Diabetes Mellitus Flashcards
Define diabetes mellitus
Type 1: metabolic disorder of hyperglycaemia due to absolute insulin deficiency
Type 2: metabolic disorder of hyperglycaemia due to impaired insulin secretion and insulin
resistance
What are the causes/risk factors of diabetes mellitus?
Type 1: destruction of pancreatic beta-cells -> absolute insulin deficiency
• Autoimmune disease with environmental trigger
• HLA-DQ, -DR
Associated autoimmune conditions
• Vitiligo
• Addison’s disease
• Hashimoto’s thyroiditis
Type 2
Causes
• MODY (maturity onset diabetes of the young) – autosomal
dominant
• Pancreatic disease e.g. chronic pancreatitis, pancreatic ca.
• Endocrinopathies e.g. Cushing’s syndrome, acromegaly, PCOS
• Drugs e.g. corticosteroids
Risk Factors
• Genetic predisposition: 90% concordance amongst monozygotic twins
• Older age
• Physical inactivity
• Obesity - ↑FFAs, hyperglycaemia
• Hypertension
• Dysplipidaemia
• Cardiovascular disease
What are the symptoms of diabetes mellitus?
- Polyuria/nocturia
- Polydipsia
- Weight loss
- Fatigue
- Blurred vision
Type 1 Symptoms of DKA: • N&V • Abdominal pain • Drowsiness • Confusion • Coma
Type 2 • Asymptomatic • Paraesthesia • Candida e.g. candidiasis, balanitis, pruritus vulvae • Skin infections e.g. cellulitis • UTIs Symptoms of HHS/HONK (hyperglycaemic symptoms as above)
What are the signs of diabetes mellitus?
Type 1 Signs of DKA: • Kussmaul breathing • Ketotic breath • Dry mucous membranes • Reduced tissue turgor
Type 2 • Acanthosis nigricans • Necrobiosis lipoidica (welldemarcated plaques with shiny atrophic surface and redbrown edges) • Granuloma annulare (fleshcoloured papules in rings) • Diabetic dermopathy (depressed pigmented scars) Signs of HHS/HONK • Dry mucous membranes • Poor skin turgor • Hypotension • Tachycardia
What investigations are carried out for diabetes mellitus?
• Bloods o Glucose ▪ Fasting blood glucose >7mmol/l ▪ 2hr after 75g OGTT ≥11.1mmol/l ▪ Random blood glucose ≥11.1mmol/l ▪ Symptomatic plus one positive result ▪ Asymptomatic plus two positive results - HbA1c >48mmol/mol or 6.5% - U&Es - Lipid profile • Urine albumin:creatinine ratio – microalbuminuria • eGFR – renal insufficiency
Suspected DKA • Bloods - FBC – elevated WCC - U&Es – high urea and Cr - Glucose >11mmol/l -o Ketones >3mmol/l - Culture - ABG – metabolic acidosis with high anion gap (VBG pH <7.3) • Urine - Glycosuria - Ketonuria ++ - MC&S
What is the management for diabetes mellitus?
Type 1 Patient education and advice • Diabetic nurse/dietitian • DAFNE (dose adjustment for normal eating) – measure carbohydrate intake and adjust insulin dose • Regular finger prick tests
Glycaemic control – insulin
• Basal bolus regimen
- Short-acting insulin e.g. lispro, aspart SC injection 3x/daily before meals
- Long-acting insulin e.g. glargine, determir SC injection 1x/daily
• Insulin pump
Hypoglycaemia
• 50g oral glucose e.g. Lucozade, sweets followed by a starchy snack
• 50ml IV 50% glucose
• 1mg IM glucagon
DKA
• IV fluid replacement with 0.9% saline
• Start IV dextrose when glucose reaches 15mmol/l
• Insulin infusion
• Potassium (in fluids)
• Monitor blood glucose, ketones, urine output and venous blood gases
Type 2 Patient education and advice • Diabetic nurse/dietitian Risk factor modification • Diet – high fibre, low GI carbohydrates, low‑fat dairy products, oily fish, reduce saturated fat • Exercise • Weight loss • BP control e.g. ACE-I +/- diuretic • Lipid control e.g. statins • Smoking cessation • Antiplatelet therapy e.g. aspirin (if associated CV disease) Glycaemic control • Measure HbA1c every 3-6 months • Metformin (biguanide) - Inhibits hepatic gluconeogenesis - SE: GI upset, MALA • Sulphonylureas (secretagogue) - e.g. gliclazide, glibenclamide - Blocks K+ sensitive channels in beta cells -> insulin release - SE: hypoglycaemia, weight gain • Thiazolinedione (insulin sensitiser) - e.g. pioglitazone - Activates PPARγ and ↓ insulin resistance • Acarbose (alpha-glucosidase inhibitor) - Reduces carbohydrate digestion - SE: bloating, flatulence • Incretin (GLP-1 analogue) - e.g. exenatide, liraglutide - ↑ insulin secretion, ↓ glucagon release, gastric emptying and appetite • Gliptin (DPP4-inhibitor) - e.g. sitagliptin, vildagliptin • Gliflozin (SGLT-2 inhibitor) - e.g. canagliflozin - ↓ renal threshold for glucose -> ↓ glucose reabsorption • Insulin - SE: weight gain, lipid hypertrophy at injection sites HHS/HONK • IV fluid replacement (0.45% saline if Na+ >170mmol/l) • Start IV dextrose when glucose reaches 15mmol/l • Insulin infusion • Potassium (in fluids) • Monitor blood glucose, ketones, urine output and venous blood gases
What are the complications of diabetes mellitus?
Type 1
• Diabetic ketoacidosis
- Infection
- Newly diagnosed diabetes
Type 2
• Hyperosmolar non-ketotic state
Type 1 and Type 2 • Microvascular - Retinopathy – regular digital retinal photography - Neuropathy – foot care/hygiene ▪ Peripheral neuropathy ▪ Painful neuropathy - amityrptilline, duloxetine, gabapentin ▪ Carpal tunnel syndrome ▪ Diabetic amyotrophy ▪ Mononeuritis multiplex e.g. pupil sparing IIIrd nerve palsy ▪ Autonomic neuropathy - Nephropathy – monitor U&Es, eGFR, Alb:Cr, BP control ▪ Microalbuminuria ▪ Proteinuria ▪ Renal failure • Macrovascular - Peripheral vascular disease - Ischaemic heart disease - Stroke/TIA • Gastroparesis • Impotence/erectile dysfunction
What are the features of different retinopathies?
Background • Hard exudates (cholesterol) • Microaneurysms • Blot haemorrhages Treatment: - Improve blood glucose control
Pre-proliferative • Cotton wool spots (soft exudates) – retinal ischaemia Treatment: - Pan retinal photocoagulation
Proliferative
• New vessels – angiogenesis
• Vessels may bleed into
vitreous humour -> blindness
Maculopathy
• Macular oedema
• Exudates/haemorrhages closeto fovea
