1 Renal medicine overview Flashcards
Key learning points
- difference between acute and chronic renal failure
- options for a patient with end stage renal disease
- lifestyle changes needed to live with end stage renal disease and renal replacement
- effects of renal disease on prescribing medication in dentistry
what does polyuria mean
urinate more than normal
what does dysuria mean
pain when passing urine
what does haematuria mean
blood in urine
what does proteinuria mean
protein in urine
what does uraemia mean
waste products not being excreted
How can you measure urine function?
- serum urea levels
- serum creatinine levels
- 24hr urine collection, creatinine clearance (best measure)
why is it better to measure creatinine levels rather than urea levels
urea levels can rise with dehydration
In what ways can renal failure occur
- loss of renal excretory function
- loss of water and electrolyte balance
- loss of acid base balance
- loss of renal endocrine function (erythropoietin, calcium metabolism, renin secretion)
What is the onset of acute renal failure like
- rapid loss of renal function
- usually over hours or days
what is the onset of chronic renal failure like
- gradual loss of renal function
- usually over many years
what are the causes of pre-renal failure
Sudden and severe drop in blood pressure (shock) or interruption of blood flow to the kidneys from severe injury or illness
hypoperfusion of the kidney
- shock
- renal artery or aorta disease
what are the causes of intrarenal failure
Direct damage to the kidneys by inflammation, toxins, drugs, infection, or reduced blood supply
- chronic disease
- drug damage
- trauma
- Rhabdomyolysis
what are the causes of post renal failure
Sudden obstruction of urine flow due to enlarged prostate, kidney stones, bladder tumour or injury
- renal outflow obstruction
What are signs of acute renal function
- rapid loss of renal function
- creatinine >200µmol/L
- no urine initially with volume overload (oedema in ankles, sacral and pulmonary, breathlessness, raised JVP, weight gain)
- gradually progresses to polyuria - development of Hyperkalaemia (high K+)
- can lead to cardiac arrest - development of uraemia and acidosis
- high urea
- low bicarbonate
- increased respiratory excretion of CO2
what usually causes acute renal failure
a pre-renal cause
what’s the prognosis for acute renal failure
usually reversible with time
how is acute renal failure treated
renal support until recover
- dialysis
- nutrition
what are the most common causes of chronic renal failure (primary and secondary causes)
Primary
- glomerulonephritis
- polycystic kidney disease
Secondary
- diabetes
- hypertension
- drug therapy
- vasculitis
- renal artery disease/ aorta disease
What is glomerulonephritis
- glomerulus is inflammed so blood, protein and cells can leak into urine in an other wise healthy individual
- won’t be producing renin angiotensin properly
- lead to blood pressure problems
how can you get nephrotic syndrome
complication of glomerulonephritis
what are the signs of nephrotic syndrome
- excessive loss of protein in the urine (3g in 24hrs)
- loss of plasma oncotic pressure
- tissue swelling (oedema)
- hypercoagulable state (loss of clotting factors)
what drugs shouldn’t be given to people with renal disease and why
NSAIDs
- inhibit glomerular blood flow
- cause interstitial nephritis as prostaglandins are inhibited by NSAIDs so will make renal disease worse
What causes renal vascular disease
- reduced blood flow to the kidney
- atheroma of renal artery/aorta
- hypertension (narrowing of renal artery) - microangiopathy
- immune reaction causing small blood vessel damage, RBC damage and thrombosis
