Renal Flashcards
Stages of CKD?
Stage 1- eGFR >90 if other kidney damage Stage 2- eGFR 60-89 if other kidney damage Stage 3- eGFR 30-59 Stage 4- eGFR 15-29 Stage 5- Less than 15, renal failure
Causes of an enlarged kidney
ballotable, moves with respiration
Renal carcinoma, nephroblastoma
Hydronephrosis
Pyonephrosis, abscess
Polycystic disease
How does the urea and creatinine ratio in the blood indicate dehydration status?
If urea: creatinine is more than 20:1, suggests hypoperfusion or dehydration as urea reabsorption is increased as the urine flows very slowly through the tubules. Creatinine doesn’t get reabsorbed at all so it remains normally excreted at a constant rate.
What does a low urea:creatinine ratio indicate? (
Renal damage, as reabsorption of urea is less able to be absorbed
What is the normal albumin creatinine ratio?
Men
What causes microalbuminaemia?
Diabetes mellitus
Hypertension
Minimal change glomerulonephritis
When would you refer a patient with asymptomatic microscopic haematuria under 40 years?
If BP >140/90
EGFR
What will cause a false negative on a urine dip when checking bilirubin?
Urine not fresh
Rifampicin (TB)
How may an AKI be diagnosed?
Creatinine increase of 26umol/48hours
Creatinine increase 1.5x baseline
Urine output
How is AKI staged with reference to serum creatinine?
1- increase of 26umol in 48 hours or 1.5x baseline
2- increase 2-2.9x baseline
3. Increase 3x baseline or >354 umol or on renal replacement therapy
How is AKI staged according to urine output criteria?
1-
Risk factors for AKI?
Age >75
Urinary symptoms
Poor intake/increased losses
Sepsis
PMH: CKD, liver failure, heart failure
Peripheral vascular disease
Diabetes
Which hypertensive drug is commonly implicated in AKI caused by renal hypoperfusion?
ACE-inhibitors
Name three things that may cause acute tubular necrosis leading to an AKI;
- Aminoglycosides
- Contrast
- Myoglobunuria (rhadbdomyolysis)
Which things can cause crystal damage to tubules leading to an AKI? Name 4
Ethylene glycol poisoning
Uric acid (gout)
Calcium
Myeloma
What size kidney on USS would suggest chronic damage?
Indications for renal replacement therapy related to metabolic abnormalities?
Persistent hyperkalaemia (above 7mmol) Severe metabolic acidosis (pH40mmol) causing pericarditis- pericardial rub or encephalopathy
In likely AKI which drugs should be stopped?
NSAIDs
ACE inhibitors
Gentamycin (aminoglycoside)
Amphotericin (antifungal)
When should metformin be stopped in rising creatinine levels?
As creatinine goes over 150mmol/L
What volume of fluid do you prescribe for a patient with AKI if it can be determining on an hourly or daily basis?
Hourly output + 25mL/h for insensible losses
Daily output + 500mLs for insensible losses
What are the pros and cons of haemodialysis vs haemofiltration?
Haemodialysis is faster, but needs patient to be haemodynamically stable
Haemofiltration is less likely to drop BP, as fluid shifts are less significant but is slower so done continuously
Hyperkalaemia ECG changes?
Normally K+ rushes out of cells to repolarise, if outside levels are high the gradient is less steep so movement is slower and HR is slower. Tall tented T waves Small absent P wave Longer PR interval Widened QRS
Rx of an ECG with tall tented T waves?
10mL of 10% calcium gluconate IV via big vein (cardioprotective)
IV insulin + glucose
Salbutamol NEB (but needs high doses, get tachycardic)
Buy time: definitive is correct the cause or dialyse
How long do you need impaired renal function for to classify a CKD?
3 months- with abnormal structure or eGF
How low does your eGFR have to be for 3 months for a diagnosis of CKD without structural abnormality?
What symptoms occur with rising urea levels?
Vomiting, anorexia
Restless legs
Fatigue, weakness
Pruritis, bone pain
What can cause a chronically damaged kidney to look large rather than small and fibrosed on ultrasound?
Infiltration: amyloid, myeloma
Adult polycystic kidney disease
Diabetes mellitus
When would you think about biopsying a kidney in impaired function?
If rapidly progressive disease
Unclear cause + normal sized kidneys
What are the stages of CKD?
GFR values 1. >90 with evidence of other renal damage 2. 60-89 3a. 45-59 3b. 30-44 2. 15-29 1.
In stage 1 kidney disease, GFR may be >90 with evidence of kidney damage, what might that evidence be?
Proteinuria, haematuria
Abnormal anatomy
Target BP if
A. Having CKD
B. Has CKD + diabetoc
C. Has CKD + proteinuria (ACR>70)
A.
Rx for renal bone disease?
Calcichew = binder to reduce gut absorption of PO4-
Vit D analogues
Ca2+ supplements = reduce high PTH and bone disease
For those with CKD what can you give to reduce progression in patients with
A. Diabetes
B. Cardiovascular disease (IHD)
A. ACEi or ARB even if BP is normal
B. If lipids are raised, statin
CI to kidney biopsy
Abnormal clotting, current neoplasms
BP> 160/>90
CKD with kidneys
Name some drugs that are renally excreted and may accumulate in renal failure?
Aminoglycosides (gentamycin) + cephalosporin Heparin Lithium Opiates Digoxin
What substance accumulating in dialysis can lead to carpal tunnel syndrome, arthralgia and fractures?
Amyloid
What is the difference in presentation of IgA nephropathy Vs post-strep glomerulonephritis?
