Lecture 14 Diabetes Mellitus Flashcards
What are the two types of diabetes mellitus?
Deficiency of insulin & insulin resistance
Define diabetes inspidus
deficiency of antidiuretic hormone
Where are peptide hormones produced?
Beta cells of islets of langerhans (pancreas)
Where does glucagon bind to?
Cell membrane receptors
What requires insulin to absorb glucose?
skeletal muscle cells and fat cells
What do not require insulin to absorb glucose?
Neurons
What does insulin do?
Makes cell uptake glucose and amino acids. ^glycogen and fatty acid synthesis. Decreases lipolysis, proteinolysis and gluconeogenesis.
Where is insulin released from?
B-cells
How is insulin release controlled?
direct feedback. Some autonomic control and CCK releases it. B-cells absorb glucose via glucose transporter GLUT2.
What are the acute consequences of insulin deficiency?
Hyperglycaemia, ketosis, acidosis, hyperosmolar state.
What are the chronic consequences of insulin deficiency?
CV disease, nephropathy, neuropathy, retinopathy
What is type 1 diabetes mellitus?
Autoimmune destruction of B-cells
What can trigger Type 1?
Viral infections (coxsackie or rubella viruses). Gene (HLA) subtype suseptibility. Childhood.
Symptoms of type 1?
Polyuria, polydipsia, hunger, weight loss.
Where (in normal glomerulus filtration) is glucose resorbed?
proximal renal tubule
What is the threshold for resorption of glucose for glomerulus?
10mmol/l
Polyuria->
glycosuria -> osmotic polyuria
Define polydipsia
Very thirsty
How is someone biochemically diagnosed with DM?
Fasting plasma glucose at or above 7.0mmol/l. 11.1mmol/l two hrs after 75g glucose of random test 11.1
What are the acute presentations of diabetes mellitus?
Ketoacidosis, hyperosmolar nonketotic stat, hypoglycaemia, diabetic foot
What is ketoacidosis?
Rapid break down of fat and protein releasing ketones and acid into blood. In DM type 1
What is hyperosmolar nonketotic state?
Severe dehydration in DM type 2
What are the chronic presentations of DM?
Macrovascular and Microvascular diseases
What is retinopathy?
Proliferation of blood vessels in retina, retinal haemorrhages.
Examples of macrovascular diseases?
Ischaemic heart disease, stroke, peripheral vascular disease. (effect coronary arteries, aorta, brain and limb arteries)
Examples of microvascular diseases?
Retinopathy, diabetic neuropathy, nephropathy
Notes on neuropathy?
Microangiopathy of vasa nervosum -> peripheral numbness/tingling, neuropathyic pain, weakness.
Effects of autonomic neuropathy
Vomiting, diarrhoea, constipation, impotence, incontinence, anorgasmia, postural hypotension
Define vasa nervosum
Small arteries that provide blood supply to peripheral nerves
How can someone gain nephropthy?
Microangiopathy of glomerular capillaries.
Pathology of nephropathy?
Nodular and diffuse glomerulosclerosis
Clinical effects of nephropathy?
Chronic renal failure (nephrotic syndrome); hypertension
What is type 2 DM?
Noninsulin dependent, Peripheral insulin resistance, B-cell response to glucose delayed or absent.
What is gestational DM?
diabetes triggered by pregnancy (hormonal changes)
What are the risk factors for gestational diabetes?
Maternal age, fam history of type 2, African/North American, previous babe over 4Kg. Smoking.
What are the dangers to mother of gastational diabetes?
^ risk of DM type 2 later in life, hypertension, pre-eclamsia/clampsia (one of more convulsions. Obstructed labour.
Dangers of gastational diabetes for child?
Risk of DM type 2 later in life, obesity, macrosomia, neonatal hypoglycaemia, jaundice, respiratory distress syndrome.
What is macrosomia?
Excessive child growth in uterus
What are the causes for secondary DM?
Chronic pancreatitis, CF, pancreatic surgery, endocrine disease (cushing’s syndrome), Corticosteroids.
What is haemachromatosis?
Hereditary disorder where iron salts are deposited in tissue -> liver damage/DM
Infections more likely with DM. Give top two examples
Osteomyelitis (inflam of bone or bone marrow) and septicaemia.
