Endocrine Flashcards
Where are glucagon and insulin produced?
In the islets of langerhans at the pancreas. Alpha cella = glucagon, beta cells = insulin
What does glucagon do?
Stimulates glycogenolysis and gluconeogenesis to increase blood glucose.
What does insulin do?
Stimulates glucose uptake via GLUT 4 and suppresses lipolysis to reduce blood glucose.
What are the limits for diabetes diagnosis?
Symptoms & random plasma glucose (OGTT) >11mmol/l
Symptoms & fasting plasma glucose >7mmol/l
HbA1c greater than or equal to 48mmol/mol
What are the levels of hypoglycaemia?
Level 1 = glucose <3.9mmol/l
Level 2 = glucose <3.0mmol/l
Mild = self-treated, Severe = requires help to treat
What are the autonomic symptoms of hypoglycaemia and when do they occur?
Trembling, palpatations, sweating, anxiety and hunger. These occur when glucose levels drop below 3.5mmol/l, the body will release adrenaline to get stored glucose into the blood stream more rapidly.
What are the neuroglycpenic symptoms of hypoglycaemia and when do they occur?
Difficulty concentrating, confusion, weakness, drowsiness, dizziness, vision changes, difficulty speaking. These occur once glucose levels drops below 3.2mmol/l.
What are the two main types of insulin?
Basal insulin = keeps glucose at a constant level when not eating.
Prandial insulin = acts rapidly to reduce glucose levels after eating
S&S of T1DM?
unquenchable thirst, polyuria, weight loss and fatigue, hunger, pruitis valvae and blantitis, blurred vision
What is T1DM?
Autoimmune destruction of the beta cells in the pancreas leading to no insulin being produced by the body.
What is DKA?
Diabetic Ketoacidosis = hyperglycaemia with raised plasma ketones and metabolic acidosis. Lack of insulin in the body means that cells must get energy from other sources, fat breakdown begins (insulin prevents this normally) to produce glycerol and free fatty acids. FFAs are oxidised in the liver to form ketone bodies.
S&S of DKA?
Hyperventilation, polyuria (leads to dehydration and hypotension), tachycardia, hyperkalaemia, nausea, weight loss, weakness, drowsiness, confusion and coma
Management of DKA?
Rehydration, insulin treatment, replace electrolytes (particularly potassium - levels are already low and fluid further decrease concentration, if not corrected = cardiac arrest), treat underlying cause.
Name 3 complications of DKA?
Over-rehydration = cerebral oedema in children, respiratory distress syndrome in adults.
Extreme dehydration = thromboembolism
Comatosed patients = aspiration pneumonia
Risk factors for T2DM?
Obesity, hypertension, >40 (if white) or >25 (if Afro-carribean, black african or south asian), sedentary life style, polycystic ovary syndrome
S&S of T2DM?
Polyuria (leading to dry mouth, headaches and polydypsia), hunger, weight loss/fatigue, blurred vision. DKA will NOT occur.
What is T2DM?
Impaired insulin secretion and insulin resistance leading to hyperglycaemia
How is T2DM treated?
Initially with weight loss, exercise and blood pressure control (these can reverse the diabetes). Initial medical treatment is metformin (or sulphonylurea) but if the disease progresses insulin must be given.
What is MODY?
Maturity Onset Diabetes of the Young. It is autosomal dominant and non-insulin dependant disease (insulin production is disturbed by genetic mutations)
What are the 3 types of MODY?
HNF1A mutation = MODY 3 (requires sulphonylurea)
HNF4A mutation = MODY 1 (requires suphonylurea)
GCK mutation = MODY 2 (the set point for insulin release is higher - can be modified with lifestyle changes)
Give an acute and a chronic cause of inflammatory diabetes?
Acute = transient hyperglycaemia e.g. due to pancreatic shock in acute alcohol poisoning
Chronic = chronic pancreatitis in alcoholics
Hereditary haemochromotosis can also lead to diabetes.
S&S of hyperosmolar hyperglycaemic state?
Hyperglycaemia, hyperosmolality, severe dehydration, decreased conscioussness, stupor/coma. NO KETONE BODY PRODUCTION.
Treatment for hyperosmolar hyperglycaemic state?
Insulin (small dose as these patients are EXTREMELY sensitive to insulin), fluid replacement, LMW heparin e.g. enoxaparin, restore electrolytle levels (especially K+).
Name a macrovascular complication of DM?
Atherosclerosis. This will lead to increased risk of MI/PVD/stroke.
Name the microvascular complications of DM?
Diabetic retinopathy, diabetic nephropathy, diabetic neuropathy, diabetic foot ulceration.
S&S of diabetic neuropathy?
Allodynia, paraesthesia, burning pain (worse at night), postural hypotension, glove and stocking sensory loss.. These patietns are at risk of diabetic foot ulceration.
Why does diabetes increase infection risk?
Poorly controlled DM impaires the function of polymorphonuclear leucocytes = increased infections such as UTIs and skin infections
What is lipohypertrophy?
Lumps of fat which accumulate at areas where insulin is frequently injected - avoid by altering injection sites daily
What are the two types of diabetes insipidus? Name a cause of each?
Cranial = lack of vasopressin - e.g. neurosarcoidosis Nephrogenic = resistance to vasopressin - e.g. reduction in medullary concentration due to chronic renal imapirment
S&S of Diabetes Insipidus?
Polyuria (>3L/day), polydypsia, dry skin, colourless urine, constipation, NO GLUCOSURIA
How can you tell between CDI/NDI and how do you treat?
Water deprivation test - when desmopressin is given if urine concentration increases = CDI, if it does not increase = NDI.
Treat CDI with desmopressin, NDI is hard to treat so avoid precipitating drugs and ensure patient has water access
What are the different types of hyponatraemia?
Hypovolaemic = low circulating volume (e.g. after severe diarrhoea) Euvolaemic = normal circulating volume Hypervolaemic = high circulating volume (e.g. after heart failure, liver cirrhosis and inaprropriate IV giving)
S&S of hyponatraemia?
Headaches, nausea, irritability/confusion and unstable gait.
In acute/severe patients there may also be convulsions, respiratory arrest and coma - chronic is often mild or asymptomatic.
Acute <48hrs, chronic >48hrs
What are the serum sodium concentrations for the severity of hyonatraemia?
Mild = 130-135nmol/l Moderate = 125-129nmol/l Severe = <125nmol/l
Where is vasopressin made?
Paraventricular and supraoptic nerves in the hypothalamus. Stimulated by osmoreceptors (and in emergency baroreceptors in the brain)
What are the 3 types of vasopressin and what do they stimulate?
V1a = vasculature to cause vasoconstriction V1b = pituitary gland to cause ACTH release V2 = renal collecting ducts to stimulate water reabsorption
What is SIADH? and what causes it?
Syndrome of Inappropriate ADH secretion, caused by CNS disorders e.g. meningoencephalitis, prescription drugs e.g. opiodis , ADH secreting tumours e.g. SC lung cancer and lung diseases e.g. TB
S&S of SIADH?
Hyponatraemia - this causes most of teh symptoms (e.g. confusion, headaches, nausea, coma etc.), cramps, depression, dark low volume urine
How do you treat chronic SIADH?
Veptans (V2 antagonists) and sodium saline (increase sodium slowly to prevent death of neural tissue)
What is De Quervain’s Thyroiditis? How do you treat?
Hyperthyroidism due to the acute inflammation of the thyroid gland - treat with aspirin
S&S of Grave’s disease?
Periorbital oedema, proptosis of the eyes, diploplia, peritibial myexedema, acropachy, goitre, heat sensitivity, weight loss