Renal Flashcards
AKI
definition
an acute drop in kidney function
diagnosed by measuring the serum creatinine
AKI
NICE criteria for AKI
- rise in Cr 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
AKI
RFs
- CKD
- Heart failure
- Diabetes
- Liver disease
- Older age (>65 years)
- Cognitive impairment
- Nephrotoxic meds: NSAIDS and ACEi
- Use of a contrast medium: during CT scans
AKI
how can causes be split up
pre-renal
renal
post-renal
AKI
pre-renal causes
most common. Due to inadequate blood supply to kidneys reducing the filtration of blood
- dehydration
- hypotension (shock)
- HF
AKI
renal causes
intrinsic disease in kidney leading to reduced filtration of blood:
- glomerulonephritis
- interstitial nephritis
- acute tubular necrosis
AKI
post renal causes
obstruction to the outflow of urine from the kidney causing back pressure into the kidney
- kidney stones
- masses such as cancer in the abdo or pelvis
- ureter or uretral strictures
- enlarged prostate or prostate cancer
AKI
inx
urinalysis for protein, blood, leucocytes, nitrites and glucose
US: look for obstruction if suspected
AKI
what do leucocytes and nitrites suggest
infection
AKI
what does protein in the blood suggest
acute nephritis
but can be +ve in infection
AKI
what does glucose suggest in the urinalysis
diabetes
AKI
mnx
correct underlying cause:
- fluid rehydration with IV fluids in pre-renal AKI
- stop nephrotoxic medications
- relieve obstruction in post renal AKI: e.g. insert catheter for a pt in retention from an enlarged prostate
AKI
complications (4)
- hyperkalaemia
- fluid overloads, HF, pulmonary oedema
- metabolic acidosis
- uraemia (high urea)
AKI
what can uraemia lead to
encephalopathy or pericarditis
CKD
what is it
a chronic reduction in kidney function
CKD
causes
- Diabetes
- Hypertension
- Age-related decline
- Glomerulonephritis
- Polycystic kidney disease
- Medications: NSAIDS, PPIs and lithium
CKD
RFs
- Older age
- Hypertension
- Diabetes
- Smoking
- Use of medications that affect the kidneys
CKD
presentation
usually asymptomatic
- Pruritus (itching)
- Loss of appetite
- Nausea
- Oedema
- Muscle cramps
- Peripheral neuropathy
- Pallor
- Hypertension
CKD
how to test eGFR
using a U&E blood test
CKD
how many eGFR tests are required to confirm dx
2
3m apart
CKD
inx
- eGFR
- urine albumin:creatinine ratio shows proteinuria (≥ 3mg/mmol is significant)
- urine dipstick: haematuria (1+ of blood)
- renal US
CKD
what is the G score
based on the eGFR
CKD
G1
eGFR >90
CKD
G2
eGFR 60-89
CKD
G3a
eGFR 45-59
CKD
G3b
eGFR 30-44
CKD
G4
eGFR 15-29
CKD
G5
eGFR <15 (known as “end-stage renal failure”)
CKD
what is the A score
based on the albumin : creatinine ratio
CKD
A1
< 3mg/mmol
CKD
A2
3 – 30mg/mmol
CKD
A3
> 30mg/mmol
CKD
what is needed for a dx of CKD
eGFR of <60 or proteinuria (≥ 3mg/mmol)
CKD
complications (5)
- Anaemia
- Renal bone disease
- Cardiovascular disease
- Peripheral neuropathy
- Dialysis related problems
CKD
when does NICE suggest referral to a specialist
- eGFR < 30
- ACR ≥ 70 mg/mmol
- Accelerated progression: decrease in eGFR of 25% or 15 ml/min in 1 year
- Uncontrolled hypertension despite ≥ 4 antihypertensives
CKD
what are the aims of mnx
- Slow the progression of the disease
- Reduce the risk of cardiovascular disease
- Reduce the risk of complications
- Treating complications
CKD
how would you slow the progression of the disease
- optimise diabetic control
- optimise hypertensive control
- treat glomerulonephritis
CKD
how would you reduce the risk of complications
- exercise, maintain a healthy weight, stop smoking
- dietary advice about phosphate, Na, K + water intake
- offer atorvastatin 20mg for primary prevention of CVD
CKD
how would you treat complications
- Metabolic acidosis: PO sodium bicarb
- Anaemia: iron + EPO
- renal bone disease: vit D
- end stage renal failure: dialysis, renal transplant
CKD
which pts are offered ACEi to treat HTN
- Diabetes plus ACR > 3mg/mmol
- Hypertension plus ACR > 30mg/mmol
- All patients with ACR > 70mg/mmol
CKD
what is the aim BP
<140/90
(or < 130/80 if ACR > 70mg/mmol).
