1DM
- Addison’s disease
- Pernicious anaemia
- Vitiligo
- Alopecia areata
- Rheumatoid arthritis
What would you see histological in someone with Graves disease?
Lymphocyte infiltration and thyroid follicle destruction
What is goitre?
Palpabel and visible thyroid enlargement
Why does goitre occur and when is is most commonly found?
Due to TSH receptor stimulation resulting in thyroid growth
Seen in hypo and hyperthyroidism
Name 4 types of sporadic non toxic goitre
- Diffuse –> physiological –> Graves
- Multi nodular
- Solitary nodule
- Dominant nodule
Define hyperthyroidism
Overactivity of the thyroid gland
Define thyrotoxicosis
Excess of thyroid hormone in the blood (can be used interchangeably with hyperthyroidism)
Name the 3 mechanisms of how hyperthyroidism may come about
- Overproduction of thyroid hormone
- Leakage of preformed hormone from the thyroid
- Ingestion of excess thyroid hormone
what are the causes of hyperthyroidism?
- Grave’s disease
- Toxic multinodular goitre
- Solitary toxic nodule/adenoma - benign
- De Quervarians thyroiditis
- Postpartum thyroiditis
- Drug induced
Name 4 drugs which can induce hyperthyroidism
- Iodine
- Amiodarone
- Lithium
- Radioconstrast agents
what are the clinical features of hyperthyroidism?
SYMPTOMS: hot and sweaty, diarrhoea, wt. loss, anxiety/restlessness, hyperphagia
SIGNS:
periorbital swelling,
goitre,
tachycardia
What investigations are done to diagnose hyperthyroidism?
TFTs:
primary = high T3 and T4, low TSH
secondary = high T3 and T4, high TSH
What are the thyroid function test results in primary hyperthyroidism?
high T4
high T3
low TSH
What are the thyroid function rests in secondary hyperthyroidism?
high T4
high T3
high TSH
What are the 4 main treatments for hyperthyroidism?
- Beta blockers - PROPRANOLOL
- Anti-thyroid drugs - CARBIMAZOLE
- Radioiodine
- Surgery - partial/total thyroidectomy
Why are beta blockers used to treat hyperthyroidism?
For rapid control of symptoms
Give examples of anti-thyroid drugs and why are they used?
- Carbimazole, methimazole, proplythiouracil (PTU) - (thionamides)
- Decreases synthesis of new thyroid hormone by targeting thyroid peroxidase
- PTU also inhibits conversion of T4 to T3
Give 4 poor prognostic factors of those on anti-thyroid drugs
- Severe biochemical hyperthyroidism
- Large goitre
- Male
- Young age of disease onset
Give 5 side effects of anti-thyroid drugs
- Rash
- Arthralgia
- Hepatitis
- Neuritis
- Vasculitis
- Agranulocytosis - very serious
Why can radioiodine be used as a treatment for hyperthyroidism?
Emit beta particle that destroy thyroid follicle and therefore reducing the production of thyroid hormones
Give 4 potential consequences of a partial thyroidectomy
- Bleeding
- Hypoglycaemia
- Hypothyroidism
- Recurrent laryngeal nerve palsy
What is a complication of hyperthyroidism?
Thyroid crisis/storm
graves ophthalmopathy
hypothyroidism
Briefly explain thyroid crisis/storm
Rapid deterioration of thyrotoxicosis
Hyperpyrexia, tachycardia and extreme restlessness Delirium –> coma –> death
What is the treatment for a thyroid crisis?
Large doses of oral carbimazole, oral propranolol, oral potassium iodide and IV hydrocortisone
Define hypothyroidism
Under-activity of the thyroid gland
Name the 3 types of hypothyroidism
- Primary - absence/dysfunction of thyroid gland
- Secondary - reduced TSH from anterior pituitary
- Tertiary - associated with treatment withdrawal
Briefly describe the pathophysiology of primary hypothyroidism
Underactivity usually primary from disease of the thyroid but may be secondary due to hypothalamic-pituitary disease resulting in reduced TSH
Briefly describe the pathophysiology of secondary hypothyroidism
Reduced release or production of TSH so reduced thyroid hormone release
Briefly describe the pathophysiology of tertiary hypothyroidism
Thyroid gland overcompensates until it can reestablish correct concentration fo thyroid hormone
Name 4 causes of primary hypothyroidism
- autoimmune thyroiditis
- postpartum thyroiditis
- iatrogenic
- drug induced
- iodine deficiency
- congenital
Give 2 examples of iatrogenic causes of hypothyroidism
- Thyroidectomy
2. Radioiodine therapy
Give an example of a transient cause of primary hypothyroidism
Post-partum thyroiditis
Name 4 drugs that can cause hypothyroidism
- Carbimazole (used to treat hyperthyroidism)
- Amiodarone
- Lithium
- Iodine
Name 3 causes of secondary hypothyroidism
- Hypopituitarism
- Hypothalamic disease
- Isolated TSH deficiency
Why can amiodarone cause both hypo and hyperthyroidism?
