Renal Flashcards
what are the nice criteria for AKI?
Rise in creatinine of ≥ 25 micromol/L in 48 hours
Rise in creatinine of ≥ 50% in 7 days
Urine output of < 0.5ml/kg/hour for > 6 hours
what are the risk factors for AKI?
- CKD
- HF
- DM
- Liver disease
- > 65
- cognitive impairment
- nephrotoxic meds - NSAID, ACEi
- contrast during CT scans
what are the causes of renal impairment?
- pre renal
- renal
- post renal
what are the pre renal causes of AKI?
inadequate blood supply to kidneys -
dehydration
hypotension
HF
what are the renal causes of AKI?
reduced filtration of blood -
ATN
interstitial nephritis
glomerulonephritis
what are the post renal causes of AKI?
obstruction of outflow of urine…backpressure and reduced kidney function -
kidney stones
masses in abdomen and pelvis
ureter or urethral strictures
BPH or prostate cancer
how do we investigate AKI?
urinalysis:
bloods, protein - acute nephritis/infection
leucocytes, nitrites - infection
glcuose - diabetes
how is post renal aki diagnosed?
USS of KUB - obstruction
how is AKI managed?
- fluid resus - pre renal
- stop nephrotoxic drugs - renal
- relieve obstruction, ie catheter - post renal
if severe - renal specialist +/- dialysis
what are the complications of AKI?
Hyperkalaemia
Fluid overload, heart failure and pulmonary oedema
Metabolic acidosis
Uraemia (high urea) can lead to encephalopathy or pericarditis
define CKD
chronic reduction in kidney function
what are the causes of CKD?
- DM
- HTN
- age
- glomerulonephritis
- PCKD
- medications - NSAIDS, PPI, lithium
what are the risk fx for CKD?
Older age
Hypertension
Diabetes
Smoking
Use of medications that affect the kidneys
what are the signs and sx of CKD?
Pruritus (itching)
Loss of appetite
Nausea
Oedema
Muscle cramps
Peripheral neuropathy
Pallor
Hypertension
which investigations are required for CKD?
UandE’s - eGFR , two tests 3 months apart to diagnose CKD
urine albumin:creatinine ratio - >3mg/mmol
urine dipstick - 1+ blood (malignancy)
renal USS
what are the stages of CKD?
G score - eGFR
G1 = eGFR >90
G2 = eGFR 60-89
G3a = eGFR 45-59
G3b = eGFR 30-44
G4 = eGFR 15-29
G5 = eGFR <15 (known as “end-stage renal failure”)
A score - albumin:creatinine ratio
A1 = < 3mg/mmol
A2 = 3 – 30mg/mmol
A3 = > 30mg/mmol
what stage does a patient need to HAVE CKD?
not have if A1 + G1 or G2
require either eGFR<60 or proteinuria
what are the complications of CKD?
Anaemia
Renal bone disease
Cardiovascular disease
Peripheral neuropathy
Dialysis related problems
what are the guidlines for referring to a specialist with CKD?
eGFR < 30
ACR ≥ 70 mg/mmol
Accelerated progression defined as a decrease in eGFR of 15 or 25% or 15 ml/min in 1 year
Uncontrolled hypertension despite ≥ 4 antihypertensives
how is CKD managed?
Slowing the progression of the disease-
Optimise diabetic control
Optimise hypertensive control
Treat glomerulonephritis
Reducing the risk of complications-
Exercise, stop smoking
Special dietary advice about phosphate, sodium, potassium and water intake
Offer atorvastatin 20mg for primary prevention of cardiovascular disease
Treating complications-
Oral sodium bicarbonate to treat metabolic acidosis
Iron supplementation and erythropoietin to treat anaemia
Vitamin D to treat renal bone disease
Dialysis in end stage renal failure
Renal transplant in end stage renal failure
what is the first line drug in treating HTN for CKD?
ACEi
offered to all -
Diabetes plus ACR > 3mg/mmol
Hypertension plus ACR > 30mg/mmol
All patients with ACR > 70mg/mmol
what is the target for blood pressure in pts with HTN?
<140/90 or <130/80 if ACR >70
what is a complication shared by treatment and as a consequence of CKD?
hyperkalamia from CKD and ACEi
why is anaemia is caused by CKD and how can it be treated?
damage kidney cells can not produce EPO - reduced production of RBC’s
treated with exogenous EPO and IV/oral iron (blood transfusions should be limited as they sensitise the immmune system so transplated organs more likely to be rejected)
what are the features of renal bone disease and how dot they appear on x ray of the spine?
osteomalacia - softening of bone - less white in centre
osteoporosis - brittle bones
osteosclerosis - denser white at booth ends
…‘rugger jersey’ spine - stripes
why does CKD cause mineral bone disease?
reduced phosphate excretion
low active vit D as kidney usually metabolises to active form
active vit D is required for calcium absorption from intestines and kidneys and regulates bone turnover
due to reduced serum calcium and high serum phosphate - secondary hyperparathyroidism - this increases osteoclast activity leading to absoption of calcium from bone
Osteomalacia occurs due to increased turnover of bones without adequate calcium supply.
