Endocrine Flashcards
What is the definitive management of tertiary hyperparathyroidism?
Surgery to remove the parathyroid glands
How will tertiary hyperparathyroidism manifest in blood tests?
Inappropriately high PTH levels
Increased serum calcium
Increased serum phosphate
Why does CKD cause secondary hyperparathyroidism?
In response to hypocalcemia
How does secondary hyperparathyroidsim lead to tertiary hyperparathyroidism?
Overtime gland hypertrophy causes PTH secretion to become autonomous and independent of negative feedback, leading to raised PTH and raised calcium
What is the order of hormone loss in pituitary hormone deficiency?
Growth hormone Gonadotrophins TSH ACTH Prolactin
What is the first line treatment of SIADH?
Fluid restriction
What features indicated a diagnosis of SIADH?
Euvolaemic hyponatremia
Low serum osmolality
High urine osmolality
High urine sodium
What is MEN 1 syndrome?
Mutations in the MEN1 gene cause neoplastic mutations of pituitary, parathyroid and the pancreas?
What are the symptoms of hypernatremia?
Thirst Apathy Irritability Weakness Confusion Reduced conciousness Seizures Hyperreflexia Spasticity Coma
Causes of HYPOvolemic hypernatremia?
Renal free water losis (osmotic diuresis (NG feed), loop diuretics, intrinsic renal losses)
Non-renal free water loses (excess sweating, burns, diarrhoea, fistulas)
EUvolemic hypernatremia causes?
Renal losses (Diabetes insipidus, hypodispia) Extra-renal losses (insensible, resp losses)
HYPERvolemic causes of hypernatremia?
Primary hyperalodsteronism Cushing's syndrome Hypertonic dialysis Hypertonic sodium bicarbonate Sodium chloride tablets
Main differential for diabetes insipidus?
Psychogenic polydipsia
What is the urine osmolality in DI?
Urine osmolality <300 (dilute urine)
What is the sodium status of a patient with DI?
Hypernatermic
Or Normal
Causes of cranial DI?
Impaired release of ADH
Tumours
Trauma/post-op
Cerebral vasculitits (SLE, Wegener’s_
Causes of Npehrogenic DI?
Resistance to ADH: Congenital Drugs (lithium, amphoterecin, demeclocycline) Hypokalaemia Hypercalcemia Tubulointersitial disease
How is hypernatremia treated?
Treat underlying cause
Free water
Symptoms of hyponatremia?
Decreased perception Gait disturbance Yawning Nausea Reversable ataxia Headache Apathy COnfusion seizures Coma
What is the plasma osmolality in hyponatremia?
Low
If normal or raised it is psudohyponatremia
Why does pseudohyponatremia occur?
High Lipids
Myeloma
Hyperglycemia
Uraemia
Causes of HYPOvoaemia hyponatraemia?
Renal loss
-Diuretics (thiazides)
-Osmotic diuresis (glucose, urea in recovering ATN)
Addison’s disease - mineralcortocoid deficiency
Non-renal loss
-Diarrhoea
-Vomiting
-Sweating
-Third space losses (burns, bowel obstruction pancretatitis)
At which rate should you correct hypovolaemic hyponatremia?
0.9% NaCl at 1-3ml/kg/hour
What will the urine sodium be in a patient with hypovoaemic hyponatraemia due to renal losses?
> 20mmol/L
What will the urine sodium be in a patient with hypovoaemic hyponatraemia due to non-renal losses?
<20mmol/L
Causes of Euvolaemic Hyponatremia?
Primary polydipsia (urine osmolality <100) Glucocorticoid deficiency - adrenal insufficiency, SIADH Hypothyroidism
What is SIADH
Euvolaemic hyponatraemia
Low serum osmolality
Inappropriately concentrated urine - urine osmolality >100, Na>20
Not on diuretics
DIagnosis of elimintation - normal renal, thyroid, adrenal function
How is SIADH managed?
Fluid restrict <800ml/day
PO sodium chloride
May give furosemide
Demeclocycline/tolvaptan
Causes of hypervolaemic hyponatremia?
CCF
Nephrotic syndrome
Liver cirrhosis
How is hypervolaemic hyponatremia treated?
Fluid restriction
COnsider furosemide
What is the risk of correcting hyponatraemia too quickly, and how much should be aimed to correct each day?
Central pontine/osmotic myelinosis
Aim to correct <12 mmol/L/day
How is acute hyponatremia treated (within 48 hours) if symptomatic?
Given 3% hypertonic saline IV boluses +/- furosemide
How is symptomatic chronic (48 hours or more) hyponatermia treated?
Hypertonic saline boluses only if fitting
Otherwise isotonic saline and furosemide - aim for 8mmol/L in 24 hours
How is chronic, asymptomatic hyponatermia treated
Stop offending drug
Water restriction
If dehydrated, restore volume, if overloaded - Na and water restriction and diuretics
Causes of hyperkaelmia?
CKD
K rich diet (dried fruit, potatoes, oranges, tomatoes, avacados, nuts)
Drugs
Hyperalodsteronism, Addison’s disease, Acidosis, DKA, rhabdomyolysis, tumour lysis, massive haemolysis, succinylocholine use
Rarer - hyperkalaemic periodic paralysis, Gordons syndrome
Artifcat hyperkalaemia, haemolysis, leucocoytosis, thrombocytosis
What drugs can cause hyperkalaemia?
ACEi ARBs Sprinolactone Amiloride NSAIDs Heparin LMWH CYclosporin Calcineurin inhibitors High dose trimethoprim Digoxin toxicity B-blockers
How can hyperkalemia be treated?
Low K diet
Lopp diuretic if fluid overloaded
IV calcium gluconate
IV insulin with glucose, B2 agonist nebs
Less common causes of hyperkalemia?
Hyporeninaemic Hypoaldosteronism (Type IV RTA)
Hypochloraemic acidosis in about 50%, hyperkalaemia,
typically with increased age and reduced eGFR classically
in diabetes nephropathy, acute GN (nephritis), TIN/sickle
cell, NSAIDs, CNIs, lupus nephritis
What are the symptoms of hypokalaemia?
Fatigue Constipation Proximal muscle weakness Paralysis Cardiac arrythmias Worsened glucose control in diabetics HTN
Causes of hypokalaemia?
Pseudohypokalaemia - acute leukaemia
Extra-renal losses - indadequete PO intake, gut losses (NG, vommiting, secretory diarrhoea, laxatives, VIPoma, zollinger-ellison, ileostomy , enteric fistula)
Redisribution - delerium tremens, beta agonists, insulin caffine, theophylline, alpha-blockers (doxazosin), hypokalaemic periodic paralysis
Refeeding syndrome, alkalosis, vigourous exercise,
glue sniffing
Primary hyperaldosteronism (conn’s syndrome), cushings synfrome, secondary hyperaldosteronism
Renal losses (diuretics, RTA, tubulopathies, bartters/liddles/gittlmans), liqiorice, flucocorticoids, hypomagesaemia)
What proportion of the basal bolus insulin regime should be short acting (so the peak corresponds to the glycemic load of each of the three daily meals)?
60%, across 3 doses
What proportion of the basal bolus insulin regime should be long acting?
40%
What is Felty’s syndrome?
Triad of rheumatoid arthritis, splenomegaly and neutropenia
Notable side effects of corticosteroids?
Oedema Fluid retention Hypokalemia Supine HTN Glucose intolerance
How does Conn’s syndrome present?