Because it is iodine rich
what are the clinical features of hypothyroidism?
SYMPTOMS: wt. gain, depression, constipation, cold intolerance, “brain fog”
SIGNS: bradycardia, delayed reflexes
What investigations are conducted to diagnose hypothyroidism?
Thyroid function tests
Thyroid antibodies
What are the TFT results for primary hypothyroidism?
High TSH
Low T4 and T3
What are the TFT results for secondary hypothyroidism?
Inappropriately low TSH for low T4 and T3
Name 3 antibodies that may be present in the serum in someone with autoimmune thyroiditis
- TPO (thyroid peroxidase)
- Thyroglobulin
- TSH receptor
What is the treatment for primary hypothyroidism?
Thyroid hormone replacement - levothyroxine Resection of obstructive goitre
what are the complications of hypothyroidism?
Myxoedema coma - medical emergency
heart disease
pregnancy problems
Briefly explain a myxoedema coma
Severe hypothyroidism
Reduced level of consciousness, seizures, hypothermia IV/oral T3 and glucose infusion needed
What is Hashimoto’s thyroiditis?
Hypothyroidism due to aggressive destruction of thyroid cells
Give 3 symptoms of Hashimoto’s thyroiditis
- Rapid formation of Goitre
- Dyspnoea or dysphagia
- General hypothyroidism symptoms
Name 3 triggers of Hashimoto’s thyroiditis
- Iodine
- Infections
- Smoking
- Stress
What are the investigations for Hashimoto’s thyroiditis?
TFTs - high TSH, low T3 and T4
high TPO antibodies
What is the treatment for Hashimoto’s thyroiditis?
Levothyroxine
Name a complication fo Hashimoto’s thyroiditis
Hyperlipidaemia
what are the complications of Hashimoto’s thyroiditis?
Hashimoto’s encephalopathy
What disease would you treat with Carbimazole?
Hyperthyroidism/Graves disease
What disease would you treat with Levothyroxine?
Hypothyroidism
Name 3 disease associated with the posterior pituitary
- Cranial diabetes insipidus - lack of ADH
- Nephrogenic diabetes insipidus - resistance to action of ADH
- Syndrome of antidiuretic hormone secretion - too much ADH release inappropriately
Define diabetes insipidus
Passage of large volumes (>3L/day) of dilute urine due to impaired water reabsorption in the kidney due to hypo secretion or insensitivity to ADH
Name the 2 types of DI
- Cranial DI = reduced vasopressin (ADH) produced by hypothalamus and secreted by the posterior pituitary
- Nephrogenic DI = impaired response of the kidney to ADH
what are the clinical features of DI?
SYMPTOM
- Polyuria
- Polydipsia
- No glycosuria
SIGNS
- Dry mucosa
- Sunken eyes
- Changes in skin turgidity
- Can lead to dehydration
- Hypernatremia
what are the causes of cranial DI?
Idiopathic Congenital defects in ADH gene Disease of hypothalamus Tumour – metastases, posterior pituitary Trauma – neurosurgery Infiltrative disease
what are the causes of nephrogenic DI?
- Hypokalaemia
- Hypercalcaemia
- Drugs
- lithium chloride
- Demeclocycline
- glibenclamide - Renal tubular acidosis
- Sickle cell disease
- Prolonged polyuria of any cause
- Familial (mutation in ADH receptor)
Give 3 possible differential diagnosis’s of DI
- DM
- Hypokalaemia
- Hypercalcaemia
what are the investigations for diabetes insipidus?
- Water deprivation test
- Desmopressin given and urine osmolality measured for 2-4 hrs with free fluids allowed
- NDI diagnosed if urine osmolality stays the same
- CDI diagnosed if urine osmolality increases by >50%ADH suppression test- shows neurogenic - Urine dip, glucose, U&E, fluid status
What is the treatment for cranial DI?
