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Endocrinology 1

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oelomar's version from 2016-05-14 15:13

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What is type I diabetes mellitus characterised by?An autoimmune disease characterised by pancreatic β-cell destruction and an absolute deficiency of insulin. Without insulin they develop ketoacidosis and coma.
At what age is someone typically diagnosed with type I diabetes mellitus?Younger than 20.
What percentage of diabetes cases are type I?Around 10%.
What causes type I diabetes mellitus?Unknown.
What are the classic symptoms of type I diabetes mellitus?Polyuria, polydipsia, polyphagia, and weight loss.
What is type II diabetes mellitus characterised by?A combination of resistance to insulin and an inadequate secretory response by the pancreatic β cells.
At what age is someone typically diagnosed with type II diabetes mellitus?Older than 40.
What percentage of diabetes cases are type II?Around 90%.
What causes type II diabetes mellitus?Obesity is thought to be the primary cause of type II diabetes in people who are genetically predisposed to the disease.
What are the classic symptoms of type II diabetes mellitus?Polyuria, polydipsia, polyphagia, and weight loss (but these symptoms are less common than in type I DM).
How can one distinguish between type I and type II diabetes mellitus?The C-peptide assay, which measures endogenous insulin production, can be used. A very low C-peptide confirms Type 1 diabetes.
Is genetic predisposition strong in type I diabetes?No, it is relatively weak (50% concordance in identical twins).
Is genetic predisposition strong in type II diabetes?Yes, it is relatively strong (90% concordance in identical twins).
What will histology show in the islets of Langerhans in a patient with type I diabetes?Leukocyte infiltration.
What will histology show in the islets of Langerhans in a patient with type II diabetes?Amyloid deposit.
What is the WHO criteria for the diagnosis of diabetes?Fasting plasma glucose ≥ 7.0mmol/L; Random plasma glucose ≥ 11.1mmol/L. One abnormal laboratory value is diagnostic of in symptomatic individuals. Two values are needed in asymptomatic people.
What are normal/abnormal levels of HBA1c?Normal = below 42mmol/mol (6.0%); Prediabetes = 42-47mmol/mol (6.0-6.4%); Diabetes = 48mmol/mol (6.5%) or over.
Drugs aside, how is type II diabetes managed?Lifestyle changes. Also set an individual HBA1c target level.
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Question Answer
What is the first line drug used in the treatment of type II diabetes?Metformin.
What is metformin and how does it work?Metformin is a biguanide and is used for treating type II diabetes. It works by activating AMP-kinase which is a liver and muscle enzyme important in insulin signalling. It results in peripheral glucose uptake i.e. increases insulin sensitivity.
What is the gravest adverse effect of metformin?Lactic acidosis.
In order to minimise GI side effects, how should metformin be administered?It should be stepped up slowly.
When should metformin treatment be stopped?If serum creatinine > 150µmol/L or if eGFR < 30ml/min/1.73m2.
What are sulfonylureas and how do they work?Sulfonylureas are drugs used for the treatment of type II diabetes. They work by binding to the ATP-dependent K+ channel on the β-cell thereby inhibiting the efflux of K+ thereby resulting in depolarisation and Ca2+ influx, thereby leading to insulin release i.e. they stimulate the release of endogenous insulin. This requires some islet function, and is therefore useless in type I diabetes.
Name a sulfonylureaGliclazide, glimepiride.
What are the side effects of sulfonylureas?Hypoglycaemia, weight gain, syndrome of inappropriate ADH secretion.
What are thiazolidinediones and how do they work?These are PPARγ agonists. Thiazolidinediones bind to the PPARγ receptors on adipocytes and thereby increase adipogenesis. This results in increased glucose uptake and therefore lowers the blood glucose levels.
Name a thiazolidinedioneGlitazone, pioglitazone.
What are the side effects of thiazolidinediones?Weight gain of 5-6kg, hypoglycaemia, oedema.
Thiazolidinediones are contraindicated in what?CHF, osteoporosis.
When should thiazolidinedione therapy be stopped?Thiazolidinedione therapy should only be continued if there is a reduction of ≥0.5% in HbA1c in 6 months, otherwise it should be stopped.
What are DPP-4 inhibitors and how do they work?There are hormones known as incretin hormones that stimulate the secretion of insulin and inhibit glucagon release. The two main incretin hormones are GLP-1 and GIP. The enzyme DPP-4 degrades these hormones and makes them inactive. Therefore, DPP-4 inhibitors increase the action of incretins, thereby increasing insulin secretion and reducing glucagon secretion.
Name a DPP-4 inhibitorSitagliptin, vildagliptin.
What are the side effects of DPP-4 inhibitors?GI disturbances (N&V), headache, drowsiness, dizziness, hypoglycaemia (rare, only in overdose).
When should DPP-4 therapy be stopped?DPP-4 therapy should only be continued if there is a reduction of ≥0.5% in HbA1c in 6 months, otherwise it should be stopped.
What is exenatide?Exenatide is a GLP-1 agonist used in the treatment of type II diabetes.
What are the side effects of GLP-1 agonists?Nausea, vomiting, pancreatitis.
When should insulin therapy be started in type II diabetes?Start insulin therapy if other measures do not keep HBA1c to < 7.5% (or other agreed target).
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What is the “Somogyi effect”?When people with type I diabetes over-inject insulin, it can result in hypoglycaemia. Rebound hyperglycaemia can follow insulin-induced hypoglycaemia because of the release of counter-regulatory hormones. This is the “Somogyi effect”.