Metabolic alklaosis Hypokalaemia HTN Hypernatremia Patients do not present with vomiting
How is diabetes insipidus investigated (first line test)?
Water deprivation test
Patients are deprived of fluids for 8 hours or until 3% loss of their body weight is reached.
Serum osmolaity, urine volume and urine osmolality are all measured hourly.
Positive if suboptimal response in urinary concentration to dehydration (urine osmolality<700mOsm/kg)
The level of concentration in urine osmolality gives and indication of renal concentrating capacity, and thus the severity of diabetic insipidus
Why do patients with Addisons disease not always have hyponatremia?
Although aldosterone normally enhances sodium reabsorption, other sodium retaining mechanisms such as the renin-angiotensin-aldosterone system are able to compensate to an extent
COmplication of severe hyponatremia?
brain herniation
What type of hyponatermia does SIADH cause?
Euvolemic hyponatremia
Urine sodium is above 40mmol/L and serum osmolality is above 100mosmol/L
How is acute severe hypercalcemia (>3.5) treated initially?
IV 0.9% saline 4L/24 hours
Agressive fluid rehydration will improve kidney function and help excess calcium be excreted
What is the combination of raised PTH, raided calcium and decreased phosphate charcteristic?
Primary hyperparathyroidism (overproduction of PTH by the parathyroid glands)
Most common causes of pseudohyponatremia?
Secondary to hyperlipidemia
Paraproteinaemia as seen in multiple myeloma
High blood glucose levels and use of mannitol or glycine
How to confirm a diagnosis of pseudohyponatraemia?
Measure serum osmolality level
Level of 275 mOsm/kg + supports the diagnosis
What blood test abnormalities can haemolysis of a sample before laboratory processing cause?
Pseudohyperkalemia due to potassium from inside red cells released into the serum
Potassium levels are significantly higher in red cells than in the serum hence significant alteration of true potassium level
What can cause pseudohyperkalemia?
Prolonged torniquet time during venepuncture (lactic acid production from temp ischema)
Haemolysis of blood sample before the lab
What is the first-line investigation for Addison’s disease
Morning serum cortisol - between 8 and 9 am when cortisol levels peak
Do not wait for result in an addisonian crisis, give IV hydrocortisone straight away
What paroneoplastic syndrome can cause SIADH?
Small cell lung cancer
What is the gold standard diagnostic test for a phaeochromocytoma?
Urine metanephrines
Plasma metanephrines
How is carcinoid syndrome diagnosed?
Urinary 5-HIAA excertion in a 24 urinary collection
What is Cushing’s Syndrome?
Signs and symptoms developing after prolonged abnormal elevation of cortisol
What is Cushing’s disease?
Subtype of cushing’s syndrome which occurs when a pituitary tumour secretes excessive ACTH.
Features of Cushing’s syndrome features?
ROUND IN THE MIDDLE WITH THIN LIMBS Round 'moon' face Central obesity Abdnominal striate Buffalo Hump (fat pad on upper back) Proximal limb muscle wasting HTN Cardiac hypertrophy Hyperglycaemia (Type 2 Diabetes) Depression Insomina Osteoporosis Easy bruising and poor skin
Causes of Cushing’s Syndrome?
Exogenous steroids - long term high dose steroid medication
Cushing’s DIsease (a pituitary adenoma releasing excessive ACTH)
Adrenal Adenoma
Paraneoplastic Cushing’s
What is Paraneoplastic Cushing’s?
Ectopic ACTH
Excess ACTH relased from a cancer (not of the pituitary) and stimulates cortisol release.
What is the most common cause of Paraneoplastic Cushing’s?
Small cell lung cancer
What is the gold standard investigation for Cushing’s disease?
Dexamethasone suppression test
How does the dexamethasone supression test work?
Initial low dose test - if normal, excludes Cushing’s syndrome
Abnormal test - perform high dose test performed
Dose of dexamethasone given at night time.
Cortisol and ACTH is measured in the morning (9AM)
Goal is to find out if dexamethasone supresses their normal morning cortisol spike.
Low dose dexamethasone suppression test dosage?
1mg
What is the dose for high dose dexamethasone suppression test?
8mg
What is a normal response to the low dose dexamethasone supression test (1mg)?
Dexamethasone supresses the release of cortisol be effecting negative feedback on the hypothalamus and pituitary.
What response will be shown in cushing’s disease in the high dose dexamethasone supression test?
Pituitary still show some response to the negative feeback and 8mg is enough to suppress the cortisol (but 1mg in the low dose test is not hence abnormal response there)
What is the response to the high dose dexamethasone supression test in an adrenal adenoma and why?
Cortisol not supressed as cortisol production is happening independent of the pituitary.
ACTH is supressed due to negative feedback on hypothalamus and pituitary gland
What is the response to the high dose dexamethasone suppression test where ectopic ACTH is being produced?
Neither cortisol of ACTH are suppressed because the ACTH production is independent of the hypothalamus or pituitary gland.
Why is 24 hour urinary free cortisol not the first line investigation for Cushing’s syndrome?
Can diagnose cushings, but
Cumbersome to carry out
And no indication of underlying cause
What investigations unrelated directly to cortisol and ACTH may be carried out when investigating Cushing’s
FBC: raised WCC Electrolytes: in an adrenal carcinoma, if alodsterone is also secreted there may be hypokalemia MRI brain for pituitary adenoma Chest CT - SCLC Abdonminal CT - adrenal tumor
How is Cushing’s syndrome treated?
Transpehenoidal removal of pituitary adeoma
Surgical removal of adrenal tumour
Surgical removal of tumour producting ectopic ACTH
If the above are not possible: removal of adrenal glands and give the patient replacement steroid hormones for life
What is Addison’s disease?
Primary adrenal insufficiency, usually caused by an autoimmune process damaging the adrenal glands which leads them to not produce sufficient cortisol or aldosterone.
What is secondary adrenal insufficiency?
Result of inadequate ACTH stimulating the adrenal glands resulting in low cortisol release.
This is a result of loss or damage tk the pituitary gland:
Surgery
Pituitary tumour
Lack of blood to pituitary gland
Radiotherapy
Sheenans syndrome
What causes Sheenans syndrome?
Loss of blood during child birth causes necrosis of the pituitary gland
What is tertiary adrenal gland sufficiency?
Result of inadequate CRH release by the hypothalamus
Usually the result of >3 week course of steroids causing hypothalamic suppression, when the exogenous steroids are withdrawn the hypothalamus does not respond adequately and endogenous steroids are not produced
Why must high dose long term steroids be tapered down slowly?
Allow adrenal axis to regain normal function
Describe how the adrenal axis leads to steroid production?
CRH from the hypothalamus acts on anterior pituitary gland
ACTH from the AP acts on the adrenal glands
Adrenal glands release cortisol which has a negative feedback on the hypothalamus and AP
Signs and symptoms of adrenal insufficiency?
Fatigue Nausea Cramps Abdominal pain Reduced libido Hyperpigmentation Hypotension
Why is early morning cortisol not the investigation of choice for Adrenal Insufficiency?
Often falsely normal
What viruses may trigger T1DM?
Coxsakie B virus
Enterovirus
Pathophysiology of T!DM?
Pancreatic B cell loss in the Islets of Langerhans in the pancrea due to T cell mediated destruction
No production of insulin (anabolic hormone)
Cells of the body can not take up glucose, muclse and liver cells don’t take up glucose and store it as glycogen
Cells cannot take up glucose
Blood glucose rises - hyperglycemia
What blood sugar does the body aim to maintain?