- Treat underlying condition
- Thiazide diuretics (BENDROFLUMETHIAZIDE) - sensitise renal tubules to endogenous vasopressin
- DESMOPRESSIN - high activity at V2 receptor
What is the treatment for nephrogenic DI?
- treat cause
- thiazide diuretics - (BENDROFLUMETHIAZIDE) - Produces hypovolaemia which will encourage the kidneys to take up more Na+ and water in proximal tubule
- NSAIDs - IBUPROFEN - Lower urine volume and plasma Na+ by inhibiting prostaglandin synthase. Prostaglandins locally inhibit the action of ADH
Do you have hyponatraemia or hypernatraemia in diabetes insipidus?
Hypernatraemia
Give 4 causes of polyuria
- Hypokalaemia
- Hypercalcaemia
- Hyperglycaemia
- Diabetes insipidus
What is SIADH?
Syndrome of inappropriate ADH secretion
Continuous ADH secretion inspire of plasma hypotonicity, leading to retention of water and excess blood volume and thus hyponatraemia
what are the clinical features of SIADH?
SYMPTOMS: Nausea and vomiting Headache Lethargy Cramps Weakness Confusion / irritability
SIGNS
raised JVP
oedema
ascites
what are the causes of SIADH?
brain injury infection hypothyroidism cancers lung diseases
what are the investigations for SIADH?
- ADH levels
- U and Es (low sodium normal potassium),
- fluid status
distinguish SIADH from salt & water depletion - test with 1-2L of
0.9% saline:
• Sodium depletion will respond
• SIADH will NOT RESPOND
what is the pathophysiology of SIADH?
- Excess release of ADH will result in increased insertion of aquaporin 2 channels in apical membrane of collecting duct
- Excess water retention which dilutes blood plasma
- Result in hyponatremia as Na+ conc decreases
Describe the treatment for SIADH
- Restrict fluid - <1L/day
- Give salt
- Loop diuretics - furosemide
- Demeoclocycline - inhibitor of ADH
- ADH-R antagonists - vaptans - primate water excretion with no loss of electrolytes
How do you treat asymptomatic SIADH?
Fluid restriction
How do you treat very symptomatic SIADH?
Give 3% saline (hypertonic)
Would you expect a patient with SIADH to be hypovolaemic, euvolaemic or hypervolaemic?
Euvolaemic
Would you associate SIADH with hyponatraemia or hypernatraemia?
Hyponatraemia - <135 mmol/L
Would you associate SIADH with plasma hypo-osmolality or hyper-osmolality?
Plasma hypo-osmolality - <275 mOsmol/Kg
Would you associate SIADH with a high to low urine osmolality?
High urine osmolality
Define hyponatraemia
<135 mmol/L
Biochemically severe = serum sodium <125 mmol/L
What stimulates the posterior pituitary to release ADH?
Osmoreceptors in the hypothalamus detect raised plasma osmolality Posterior pituitary is signalled to release ADH
Give 4 local effects a pituitary adenoma
- Headaches
- Visual field defects - bitemporal hemianopia
- Cranial nerve palsy and temporal lobe epilepsy
- CSF rhinorrhoea
What investigations are done when pituitary dysfunction is suspected?
Hormonal tests If hormonal tests are abnormal or tumour mass effect perform MRI pituitary
What do you test the thyroid axis for in pituitary disease?
Measure Free T4 and TSH
What is the affect of primary hypothyroidism on TSH and T4 levels?
TSH highT4 low
What is the effect of secondary hypopituitarism on TSH and T4 levels?
TSH low
T4 low
What can lead to elevated levels of prolactin?
- Stress
- Drugs
- Pressure on pituitary stalk
- Prolactinoma
What is the best radiological evaluation for the pituitary?
MRI - better visualisation of soft tissue and vascular structures
Name 3 ketone bodies
- Beta hydroxybutyrate
- Acetoacetate
- Acetone
Does diabetic ketoacidosis occur in T1 or T2 DM?
