Endocrine Flashcards
What is Type 1 Diabetes?
- Type 4 hypersensitivity
- autoimmune destruction of pancreatic beta cells (absolute insulin deficiency)
What are the risk factors for Type 1 diabetes?
- Genetic predisposition
- Geographical region = more common in Europeans than asians
- Infectious agents = human enteroviruses
- Dietary factors = supplementation with Vitamin D may be protective
What is the pathophysiology for Type 1 Diabetes?
- Autoimmune pancreatic beta-cell destruction
- Hyperglycaemia develops = insulin deficient
- unable to utilise glucose in peripheral muscle and adipose tissue -> increased lipolysis + gluconeogenesis
- long term leads to vascular complications = glycosylation of proteins
What are the signs and symptoms for Type 1 diabetes?
Main
- hyperglycaemia
- polyuria
- polydipsia
Other
- young age
- weight loss
- blurred vision
- nausea and vomiting
- abdominal pain
- tachypnoea
- lethargy
- coma
What are the investigations for Type 1 diabetes?
1st
- random plasma glucose & 2hr plasma glucose
T1D = ≥11.1 mmol/L
Normal = <11.1 mmol/L
- fasting plasma glucose
T1D = ≥7.0 mol/L
Normal = <7.0 mol/L - HbA1c
T1D = ≥ 6.5% - clinical diagnosis (adults)
When is an Oral Glucose Tolerance Test used?
In pregnancy - to test for gestational diabetes
Where is insulin and glucagon secreted?
Islets of langerhans
beta cells = insulin
alpha cells = glucagon
Define paracrine ‘crosstalk’
Communication between alpha and beta cells is physiological
- insulin release inhibits glucagon
vice versa
What is the process of secretion of insulin by beta cells?
- High levels of glucose in the blood
- Glucose enters beta cells through GLUT2 glucose transporter
- Glucose metabolised by glucokinase to produce ATP
- ATP will bind to potassium channels in membrane and close them
- Causes depolarisation
- Causing calcium voltage gated ion channels to open
- Calcium enters beta cell and
- Causes exocytosis
- Vesicles containing insulin release insulin into the blood
What is the action of insulin in muscle and fat cells?
- Insulin released into blood binds to insulin receptor on plasma membrane of muscle/fat cells
- Triggers an intracellular signalling cascade
- GLUT4 vesicles mobilisation to plasma membrane
- GLUT4 vesicles integration into plasma membrane
- Glucose entry into cell via GLUT4
What is the likelihood of developing type 1 diabetes from different family members?
Higher chance of getting the condition if the father has the condition
- mother = 2%
- father =8%
- both parents = 30%
- sibling = 10%
- identical twins = 40%
What are the microvascular and macrovascular complications of Type 1 diabetes?
- diabetic neuropathy
- retinopathy
What is diabetes mellitus?
A disorder of carbohydrate metabolism characterised by hyperglycaemia
- cause morbidity and mortality through acute/chronic hyperglycaemia
What are all the types of diabetes?
- Type 1
- Type 2
- Maturity onset diabetes of youth (MODY) aka. monogenic diabetes
- pancreatic diabetes
- endocrine diabetes (acromegaly/cushings)
- malnutrition related diabetes
What is the HbA1c?
Measures glucose level over the last 3 months
- glucose attaches to the haemoglobin so can measure how much glucose has attached since RBCs have a lifespan of 3 months
What does failure of insulin secretion lead to?
- continued breakdown of liver glycogen (insulin or glucagon in communication, so one is always produced)
- unrestrained lipolysis and skeletal muscle breakdown providing gluconeogenic precursors
- inappropriate increase in hepatic glucose output and suppression of peripheral glucose uptake
What does failure to treat with insulin lead to?
- increase in circulating glucagon (loss of local increases in insulin within the islets leads to removal of inhibition of glucagon release), further increasing glucose
- perceived ‘stress’ leads to increased cortisol and adrenaline
- progressive catabolic state and increasing levels of ketones
What is the aetiology of type 2 diabetes?