4.4-6.1 mmol/L
What is glucagon?
Catabolic homrone that increases blood sugar levels
Produced by alpha cells in the Islets of Langerhans in the pancrea
Causes liver to break down glycogen stores into glucose - glycoenolysis
Causes liver to convert proteins and fats in to glucose - gluconeogensis
What is ketogenesis and when does it occur?
Production of ketones - water soluble acids that can be used as fuel and are able to cross the blood brain barrier
Insufficient supply of glucose and glycogens stores are exchausted (prolonged fasting state)
Liver converts fatty acids to ketones
Normal in fasting conditions or on a very low carbohydrate, high fat diet
Presentation of DM?
Hyperglycemia triad - polyuria, polydipsiya, weight loss
Secondary enuresis
Reccurent infections
TYPE 1 - DKA
Investigating suspected diabtetes?
Baseline bloods including FBC, renal profile (U&E) and a formal laboratory glucose
Blood cultures should be performed in patients with suspected infection (i.e. with fever)
HbA1c can be used to get a picture of the blood sugar over the previous 3 months. This gives an idea of how long they have been diabetic prior to presenting.
Thyroid function tests and thyroid peroxidase antibodies (TPO) to test for associated autoimmune thyroid disease
Tissue transglutaminase (anti-TTG) antibodies for associated coeliac disease
Insulin antibodies, anti-GAD antibodies and islet cell antibodies to test for antibodies associated with destruction of the pancreas and the development of type 1 diabetes
What HbA1c indicates diabetes?
48 mmol/mol or higher
Situations where HbA1c must not be used as the sole test to diagnose diabetes?
Symptomatic children and young people <19 years
Symptoms suggesting T1DM
Short duration (<2 months)
Patients at high risk of diabetes who are acutely ill
Taking medication that may cause rapid glucose increase (steroids, antipsychotics)
Acute pancreatic damage/pancreatic surgery
In pregnancy
Presence of genetic, haematologic and illness related factors that influence HbA1c and its measurement
NOTE repeat readings same lab within 2 weeks if asymtomatic
Patients with what HbA1c should be monitored annually?
42-47 mmol/mol
Long term management of T1DM?
Subcutaneous insulin regimes
Monitoring dietary carbohydrates
Monitoring blood sugar levels on waking, before each meal and before bed
Monitoring for and managing complications
Describe a basal bolus insulin regime
Basal - long acting insulin such as Lantus - gives a constant background of insulin throughout that day. Typically given OD at night
Bolus - short acting insulin such as Actrapid - given three times a day before meals - also injected as per the number of carbohydrates consumed every time the patient has a snack.
What are the two types of insulin pump?
Tethered pump - devices with replaceable infusion sets and insulin
Patch pump - sits directly on the skin, controlled by a seperate remote. Disposable
Both constantly insfuse insuling via a cannula, site changed every 2-3 days to prevent lipodystrophy
Advantages of insulin pump?
Better blood sugar control
More flexability with eating
Less injections
Disadvantages of an insulin pump?
Difficulties learning to use it
Having it attatched at all times
Blockages in the infusion set
Small risk of infection
Short term complications of T1DM?
Hypogylcemia
Hyperglycemia and DKA
What causes hypoglycemia?
Too much insulin Not enough carbohydrates Not processing carbohydrates correctly - malabsorbtion, diarrhoea, vomitting, sepsis Hypothyroidism Glycogen stoarge disorders Growth hormone deficicency Liver cirrhosis Alcohol Fatty acid oxidation defects such as MCADD
Symptoms of hypoglycemia?
Hunger Tremor Sweating irritablility Dizziness Pallor Reduced conciousness Coma Death
How should hypoglycemia be treated?
No impairment of consciousness - rapid acting glucose such as lucozade and slower acting carbohydrates such as biscuits or toast to maintain the blood sugar level when the rapid acting glucose is used up
Impairment of conciousness - IV dextrose (10% - 2mg/kg bolus followed by 5mg/kg/hour infusion) and intramuscular gulcagon
What is nocturnal hypoglycemia and how can it be treated?
Hypoglycemia overnight
Child may be sweaty overnight
Morning blood glucose levels may be raised
Diagnosis made by continuous glucose monitoring
Alter bolus insulin regime and give snacks at bedtime
Why do patients with DM experience complications?
Chronic exposure to hyperglycemia causes
1. Damage to the endothelial cells of blood vessels
This leads to leaky, malfunctioning vessels that are unable to regenerate
2. Supression of the immune system and creates an optimal environement for microorganisms to thrive
Macrovascular complications of diabetes?
Coronary artery disease
Peripheral ischemia (poor healing, diabetic foot)
Stroke
HTN
Microvascular complications of diabetes?
Urinary tract infections
Pneumonia
Skin and soft tissue infections -particularly in the feet
Fungal infections - particularly oral and vaginal candidiasis
What is HbA1c considered to reflect?
Count of glycated Hb with is how much glucose is attatched to the haemoglobin molecules inside the RBC
Average blood glucose level over the last 3 months (RBC lifespan around 3-4 monthhs)
How can blood sugar be monitored?
HbA1c - 3 to 6 months
CBG with glucose meter - daily
Flash Glucose monitoring (FreeStyle Libre) - daily
How does the FreeStyle Libre machine work?
This uses a sensor on the skin that measures the glucose level of the interstitial fluid in the subcutaneous tissue
There is a 5 min lag behind blood glucose
Sensor records the glucose readings at short intervals
Swipe over reader with a sensor - this needs replacing every 2 weeks
Pathophysiology of DKA?
Patient not producing adequete insulin and not injecting adequete insulin to compensate for this. Not enough insulin to use and process glucose. Cells of the body interperit this as a state of starvation and initiates the process of ketogenesis
Glucose increases, ketones increase
Initially the kidneys produce bicarbonate to counteract the ketone acids in the blood and maintain a normal pH
Over time the ketone acids use up the bicarbonate and the blood becomes acidic - ketoacidosis
Why does DKA cause polydipsia and polyuria?
Hyperglycemia overwhelms the kidenys and glucose starts being filtered into the urine
The glucose in the urine draws water out with it (osmotic diuresis). This leads to polyuria, which leads to severe dehydration which stimulates the thirst centre in the hypothalamus, hence polydipsia.
Why can DKA cause arrhythmia?
Insulin normally drive potassium into the cells
Serum potassium and be high or normal as the kidneys continue to balance blood potassium excreted in the urine - however total body potassium is low
Without treatment patients can develop severe hypokalaemia very quickly
This can lead to fatal arrythmias
How does DKA presents?
Hyperglycaemia Dehydration Ketosis Metabolic acidosis (with a low bicarbonate) Potassium imbalance Polyuria and polydipsia N&V Acetone smell to their breath Dehdration and subsequent hypotension Altered conciousness Symptoms of an underlying trigger (sepsis)
Most dangerous aspects of DKA?
Dehydration
Potassium imbalance
Acidosis
Diagnostic criteria for DKA?
Hyperglycemia (CBG > 11 mmol/L)
Ketosis (blood ketones > 3 mmol/l)
Acidosis (ie. pH < 7.3)
How is DKA treated?