Type 1
Describe the triad of DKA
- Hyperglycaemia - blood glucose >11 mmol/L
- Acidaemia - blood pH <7.3 or plasma bicarbonate <15 mmol/L
- Raised plasma ketones - urine ketones >2+
Give 4 causes of DKA
- Unknown
- Infection
- Treatment error - not administering enough insulin
- Having undiagnosed T1DM
Give 5 symptoms of DKA
- Polyuria
- Polydipsia
- Weight loss
- Nausea and vomiting
- Confusion
- Weakness
Give 3 signs of DKA
- Hyperventilation
- Dehydration
- Hypotension
- Tachycardia
- Coma
What is the treatment for DKA
Rehydration (3L in first 3 hours)
Insulin
Replacement of electrolytes - K+Treat underlying cause
Give 4 potential complications of untreated DKA
- Cerebral oedema
- Adult respiratory distress syndrome
- Aspiration pneumonia
- Thromboembolism
- Death
In what class of drugs does metformin belong?
Biguanide
Give an example of a sulfonylurea
Tolazamide
Gliclazide
What are the physiological defences to hypoglycaemia?
Release of glucagon and adrenaline
What are the symptoms of hypoglycaemia?
Autonomic - sweating, tremor, palpitations
Neuroglycopenic - confusion, drowsiness, incoordination
Severe neuroglycopenic - convulsions, coma
Name 3 other types of diabetes other than T1DM, T2DM and DI
- Maturity onset diabetes of the young (MODY)
- Permanent neonatal diabetes
- Maternal inherited diabetes and deafness
Name 3 exocrine causes of Diabetes
- Inflammatory - actue/chronic pancreatitis
- Hereditary haemochromatosis
- Pancreatic neoplasia
- Cystic fibrosis
Name 3 endocrine causes of Diabetes
- Acromegaly
- Cushing’s syndrome
- Peochromocytoma
What is Pheochromocytoma?
A rare catecholamine secreting tumour in the adrenal medulla (chromatin cells)
what are the different types of pheochromocytoma?
- Familial type - more NAd
2. Sporadic - more Ad
what are the clinical features of pheochromocytoma?
SYMPTOMS Headache Profuse Sweating Palpitations Tremor
SIGNS Hypertension Postural hypotension Tremor hypertensive retinopathy Pallor
What are the investigations for pheochromocytoma?
- Plasma metanephrines and normetanephrines
- 24 hour urinary total catecholamines
- CT – look for tumour
What is the treatment for pheochromocytoma?
Without HTN crisis:
1st Line: Alpha blockers: PHENOXYBENZAMINE
Most patients will eventually get the tumour removed and then managed medically.
With HTN crisis:
1st Line: Antihypertensive agents: PHENTOLAMINE
What is the major complication of surgery on a patient with a pheochromocytoma?
Can stoke out during surgery due to rapid effect of adrenaline on the BP
What is the major concern in someone with pheochromocytoma?
Dangerous cause of hypertension
17 year old man presents with intermittent headaches and anxiety. He is sweating and vomiting. His BP is 223/159 and his pulse is 115. What is the likely cause?
Phaeochromocytoma crisis
Hypertension and tachycardia = phaeochromocytoma until proved otherwise (especially in younger patients)
What is the management of a phaeochromocytoma crisis?
Non-competitive alpha-blocker e.g. phenoxybenzamine
Excision of paraganglioma
Biochemistry: measure plasma and serum metanephrines
What are the 3 main sites where microvascular complications of Diabetes cause particular damage?
- Retina = retinopathy
- Glomerulus = nephropathy
- Nerve sheath = neuropathy
How long after a young patient has been diagnosed do microvascular complications start to manifest?
10-20 years after diagnosis
Give 5 risk factors for diabetic retinopathy
- Long duration DM
- Poor glycaemic control
- Hypertensive
- On insulin treatment
- Pregnancy
- High HbA1c
Describe the pathophysiology of diabetic retinopathy
Micro-aneurysms –> pericyte loss and protein leakage –> occlusion –> ischaemia
How can diabetic retinopathy be sub-divided?
R1 = non-proliferative/background R2 = pre-proliferative R3 = Proliferative
What would you see in someone with an R1 retinopathy grade?
Non-proliferative/background
Micro-aneurysms
Intraretinal haemorrhages
Exudates
What would you see in someone with an R2 retinopathy grade?
Pre-proliferative
Venous bleeding
Growth of new vessels
What would you see in someone with an R3 retinopathy grade?
Proliferative
New blood vessel on disc
What is the treatment for diabetic retinopathy?
Regular screening to assess visual acuity
Laser therapy treats neovascularisation - doesn’t improve sight but stabilises
What are the main risks of laser treatment of diabetic retinopathy?
