Renal Flashcards
What are the functions of the kidneys?
Endocrine release - epo, renin, prostaglandins
Removal of waste products - urea, drugs
Metabolism - proteins, vit D
Fluid regulation
What are the 3U’s that must always be remembered in investigation for renal disease?
U&E, urinalysis, USS
How is proteinuria measured?
Albumin:creatinine ratio (<2.5 men, <3.5 women)
24 hr collection albumin
If they have proteinuria do culture of urine
What is the main cause of haematuria? What are some other causes?
- Glomerular disease (>1g)
- Transient causes - orthostatic, exercise, fever (<1g)
- Tubulointerstitial disease (<1g)
- Upper/lower UTI (<1g)
- Diabetes (30-300mg)
- Minimal change disease (30-300mg)
In terms of proteinuria, what are the indications for biopsy?
Persisent (>3g) or alongside haematuria
How much blood is usually lost in the urine?
<1uL/day
What is the main cause of proteinuria? What are some other causes?
- Glomerular disease (IgA nephropathy, thin basement membrane disease)
- Transient causes (UTI, exercise, menstruation)
- Neoplasia (painless, bladder/renal)
- Drugs
Which drugs may cause haematuria?
Cephalosporins
Ciprofloxacin
Furosemide
NSAIDS
What is the 2WW criteria for haematuria?
Visible >45 yers
Non-visible >60yrs
Do renal USS and cystography
What are the normal values for glucose in the urine?
0-0.8mmol/L
What causes glycosuria?
DM
Pregnancy
Sepsis
Renal tubular damage
What causes nitrites/leucocytes in the urine?
UTI, high protein meal
What causes ketones in the urine?
Starvation, ketoacidosis
What does urine microscopy look for? What do they show?
CASTS
white cell casts - UTI, acute interstitial nephritis
red cell casts - glomerular bleeding, vasculitis, nephritis
epithelial casts - acute tubular necrosis
What factors influence creatinine levels?
Muscle mass
Muscle catabolism
Liver function
What causes high creatinine levels?
- Kidney dysfunction
- Hypertension
- Drugs (statins)
- Rhabdomyolysis
- Large muscle mass
What are the problems associated with measuring creatinine levels?
- Muscle mass
- Log relationship to GFR ( as GFR decreases lots, creatinine only increases a little)
- Tubular and gut secretion
- Variability of assay
How is eGFR calculated?
Takes into account creatinine, age, gender and ethnicity
What is the definition of AKI?
A rapid reduction in kidney function over hours to days, as measured by serum urea and creatinine and leading to a failure to maintain fluid, electrolyte and acid-base homeostasis
How is AKI diagnosed?
- Rise in creatinine >26umol/L in 48hours
- Rise in creatinine >1.5 x the baseline
- Urine output <0.5ml/kg/h for 6 consecutive hours
1st line investigations - U&Es and creatinine
What are the symptoms of AKI?
Urinary - dysuria, oliguria, anuria, haematuria,
Systemic - fever, vomiting, myalgia, diarrhoea
Kidney dysfunction - oedema, bruising
What are the risk factors for AKI?
- Age>75
- CKD
- Cardiac failure
- Sepsis/infection
- PVD
- Chronic liver disease
- Diabetes
- Drugs
- Poor fluid intake
Which investigations results would raise your index of suspicion for AKI secondary to CKD?
- Small kidneys
- Anaemia
- Low calcium
- High phosphate
- Previous bloods
What investigations should be done in AKI?
BEDSIDE - urinalysis, BP, ECG
BLOODS - FBC, U&E, CRP, LFTs, bone profile, CK, clotting, ESR, cultures, immunoglobulins, complement, autoantibodies
IMAGING - renal USS, CXR
SPECIAL - kidney biopsy