Fluids
Insulin (infusion, e.g. actrapid at 0.1 unit/kg/hour)
Glucose - closely monitor, add a dextrose infusion if below a certain level (e.g. 14 mmol/l)
Potassium - closely monitor serum potassium (e.g. 4 hourly) and correct as required - no more than 10 mmol per hour
Infection - treat underlying triggers such as infection
Chart - fluid balance
Ketones - monitor blood ketones (or bicarbonate if ketone monitoring)
Establish the patient on their normal subcut insulin regime prior to stopping the insulin fluid infusion
Non-modifiable risk factors?
Older age
Ethnicity (black, chinese, south asian)
Family history
Modifiable risk factors for type 2 DM?
Obesity
Sedentary lifestyles
High carbohydrate (particularly refined carbohydrate) diet
How might T2DM present?
Fatigue Polydipsia and polyuria (thirsty and urinating a lot) Unintentional weight loss Opportunistic infections Slow healing Glucose in urine (on dipstick)
Usually in patients with risk factors
How is the OGTT performed?
Take baseline fasting plasma glucose result
Give 75g glucose drink
Measure plasma glucose 2 hours later
How can pre-diabetes be diagnosed?
HbA1c 42-47 mmol/mol
Impaired fasting glucose 6.1-6.9 mmol/mol
Impaired glucose tolerance - plasma glucose at 2 hours - 7.8 - 11.1 mmol/l on an OGTT
How can diabetes be diagnosed?
HbA1c > 48 mmol/mol
Random Glucose > 11 mmol/l
Fasting Glucose > 7 mmol/l
OGTT 2 hour result > 11 mmol/l
Management of T2DM?
Dietary Modification
Vegetables and oily fish
Typical advice is low glycaemic, high fibre diet
A low carbohydrate may in fact be more effective in treating and preventing diabetes but is not yet mainstream advice
Optimise Other Risk Factors
Exercise and weight loss
Stop smoking
Optimise treatment for other illnesses, for example hypertension, hyperlipidaemia and cardiovascular disease
Monitoring for Complications
Diabetic retinopathy
Kidney disease
Diabetic foot
What is the first line medical management of T2DM?
Metformin titrated from initially 500mg once daily as tolerated
What s the second line medical management of T2DM?
Metformin +
sulfonylurea/pioglitazone/DPP-4 inhibitor/SGLT-2 inhibitor
What is the third line medical management of T2DM?
Metformin + 2 of:
sulfonylurea/pioglitazone/DPP-4 inhibitor/SGLT-2 inhibitor
OR
Metformin+insulin
What do SIGN Guidelines 2017 reccommend for the prefential use in medical management for patients with T2DM in patients with CVD?
SGLT-2 inhibiotrs and GLP-1 mimetics
What are the HbA1c targets for type 2 diabetes?
48 mmol/mol for new type 2 diabetics
53 mmol/mol for diabetics that have moved beyond metformin alone
What drug class is metformin?
Biguanide
Notable side effects of metformin?
Diarrhoea and abnominal pain (dose dependent)
Lactic acidosis (rare)
Doesn’t cause hypoglycemia
Weight neutral
How does metformin work?
Increases insulin sensitivity
Decreases liver production of glucose
What drug class is pioglitazone?
Thiazolidinedione
How does pioglitazone work?
Increases insulin sensitivity
Decreases liver production of glucose
Side effects of pioglitazone?
Weight gain Fluid retention Anaemia Heart failure Extended use may increase the risk of bladder cancer Does NOT typically cause hypoglycemia
What drug class is glicazide?
Sulfonylurea
How do sulfonylureas such as glicazide work?
Stimulate insulin release from the pancreas
Notable side effects of sulfonylureas such as glicazide?
Weight gain
Hypoglycemia
Increased risk of CVD and MI when used as monotherapy
What are incretins? What do they do?
Hormones produced by the Gi tract secreted in response to large meals and act to reduce blood sugar by:
Increase insulin secretions
Inhibit glucagon production
Slow absorption by the GI tracts
Main incretin is glucagon-like peptide 1
Incretins are inhbited by DPP-4
What drug class is sitagliptin?
DPP-4 inhibitor
How do DPP-4 inhibitors/gliptins work?
Inhibit DPP-4
Therefore reducing the inhibiton of incretins
Therefore increaseing insulin secretions, inhibiting glucagon production, slowing absorption by the Gi tract
Notable side effects of DPP-4 inhibitors?
Gi tract upset
Symptoms of URTI
Pancreatitis
What drug class is exenatide? How is it given?
GLP-1 mimic
Subcut injection either twice daily or modifiable release once weekly
What drug class is liraglutide and how is it administered?
GLP-1 mimic
Subcut injection once a week
Notable side effects of GLP-1 mimics?
GI tract upset
Weightloss
Dizziness
Low risk of hypoglycemia
What drug class is empagliflozin (and other drugs ending in -gliflozin)?
SGLT-2 inhbitor
How does SGLT-2 inhibitors such as empagliflozin work?
Inhibition of SGLT-2, the protein responsible for reabsorbing glucose from the urine into the blood in the proximal tubules of the kidneys
Increase excretion og glucose into urine
Side effects of SGLT-2 inhbiitors?
Glucoseuria Increased rate of UTI Weight loss Diabetic ketoacidosis Lower limb amputation associated with canagliflozin
Example of rapid acting insulins?
Novorapid
Humalog
Apidra
Short acting insulins?
Actrapid
Humulin S
Insuman rapid
How long do rapid-acting insulins take to start working and how long do they last?
10 mins
4 hours
How long do short acting insulins take to work and how long do they last?
30 mins
8 hours
Examples of intermediate-acting insulins?
Insulatard
Humulin I
Insuman basal
How long do intermidiate acting insulins take to work and how long do they last?
1 hour
16 hours
How long do long acting insulins take to work and how long do they last?
1 hour
24 hours
Examples of long acting insulins?
Lantus
Levemir
Degludec (last over 40 hrs)
Examples of combination insulins (rapid+intermediate)
Humalog 25 (25:75 rapid:inter) Humalog 50 (50:50 rapid:inter) Novomix 30 (30:70 rapid:inter)
Hyperthyroidism vs thyrotoxicosis?
Hyperthyroidism - over-production of thyroid hormone by the thyroid glsnd
Thyrotoxicosis - refers to an abnormal and excessive quantity of thyroid hormone int he body
What is Grace’s disease?
A type of primary hyperthyroidism
Due to thyroid pathology - it is the thyroid itself that is behaving abnormally and producing excessive quantity of thryoid hormone.
Graves disease is an autoimmune condition in which TSH receptor antibodies (abnormal antibodies which mimic TSH and stimulate TSH receptors on the thyroid) cause hyperthryoidsism
Where is the pathology in secondary hyperthyroidism?
Overstimulation bt TSH, pathology in hyporthalamus or piuitary
What is Plummer’s disease
Toxic multinodular goitre
Coniditon where nodules develop on the thyroid gland that act independently of the normal feedback system and continuously produce excessive thyroid hormone
|n what thyroid disorder is exopthalmos seen? What is it? Why does it happen?
Buldging of the eyeball out of the socket cause by Graves Disease (primary hyperhtyroidism)
Due to inflammation, swelling and hypertrophy of the tissue behind the eyeball that forces the eyeball forward
Which thyroid disorder is pretibial myxoedema specific to? What is it? Why does it happen?
Dermatological condition where there are depositis of mucin under the skin on the anterior aspect of the leg (pre-tibial area)
Gives discoloured, waxy, oedmatous apparence to the skin ober this area.