CKD
what needs to be monitored
serum K because CKD and ACEi both cause hyperkalaemia
CKD
why is there anaemia of CKD
- healthy kidney cells produce EPO (hormone that stimulates production of RBCs)
- damaged kidney cells produce less EPO
- therefore drop in RBCs and subsequent anaemia
CKD
how can anaemia of CKD be treated
with erythropoiesis stimulating agents such as exogenous erythropoietin
CKD
why are blood transfusions limited in anaemia of CKD
they can sensitise the immune system (allosensitisation)
so that transplanted organs are more likely to be rejected
CKD
what should be treated before offering erythropoetin
iron deficiency
CKD
what is renal bone disease aka?
CKD mineral bone disorder (CKD-MBD)
CKD
what are 3 features of renal bone disease
- osteomalacia (softening)
- osteoporosis (brittle bones)
- osteosclerosis (hardening)
CKD
what are the spinal x-ray changes in someone with renal bone disease
‘rugger jersey’ spine (stripes found on a rugby shirt)
sclerosis of both ends of the vertebra (denser white)
osteomalacia in the centre of the vertebra (less white)
CKD
renal bone disease: why is there high serum phosphate
reduced phosphate excretion
CKD
renal bone disease: why is there low active vit D
because the kidney cannot metabolise vit D to its active form as effectively
CKD
renal bone disease: what is Active vit D essential in
- calcium absorption from the intestines and kidneys
- bone turnover
CKD
renal bone disease: why does secondary hyperparathyroidism occur
because the parathyroid glands react to low serum Ca and high serum phosphate by excreting more PTH
this leads to increased osteoclast activity which leads to the absorption of Ca from bone
CKD
renal bone disease: why does osteomalacia occur
due to increased turnover of bones without adequate Ca supply
CKD
renal bone disease: why does osteosclerosis occur
occurs when the osteoblasts respond by increasing their activity to match the osteoclasts
by creating new tissue in the bone. But due to low Ca level, this new tissue is not properly mineralised
CKD
renal bone disease: why does osteoporosis occur
due to other RFs such as ages and use of steroids
CKD
mnx of renal bone disease
- active forms of vit D (alfacalcidol + calcitriol)
- low phosphate diet
- bisphosphonates to treat osteoporosis
Acute Tubular Necrosis
what is it
damage and death (necrosis) of the epithelial cells of the renal tubules
what is the most common cause of AKI
acute tubular necrosis
Acute Tubular Necrosis
why does damage to the kidney cells occur
due to ischaemia or toxins
Acute Tubular Necrosis
is it reversible
yes because epithelial cells have the ability to regenerate
usually takes 7-21d to recover
Acute Tubular Necrosis
causes from ischaemia (3)
- shock
- sepsis
- dehydration
Acute Tubular Necrosis
causes from toxins (3)
- radiology contrast dye
- gentamycin
- NSAIDs
Acute Tubular Necrosis
pathognomonic finding specific to it
‘muddy brown casts’ found on urinalysis
Acute Tubular Necrosis
urinalysis findings
- muddy brown casts
- renal tubular epithelial cells in the urine
Acute Tubular Necrosis
trx
the same as with other causes of an AKI
- supportive mnx
- IV fluids
- stop nephrotoxic medications
- treat complications
Renal Transplant
how many years of life is added compared with just using dialysis in end stage kidney failure
10 years
Renal Transplant
how are patients and donor kidneys matched
based on the HLA type A, B and C on Ch6
they don’t have to fully match but the less they match, the more likely the transplant is to fail
Renal Transplant
procedure
pt’s own kidneys are left in place