- genes and environment
- impaired insulin secretion/ insulin resistance
- cause impaired glucose tolerance
- lead to type 2 diabetes
- leading to progressive hyperglycaemia and high free fatty acids
Why do beta cells stop working in Type 2 diabetes?
- When pancreas has to work really hard over a long period of time to produce very high levels of insulin the beta cells start failing
- as insulin resistance increases the pancreas tries to keep up but starts to fail
- so less insulin produced, glucose not taken into cells, more glucose in blood, glucose starts sticking more to RBCs causing vascular complications
What is the pathogenesis of type 2 diabetes?
- Impaired insulin secretion
- hepatic insulin resistance
- excessive glucose production
- more glucose enters the blood stream - Muscle/fat insulin resistance
- impaired glucose clearance
- less glucose enters peripheral tissues - Hyperglycaemia
What are the key presentations for type 2 diabetes?
Hyperglycaemia with presence of risk factors
e.g. overweight, ethnic groups etc.
What are symptoms of type 2 diabetes?
Polydipsia
Polyuria
candidal infections,
skin infection,
UTIs,
fatigue,
blurred vison
uncommon symptoms
Does ketosis occur in type 2 diabetes?
- early on the body still produces insulin inhibiting ketosis
- as beta cells are destroyed, less insulin is produced
- this then causes late stage ketosis
What causes insulin resistance?
- from a high fat diet, more fat is deposited in liver and pancreas
What are first line investigations for type 2 diabetes?
Fasting glucose, 2-hour post load glucose (75g orally) random plasma glucose
What is the treatment of type 2 diabetes?
- weight loss, exercise, healthier diet
- Metformin
- Sulphonylureas (gliclazide, glibenclamide)
- thiazolidinediones
- GLP-1
- SGLT-1 inhibitors
- DPP 4
- Bariatric surgery (gastric bypass, sleeve gastroectomy )
How do DPP 4 inhibitors work?
Dipeptidyl-peptidase 4 is an enzyme present in vascular endothelial lining which inactivates the incretin hormone GLP and GLP-1
DPP-4 Inhibitors are competitive antagonists of the DPP-4 enzyme - enhancing the effects of both GIP and GLP-1
(Incretins slow gastric emptying , involved in insulin secretion)
How does metformin work?
- Used to treat Type 2 and gestational diabetes
- reduce production of glucose by the liver
- decrease absorption of glucose by the gastrointestinal tract
- increase target cell insulin sensitivity.
Metformin does not influence the production of insulin; it simply increases the body’s sensitivity to the hormone.
How is metformin excreted?
Unchanged in urine
via active tubular secretion
What are the side effects of Metformin?
- lactic acidosis = when given with IV contrast (metformin held for 48hrs prior to contrast)
- GI disturbances
How does Sulphonylureas work?
- stimulates insulin release by binding to beta cell receptors (only works on people who are still producing some insulin)
- improve glycaemic control
- prevent gradual failure of insulin secretion
- can cause hypoglycaemia
- use gliclazide in most people
What is the action of thiazolidinediones?
- bind to nuclear receptor PPARy
- activate genes concerned with glucose uptake and utilisation and lipid metabolism
- improve insulin sensitivity
-need insulin for a therapeutic effect - glitazones rarely used
e.g. pioglitazone - ACTOS
What is the action of GLP-1?
Glucagon like peptide-1
(secreted from L cells in the intestines)
- stimulates insulin secretion
- suppresses glucagon secretion
- slows gastric emptying
- reduces food intake
- increases beta cell mass and maintains Beta cell function
- improves insulin sensitivity
- enhances glucose disposal
What is the action of SGLT-2 inhibitors?
- they block the reabsorption of glucose in the kidney (in type 2 diabetes there is too much glucose in the blood, so enables for it to be excreted quickly)
- increase glucose excretion
- lower blood glucose levels
- reduce CV mortality
What are the side effects of SGLT2?
