Polyuria Flashcards
Causes of polyuria
Diabetes Diuretics Heart failure Hyperthyroidism Hypercalcaemia Diabetes insipidus (either type) can be induced by renal failure
Features of diabetes
Weight loss
Fatigue
Polyuria/polydipsia
Recurrent infection
Lower urinary tract symptoms
Terminal dribbling Hesitancy Frequency Incomplete voiding Urgency
Low urine osmolality implies…
Unable to concentrate
Either drinking loads or unable to get the water back (diabetes insipidus)
High urine osmolality with high volume implies…
Diabetes (glucose staying in the urine and bring fluid out with it)
Serum osmolality low, urine osmolality low
Primary polydipsia
In diabetes insipidus what are you unable to do?
Retain water from the collecting ducts
Can’t concentrate urine
EIther cranial (no vasopressin) or nephrogenic (doesn’t respond to vasopressin)
Causes of cranial diabetes insipidus
Trauma Pituitary tumours Metastases Surgery Meningitis
Causes of nephrogenic diabetes insipidus
Follows renal damage (hypokalaemia, drugs, pyelonephritis)
Also hypercalcaemia
Which test do you do to determine if cranial or nephrogenic?
Water deprivation test
Give desmopressin and see if it concentrates their urine! (means it was cranial, because they didn’t have any vasopressin)
Medication for diabetes insipidus
Desmopressin
Medication for nephrogenic diabetes insipidus
Thiazide diuretic
Pathology of type 1 diabetes
Reduction in production of insulin due to reduction in pancreatic beta cells
Antibodies in T1DM
Anti GAD autoantibodies
Diagnostic criteria fo diabetes
Fasting BM >7
Plasma glucose >11.1 2hr after 75g of glucose
What should Type 1 diabetics do when they are ill?
Increase insulin dose, because the corticosteroid desensitises a bit from the insulin
Make sure to keep a close eye on capillary glucose
What investigations do you need with calcium?
PTH
Phosphate
ALP
CRAB Sx from which pathology?
Multiple myeloma
Hyponatraemia and excess drinking
Psychogenic polydipsia
Long term complications of diabetes
Microvascular
Retinopathy
Neuropathy (usually glove and stocking distribution and autonomic dysfunction)
Nephropathy
Macrovascular
Cardiovascular disease
Peripheral vascular disease
IHD
HHS is…
Hyperosmotic hyperglycaemic state
No ketones in the urine
What can precipitate HHS?
Illness
Poor compliance with treatment (causing glucose to go REALLY HIGH)
Pathology of HHS
Blood filled with glucose (hyperglycaemia), very thick
Where is vasopressin produced?
Posterior pituitary
What stimulates vasopressin release?
Rise in sodium concentration (you are becoming dehydrated)
What do gliptins do?
Inhibit DPP4, an incretin, which normally stimulates insulin release
What do sulphonylureas do?
Stimulate insulin release
What does metformin do?
Reduces glucose production from liver and stimulates glucose uptake from the blood (sensitises insulin)
What does acarbose do?
Reduce food breakdown, slows down glucose release after meals
Side effect of acarbose
Flatulence
Whats the big risk of HHS?
Thrombotic events
What do you need to give in HHS?
Fluid
Anti-coagulation