Loss of night vision and peripheral vision
What is diabetic maculopathy?
Fluid form leaking vessel is cleared poorly in macular area causing macula oedema which distorts and thickens the retina at the macula
Leads to loss of central vision
What is the hallmark of diabetic nephropathy?
Development of proteinuria and progressive decline in renal function
What happens to the glomerular basement membrane in someone with diabetic nephropathy?
On microscopy there is thickening of the glomerular basement membrane
Give one way in which the presentation of diabetic nephropathy differs between T1 and T2DM
T1DM - microalbuminuria develops 5-10 years after diagnosis
T2DM - microalbuminuria is often present at diagnosis
Give 2 risk factors for diabetic nephropathy
- Poor blood pressure
2. Poor blood glucose control
Describe the treatment for diabetic nephropathy
- Glycaemic and BP control
- Angiotensin receptor blockers/ACE inhibitors - RAMIPRIL or CANDESARTAN
- Proteinuria and cholesterol control
What is the commonest form of diabetic neuropathy?
Distal symmetrical neuropathy
Give 5 risk factors for diabetic neuropathy
- Poor glycaemic control
- Hypertension
- Smoking
- High HbA1c
- Overweight
- Long duration DM
Why do isolated mononeuropathies result from in diabetic neuropathy?
Occlusion of vasa nervorum - small arteries that provide blood supply to peripheral nerves
Why do more diffuse neuropathies arise in diabetic neuropathy?
Accumulation of fructose and sorbitol which disrupts the structure and formation of the nerve
Give 3 major clinical consequences of diabetic neuropathy
- Pain
- Autonomic neuropathy
- Insensitivity
Describe the pain associated with diabetic neuropathy
Burning
Paraethesia
Allodynia - triggering of pain from stimuli that doesn’t usually cause pain
What is autonomic neuropathy in relation to diabetic neuropathy?
Damage to the nerves that supply body structures that regulate function such as BP, HR, bowel/bladder emptying
Give 5 signs of autonomic neuropathy in diabetic neuropathy
- Hypotension
- HR affected
- Diarrhoea/constipation
- Incontinence
- Erectile dysfunction
- Dry skin
What are the consequences of insensitivity as a result of diabetic neuropathy?
Insensitivity –> foot ulceration –> infection –> amputation
Describe the distribution of insensitivity as a result of diabetic neuropathy
Glove and sticking distribution - starts in the toes and moves proximally
Describe the treatments for diabetic neuropathy
- Improve glycaemic control
- tricyclic antidepressants - AMITRIPTYLINE
- Pain relief - PARACETAMOL and TRAMADOL
Give 5 ways in which amputation can be prevented in someone with diabetic neuropathy
- Screening for insensitivity
- Education
- MDT foot clinics
- Pressure relieving footwear
- Podiatry
- Revascularisation and antibiotics
What are the 4 main threats to skin and subcutaneous tissues in someone with diabetic neuropathy
- Infections
- Ischaemia
- Abnormal pressure
- Wound environments
Would there be increased or decreased pulses in diabetic neuropathic foot?
Decreased foot pulses
Peripheral vascular disease is a complication of Diabetes. Give 6 signs of acute ischaemia
- Pulseless
- Pale
- Perishing cold
- Pain
- Paralysis
- Paraesthesia
what infections can poorly controlled diabetes lead to?
- UTIs
- Staphylococcal infection of skin
- Mucocutaneous candidiasis
- Pyelonephritis
- TB
- Pneumonia
- rectal abscess
Why does the site of insulin injection need to be varied day to day?
Can cause lipohypertrophy if the same site is used everyday
Name 4 non insulin treatments for diabetes
- Metformin
- Sulphonylurea
- Incretin based agents
- Thiazolidinediones (TZDs)
- SGLT-2 inhibitors
Why is metformin the first line therapy for diabetes?
Associated with less weight gain and less hypoglycaemia than insulin and sulfonylurea
When is sulfonylurea considered as treatment for diabetes?
In individuals:
- Who are not overweight (as causes weight gain)
- Require rapid response due to hyperglycaemia symptoms
- Are unable to tolerate metformin or where metformin is contraindicated
How do incretin based agents treat diabetes?
Influence glucose homeostasis via:
- glucose dependent insulin secretion
- postprandial glucagon suppression
- slowing gastric emptying
Give examples of Thiazolidinediones (TZDs)
Rosiglitazone and Pioglitazone
How do Thiazolidinediones treat diabetes?
