Diabetes mellitus Flashcards
What is type 1 diabetes mellitus?
Metabolic hyperglycaemic condition caused by absolute insufficiency of pancreatic insulin production
What is the aetiology of type diabetes mellitus?
- Caused by destruction of the pancreatic insulin producing B cells, resulting in absolute insulin deficiency. The B cell destruction is caused by an autoimmune process in 90% of patients - Likely to occur in genetically susceptible subjects and is probably triggered by environmental agents. Polymorphisms of a number of genes may influence the risk of type 1 diabetes. These include the gene encoding preproinsulin and a number of genes related to immune system function - Pancreatic B cell autoantigens may play a role in the initiation or progression of autoimmune islet injury. These include gluatmic acid decarboxylase (GAD) insulin, insulinoma associated protein 2 and cation efflux zinc transporter (ZnT8)
What is the epidemiology of type 1 diabetes mellitus?
- On of the most common chronic diseases in childhood with a prevalence of 0.25% in UK - Considerable geographic variation in incidence
What are the presenting symptoms of type 1 diabetes mellitus?
- Often of juvenile onset (under 30yrs). Polyuria/nocturia (osmotic diureses caused by glycosuria), polydipsia (thirst), tiredness, weight loss. Symptoms of complications. Diabetes ketoacidosis: Nausea, vomiting, abdominal pain, polyuria, polydipsia, drowsiness, confusion, coma, Kussmaul breathing (deep and rapid) ketotic breath, signs of dehydration (e.g. dry mucous membranes & reduced tissue turgor) - Signs of complications: examination of feed, test for neuropathy - Signs of associated autoimmune conditions e.g. vitiligo, Addison’s disease, autoimmune thyroid disease
What are the investigations for type 1 diabetes mellitus?
Blood glucose: Fasting blood glucose over 7mmol/L or random blood glucose over 11 mmol. 2 pos results needed before diagnosis HbA1C: Estimates overall blood glucose levels in past 2-3 months FBC: MCV, reticulolytes ( raised erythrocyte turnover causes misleading HbA1c levels) U&E: Monitor for nephropathy and hyperkalaemia caused by ACE inhibitors Lipid profile Urine albumin creatinine ratio CXR: exclude infection ECG: Look for ischaemic changes
How is type 1 diabetes mellitus managed?
Diabetes keoacidosis consider HDU/ICU input, central line, arterial line and urinary catheter if severe acidosis, hypotensive or oliguric - Insulin - Fluids - Potassium replacement - Monitor blood glucose - Broad spectrum antibiotics if infection suspected - NBM for at least 6h (gastroparesis is common) - NG tube: If GCS is reduced to prevent vomiting and aspiration - Refer to diabetes team for patients education
What does glycaemic control involve in type 1 diabetes mellitus?
- Advice and patient education: Diabetes nurse specialist dietitians. SC insulin: Short acting insulin (e.g. Lispro, aspart, glusine) three times daily before each meal and one long-acting insulin. Injection sites should be rotated - Insulin pumps slightly better glycaemic control but are costly and cumbersome for some patients and ketoacidosis may occur if pump malfunction - Monitor: control of symptoms, regular finger prick tests by patient, monitoring HbA1c levels - Screening and management of complications Treatment of hypoglycaemia
What are the possible complications of type 1 diabetes mellitus?
- Diabetic ketoacidosis: reduced insulin and increased counter-regulatory hormones result in raised hepatic gluconeogenesis and decreased peipheral glucose utilisation. - Microvascular: Retinopathy, nephropathy, neuropathy - Macrovascular: Peripheral vascular disease, ischaemic heart disease, stroke (TIA) - Complications of insulin treatment: Weight gain, fat hypertrophy at insulin injection sites - Hypoglycaemia caused by missed a meal r overdosage of insuline
What is the prognosis of type 1 diabetes mellitus?
Depends on early diagnosis, good glycaemic control and compliance with screening and treatment - Vascular disease and renal failure are major causes of increased morbidity and mortality
What is type 2 diabetes mellitus?
Characterised by increased peripheral resistance to insulin action, impaired insulin secretion and increased hepatic glucose output
What is the aetiology of type 2 diabetes mellitus?
- Multi-factoiral ( fenetic and environmental - Obesity: raised plasma free fatty acid levels and adipokines secreted by adipocytes (e.g. leptin, adinonectin, TNF-a, resistin) contribute to peripheral insulin resistance. Chronic hyperglycaemia can have a toxic effect on B cells - Secondary diabetes: Pancreatic diseases (chronic pancreatitis, hereditary haemochromatosis, pancreatic cancer, surgical removal of pancreas), Endocrinopathies (Cushings), Drugs (eg. corticosteroids
What is the epidemiology of type 2 diabetes mellitus?
People of Asian, African and Hispanic descent are at greater risk. Incidence has increased over last 20 years, in parallel with increased obesity worldwise
What are the presenting symptoms of type 2 diabetes mellitus?
- May be incidental finding - Polyuria, polydipsia, tiredness. Patients may present with hyperosmolar hyperglycaemic state (also known as hyperosmolar, non ketotic state). Infections - Assess for other cardiovascular risk factors: hypertension, hyperlipidaemia and smoking
What are the signs of type 2 diabetes mellitus on examination?
- Measure weight and height, weight circumference, blood pressure - Look for signs of complications - Diabetic foot: both ischaemic and neuropathic signs. Dry skin, reduced subcutaneous tissue, corns and calluses, ulceration, gangrene - Charcot’s arthropathy and signs of peripheral neuropathy, foot pulses are decreased in ischaemic foot - Skin changes: aNecrobiosis lipoidica diabeticorum (well-dermacated plaques on the shins or arm with shiny atrophic surface and red-brown edges), granuloma annulare (flesh coloured paplules coalescing in rings on the back of hands and fingers), diabetic dermopathy (depressed pigmented scars on shins)
What are the investigations for type 2 diabetes mellitus?
Diagnosed if one or more of the following are present - Symptoms of diabetes and random plasma glucose over 11.1mmol/L - Fasting plasma glucose over 7mmol - Two hour plasma glucose over 11.mmol after a 75g oral glucose tolerance test Monitor: HbA1c, U&Es, lipid profile, estimated glomerular filtration rate using MDRD calculator - Spot urine albumin. Creatinine ratio (to detect microalbuminaria)