the donor kidney’s blood vessels are connected (anastomosed) with the patient’s pelvic vessels, usually the external iliac vessles
the donor kidney’s ureter is anastomosed directly with the pt’s bladder
Renal Transplant
where is the donor kidneyplaced
anterior in the abdomen and can be palpated in the iliac fossa
Renal Transplant
what incision is used
hockey stick incision
there will be a hockey stick scar
Renal Transplant
how to reduce the risk of transplant rejection
life long immunosuppression regime:
- Tacrolimus
- Mycophenolate
- Prednisolone
other possible immunosuppressants:
- Cyclosporine
- Sirolimus
- Azathioprine
Renal Transplant
complications relating to the transplant (3)
- transplant rejection (hyperacute, acute, chronic)
- transplant failure
- electrolyte imbalances
Renal Transplant
complications related to immunosuppressants
- IHD
- T2DM (steroids)
- infections more likely
- inidal infections (PCP. CMV, PJP, TB)
- non-Hodgkin’s lymphoma
- skin cancer (SCC)
Glomerulonephritis
define nephritis
inflammation of the kidneys
not a syndrome or diagnosis
Glomerulonephritis
define nephritic syndrome or acute nephritic syndrome
a group of symptoms. not a diagnosis. Has no set criteria
- haematuria
- oliguria
- proteinuria
- fluid retention
Glomerulonephritis
what amount of protein in the urine points towards nephritic syndrome
<3g/24hrs
Glomerulonephritis
define nephrotic syndrome
a group of symptoms without specifying the underlying cause
they must fulfil this criteria:
- peripheral oedema
- proteinuria (>3g/24hrs)
- serum albumin <25g/L
- hypercholesterolaemia
Glomerulonephritis
what is Glomerulonephritis
an umbrella term applied to conditions that cause inflammation of or around the glomerulus and nephron
Glomerulonephritis
define interstitial nephritis
inflammation of the space between cells and the tubules (interstitium) within the kidney
Glomerulonephritis
what are the 2 types of interstitial nephritis
acute interstitial nephritis
chronic tubulointerstitial nephritis
Glomerulonephritis
define glomerulosclerosis
the pathological process of scarring of the tissue in the glomerulus
not a diagnosis
Glomerulonephritis
what can glomerulosclerosis be caused by (3)
- any type of glomerulonephritis
- obstructive uropathy (blockage of urine outflow)
- focal segmental glomerulosclerosis
Glomerulonephritis
name some specific types
- 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
glomerulonephritis
what are most types treated with
- immunosuppression (e.g. steroids)
- BP control by blocking the renin-angiotensin system (ACEi or ARB)
glomerulonephritis
what might frothy urine suggest
proteinuria –> nephrotic syndrome
glomerulonephritis
what may nephrotic syndrome predispose pts to
- thrombosis
- HTN
- high cholesterol
glomerulonephritis
what is the most common cause of nephrotic syndrome in children
cause and trx
minimal change disease
idiopathic
steroids
glomerulonephritis
what is the most common cause of nephrotic syndrome in adults
focal segmental glomerulosclerosis
glomerulonephritis
what is IgA nephropathy aka
Berger’s disease
glomerulonephritis
what is the most common cause of primary glomerulonephritis (not caused by another disease)
IgA nephropathy (Berger’s disease)
glomerulonephritis
what is the peak age of presentation of IgA nephropathy (Berger’s disease)
20s
glomerulonephritis
what does histology show in IgA nephropathy (Berger’s disease)
IgA deposits and glomerular mesangial proliferation
glomerulonephritis
what is the most common glomerulonephritis overall
membranous glomerulonephritis
glomerulonephritis
what is the peak age in Membranous glomerulonephritis
bimodal peak in age in the 20s and 60s