- genital thrush (excreting more glucose in urine so provides good environment for bacteria to grow)
- increased risk of euglycaemia ketoacidosis (peeing out glucose, so body goes into a state of starvation causing ketosis)
What is the initial management for type 2 diabetes?
1st lifestyle changes plus agree glycaemic (HbA1c) target
Adjunct of BP and lipid management
What is the management for acute type 2 diabetes?
HbA1c is above target 1st metformin plus lifestyle measures, cardiovascular risk reduction, and specific considerations
How would you manage type 2 diabetes?
Every 3 to 6 months (tailored to individual needs), until the patient’s HbA1c is stable on unchanging therapy *
Every 6 months once the patient’s HbA1c level and blood glucose-lowering therapy are stable.
What else would you monitor in a patient with type 2 diabetes?
Measure blood pressure at least once a year in an adult with type 2 diabetes without previously diagnosed hypertension or renal disease.
What are the most likely complications associated with type 2 diabetes?
Cardiovascular disease, congestive heart failure, stroke.
Diabetic ketoacidosis if very poorly managed
What are basal insulin?
Aims to keep blood glucose levels at consistent levels during periods of fasting
What are the different insulins used in Type 1 and 2?
Once-daily basal insulin
- only in Type 2
Twice daily mix insulin
- Both types
Basal-bolus therapy
- mostly in type 1
(rarely in type 2)
What are the advantages and disadvantages of basal insulin in type 2?
Advantages:
- simple for the patient, adjust insulin themselves
- less risk of hypoglycaemia at night
Disadvantages:
- doesn’t cover meals
- best used with long acting insulin analogues (expensive)
What is the advantages and disadvantages of pre-mixed insulin?
Advantages:
- can cover insulin requirements through most of the day
- don’t need to adjust
Disadvantages:
- not physiological
- requires consistent meal and exercise pattern
- increased risk for nocturnal hypoglycaemia
What 2 complications occur in the eyes in diabetic retinopathy?
- Leakage
Basement membrane thickening
Pericyte loss
reduces junctional contact with endothelial cells - Ischaemia/occlusion
- Pericyte loss, endothelial cells respond by increasing turnover > thickening > ISCHAEMIA
- Glial cells grow down capillaries > OCCLUSION
- Ischaemia/Occlusion > Proliferation
What is diabetic nephropathy?
Disrupts filtration process of the kidney causing albumin to be excreted and reducing GFR
glomerulus changes > increase of injury glomerular > filtration of proteins > diabetic nephropathy
What are the consequence of diabetic peripheral neuropathy?
- diabetic foot ulceration
- pain or numbness (can’t fill pin in foot)
- lower limb amputation
- motor nerve damage
What is DESMOND?
Diabetes Education and Self Management for Ongoing and Newly Diagnosed
- help educate people with diabetes
What is DAFNE?
Dose Adjustment For Normal Eating
Educational course to help people with Type 1 diabetes manage their insulin
What is MODY?
Maturity Onset Diabetes of the Young
- Autosomal dominant
- Non-insulin dependent
- Single gene defect altering beta cell function
- Tend to be non-obese
- acts more likely type 2 diabetes but is found in young people
What are the 2 types of MODY gene mutations that can occur affecting insulin sensitivity?
Transcription Factor MODY
- hepatic nuclear factor (HNF) mutation alter insulin secretion. reduce beta cell proliferation
Glucokinase Gene (GCK) mutation (MODY2)
- GCK is the glucose sensor of beta cells, rate determining step in glucose metabolism controlling the release of insulin
- no treatment required
- high amount of glucose needed to release insulin
When would people have MODY and not diabetes?
- Parent affected with diabetes
- absence of islet autoantibodies
- evidence of no insulin dependence
- C peptide persists, whereas in type 1 is negative
What is permanent neonatal diabetes?