Effective glucose lowering agents
What diseases are associated with polycystic ovary syndrome?
- Insulin resistance - T2DM
- Hypertension
- Hyperlipidaemia
- CV disease
Give 5 symptoms of polycystic ovary syndrome
- Amenorrhoea
- Oligomenorrhoea
- Hirsutism
- Acne
- Overweight
- Infertility
What criteria can be used to make a diagnosis of polycystic ovary syndrome?
Rotterdam diagnostic criteria
- Menstrual irregularity
- Clinical or biochemical evidence of hyperandrogenism
- Polycystic ovaries on USS
Describe the treatment for polycystic ovary syndrome
- Hirsutism therapy - shaving/waxing excess hair OR oestrogen (e.g. OCP)
- Menstrual disturbance therapy - cyclic oestrogen/progesterone
- Metformin can improve hyperinsulinaemia and regulates menstrual cycle
A 27-year- old woman comes to see you because she is having infrequent periods (oligomenorrhoea). You note, on examination, that she has facial acne and is overweight. What is the most likely diagnosis? Give 3 other signs you might see in this patient
Polycystic ovary syndrome Other signs: 1. Hirsutism 2. Amenorrhoea 3. Infertility
What is Conn’s syndrome?
Primary hyperaldosteronism
High aldosterone levels independent of RAAS activation - H20 and sodium retention and potassium excretion
What are the clinical features of Conn’s syndrome?
- hypertension
- nocturia and polyuria
- mood disturbance
- difficulty concentrating
- hypokalaemia
A deficiency in which electrolyte causes the symptoms of Conn’s syndrome?
- Muscle weakness
- Tiredness
- Polyuria
Due to potassium deficiency
What are the causes of Conn’s syndrome?
Adrenal adenoma (2/3) Bilateral adrenal hyperplasia (1/3)
What hormone is raised in Conn’s syndrome and what hormone is reduced? Where are these hormones synthesised?
- Aldosterone is raised - synthesised in the zone glomerulosa
- Renin is reduced - synthesised in the juxta-glomerular cells
What investigations might you do in someone to confirm a diagnosis of Conn’s syndrome?
- first line = aldosterone renin ratio - high
- increased plasma aldosterone levels that aren’t suppressed with 0.9% saline infusion or fludrocortisone administration - DIAGNOSTIC
- Bloods - plasma potassium = low
4. ECG - flat T waves, ST depression and long QT
Give 4 ECG changes you might see in someone with Conn’s syndrome
- Increased amplitude and width of P waves
- Flat T waves
- ST depression
- Prolonged QT interval
- U waves
What is the treatment for Conn’s syndrome?
- If the cause is a single benign adrenal tumour - Unilateral adrenalectomy
- If the cause is due to bilateral adrenal hyperplasia - Aldosterone antagonists (spironolactone)
What is adrenal hyperplasia?
Defective enzymes mediating the production of adrenal cortex products - low levels of cortisol and high levels of male hormones
How does adrenal hyperplasia present?
Salt loss
Females - ambiguous genitalia with common urogenital sinus
Males - no signs at brith, subtle hyperpigmentation and possible penile enlargement
Briefly describe the pathophysiology of adrenal hyperplasia
Defective 21-hydroxylase –> disruption of cortisol biosynthesis
With or without aldosterone deficiency and androgen excess
What diagnostic test would be done to confirm adrenal hyperplasia?
Serum 17-hydorxyprogesterone (precursor to cortisol) = high
What is the treatment for adrenal hyperplasia?
Glucocorticoids - hydrocortisone
Mineralocorticoids - control electrolytes
If salt loss - sodium chloride supplement
What is hyperkalaemia?
Excess of potassium Serum K+ >5.5 mmol/L
Serum K+ >6.5 mmol/L = medical emergency
what are the clinical features of hyperkalaemia?
SYMPTOMS Fatigue Generalised weakness Chest pain Palpitations
SIGNS Arrhythmias Reduced power Reduced reflexes Signs of underlying cause
what are the causes of hyperkalaemia
IMPAIRED EXCRETION
- AKI and CKD
- drug effect
- renal tubular acidosis (T4)
INCREASED INTAKE
- IV therapy
- increased dietary intake
SHIFT TO EXTRACELLULAR
- metabolic acidosis
- rhabdomyolysis
What ECG changes might you see in someone with hyperkalaemia?