Reaction to TSH receptor antibodies
Which thyroid disorder is pretibial myxoedema specific to? What is it? Why does it happen?
Dermatological condition where there are depositis of mucin under the skin on the anterior aspect of the leg (pre-tibial area)
Gives discoloured, waxy, oedmatous apparence to the skin ober this area.
Reaction to TSH receptor antibodies
Causes of hyperthyroidism?
Grave’s disease
Toxic multinodular goitre
Solitary toxic thyroid nodule
Thyroiditis (De Quervain’s, Hashimotos, postpartum, drug-induced)
Universal features of hyperthyroidism?
Anxiety Irritability Sweating Heat intolerance Tachycardia Weight loss Fatigue Frequent loose stools Sexual dysfunction
Unique features of Grave’s disease (ie. features causes by presence of TSH antibodies)?
Diffuse goitre (without nodules)
Graves eye disease
Bilateral exopthalmos
Pretibial myxoedema
Unique features of toxic multinodular goitre?
Goitre with firm nodules
Patients almost always over 50
Second most commmon cause of thyrotoxicosis (after Grave’s)
What is a solitary toxic thyroid nodule and how is it treated?
Single abnormal thyroid nodule is acting alone to release thyroid hormone.
Normally benign adenomas. Treated with surgical removal of the nodule.
What is De Quervain’s Thyroiditis?
Presentation of a viral infection with fever, neck pain and tenderness, dysphagia and features of hyperthyroidism.
There is a hyperthyroid phase followed by a hypothroid phase as the TSH levels fall due to negative feedback.
Self limiting, symptoms can be managed by NSAIDs and beta blockers
What is a thyroid storm?
Rare presentation of hyperthyroidism - AKA thyrotoxic crisis.
Presents with pyrexia, tachycardia and delirium.
Patients may require supportive care with fluid resuccitation, anit-arrhythmic medication and beta-blockers.
What is the first line anti-thyroid drug?
Carbimazole
Will leave patients with Grave’s disease with normal thyroid function after 4-8 weeks.
Once the patient has normal thyroid hormone levels, they continue on maintenance carbimazole and either:
The dose is titrated to maintain normal levels (titration block)
Or the dose is sufficient to block all production and patient takes levothyroxine tirated to effects (block and replace)
Complete remission and the ability to stop taking carvimazole is usually achieved within 18 months of treatment
What is the second line anti-thyroid drug?
Propylthiouracil
Risks associated Propylthiouracil?
Small risk of severe heaptic reactions, including death
What strict rules should be followed after a patient is treated with radioactive iodine?
Must not be pregnant, patient is not allowed to get pregnant within 6 months
Must avoid close contact with children and pregnant women for 3 weeks
Limit contact with anyone for several days after receiving the dose
How is radioactive iodine used to treat hyperthyroidism?
Single dose of raidoactive iodine drunk
Taken up by thyroid glands and the emmited radiation destorys a proportion of the thyroid cells
Reduction in functioning cells results in a decrease of thyroid hormone production and thus remission
Remission can take up to 6 months
Patients can be left hypothyroid and requiring levothyroxine replacement
Beta blockers are used to block the adrenaline related symptoms of hyperthroidism, particullary in thyroid storm, which is the best choice?
Propanolol as it non-selectively blocks adrenergic activity as opposed to more selective beta blockers which only work on the heart
What is the disadvantage of surgery to remove the whole thyroid or toxic thyroid nodules in hyperthyroidism?
Patient will be left hypothyroid post thyroidectomy and require levothyroxine replacement for life
Causes of hypothyroidism?
Hashimotos thyroiditis (most common in developed world)
Iodine (most common in developing world)
Secondary to treatment of hyperthyroidism: Carbimazole, Propylthiouracil, Radioactive iodine, Thyroid surgery
Medications
Secondary causes: tumours, infection, radiation, vascular (Sheehan syndrome)
What medications can cause hypothyroidism?
Lithium - inhibits production of thyroid hormone, can cause goitre
Amiodarone - interferes with thyroid hormone production and metabolism, can also cause thyrotoxicosis
Presentation and features of hypothyroidism?
Weight gain Fatigue Dry skin Coarse hair and hair loss Fluid retention Heavy or irregular periods Constipation
Thyroid function test results in primary hypothyroidism vs secondary hypothyroidism?
Primary: thyroid gland insufficiency therefore T3+T4 are low, TSH will be high as no negative feedback to the bran (so increase production of TSH in the pituitary gland)
Secondary: pituitary pathology, resulting in low production of TSH. This, in turn, means T3 and T4 will be low
What thyroid hormone is used to manage the dose of levothyroxine?
TSH
What is levothyroxine?
Synthetic T4
Also metabolised T3 in the body
How often should TSH be checked when starting levothyroxine?
Monthly, until stable
What TSH would you expect in hyperthyroidism and why?
TSH is supressed by high T4 and T3
In which case of hyperthyroidism would TSH be high?
Pituitary adenoma which secrets TSH
What antibodies can cause thyroid disorder? What disorders are each found in?
Antithyroid peroxidase (anti-TPO) antibodies - most relevant. Present in Grave;s disease and Hashimoto's thyroiditis. Antithyroglobulin antibodies - antibodies against thyroglobulin (a protein produced and extensively present in the thyroid gland). Present in Graves disease, Hashimotos Thyroiditis and thyroid cancer. TSH receptor antibodies are autoantibodies that mimic TSH and bind to its receptor - they are ALWAYS present in Graves disease
How can USS of the thyroid be utilised?
DIagnosing thyroid nodules
Distinguishing between cystic (fluid filled) and solid nodules.
Ultrasound can also be used to guide biopsy of a thyroid lesion.
How radioisotope scans used to investigate the thyroid?
Radioisotope scans are used to investigates hyperthyroidism and thyroid cancers.
What happens in radioisotope scans of the thyroid?
Radioactive iodine is given orally or IV and travels to the thyroid where it is taken up by the cells.
The more active the thyroid cells, the faster the radioactive iodine.
The more gamma rays that are emitted from an area the more radioactive iodine has been taken up.
This gives really useful functional information about the thyroid gland
Radioactive iodine uptake in Grave’s disease?
Diffuse high uptake
What will be seen in multinodular goitre and adenomas on a radioisotope scan?
Focal high uptake is found in toxic multinodular goitre and adenomas
What indicates thyroid cancer on radioisotope scan?
‘Cold’ areas (ie. abnormally low uptake)
What is Hashimoto’s thyroiditis?
Autoimmune inflammation of the thyroid gland
Associated with antithyroid peroxidase (anti-TPO) antibodies and anythyroglobulin antibodies.
It initially causes goitre, then atrophy of the thyroid gland
Why is iodine deficiency uncommon in the UK?
Iodine is added to foods such as table salts
What investigations are important when suspecting adrenal insufficiency?
U&Es- hyponatremia may be the only presenting feature of adrenal insufficiency. Hyperkalemia may be present
Short synacthen test - test of choice
ACTH (high in primary adrenal failure, low in secondary)
Adrenal cortex antibodies and 21-hydroxylase antibodies - autoimmune antibodies
CT/MRI adrenals is suspecting an adrenal tumour, haemorrhage or other structual pathology
MRI pituitary give further information about pituitary pathology
How is the short synacthen test performed?