- diagnosed <6 months
(small, epilepsy, muscle weakness) - mutations in Kir6.2 and SUR1 subunits of the beta cell ATP sensitive potassium channel
-> mutations prevent closure of the potassium channel with ATP so beta cells unable to secrete insulin - sulphonylureas close Katp channel
What is maternally inherited diabetes and deafness (MIDD)?
- mutations in mitochondrial DNA (always inherit mitochondria just from the mother)
- loss of beta cell mass
- wide phenotype
- similar presentation to type 2
What is lipodystrophy?
- selective loss of adipose tissue
- associated with insulin resistance, dyslipidaemia, hepatic steatosis, hyperandrogegism, PCOS
(small lumps of fat appear when injecting insulin at the same ejection site, need to change around )
What are the acute and chronic complications of inflammation of the exocrine pancreas?
Acute: usually transient hyperglycaemia, due to increased glucagon secretion
Chronic Pancreatitis:
Alcohol
Alters secretions, formation of proteinaceous plugs that block ducts and act as a foci for calculi formation
Stop alcohol, treat with insulin
How is hereditary haemochromatosis an exocrine cause of diabetes?
Autosomal recessive – triad of cirrhosis, diabetes and bronzed hyperpigmentation
Excess iron deposited in liver, pancreas, pituitary, heart and parathyroids
Most need insulin
How is pancreatic neoplasia an exocrine cause of diabetes?
- Common cause of cancer death (rather it is in the tail so can be removed easily surgically)
- 4-5 resections per week at STH
- Require sc insulin
- Prone to hypoglycaemia due to loss of glucagon function
- Frequent small meals, enzyme replacement
- Insulin pumps
How is cystic fibrosis an exocrine cause of diabetes?
- Cystic fibrosis transmembrane conductance regulator (CFTR) gene located on chromosome 7q22
- Regulates chloride secretion (increased secretions)
- Increased viscous secretions lead to duct obstruction in pancreas, and fibrosis
- Incidence is 25 to 50% in adults
- Ketoacidosis rare
- Insulin treatment required (ducts blocked so can’t be released)
- CF survival better, so microvascular complications increasing
How does acromegaly cause diabetes?
- excessive secretion of growth hormone
(similar to type 2) - insulin resistance rises, impairing insulin action in liver and peripheral tissues
(reversible if cut tumour out)
How does cushings syndrome cause diabetes?
- Hypercortisolaemia = increased gluconeogenesis so increased blood glucose levels
- Hepatic glucose production increased through stimulation of gluconeogenesis via increased substrates (proteolysis and lipolysis)
How is pheochromocytoma an endocrine cause of diabetes?
Catecholamine, predominately epinephrine excess
Adrenaline decreases insulin levels, decreasing glucose uptake but increases gluconeogenesis
Higher blood glucose concentration
(reversible with surgery)
What drugs can induce diabetes?
- Glucocorticoids increase insulin resistance
- Thiazides / protease inhibitors (HIV) / antipsychotics – mechanisms not clearly understood
What are the current classifications of hypoglycaemia?
Level 1 = Alert value
(plasma glucose <3.9 mmol/l and no symptoms)
Level 2 = serious biochemical
(plasma glucose <3.0 mmol/l)
Level 3 = severe
(patient has impaired cognitive function sufficient to require external help to recover)
What effects does hypoglycaemia have on the body?
- brain = cognitive dysfunction, blackouts, seizures
- Heart = increased risk of myocardial ischaemia
- musculoskeletal = fall, accidents
- circulation = inflammation, blood coagulation abnormalities
What are the common symptoms of hypoglycaemia?
- Development of symptoms
- autonomic = anxiety, hunger, sweat
- neuroglycopenic = confusion, can’t focus, dizziness
- non-specific = nausea, headache - Low blood glucose
- Response to treatment with carbohydrate
What is the normal physiological response to prevent hypoglycaemia?
- inhibition of endogenous insulin secretion
- release of glucagon and adrenaline
- Liver breaks down glycogen and gluconeogenesis occurs
What is impaired awareness of hypoglycaemia?