GO - absent P waves
GO LONG - prolonged PR
GO TALL - Tall T waves
GO WIDE - Wide QRS
What is the treatment for hyperkalaemia?
- ABC assessment
- Consider cardiac monitoring
- Protect myocardium: 10ml, 10% calcium gluconate
- Drive K+ intracellularly: Insulin/Dextrose, Nebulised Salbutamol
What is a complication for someone with hyperkalaemia?
Myocardial infarction –> death
What is hypokalaemia?
Deficiency in potassium
Serum K+ <3.5 mmol/L
Serum K+ <2.5 mmol/L = medical emergency
what are the clinical features of hypokalaemia?
SYMPTOMS: Asymptomatic Fatigue Generalised weakness Muscle cramps and pain Palpitations
SIGNS:
Arrhythmias
Muscle paralysis and rhabdomyolysis
Give 3 causes of hypokalaemia
- INCREASED EXCRETION
- drugs e.g. thiazide, loop
- renal disease
- GI loss
- increased aldosterone
REDUCED INTAKE
- dietary deficiency
SHIFT TO INTRACELLULAR
- drugs e.g. insulin, salbutamol
What ECG changes might you see in someone with hypokalaemia?
- Increased amplitude and width of P waves
- ST depression
- Flat T waves
- U waves
- QT prolongation
What is the treatment for hypokalaemia?
- Potassium PO/IV
- Other electrolyte replacements
- Treat underlying cause
What are 2 possible complications of hypokalaemia?
- Cardiac arrhythmias
2. Sudden death
Name 5 types of thyroid cancer
- Papillary - thyroid epithelium
- Follicular - thyroid epithelium
- Anaplastic - thyroid epithelium
- Lymphoma
- Medullary - calcitonin C cells
What types of thyroid cancers are usually asymptomatic thyroid nodule (usually hard and fixed)?
Papillary
Follicular
Anaplastic
what is the clinical presentation of thyroid cancer?
- In 90% present as thyroid nodules
- Occasionally they present with cervical lymphadenopathy or with lung, cerebral, hepatic or bone mets.
- If thyroid gland increases in size, becomes hard and irregular in shape think cancer
- May experience dysphagia or hoarseness of voice if tumour presses on surrounding structures
How does a medullary cancer of the thyroid present?
Diarrhoea
Flushing episodes
Itching
Why is an anaplastic cancer of the thyroid one of the most aggressive cancers?
Cancer of the follicular cells of the thyroid but doesn’t retain original cell features like iodine uptake or synthesis of thyroglobulin
What hormone does a medullary cancer of the thyroid produce?
Calcitonin from C cells
What is the most common form of thyroid cancer?
Papillary - 70%, young people, 3x more common in women
Follicular - 20%
What investigations can you do to confirm a thyroid cancer?
Fine needle aspiration
For a Medullary cancer - elevated serum calcitonin
Blood tests – check TFTs (TSH, T4, T3) – check if hyper or hypo thyroid
Ultrasound - benign/malignant
What is the treatment for thyroid cancer?
- LEVOTHYROXINE T4 to keep TSH reduced as this is a growth factor for cancer Papillary and follicular
- total thyroidectomy
- ablative radioactive iodine Anaplastic and lymphoma
- external radiotherapy to provide relief
- largely palliative Medullary
- total thyroidectomy and prophylactic central lymph node dissection
what is de quervain’s thyroiditis?
Transient hyperthyroidism sometimes results from acute inflammation of
the thyroid gland, probably due to viral infection
what is the clinical presentation of de quervain’s thyroiditis?
Usually accompanied by fever, malaise and pain in the neck
what is the treatment for de quervain’s thyroiditis?
Treat with aspirin and only give prednisolone for severely symptomatic
cases
what are the side effects of metformin?
GI upset
lactic acidosis
what is the mechanism of action for SGLT-2 inhibitors?
inhibits resorption of glucose in the kidney
what are the side effects of SGLT-2 inhibitors?
UTI
what is the mechanism of action for glitazones?
Activate PPAR-gamma receptor in adipocytes to promote adipogenesis and fatty acid uptake
what are the side effects of glitazones?
Weight gain
Fluid retention
what is the mechanism of action for levothyroxine?
synthetic T4
what is the diagnostic criteria for diabetic ketoacidosis?
glucose >11mmol/L
pH <7.3
bicarbonate <15mmol/L
ketones >3mmol/l or ketones in urine
what is hyperosmolar hyperglycaemic state?