Test of choice for adrenal insufficiency
Performed in AM
Give syncathen (synthetic ACTH)
Measure blood cortisol at baseline, 30 mins and 60 mins after administration
The synthetic ACTH will stimulate healthy adrenal glands to produce cortisol and cortisol should at least double
A failure in cortisol to rise less than x2 the baselin indicates primary adrenal insufficiency
What is the long synacthen test?
The long synacthen test is rarely used anymore because we can now measure ACTH levels. It was used to distinguish between primary adrenal insufficiency and adrenal atrophy secondary to prolonged under stimulation in secondary adrenal insufficiency. It involves giving an infusion of ACTH over a long period.
In primary adrenal failure there is no cortisol response as the adrenals no longer function.
In adrenal atrophy (secondary adrenal insufficiency), the prolonged ACTH eventually gets the adrenals going again and cortisol rises.
Now we can simply measure ACTH and this indicates the underlying cause.
How is adrenal insufficiency treated?
Replacement steroids titrated to signs, symptoms and electrolytes
Hydrocortisone (cortisol def) and/or fludrocortisone (aldosterone)
What is hydrocortisone?
Glucocorticoid hormone used to replace cortisol
What is fludrocortisone?
Mineralcorticoid hormone used to replace aldosterone
How does an Addisonian crisis present?
Reduced conciousness Hypotension Hypoglycemia Hyponatremia Hyperkalemia
Triggers of an Addisonian crisis?
Infection
Trauma
Sudden withdrawal of long term steroids
How is an Addisonian crisis managed?
Intensive monitoring if unwell
Parenteral steroids (IV hydrocrotisone 100mg stat, then 100mg every 6 hours)
IV fluid resusitation
Correction of hypoglycemia
Careful monitoring of electrolytes and fluid balance
What is acromegaly?
Clinical manifestation of excessive growth hormone
Where is growth hormone produced?
Anterior pituitary gland
What is the most common cause of unregulated growth hormone secretion?
Pituitary adenoma - microscopic or macroscopic (causes compression of local structures)
What is the most common cause of unregulated growth hormone secretion?
Pituitary adenoma - microscopic or macroscopic (causes compression of local structures)
Rarely acromegaly can be secondary to a cancer, such as what?
Lung of pancreatic cancer secreting ectopic growth hormone releasing hormone (GHRH) or growth hormone (GH)
Why might a patient with acromegaly have loss of vision in the outer half of both eyes?
Optic chiasm sits just above the pituitary gland
Optic chiasm is the point at which the optic nerves cross
A pituitary tumour of sufficient size can cause bitemporal hemianopia
How does acromegaly present?
If SOL: Headaches, visual field defects
Overgrowth of tissues: prominent forehead and brow (frontal bossing), large nose, large tongue (macroglossia), large hands and feet, large protuding jaw ‘prognathism’, arthritis from imbalanced growth of joints
Organ dysfunction: hypertrophic heart, HTN, type 2 diabetes, colorectal cancer
Symptoms suggesting active raised growth hormone: development of new skin tags, profuse sweating
How do you investigate suspect acromegaly?
Insulin-like growth factor (IGF-1) is the initial screening test
Oral glucose tolerance test whilst measuring growth hormone (high glucose normally)
MRI brain for the pituitary tumour
Refer to opathalmology for formal visual feild testing
Definitive treatment of acromegaly secondary to pituitary adenoma?
Transphenoidal removal of pituitary adenoma
What medications can be used to block GH?
Pegvisomant (GH antagonist, s/c, OD)
Somatostation analogue (blocks GH release) e.g. ocreotide
Dopamine agonists to block GH release e.g. bromocriptine
Somatostain is known as growth hormone inhibiting hormone, where is it normally secreted from?
The brain, GI tract Pancreas Released in response to complex triggers (note dopamine also inhibits GH but less potent)
Which cells release parathyroid hormone?
Cheif cells of the parathyroid gland
How does parathyroid hormone related to serum calcium?
Produced in response to hypocalcemia
Acts to raise blood calcium
How does PTH act to raise serum calcium?
Increases osteoclast activity in the bones (reabsorbing calcium from bones)
Increases calcium absorption from the gut
Increasing calcium absorption from the kidneys
Increases vitamin D activity - converts it to its active form
How does vitamin D increase serum calcium?
Increases calcium absorption from the intestines
Symptoms of hypercalcemia?
Renal stones
Painful bones
Constipation, N&V
Depression, psychosis, fatugue
What causes primary hyperparathyroidism?
Primary hyperparathyroidism is caused by uncontrolled parathyroid hormone produced directly by a tumour of the parathyroid glands
How is primary hyperparathyroidism treated?
Surgical removal of the tumour
What will the serum calcium abnormality be in primary hyperparthyroidism?
Hypercalcemia (bones, stones, groans, moans)
What causes secondary hyperparathyroidism?
Insufficient vit D or chronic renal failure leads to low absorption of calcium.
Parathyroidglands react to hypocalcemia, by excereting more parathyroid hormone - hyperplasia.
How is secondary hyperparathyroidism treated?
Renal transplant or correct vitamin D deficiency
What will the serum calcium be in secondary hyperparathyroidism?
Low or normal
What causes tertiary hyperparathyroidism?
Prolonged secondary hyperparathyroidism (vit d def or renal failure), leads to hyperplasia of the parathyroid gland.
The baseline level of PTH increases dramatically, so when secondary hyperparathyroidism is treated the parathyroid hormone remains inappropriately high.
How is tertiary hyperparathyroidism treated?
Surgical removal of part of the parathyroid tissue to return PTH to an appropriate level
How does low BP lead to secretion of aldosterone?
Juxtaglomerular cells in the afferent arteriole of the kidney sense blood pressure
Low BP: Juxtaglomerular cells secrete renin
Renin allow angiotensin (secreted by the liver) to be converted in to angiotensin I
In the lungs Angiotensin I is converted to Angiotensin II by ACE
Angiotensin II stimulates the release of aldosterone from the ADRENAL GLANDS
How does aldosterone act on the kidney?
- Increases sodium reabsorption from the DISTAL TUBULE
- Increases potassium secretion from the DISTAL TUBULE
- Increases hydrogen secretion from the COLLECTING DUCTS
What is primary hyperaldosteronism?
Adrenal glands are directly responsible for producing too much aldosterone
What level is serum renin in hyperaldoseronism?
Low, as suppressed by high BP
What are the causes of primary hyperalodsteronism?
Bilateral adrenal hyperplasia
Adrenal adenoma secreting aldosterone - CONNS SYNDROME
Famililal hyperaldosteronism type 1 and type 2 (rare)
Adrenal carcinoma
What is secondary hyperaldosteroism?
Adrenal glands are stimulated to produce more aldosterone by excessive renin
What causes secondary hyperaldosteronism?
Renal artery stenosis
Renal artery obstruction
Heart failure
Best screening tool for hyperaldosteronism?
Check renin and aldosterone levels.
Check ratio to determine cause if aldosterone high
Low renin - primary
High renin - secondary
What investigations may you want to undertake in relation to the effects of aldosterone?
Blood pressure
Serum electrolytes (hypokalemia)
Blood gas analysis (alkalosis)
How would you further investigate a high aldoserone level with imaging?
CT/MRI to look for an adrenal tumour
Renal doppler ultrasound
CTA angiogram or MRA for renal artery stenosis of obstruction
What pharmacological threapy can be used to treat hyperaldosteronism?