- people don’t realise they are hypo until they collapse on the floor
- usually due to having frequent hypoglycaemia
- glucose sensors in the brain turn off so no longer get symptoms
What are the causes of hypoglycaemia?
- long duration of diabetes (lose glucagon after a few years)
- use of drugs
- tight glycaemic control with repeated episodes of non-severe hypoglycaemia
- increasing age
- sleeping (dampened response of glucagon and adrenaline, and can’t detect symptoms at night)
- increased physical activity
What are the risk factors of severe hypoglycaemia?
Low HbA1c; high pre-treatment HbA1c in T2DM
Long duration of diabetes
A history of previous hypoglycaemia
Impaired awareness of hypoglycaemia (IAH)*
Recent episodes of severe hypoglycaemia
Daily insulin dosage >0.85 U/kg/day
Physically active (e.g. athlete)
Impaired renal and/or liver function
Strategies to prevent hypoglycaemia?
Discuss hypoglycaemia risk factors and treatment with patients on insulin or sulphonylureas
Educate patients and caregivers on how to recognize and treat hypoglycaemia
Instruct patients to report hypoepisodes to their doctor/educator
What is the treatment for hypoglycaemia?
- Recognize symptoms so they can be treated as soon as they occur
- Confirm the need for treatment if possible (blood glucose <3.9 mmol/l is the alert value)
- Treat with 15 g fast-acting carbohydrate to relieve symptoms
- Retest in 15 minutes to ensure blood glucose >4.0 mmol/l and re-treat (see above) if needed
- Eat a long-acting carbohydrate to prevent recurrence of symptoms
What is the action of the parathyroid hormone?
To maintain a high level of calcium in the blood
- Increased calcium reabsorption (kidney)
- increased calcium absorption (from gut due to vitamin D)
- decrease in phosphate reabsorption
- increase 1 alpha-hydroxylation of 25-OH VitD
- increase bone remodelling and resorption (releases calcium into blood)
What are the consequences of hypocalcaemia?
- parathesia
- muscle spasm (premature labour, hands, feet, larynx)
- seizures
- basal ganglia calcification
- cataracts
- ECG abnormalities (long QT interval)
What is the calculation for corrected calcium?
corrected calcium = total serum calcium + 0.02*(40 - serum albumin)
What is Chvostek’ signs?
Tap over the facial nerve
- look for spasm of facial muscles
(in hypocalcaemia)
What is trousseau’s signs?
Initiate the blood pressure cuff to 20mm Hg above systolic for 5 mins
- If hypocalcaemia = this will initiate finger and hand spasms
What are the causes of hypoparathyroidism?
- neck surgical
- radiation
- autoimmune (isolated, polyglandular type 1)
- genetic
- syndromes (Di George, HDR etc.)
- infiltration (haemochromatosis, Wilson’s disease)
- magnesium deficiency
What are the levels of PTH, Ca2+ and Phosphate in hypoparathyroidism?
Low PTH (inappropriate response)
Low Ca2+
High Phosphate
What is pseudohypoparathyroidism?
resistance to parathyroid hormone
leads to:
- short stature
- obesity
- mild learning difficulties
What are the levels of PTH, Ca2+ and Phosphate in pseudohypoparathyroidism?
High PTH (resistant to PTH)
Low calcium
High phosphate
What are symptoms and consequences of hypercalcaemia?
- thirst, polyuria (pee out a lot of calcium)
- nausea
- constipation (gut muscle not working properly)
- confusion -> coma
Develop
- renal stones
- ECG abnormalities (short QT)
Groans, Stones, Moans, Bones
What are the causes of hypercalcaemia?
- malignancy - some cancers produce PTHrP that responds like PTH, lymphoma
- primary hyperparathyroidism
- thiazides (make you retain calcium)
- thyrotoxicosis (excessive production of thyroid hormone)
- Sarcoidosis (abnormal collections of inflammatory cells)
- Familial hypocalciruic/benign hypercalcaemia
- immobilisation
- Milk-alkali
- Adrenal insufficiency
- pheochromocytoma
What happens in hypercalcaemia of malignancy?
