Renal Flashcards
If taking a history from someone with known CKD, what symptoms should you enquire about? (6)
- Breathlessness
- Weight loss
- Fatigue
- Swollen ankles
- Change in urinary frequency
- Pruritis
What are the causes of AKI?
Pre-renal - sepsis, dehydration
Renal - progression of pre-renal with acute tubular necrosis, glomerulonephritis, nephrotoxic drugs
Post-renal - obstruction
According to NICE, how is AKI defined?
Rise in creatinine from baseline of >50% in 7 days OR Rise by 26mmol OR Oliguria <0.5ml/kg/hour
What are the common nephrotoxic drugs? (4)
- NSAIDs
- ACE inhibitors
- Diuretics
- Aminoglycosides
Which drugs do you want to stop if someone has an AKI? (DAMN)
- Diuretics
- ACE inhibitors/ARBs
- Metformin
- NSAIDs
What are the indications for dialysis in AKI? (AEIOU)
Acidosis pH <7.1 Electrolytes - hyperkalaemia Intoxications - lithium Overloaded with fluid Uraemic symptoms e.g. encephalopathy
What is CKD?
A chronic irreversible deterioration in renal function
What are the causes of CKD - using the mnemonic HIDDEN?
H - hypertension
I - infection
D - diabetes
D - drugs
E - exotica e.g. SLE and other vasculitis
N - nephritis, especially glomerulonephritis
What are the indications for dialysis in CKD?
- Progressive decline in renal function e.g. end stage with eGFR <15ml/min
- Symptomatic ureamia despite conservative treatment
- Volume overload despite fluid restriction and diuretics
- Other indications e.g. pericarditis, bone disease, hyperkalaemia despite treatment
What is the best method of access for renal replacement therapy?
An AV fistula
What is a fistula?
An abnormal connection between two epithelial surfaces
How long does it take for an AV fistula to form and be used for dialysis?
6 weeks
Which arteries/veins are commonly used for AV fistula?
Radial artery to cephalic vein
OR
Ulnar artery to basilic vein
(or a brachiocephalic fistula at elbow)
What is steal syndrome?
This is when an AV fistula leads to distal tissue ischaemia
What are the complications of a fistula? (4)
- Infection
- Stenosis
- Thrombosis
- Bleeding
How is the artery connected to the vein in an AV fistula?
Usually a side-to-end anastamosis with ligation of the distal vein
What are the alternatives to an AV fistula?
Continuous ambulatory peritoneal dialysis
How is continuous ambulatory peritoneal dialysis done, what are the positives/negatives?
Tenckhoff catheter in the abdomen
Positives: Less expensive than haemodialysis and more convenient, with a relatively easy to teach technique
Negatives: many have to stop due to peritonitis and fibrosis may reduce permeability of the peritoneal membrane
How will peritoneal dialysis peritonitis present?
Abdominal pain +/- fever - normally exit site infection will mean taking swabs and/or blood cultures.
There may be a cloudy effluent - patients are often told to look and save the first cloud bag for culture.
What are the gram positive organisms known to cause peritoneal dialysis peritonitis, and how are they treated?
Staph or strep or MRSA - treated with intrapertioneal vancomycin
If the organism to cause peritoneal dialysis peritonitis is gram negative or pseudomonas, what is the treatment?
IV ciprofloxacin
What are the symptoms associated with CKD? (5)
- Low energy (renal anaemia, solute retention (cerebral depressant), psychosocial e.g. loss of employment)
- Breathless - anaemia, fluid overload, heart failure
- Itching - hyperphosphataemia
- Bone pain or gout - high uric acid levels
- Tingling or numb peripheries - peripheral neuropathy
The mnemonic BIG BEAN is used for the features of CKD, what are they?
B - breathlessness I - itching G - gout B - bone pain E - energy levels low A - anaemia/ankle swelling N - neuropathy
What are the bone diseases associated with CKD?
- Osteoporosis
- Hyperparathyroidism
- Osteomalacia
- Osteosclerosis
Why does CKD lead to bone disease?
