Diabetes Mellitus Introduction Name comes from high volumes of sweet urine Caused by lack of insulin action Reduced or absent secretion type 1 Insulin resistance and lack of beta cell reserve type 2 Type 1 diabetes mellitus Results from autoimmune destruction of the islets of Langerhans In the absence of insulin the body reacts as though it is experiencing starvation cid 127 Gluconeogenesis glycogenolysis cid 127 When insulin is absent ketogenesis occurs ketones provide an alternate energy source for the brain and kidney Peak incidence is between 12 and 14 years old cid 127 Without insulin GLUT4 is not activated and glucose transport into dependent cells cannot occur Increased plasma glucose is filtered out of the blood by the kidneys and excreted in the urine glycosuria cid 127 Glucose draws water by osmosis causing polyuria increased urine volume and polydipsia increased thirst If ketones are produced in excess they can cause a harmful reduced blood pH diabetic ketoacidosis Type 2 diabetes mellitus Results from combination of insulin resistance and failure of the beta cells to increase insulin secretion cid 127 Obesity worsens insulin resistance There is enough insulin to prevent ketogenesis but not enough to prevent hyperglycemia Polyuria and polydipsia without ketoacidosis Stronger heritable component than in type 1 Clinical presentation of patients with diabetes mellitus In type 1 diabetes the sudden and complete lack of insulin causes hyperglycemia and acidosis Short history of polyuria and polydipsia accompanied by weight loss cid 127 May present to ER with confusion and breathlessness due to ketoacidosis Kussmaul respiration Insulin is initially administered intravenously then self injections must continue for life Clinical presentation of type 2 diabetes mellitus The onset of type 2 diabetes is insidious Patients may not notice their symptoms until the glucose concentration rises above 10 mM and glycosuria occurs Polyuria and nocturia may then occur cid 127 May develop urinary tract infections due to glucose concentration Severe hyperglycemia can cause a hyperosmolar state of the blood that can be life threatening Hyperosmolar non ketotic coma HONKC High blood glucose accompanied by hypernatremia high sodium Causes confusion and loss of consciousness Diagnosis requires two fasting glucose levels of 7 0 mM or above and symptoms such as polyuria Can also be diagnosed by glucose tolerance test patients who have a plasma glucose over 11 1 mM 2 hours post administration of oral glucose have diabetes Another measure that can be used is the hemoglobin A1c test which measures glycated hemoglobin in the blood Treatment of type 1 diabetes Immediate treatment of diabetic ketoacidosis Regular administration of insulin by subcutaneous injection Careful control of diet and increase in exercise Treatment of type 2 diabetes cid 127 Weight reduction improved diet exercise cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 Insulin treatment when the glucose falls to between 2 4 mM hypoglycemic stress symptoms of sympathetic overactivity can develop cid 127 Monitoring blood glucose can help improve management If glucose levels are not decreased medication can be added to treatment Drugs to increase insulin sensitivity metformin thiozolidiniodines Drugs to stimulate insulin release sulfonylureas Incretins stimulate insulin release glucagon like peptide 1 and its analogs Sweaty rapid heart rate If the glucose falls below 1 5 mM neuroglycopenia can cause unconsciousness Treated with intravenous glucose or subcutaneous glucagon Long term complications of diabetes mellitus High levels of circulating glucose result in glycation of proteins can be measured with HbA1c cid 127 Glycation of endothelial proteins results in large and small vessel vascular disease cid 127 Microvascular complications The kidneys retina and nerves depend on microvascular blood vessels Damage can cause nephropathy that leads to the need for dialysis If the vasa nervorum become occluded neuropathy can occur cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127 cid 127