Aldosterone antagonists such as eplerenone and spironolactone
What is the most common cause of secondary HTN?
Hyperaldosteronism
You should consider screening if high blood pressure without response to treatment or with hypokalemia
Management of hyperalodsteronism - treatment of underlying cause?
Surgical removal of adenoma (Conns syndrome, adrenal carcinoma)
Percutaneous renal artery angioplasty via the femoral artery to treat in renal artery stenosis
What is ADH secreted?
posterior pituitary gland
Where is ADH produced?
Hypothalamus
What does ADH/vasopressin do?
Stimulates water reabsorption from the collecting ducts in the kidneys
What is the pathophysiology of hyponatremia in SIADH
Excessive ADH results in excessive water reabsorption in the collecting ducts, which dilutes serum sodium resulting in hyponatermia.
What wiil the urine of patients with SIADH be like and why?
High sodium
High osmolality
(concentrated as kidneys excreting less urine)
Symptoms of SIADH?
Headache Fatigue Muscle aches and cramps Confusion Seizures and reduced conciousness (severe hyponatremia)
Causes of SIADH?
Either the posterior pituitary secretes too much ADH or the ADH may be coming from somwehere else
Post-operative (major surgery)
Infection, particularly atypical pneumonia and lung abscesses
Head injury
Medications (thiazide diuretics, carbamazepine, vincristine, cyclophosphamide, antipsychotics, SSRIs, NSAIDS)
Mallignnacy, particularly small cell lung cancer
Menigitis
How is SIADH diagnosed?
DIagnosis of exclusion
Clinical examination will show euvolaemia
U&Es (hyponatremia)
Urine sodium and osmolality (high)
Rule out
1. adrenal insufficiency (short synacthen test)
2. history of diuretic use
3. diarrhoea, vommiting, burns, fistula, excessive sweating
4. excessive water intake
5. history of chronic kidney disease or AKI
How might you establish the cause of SIADH?
History: new medication, chest infection, recent surgery
CXR: lung abscess, pneumonia, lung cancer
If mallignancy suspected CT thorax/abdomen/pelvis and brain MRI
When would you suspect mallignancy in someone with persistent hypernatremia?
No clear cause
Hx of smoking, weight loss or other features of mallignancy
How is SIADH treated?
Withdraw any offending medication
Fluid restriction
Tolvaptan (ADH receptor blocker) by specialist with close monitoring as it can cause a rapid increase in sodium levels (risk of CPM)
What is central pontine myelinolysis/ osmotic demyelination syndrome and what is its pathophysiology ?
Complication of severe hyponatremia (<120) (long term) being treated too quickly (>10 mmol/L increase over 24hrs).
Sodium levels fall: water moves by osmosis across BBB into cells of brain from an area of low conc. to high conc.
This causes the brain to swell.
Brain adapts to this by reducing the solutes in the brain cells so that water is balanced across the BBB and the brain does not become oedematous.
This adaptation takes a few days so if severe hyponatremia is present for a long time, the brain cells will also have a low osmolality,
When sodium levels suddenly increase water will rapidly shift out of the brain cellls into the blood
What are the two phases of CPM?
- Due to electrolyte imbalance patient presents encepalopathic and confused. May have new headache, N&V. Often resolves prior to the onset of phase 2.
- Dymyelination of the neurones, particularly in the pons, occurs a few days after the rapid correction of sodium. Presents as spastic quadriparesis, pseudobubular palsy and congitive and behavioural changes. Significant risk of death
What is diabetes insipidus?
Lack of or lack of response to ADH, preventing the kidneys from being able to concentrate urine.
What is primary polydipsia?
Primary polydipsia is when the patient has a normally functioning ADH system but they are drinking excessive quantities of water leading to excessive urine production. They don’t have diabetes insipidus.
Nephrogenic DI is when the collecting ducts of the kidneys do not respond to ADH. What may cause this?
Drugs, particularly lithium
Mutations in the AVPR2 gene on the X chromosome that codes for the ADH receptor
Intrinsic kidney disease
Electrolyte disturbance (hypokalemia, hypercalcaemia)
Crania diabetes insipidus occurs when the hypothalamus does not produce ADH for the posterior pituitary gland to secrete. What might cause it?
Brain tumour Head injury Brain malformations Brain infection (meningitis, encephalitis, TB) Brain surgery or raidotherapy
How does DI present?
Polyuria Polydipsia Dehydration Postural hypotension Hypernatremia
How is DI investigated?
Urine osmolality (low) Serum osmolality (high) Water deprivation test
What is the test of choice for diagnosing DI?
Desmopressin stimulation test/water deprivation test
How is the water deprivation test performed?
No fluids for 8 hour
Measure urine osmolality
Administer synthetic ADH (desmopressin)
Measure urine osmolality after 8 hours
What will the results of the water deprivation test be in nephrogenic DI?
Urine osmolality initially low (as it continues to be diluted by excessive water secretion in the kidneys) and remains low after desmopressin administered
What will the results of the water deprivation test be in cranial DI?
Kidneys are capable of responding to ADH, so urine osmolality will be low at the beginning and high 8 hours after desmopressin is administered
What will the results of the water deprivation test be in primary polydipsia?
Urine osmolality will be high before (8 hours with no water) and 8 hours after desmopressin administered.
How is DI managed?
Treat underlying cause where possible
Conservatively if mild
Desmopressin in cranial DI to replace ADH
Desmopressin in nephrogenic ADH in HIGHER doses under close monitoring
Which cells produce adrenaline?
Chromafinn cells in the adrenal medulla of the adrenal glands
What is a phaeocytoma?
Tumour of the chromaffin cells that secretes unregulated and excessive amounts of adrenaline
What is adrenaline?
A catecholamine hormone and neurotransmitter that stimulates the sympathetic nervous system and is responsible for fight or flight response
Why do patients with a phaeochromocytoma tend to have periods of worse symptoms and periods of more settled symptoms?
Adrenaline tends to be secreted by the tumour in bursts
25% of phaeochromocytomas are familial, associated with which condition?
MEN 2
Multiple endocrine neoplasia type 2
Why is phaeochromocytoma diagnosed using 24 hour urine catecholamines and plasma free metanephrines?
Serum catecholamines would be unreliabe as these naturally fluctuate - 24 hour urinary gives an idea of secretion over 24 hrs
Adrenaline has a short half life in the blood (few mins) where as metanephrines (their breakdown product) have a longer half life, therefore are less prone to dramatic fluctuations
How does a phaeochromocytoma present?
Anxiety Sweating Headache HTN Palpitations, tachycardia, paroxmysal AF
How is phaeochromocytoma managed?
Initially medically:
1. Alpha blockers ie. phenoxybenzamine
2. Beta blockers once alpha blockers established
Once managed medically (to reduce risks of anesthetic and surgery):
Adrenalectomy
Hormones released by the anterior pituitary?
TSH ACTH FSH LH Prolactin Growth hormone
What hormones are released by the posterior pituitary gland?
Oxytocin
ADH (antidiuretic hormone)
Describe the thyroid axis
TRH: thyrotropin-releasing hormone released from the hypothalamus
Stimulates AP to release TSH
Stimulates thyroid gland to release T3 and T4
Hypothalamus and AP sense T3 and T4 levels (negative feedback) supressing release of TRH and TSH
Describe the adrenal axis
Hypothalamus releases corticotrophin releasing hormone (CRH) which
Stimulates AP to release ACTH
Which stimulates adrenal glands to release cortisol
Cortisol secreted by (2) adrenal glands
(Released in pulses in response to stress stimuli
Diurnal variation)
Cortisol sensed by hypothalamus and AP supressing the release of CRH and ACTH - negative feedback
What are the actions of cortisol in the body?