This is a life-threatening emergency characterised by marked hyperglycaemia,
hyperosmolality and mild or no ketosis
characteristic of uncontrolled type 2 diabetes
what are the risk factors for hyperosmolar hyperglycaemic state?
- infection
- consumption of glucose rich fluids
- concurrent medication (thiazides or steroids)
what is the pathophysiology of hyperosmolar hyperglycaemic state?
- Endogenous insulin levels are reduced but are still sufficient to inhibit hepatic ketogenesis but insufficient to inhibit hepatic glucose production
what is the clinical presentation of hyperosmolar hyperglycaemic state?
- severe dehydration
- decreased level of consciousness
- hyperglycaemia
- hyperosmolality
- not ketones in blood or urine
- stupor or coma
- bicarbonate NOT LOWERED
what are the investigations for hyperosmolar hyperglycaemic state?
Random plasma glucose >11mmol/L
Urine dipstick: glucosuria
Plasma osmolality - high
U+E - ↓ total body K+, ↑serum K+
what is the treatment for hyperosmolar hyperglycaemic state?
- Replace fluid - 0.9% saline IV
- Insulin - At low rate of infusion!
- Restore electrolytes - e.g. K+
- LMWH
what conditions is hashimotos thyroiditis associated with?
- other autoimmune conditions - coeliac disease, T1DM, vitiligo
- MALT lymphoma
what are the side effects of levothyroxine?
- usually due to excessive doses
- GI disturbance, cardiac arrhythmias and neurological tremors
what is the mechanism of action for carbimazole?
prevents thyroid peroxidase from producing T3 and T4
what is the mechanism of action for GH receptor antagonist’s e.g. pegvisomant?
blocks action of GH at GH receptor -> reduces production of IGF-1
what are the side effects of GH receptor antagonists e.g. pegvisomant?
- reactions at injection site
- GI disturbance
- hypoglycaemia
- chest pain
- hepatitis
what is the mechanism of action for vasopressin antagonists e.g. tolvaptan?
- inhibits vasopressin-2 receptor -> increases fluid excretion
- causes aquaresis (excretion of H2O with no electrolyte loss) -> increased Na+
what are the side effect of vasopressin antagonists e.g. tolvaptan?
- GI disturbance
- headache
- increased thirst
- insomnia
what is the mechanism of action for vasopressin analogues e.g. desmopressin?
binds to V2 receptors -> aquaporin 2 inserted in collecting duct which increases water reabsorption
what are the side effects of vasopressin analogies e.g. desmopressin?
- headache
- facial flushing
- nausea
- seizures
what is the mechanism of action for metyrapone?
- blocks cortisol synthesis by irreversibly inhibiting steroid 11 beta-hydroxide enzyme
what are the side effects of metyrapone?
- GI disturbance
- headache
- dizziness
- drowsiness
- hirsutism
how would cortisol levels react to the synacthen test if there was secondary adrenal insufficiency?
short ACTH = no change
long ACTH = increase
where is the most common site for carcinoid tumours to metastasise?
liver
what is the most common cause of hypothyroidism in the developing world and the developed world?
developing = iodine deficiency
developed = Hashimoto’s thyroiditis
what is the levels of HbA1c in normal, pre-diabetes and diabetes?
normal = < 42 pre-diabetes = 42-47 diabetes = >48
what is the difference between cushing’s syndrome and cushing’s disease?
syndrome = elevated cortisol levels disease = caused by ACTH secreting pituitary adenoma
what investigation can be used to differentiate between cushing’s syndrome and cushing’s disease?
dexamethasone suppression test
- overnight = cushing’s syndrome (including disease) is confirmed when there is no suppression
- 48 hours = cushing’s syndrome (not disease) = no suppression
which condition would cause TSH = low and T4 = high?
hyperthyroidism
thyrotoxicosis
graves
which condition would cause TSH = high T4 = normal?
subclinical hypothyroidism
poor compliance with thyroxine
which condition would cause TSH = high T4 = low?
primary hypothyroidism
hashimotos
which condition would cause TSH = low T4 = low?
secondary hypothyroidism
what arrhythmia is a consequence of untreated hyperkalaemia?
ventricular tachycardia
- due to cell membranes becoming partially depolarised -> lower threshold potential so ventricles contract faster