- increase in calcium
- so PTH reduces
- decreases bone resorption, calcium absorption and reabsorption
What are the levels of PTH, Ca2+ and Phosphate in hypercalcaemia of malignancy?
Low PTH (appropriate)
High Calcium
Neutral phosphate
What are the consequences of primary hyperparathyroidism?
- Bone - osteoporosis (high PTH increased bone turn over)
- Stones - kidney stones
- Groans - psychic groans, confusion
- Moans - abdominal moans, constipation, acute pancreatitis
What are the levels of PTH, Ca2+ and Phosphate in primary hyperparathyroidism?
High PTH (Inappropriate)
High calcium
Low phosphate
What are the levels of PTH, Ca2+ and Phosphate in Vit D deficiency (secondary hyperparathyroidism)?
High PTH (appropriate)
Low calcium
Low phosphate
What 5 diseases can occur in the pituitary?
- benign pituitary adenoma
- craniopharygioma
- trauma
- apoplexy/ sheehans
- sarcoid/ TB
What are the 3 ways that pituitary tumours cause disease?
- Pressure on local structures
- optic chiasm -> bitemporal hemianopia
- cerebrospinal fluid rhinorhoea (through nose) - Pressure on normal pituitary
- hypopituitarism (pale, no body hair, central obesity) - Functioning tumour (producing hormones)
- prolactinoma
- acromegaly (adults - large hands and long jaw) and gigantism (in kids - puberty doesn’t happen and suppress the GH)
- Cushing’s disease
What are prolactinomas?
Prolactin producing tumour of the pituitary gland.
Benign lactotroph adenomas expressing and secreting prolactin (should be inhibited by dopamine)
What is the epidemiology of prolactinoma?
- very high prevalence
- more in women
What are the clinical features of a prolactinoma?
- headache
- visual field defect
- CSF leak
- Menstrual irregularity (with off LH and FSH)
- infertility
- galactorrhoea
- low libido
What are the key diagnostic factors of prolactinomas?
- presence of risk factors (women 20 to 50 yrs old)
- amenorrhoea (absence of periods) or oligomenorrhoea (infrequent periods)
- infertility
- galactorrhoea
- loss of sexual desire
- erectile dysfunction
- visual deterioration
Why must you take a careful drug history for prolactinoma?
Many psychiatric drugs are antidopiminergic therefore cannot inhibit prolactin
What is the treatment for prolactinomas?
Compared to other pituitary tumours the management is medical rather than surgical:
dopamine agonist
(negative feedback loop - more dopamine, reduces prolactin release and shrinks tumour)
What is acromegaly?
a rare, chronic disease caused by excessive secretion of growth hormone (GH), usually due to a pituitary somatotroph adenoma.
It is associated with increased morbidity and premature mortality if not appropriately treated.
What are the key diagnostic features for acromegaly?
- coarsening of facial features
- soft-tissue and skin changes
- aural enlargement (hands, chin and feet)
- excessive sweating
- carpal tunnel syndrome
- joint pain and dysfunction
- snoring
- alterations in sexual functioning
- history or family history of inherited syndrome
What are the risk factors for acromegaly?
- GPR101 over-expression
- multiple endocrine neoplasia type 1 syndrome
- isolated familial acromegaly
- McCune-Albright syndrome (develop areas of scar tissue in their bones)
- Carney complex (develop skin pigmentation and benign tumours)
What are the co-morbidities of acromegaly?
- cerebrovascular events and headaches
- arthritis
- insulin-resistant and diabetes
- sleep apnea
- hypertension and heart diabetes
What are the treatment options for acromegaly?
- Pituitary tumour surgery - rapid fall in GH, based on size of tumour
- Medical therapy -
- Radiotherapy - conventional (multi-fractional) or stereotactic (single fraction)
What medical therapy is used for acromegaly?