Osteosclerosis occurs when the osteoblasts respond by increasing their activity to match the osteoclasts by creating new tissue in the bone, however due to the low calcium level this new tissue is not properly mineralised.
Osteoporosis can exist alongside the renal bone disease due to other risk factors such as age and use of steroids.
how is mineral bone disease managed?
- active forms of vit D - calcitriol
- low phosphate diet
- bisphosphonates to treat osteoporosis
acute tubular necrosis
urine is very pale even if dehydrated
acei
decreases tubular pressure as decreases BP, so less protein in urine but lower eGFR….helps CKD long term but also potentiates it
what is the biggest consequence of dialysis?
cardiovascular event
when is dialysis considered?
end stage renal failure
any acute indications which continue long term
what are the indications for acute dialysis?
A – Acidosis (severe and not responding to treatment)
E – Electrolyte abnormalities (severe and unresponsive hyperkalaemia)
I – Intoxication (overdose of certain medications)
O – Oedema (severe and unresponsive pulmonary oedema)
U – Uraemia symptoms such as seizures or reduced consciousness
what are the three main options for dialysis when required long term?
continous ambulatory peritoneal dialysis
automated peritoneal dialysis
haemodialysis
how does peritoneal dialysis work?
uses peritoneal membrane as filtration membrane and a dextrose solution is added to the peritoneal cavity. Ultrafiltration occurs from the blood across the membrane and into the solution…the solution is then replaced - so waste products that have been filtered are taken away
- tenckhoff catheter - plastic tube used to insert solution into peritoneal cavity
if continious - eg: 2L changed 4 times a day
or automated - overnight, replaces fluid overnight
what are the complications of peritoneal dialysis?
- bacterial peritonitis - due to glucose solution
- peritoneal sclerosis - thickening and scarring of membrane
- ultrafiltration failure - absorbs the dextrose in the filtration solution so gradient less
- weight gain - absorb carbs from dextrose
- psychosocial
what is a typical regime for haemodialysis?
4 hours 3 days a week
what are the access options for haemodialysis?
tunnelled cuffed catheter (right side below clavicle) - tube into subclavian or jugular vein with a tip that sits in SVA or RA
two lumens - one where blood exits and one where enters
ring called dacron cuff that surrounds catheter - promotes healing and adhesion of tissue to cuff so catheter is more permanent and provided barrier to infection…infection and bloods clots are main complications
AV fistula - artificial connection between artery to a vein, bypasses capillary system and allows blood to flow under high pressure.you create the fistula during surgery and requires 4 weeks-months without use,permanent large easy access blood vessels with high flow - radio cephalic, brachio-cephakic, brachio-basilic
how do you examine an AV fistula?
Skin integrity
Aneurysms
Palpable thrill (a fine vibration felt over the anastomosis)
Stereotypical “machinery murmur” on auscultation
what are the complications of AV fistula?
Aneurysm
Infection
Thrombosis
Stenosis
STEAL syndrome
High output heart failure
define STEAL syndrome
inadequate blood supply to limb distal to AV fistula, the blood is diverted away from where it is supposed to supply and flows to venous system causing distal ischaemia
define high output heart failure
where AV fistula blood is flowing v quickly from arterial to venou system through fistula…rapid return of blood to heart..increasing pre load in heart causing hypertrophy and HF
never….from a fistula
NEVER TAKE BLOOD
what is the examination of the renal system?
- tunnel cuffed catheter scar - right side, below clavicle
- hockey stick scar on abdomen - renal transplant
- peritoneal dialysis scars
- fistula on arms
- palpable implanted kidney in RIF or LIF
how are donors matched for kidney transplants?
based on HLA type A, B, C on chromosome 6…do not have to match and would be immunocompromised to desensitise them to donor HLA if a living donor
how does a kidney transplant work?
- patient’s kidneys left
- donor’s kidney blood vessels are anastomosed with patient’s pelvic vessels…external iliac
- donor’s ureter is anastomosed with patient’s bladder
-donor kidney in anterior of abdomen, palpated in ILIAC area
which drugs are used to immunosuppress the patient?
Tacrolimus - IL 2 inhibition
Mycophenolate mofetil
Prednisolone - not for a long term
what are the complications of a renal transplant?
Transplant rejection (hyperacute, acute and chronic)
Transplant failure
Electrolyte imbalances
what are the complications relating to immunosuppressants?
Ischaemic heart disease
Type 2 diabetes (steroids)
Infections are more likely and more severe
Unusual infections can occur (PCP, CMV, PJP and TB)
Non-Hodgkin lymphoma
Skin cancer (particularly squamous cell carcinoma)
what are the criteria for nephritic syndrome?
Haematuria- microscopic (not visible) or macroscopic (visible).
Oliguria - reduced urine
Proteinuria - there is less than 3g / 24 hours. Any more and it starts being classified as nephrotic syndrome.
