Renal Flashcards
About how much is GFR
120 ml/min/1.73m2
What is creatinine?
Chemical waste product from muscle metabolism
What can cause a misleadign creatinine level ?
Extreme muscle mass e.g. cachexia/body builder = misleading
Why is creatinine clearance > GfR
Secreted as well as filtered
[Therefore inhibitors of secretion will make Cr rise and function look worse e.g. trimethoprim]
3 hormones in Na excretion and therefore volume control
Aldosterone (adrenal) -> decreased excretion
Angiotensin II -> decreased excretion
ANP - released by heart in response to high pressure -> increases excretion
In kidney which hormone dilates afferent arteriole? constricts?
Prostaglandin
Angiotensin II
[angi is a bit constrictive - the bitch]
Name 2 SEs od ACEi
May impair renal function: decrease GFR (avoid NSAIDs), hyperkalaemia (avoid K+ spare diuretics)
Postural hypotension
Bradykinin mediated dry cough
Fatigue
Name an ARB and 2 SEs
Losartan
Renal impairment
Postural hypotension
Hyperkalaemia
Name 1 med causing hypo K and 1 causing hyper K
Hypokalaemia meds
Loop diuretics, thiazide diuretics
Hyperkalaemia meds
Spironolactone, amiloride, ACEI, ARB
Key transporter in loop of henle
NKCC2:
Na K Cl Cotransporter (energy dependent)
Where do ADH and aldosterone take effect on?
Distal convoluted tubule and collecting duct
Barter’s syndrome .. same as?
When?
2 features
Effect of loop diuretics
Children
Metabolic alkalosis
Low Mg
High urinary Ca
[C’s - Children, [loop=Circle], high Ca]
Gitelmans syndrom same as?
age?
2 features?
same effect as Thiazide diuretic (Distal convoluted tubule)
Late childhood
Mg decreased, urine calcium normal/low,
Metabolic alkalosis
What does renal tubular acidosis result in?
Hyperchloraemic metabolic acidosis
+ hypobicarbonataemia + decreased arterial pH
+ normal anion gap
2 Most common cause of renal tubular acidosis
fanconi syndrome
drug induced
What happens in fanconi syndrome
Generalised dysfunction of renal proximal tubule ->
urinary loss of bicarb, [glucose, aa, phosphate, peptides, organic acids. ]
Leads to salt wasting and volume depletion
Name 2 Rfs for RTA
Childhood, urinary tract obstruction, DM, [stones, adrenal insufficiency]
Name 3 ways RTA could present?
Growth retardation/failure to thrive (children)
Muscle weakness (Fanconi)
Hypoglycaemia after fructose
Rickets (Fanconi and Type 2 proximal have persistent phosphate loss)
Kussmaul breathing if severe
2 key findings from Ix in RTA? name another one
Low serum bicarbonate
serum anion gap normal (12-18)
[high serum chloride, variable potassium, arterial pH low, ]
Mx of RTA
if Hyperkalaemia + mineralocorticoid deficiency?
Sodium alkali
Fludrocortisone + dietary restriction of potassium
Mx of Hyperkalaemia + mineralocorticoid deficiency
in RTA
Fludrocortisone + dietary restriction of potassium
Name 2 comps of RTA
volume depetion (due to loss of Na)
Nephrocalcinosis - due to bone buffering of acidosis
Osteoperosis - due to bone buffering of acidosis
Grow retardation - acidosis -> muscle catabolism
Renal rickets - in fanconi
2 Causes of end stage renal failure
Glomerulonephritis
Pyelonephritis
Diabetes
PKD
Usual cause and bugs for pyelonephritis
Escherichia coli, UPEC
[diabetes/HIV/malignancy/transplant - think candida/klebsiella]
ascending from lower urinary tract or spread hematogenously to kidney
Name 3 RFs for severe pyelonephritis
Extremes of age
anatomical abnormality
foreign body
Immunocmpromised
obstruction
pregnant
Cause of pyelonephritis only found in men
prostatitis and BPH cause urethral blockage -> bacteriuria -> pyelonephritis
Triad of presentation in pyelonephritis
Loin pain
Fever - may not be the case if patient is on steroids or anti-inflammatory
Renal tenderness/costovertebral angle
Name 3 Ix in pyelonephritis
Imaging
- Renal USS:
- Contrast CT
Urine dip:
Urinalysis (microscopy) WBC
Gram stain:
Urine culture:
FBC: leukocytosis
ESR/CRP raised
Blood culture (systemic infection SEPSIS)
Seen on gram stain in pyelonephritis
G -ve rods (e.coli, klebsiella, proteus)
Mx of mild.mod pyelonephritis ?
Severe/comp/pregnant?
Ciprofloxacin PO BD
Severe: Admit to hospital IV ceftriaxone / cipro/gent IV fluids IV paracetamol Catheterisation if compromised
Name 2 comps of pyelo
Renal failure, abscess formation, parenchymal renal scarring, recurrent UTIs
2 main types of renal cell carcinoma
80% clear cell/adeno renal carcinoma
15% papillary tumour
3 RCC RFs
smoking, obesity and hypertension
Occupational exposure to some chemicals such as asbestos, cadmium, lead, chlorinated solvents, petrochemicals
VHL
Usual pres of RCC
asymptomatic and diagnosed incidentally
3 key are:
abdo mass + haematuria + loin pain
Which genetic cause increases risk of RCC
Von hippel lindau
AD
Principles of Ix in RCC…Name 3?
Check kidney function
Check for structure
Check for metastasis
=
Percutaneous renal biopsy
*FBC - polycythaemia (EPO)
LDH - raised is poor prognosis
Corrected calcium - >2.5 mmol/l poor prognosis
LFT - raised AST/ALT = metastatic disease
*Cr - elevated with reduced clearance
Urinalysis - haematuria and/or proteinuria
- Abdominal/pelvis USS - cyst, mass, mets
- CT abdo/pelvis - lymphadenopathy, mass, bone mets inc contralateral kidney
MRI - for local invasion etc
CXR - cannonball metastasis, bone scan, MRI brain/spine
Main comp of RCC? Name 1 other
Paraneoplastic syndrome (30% of patients) - anaemia
[Hypercalcaemia, SIADH]
Mx of RCC?
Surgical
= partial / laparoscopic nephrectomy
What could you use in late stage RCC
tyrosine kinase inhibitor = first line e.g. SUNITINIB
Childhood renal tumour
Wilm’s tumour -> nephroblastoma
What is AKI
An acute decline in *GFR from baseline/increase in creatinine with or without oliguria
Name 4 causes of AKI
Pre-renal (50%)
Azotaemia
Renovascular disease
Intrarenal 30% Acute tubular necrosis (mainly due to sepsis = most common) *Rapidly progressive glomerulonephritis *Interstitial nephritis Vascular disease
Post renal 20%
Mechanical obstruction to urinary tract
Retroperitoneal fibrosis, lymphoma, tumour, prostate hyperplasia, renal calculi, urinary retention, pyelonephritis