Renal damage –> reduced activation of vitamin D and phosphate retention –> reduced calcium absorption from the gut –> hypocalcaemia –> increased PTH –> activation of osteoclasts and osteoblasts –> subperiosteal bone resoprtion, pepperpot skull, increased bone matrix, sclerotic ‘rugger jersey spine’
What is seen on renal bone disease? (4)
- Often asymptomatic
- Low back pain/vertebral crush fractures
- Brachydactyly (short stubby fingers)
- Osteolysis of terminal phalangeal tuft (acronecrosis)
What is the name of the catheter used in ambulatory dialysis?
Tenckhoff catheter
How does the tenckhoff cathter work?
The peritoneum is used as a semi-permeable membrane - it involves instilling 3 litres of fluid, four times a day, with half hour exchanges. Water is removed via an osmotic gradient by including some bags of hypertonic fluid - with a high glucose or polymer concentration
What is the main cause of nephrotic syndrome in children and what is the first line treatment?
Minimal change disease - it is almost always steroid-responsive
What are the causes of nephrotic syndrome in adults?
- Glomerulosclerosis - especially seen in diabetes
- Membranous glomerulonephritis - usually idiopathic but can be caused by:
- malignancy
- infections e.g. malaria, hep B
- Lupus
- drugs e.g. penicillamine and gold - Amyloidosis
What is the treatment for nephrotic syndrome? (5)
- Treat oedema with diuretics and salt restriction
- Minimal change - steroids +/- cyclophosphamide
- ACE inhibitors to reduce protein excretion - by lowering glomerular filtration pressure
- Anticoagulation
- Statins
What happens in the kidneys in nephrotic syndrome?
All the causes e.g. minimal change disease and glomerulonephritis cause the basement membrane pores to increase in size and number. This leads to loss of proteins as they leak through and you get frothy urine, oedema, thrombotic tendency (due to loss of antithrombin, increase in lipid synthesis and high platelet count)
What are the signs acute nephritic syndrome - abnormal HOST response?
H - hypertension
O - oliguria
S - smoking brown haematuria with red cell casts
T - trace of oedema
What are the causes of acute nephritic syndrome? (3)
- Post streptococcal
- IgA nephropathy (commonest glomerulonephritis)
- Vasculitis e.g. lupus
What investigations are done for nephritic syndrome? (3)
- Throat swab
- ASO titre
- 24 hour urinary protein
What is the treatment for nephritic syndrome?
- Penicillin if streptococci present
- Salt restriction
- Anti-hypertensive medication
How can glomerulonephritis be classified?
Proliferative vs. non-proliferative
What are the non-proliferative glomerulonephritis conditions and what do they generally cause?
Non-proliferative = nephrotic syndrome
- minimal change disease
- membranous
- focal segmental sclerosis
What are the proliferative glomerulonephritis conditons?
- IgA
- Mesangial
- Crescentic (PAN?)
- Diffuse proliferative
The proliferative glomerulonephritis can cause what conditions? (3)
- Acute nephritic syndrome
- Recurrent haematuria
- AKI
What are the causes of raised urea? (6)
- Renal failure
- Dehydration
- Heart failure
- Diuretic use
- High protein diets (breakdown product of protein)
- Upper GI bleed
What can cause low urea levels? (2)
- Liver disease
2. Over-hydration
Why are creatinine levels alone a poor marker of renal function?
Creatinine is a breakdown product of creatine - from skeletal muscle, and plasma levels vary hugely according to muscle mass. Elderly people with CKD will have high levels but so will young athletes. Because creatinine is excreted by the kidneys, levels do rise in renal failure, but they do so relatively late in the course of progressive renal disease, so they are a poor marker.
What does creatinine clearance refer to?
Clearance means the amount of blood that could be completely cleared of a substance in a minute. If a substance is filtered at the glomerulus and neither secreted nor absorbed at the renal tubules, its clearance will be a good measure of glomerular filtration rate (GFR). Creatinine clearance is used as a measure of glomerular filtration rate.