Fluid retention
what is the criteria for nephrotic syndrome?
Peripheral oedema
Proteinuria more than 3g / 24 hours
Serum albumin less than 25g / L
Hypercholesterolaemia
define glomerulonephritis
conditions that cause inflammation of or around the glomerulus and nephron
define interstitial nephritis
inflammation of the space between cells and tubules (the interstitium) within the kidney:
acute interstitial nephritis and chronic tubulointerstitial nephritis.
define glomerulosclerosis
scarring of the tissue in the glomerulus. It is not a diagnosis in itself and is more a term used to describe the damage and scarring done by other diagnoses
- can be caused by any type of glomerulonephritis or obstructive uropathy (blockage of urine outflow), and by a specific disease called focal segmental glomerulosclerosis.
what are the specific types of glomerulonephritis?
Minimal change disease
Focal segmental glomerulosclerosis
Membranous glomerulonephritis
IgA nephropathy (AKA mesangioproliferative glomerulonephritis or Berger’s disease)
Post streptococcal glomerulonephritis (AKA diffuse proliferative glomerulonephritis)
Mesangiocapillary glomerulonephritis
Rapidly progressive glomerulonephritis
Goodpasture Syndrome
how are most types of glomerulonephritis treated?
Immunosuppression (e.g. steroids)
Blood pressure control by blocking the renin-angiotensin system (i.e. ACE inhibitors or angiotensin-II receptor blockers)
how might nephrotic syndrome look on examination?
oedema
frothy urine from proteinuria
what does nephrotic syndrome predipose a patient to?
thrombosis, hypertension and high cholesterol.
what is the most common cause of nephrotic syndrome in children?
minimal change disease
- treated with steroids
what is the most common cause of nephrotic syndrome in adults?
focal segmented glomerulosclerosis
what is the aetiology of primary glomerulonephritis?
IgA nephropathy (berger’s disease)
- 20’s
- IgA deposits and mesangial proliferation
what is the aetiology of membranous glomerulonephritis?
Most common type of glomerulonephritis
bimodal peak in age in the 20s and 60s
“IgG and complement deposits on the basement membrane”
usually idiopathic
Can be secondary to malignancy, rheumatoid disorders and drugs (e.g. NSAIDS)
define post strep glomerulonephritis
<30
1-3 weeks after a streptococcal infection (e.g. tonsillitis or impetigo)
They develop a nephritic syndrome
There is usually a full recovery
what is goodpasture’s syndrome and how might a patient present?
antibodies attack glomerulus and pulmonary basement membranes….glomerulonephritis and pulmonary haemorrhage
- AKI + haemopytsis
what is a differential for goodpasture’s syndrome?
granulomatosis with polyangiitis (AKA Wegener’s granulomatosis)
type of vasculitis associated with anti-neutrophil cytoplasmic antibodies (ANCA). Patients with Wegener’s granulomatosis may also have a wheeze, sinusitis and a saddle-shaped nose.
histology shows cresenteric glomerulonephritis, what is the diagnosis?
rapidly progressive glomerulonephritis
- very acutely unwell
- often secondary to goodpastures
what is the most common cause of CKD in Uk?
diabetic nephropathy- chronic high levels of glucose passing through glomerulus causes glomerulosclerosis
how should patients with diabetes be managed with regards to kidney damage?
regular screening for diabetic neuropathy - albumin:creatinine ratio and UE
how is diabetic nepropathy managed?
glucose levels and blood pressure
what is acute interstitial nephritis caused by?
hypersensitivity reaction to drugs (nsaids, abx) or infection
how can patients with acute interstitial nephritis present?
AKI
hypertension
rash
fever
eosinophilia
how is acute interstitial nephritis managed?
treat underlying cause
steroids
how does chronic tubointerstital nephritis present?
CKD
what are the causes of chronic tubointerstitial nephritis?
autoimmune, infectious, iatrogenic and granulomatous disease…treat underlting cause + steroids
what is the most common cause of AKI?
ATN
define ATN
damage and death (necrosis) of the epithelial cells of the renal tubules
is ATN reversible?
epithelial cells have the ability to regenerate making acute tubular necrosis reversible. It usually takes 7-21 days to recover
what are the causes of ATN?
hypoperfusion - Shock, Sepsis, Dehydration
direct damage - Radiology contrast dye, Gentamycin, NSAIDs
…managed the same as AKI
what is found on urinalysis of ATN?
muddy brown casts on histology
what is the aetiology of renal tubular acidosis?
metabolic acidosis due to pathology in the tubules of the kidney. The tubules are responsible for balancing the hydrogen and bicarbonate ions between the blood and urine and maintaining a normal pH
what is type 1 renal tubular acidosis caused by?
pathology in DCT…so unable to excrete H ions
Genetic -both autosomal dominant and recessive forms.
Systemic lupus erythematosus
Sjogren’s syndrome
Primary biliary cirrhosis
Hyperthyroidism
Sickle cell anaemia
Marfan’s syndrome