Inhibits immune system Inhibits bone formation Raises blood glucose Increases metabolism Increases alertness
What is the action of growth hormone?
Stimulates insulin-like growth factor 1 from the liver
GH works indirectly and directly on almost all body cells:
Stimulates muscle growth
Increases bone density and stregth
Stimulates cell regeneration and reproduction
Stimulates growth of internal organs
Where is GHRH released from?
Hypothalamus
acts on AP to release GH
Where is GH released from?
Anterior pituitary gland
What criteria must be fufilled for patients who are treated with insulin for diabetes to be allowed to drive?
All patients with diabetes who are treated with insulin must notify the DVLA. For the DVLA to license an insulin-treated individual with a Group 1 licence, they must meet all the following criteria:
Adequate hypoglycaemia awareness
No more than 1 episode of severe hypoglycaemia while awake in the preceding 12 months AND the most recent episode occurred more than 3 months ago
Practises appropriate glucose monitoring
Not regarded as a likely risk to the public while driving
Meets the visual standards for acuity and visual field
Under regular review
Patients with T1DM who are likely to miss a meal or more due to surgery should have what changes made to their insulin regime?
Reduce sub cut insulin basal dose by aprox 1/3
Omit morning insulin
Commence VRII
How should a patient be taken off of VRIII and back onto their sc insulin regime?
At the first oral meal, overlap the VRIII and start normal SC insulin regimes.
Rapid acting should be given aprox 20 mins prior to meal
VRIII can be stoped 30 mins to an hour after eating
What does corneal involvement in Grave’s disease suggest?
Severe eye pathology
In Sick euthyroid syndrome what will the TFTs be?
TSH normal
T3 and T4 low
What condition is Bromocriptine used to manage medically?
Prolactinoma
Why might a splenectomy mean a patients HbA1C result is innacurate?
Splenectomy can give a falsely high HbA1c level due to the increased lifespan of RBCs
What features suggest subacute thyroiditis?
Subacute thyroiditis is suggested by the tender goitre, hyperthyroidism and raised ESR. The globally reduced uptake on technetium thyroid scan is also typical
Likely outcome of papillary thyroid cancer?
Papillary thyroid cancer shows excellent prognosis, despite the tendency to spread to cervical lymph nodes early
What is the most common type of thryoid cancer?
Papillary
Sick day rules for patients with Addison’s
Addison’s patient with intercurrent illness → double the glucocorticoids, keep fludrocortisone dose the same
How does multiple endocrine neoplasia type I typically present?
Galactohorrea
Peptic ulceration
Hypercalcemia
Symptoms of hypoparathyroidism?
a tingling sensation (paraesthesia) in your fingertips, toes and lips
twitching facial muscles
muscle pains or cramps, particularly in your legs, feet or tummy
tiredness
mood changes, such as feeling irritable, anxious or depressed
dry, rough skin
coarse hair that breaks easily and can fall out
fingernails that break easily
Blood test results in hypoparathyroidism?
low parathyroid hormone levels
low calcium levels
high phosphoate levels
Medical management of hypoparathyroidism?
Calcium carbonate and vitamin D supplements – usually calcitriol (Rocaltrol) or alfacalcidol (One-Alpha)
Causes of hypocalcemia?
1. Vitamin D deficiency Malnutrition (i.e. osteomalacia) Malabsorption (e.g. gastrectomy, short bowel syndrome, Coeliac disease, chronic pancratitis) CKD 2. Hypoparathyroidism Post-parathyroidectomy Inherited Pseudohypoparathyroidism 3. Hyperphosphataemia Tumour lysis syndrome Rhabdomyolysis Phosphate administration 4. Acute pancreatitis 5. Hypomagnesaemia 6. Acute alkalosis
Clinical features of hypocalcemia?
SPASMODIC:
S – Spasms (Trousseau's sign) P – Perioral parasthaesia A – Anxiety/Irritability S – Seizures M – Muscle tone increase (colic, dysphagia) O– Orientation impairment (i.e. confusion) D – Dermatitis I – Impetigo herpetiformis C – Chvostek's sign
Assesment of hypocalcemia?
ECG (looking for arrhythmia) Bone profile (calcium, phosphate, albumin, total protein, ALP) PTH Magnesium Vitamin D Amylase (if suspected pancreatitis) X-rays (if suspected osteomalacia)
How is hypocalcemia managed?
Management of acute hypocalcaemia:
Mild: oral calcium supplementation
Severe (spasms or ECG changes): IV calcium gluconate repeated as needed
Long term management:
Treat cause
Encourage good dietary calcium and Vitamin D intake
Calcium and Vitamin D supplementation
Alphacalciferol if CKD
Magnesium supplements if concurrent hypomagnesaemia
What type of anaemia is associated with autoimmune thyroid disease?
Macrocytic, non-megaloblastic
e.g. pernicious anaemia
Triad of symptoms associated with phaeochromocytoma?
headache
sweating
tachycardia
Initial screening for acromegaly?
Level of serum IGF-1 do not fluctuate much and is therfore a fairly stable indicator
What pathopysiological mechanism is impliacted in the devlopment of diabetic neuropathy?
Advanced glycation end products resulting from hyperglycemia act on specific receptors, including monocytes and endothelial cells to increase the production of cytokines and adhesion molecules.
Advanced glycation end products have an effect on metalloproteinases which damage efferent nerve fibers
What is the most common cause of mortality in elderly patients?
Heart and circulation problems
Which diabetic drug can increase the risk of Fourniers gangrene
SGLT-2 inhibitors (e.g. canagliflozin) are a risk factor for Fournier’s gangrene as they increase the urinary excretion of glucose, which increases the risk of a UTI and progression to necrotising fasciitis.
Endocrine abnormalities in Kallman’s syndrome?
Kallman’s syndrome - LH & FSH low-normal
Testosterone
How many units of insulin is 1ml?
In 1ml of (most standard) insulin, there are 100 units
Biochemical abnormalities in congenital adrenal hyperplasia?
Increased plasma 17-hydroxyprogesterone levels
Increased plasma 21-deoxycortisol levels
Increased urinary adrenocorticosteroid metabolites
What causes congenital adrenal hyperplasia syndrome?
It is inherited via an autosomal recessive pattern.
The condition is due to a deficiency of the 21-hydroxylase enzyme (responsible for biosynthesis of aldosterone + cortisol)
Why is the risk of osmotic demylination syndrome low when treating acute hyponatremia?
Cerebral neurons have not had adequete time to lose organic osmoles to compensate for the hyponatremia
Major concern is risk of brain herniation
Half life of thyroxine?
4-6 weeks
Why should alpha blocker such as phenoxybenzamine be given in phaoechromocytoma before beta blocker added?
B blocker alone may precipitate a hypertensive crisis
Why does postural hypotension occur in addisons?
Aldosterone insufficiency
Low urine osmolality after fluid deprivation, but high after desmopressin
Cranial DI
Low urine osmolality after both fluid deprivation and desmopressin
Nephrogenic DI
What is the cut off for true hyponatremia (serum osmolality)
The maximum osmolality level cut-off for true hyponatraemia is 275 mOsm/kg