- dopamine agonists - will switch off the GH
- Somatostatin analogues - inhibits multitude of hormones, short life span so use synthetic versions
- Pegvisomant - GH competitive antagonist, very strongly binds to GH receptor, so GH still secreted loads but just cannot bind (doesn’t work if tumour too big)
What is Cushing’s syndrome?
Cushing syndrome is the clinical manifestation of pathological hypercortisolism from any cause.
What’s the most common cause of Cushing’s syndrome?
Exogenous corticosteroid exposure
For example taking steroids e.g., prednisone
What is the difference between Cushing’s syndrome and Cushing’s disease?
- Cushing’s syndrome disease is pathological hypercortisolism from any cause.
- Cushing’s disease is hypercortisolism caused by a endogenous source e.g., pituitary adenoma
What is the most common cause of Cushing’s disease?
pituitary adenomas
(70-80%)
- increased release of adrenocorticotropic hormone (ACTH), causing increased release of cortisol from the zone fasciculata in the adrenal cortex
- regulate sleep rhythms
Name 2 other causes of Cushing’s disease?
- Ectopic neuroendocrine tumours
- Adrenal carcinoma
What is ACTH-dependant Cushing’s disease?
overproduction of ACTH which stimulates adrenal gland to secrete more cortisol.
What two types of tumour are ACTH-dependant causes of Cushing’s disease?
Pituitary adenoma, ectopic neuroendocrine ACTH secreting tumours
What is ACTH-independant Cushing’s disease
When there is excessive cortisol production without high levels of ACTH
What are the 6 hormones secreted by the anterior pituitary?
Adrenocorticotrophic hormone (ACTH)
Thyroid-stimulating hormone (TSH)
Luteinising hormone (LH)
Follicle-stimulating hormone (FSH)
Prolactin (PRL)
Growth hormone (GH)
What are the two hormones secreted by the posterior pituitary?
Oxytocin
Anti-diuretic hormone (ADH)
How does Cushing’s cause disease?
The clinical manifestations is due to excess tissue exposure to cortisol.
The degree to which symptoms present is due to the amount of excess.
What are some key presentations associated with Cushing’s?
Hypertension
Glucose intolerance
Premature osteoporosis
Facial plethora (redness)
Weight gain
Purple striae (stretch marks) on abdomen
Supraclavicular fulness, torso weight gain but weak arms
Absence of pregnancy, alcoholism, malnutrition
What are some key serum levels for Cushing’s?
Increased serum glucose, elevated cortisol in saliva, high urinary cortisol
What are the 4 main diagnostic tests for Cushing’s?
- Late night salivary cortisol (4nmol)
- 1mg overnight dexamethasone suppression test (50 nmol/litre),
- 24 hour urinary free cortisol.
- 48- hour 2 mg dexamethasone suppression testing
How do you perform a late night salivary cortisol test?
Samples are collected by saturating a collection swab with saliva or by passively drooling into a collection tube between 11 p.m. and midnight.
Sampling should be done on 2 separate nights
Why is the salivary test performed at night?
This is when cortisol levels are at their lowest. Will give the most accurate baseline figure
What is the 1mg overnight dexamethasone test
Patient is given 1 mg of dexamethasone at 11 p.m., and a plasma cortisol level is obtained the following morning at 8 a.m
morning cortisol >50 nanomol/L
What other test would be performed on a patient with suspected Cushing’s?
Pregnancy test
How would you treat Cushing’s disease?
First line : If an adenoma remove adenoma as that is the cause.
Adjunct: If only mild use or very severe (before surgery) use a steroidogenesis (pasireotide) inhibitor or a glucocorticoid receptor antagonist (mifepristone).
Monitor cortisol levels after removal of pituitary adenoma. May require hormone replacement due to dysfunction of HPA
How would you monitor Cushing’s?
Recurrence of adrenocorticotrophic hormone-dependent Cushing syndrome is common, with at least a 5% to 26% risk of recurrence at 5 years.
Patients who have achieved remission should be screened periodically (every 6-12 months) for recurrence of disease.