What would the glucose level be in someone with impaired fasting glucose?A fasting glucose greater than or equal to 6.1 but less than 7.0mmol/L implies impaired fasting glucose.
What would the glucose level be in someone with impaired glucose tolerance?Fasting plasma glucose of less than 7.0mmol/L and an oral glucose tolerance test 2-hour value greater than or equal to 7.8mmol/L but less than 11.1mmol/L.
What is gestational diabetes?A condition in which women without previously diagnosed diabetes exhibit high blood glucose levels during pregnancy (especially during their third trimester). Gestational diabetes is caused when insulin receptors do not function properly. This is likely due to pregnancy-related factors such as the presence of human placental lactogen that interferes with susceptible insulin receptors.
Apart from diet controlled regimens, how is gestational diabetes managed?The only drugs that can be given are metformin and glibenclamide (2nd generation sulfonylurea which can induce severe hypoglycaemia).
What effect does alcohol have on blood glucose levels?Alcohol inhibits gluconeogenesis and thereby induces hypoglycaemia.
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Question Answer
What are the features of diabetic ketoacidosis?Hyperventilation (less marked in very severe acidosis owing to respiratory depression), nausea, vomiting, dehydration, severe abdominal pain (occasionally). Some patients are mentally alert at presentation but confusion and stupor are present in more severe cases. The smell of ketones on breath allows an instant diagnosis.
What is the immediate management for a patient with ketoacidosis?Start fluid therapy. A typical regime of IV 0.9% saline is: 1L over 30 mins, then 1L over 60 mins, then 1L over 2 hours, then 1L over 4 hours.
Is potassium added to the IV fluid in the immediate management of a patient with DKA?Yes. K+ tends to fall with treatment for DKA. Therefore, the concentration of KCl should be adjusted depending on results of 2 hourly blood K+ measurements.
In the immediate management of DKA, is insulin given?Yes. Insulin is started immediately on a sliding scale. If blood glucose is > 15.1, then 6ml/hr of insulin is given. 12.1-15.0=4ml/hr. 9.1-12.0=2ml/hr. 6.1-9.0=1ml/hr. 4.1-6.0=0.5ml/hr.
In the immediate management of DKA, when would a plasma expander (volume expander) be given?If blood pressure reaches below 80mmHg.
In the immediate management of DKA, if the pH is below 7.0, what should be done?500ml of 1.26% sodium bicarbonate + 10mmol KCl should be given. This should be repeated if necessary to bring pH up to 7.0.
In the immediate management of DKA, when would a patient be transferred to the high dependency unit?If there is a CVS compromise, or if the GCS is below 15.
In the immediate management of DKA, when would a nasogastric tube be inserted?If the patient is comatose, and if there is persistent vomiting.
In the immediate management of DKA, when would the patient be catheterised?If no urine has been passed for 3-4 hours.
What is Kussmaul breathing?Kussmaul breathing is a deep and laboured breathing pattern often associated with severe metabolic acidosis, particularly diabetic ketoacidosis (DKA) but also kidney failure.
What is hyperosmolar non-ketotic coma (HONK)?Now known as hyperosmolar hyperglycaemic state (HHS), this is a complication of diabetes (predominantly type II) in which high blood sugars cause severe dehydration, increases in osmolarity (relative concentration of solute) and a high risk of complications, coma, and death.
Ketone levels are very high in patients in a hyperosmolar hyperglycaemic state. True or false?False. Ketones are absent.
Blood glucose levels may be very high in patients in a hyperosmolar hyperglycaemic state. True or false?True. Levels may be > 30mmol/L.
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Question Answer
How is lactic acidosis treated?Rehydration and infusion of isotonic 1.26% bicarbonate.
What are the two types of diabetic retinopathy?Non-proliferative diabetic retinopathy and proliferative diabetic retinopathy.
What is non-proliferative diabetic retinopathy?Non-proliferative diabetic retinopathy (NPDR) is the earliest stage of diabetic retinopathy. Blood vessels in the retina begin to leak extra fluid and small amounts of blood into the eye. NPDR can cause changes in the eye, including: micro-aneurysms, retinal haemorrhages, exudates, macular oedema caused by fluid leaking from the retinal vessels (macular oedema is the most common cause of vision loss in diabetes) and macular ischaemia. Many people with diabetes have mild NPDR, which usually does not affect their vision. However, if their vision is affected, it is the result of macular oedema and or macular ischaemia.
What is proliferative diabetic retinopathy?Proliferative diabetic retinopathy (PDR) mainly occurs when many of the blood vessels in the retina close, preventing enough blood flow. In an attempt to compensate for this change new blood vessels proliferate in the retina and this is referred to as neovascularisation. New vessels are also often accompanied by scar tissue that may cause the retina to wrinkle or detach. PDR may cause more severe vision loss than NPDR because it affects central and peripheral vision.
What is “QRISK2”?QRISK2 is a prediction algorithm for cardiovascular disease (CVD) that uses traditional risk factors (age, systolic blood pressure, smoking status and ratio of total serum cholesterol to HDL cholesterol) together with body mass index, ethnicity, measures of deprivation, family history, chronic kidney disease, rheumatoid arthritis, atrial fibrillation, diabetes mellitus, and antihypertensive treatment.
In a diabetic, if the 10 year QRISK2 score is over 20%, what therapy is recommended?Statins (40mg simvastatin). This is preventative therapy.
What is the leading cause of premature death in young diabetic patients?Diabetic nephropathy.
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