IgA tends to be young man, haematuria whilst having a sore throat
Post-strep tends to be 1 month after a sore throat or skin infection
Difference between IgA nephropathy and post-strep glomerulonephritis on histology?
IgA nephropathy- mesangial proliferation (+ IgA deposition)
Post-strep- mesangial + endothelial proliferation (IgG deposits)
Name the nephritic syndromes:
A Hen SLEeps in the Pastures after the MeAn cock is aggressive
IgA nephropathy (sore throat)
Henoch Schonlein (purpuric rash)
SLE (anti- smith, anti dsDNA)
Goodpastures (anti GBM)
Post strep (1 month after skin/throat infection)
Mesangiocapillary (tramlines, via complement of immune complex)
Rapidly progressive (crescents)
In Goodpasture’s disease, what type of collagen is the antibody against?
Type IV in basement membranes of lungs and kidney
Which diseases are associated with immune complex deposition leading to mesangiocapillary glomerulonephritis?
Hepatitis C
SLE
Gammopathies (including myeloma)
What retinal changes may be observed in someone with mesangiocapillary glomerulonephritis?
Drusen (yellow white spots)
In complement mediated Mesangiocapillary glomerulonephritis
On a renal biopsy what causes tram-lining of the glomerulus? (A clear circumferential gap around the outside
Mesangiocapillary glomerulonephritis
Which glomerulonephritidies would you consider giving IV cyclophosphamide as Rx for?
SLE (with high dose prednisolone)
Mesangiocapillary (if rapidly reducing eGFR)
Rapidly progressive GN
Which glomerulonephritidies would you give ACEi in?
Henoch-Schonlein Purpura (IgA- small vessel vasculitis)
IgA nephropathy
Mesangiocapillary GN
Which glomerulonephritidies would you consider plasma exchange for?
Goodpasture’s (get rid of the anti-GBM)
Rapidly progessive GN (crescents on biopsy)
Causes of nephrotic syndrome
It’s not gunan taken, a minimal change, to remember + get it all in my BRANE, exams so MeAN, I gotta FOCUS, after all this, gunna have SCLEROSIS (be scarred), or diabetes, since I have no SLEep, Amyloid any HElP?
Primary: Minimal change, membranous nephropathy, mesangiocapillary GN, focal segmental glomerulosclerosis
Secondary: diabetes, SLE, amyloid, Hep B/C, drugs
Which drugs may cause nephrotic syndrome?
NSAIDs
Anti-TNF (rheumatoid, IBD, ank spond, psoriasis)
Gold (rheumatoid)
Penicillamine (rheumatoid, Wilsons)
Causes of rapidly progressive glomerulonephritis?
- Immune complex: post-infectious, SLE, IgA, Henoch
- Pauci-immune: Wegener’s (c-ANCA, saddle shaped nose)
Microscopic polyangiitis (p-ANCA)
Churg-strauss (rhinitis/asthma, p-ANCA) - Goodpastures (anti-GBM)
How is suspected Henoch-Schonlein glomerulonephritis confirmed?
Immunofluorescence of skin or renal biopsy shows C3 and IgA
Same as IgA nephropathy
What proportio of those with IgA nephropathy develop end stage renal failure in their life?
20%
What serology findings might occur in post-strep glomerulonephritis?
Anti-streptolysin O
Also C3 may be raised
Differential of nephrotic syndrome?
Congestive cardiac failure- raised JVP, pulmonary oedema, mild proteinuria
Liver failure- low albumin
What clinical features suggest a child with seeming nephrotic syndrome does not have minimal change?
PC:
What are the difficulties of renal biopsy in an adult with nephrotic syndrome?
Grossly oedematous (no albumin) Hypercoagulable (increased clotting factors, liver response to low oncotic pressure)
What happens to cholesterol levels in nephrotic syndrome?
Cholesterol increases, may be >10mmol/L
Due to liver response to low oncotic pressure trying to compensate
Rx for frequently-relapsing or steroid-dependent disease in nephrotic syndrome?
Cyclophosphamide Or Ciclosporin (gum hypertrophy)/ tacrolimus
What type of nephrotic syndrome do patient with renal transplant get?
Focal segmental glomerulosclerosis
Site of action of loop diuretics?
Block Na+/K+/2Cl- cotransporter in thick ascending limb
What ABG picture does loop diuretics give?
Hypokalaemic metabolic alkalosis (less ion uptake, includes H+ and K+)
Where do thiazide diuretics act?
Na+/Cl- transporter in the distal convoluted tubule
Which type of diuretic (loop or thiazide) increases urine calcium excretion?
Loop- can be used in severe hypercalcaemia
Thiazide increases Ca uptake, so in patient’s with hypercalcaemia, it reduces stone formation
Why do thiazide diuretics increase likelihood of gout?
They reduce uric acid excretion (more reabsorbed)
Old man has muscle ache after falling and being on the floor for some hours, plasma CK comes back >1000. What needs to be excluded?
Myocardial infarction (via troponin)
What combination of dipstick and microscopy findings suggest cola-coloured urine is due to rhabdomyolysis?
Dipstick +ve blood
Microscopy no RBCs (all been turned into myoglobin)
Complications of rhabdomyolysis?
Hyperkalaemia
AKI- from myoglobin (may use IV NaCO3 to alkinize urine and prevent the toxic form of myoglobin forming)
DIC
Compartment syndrome from muscle injury
What Rx can be given in rhabdomyolysis to reduce myoglobin toxicity damaging the kidney and causing an AKI?
IV sodium bicarbonate to alkalinize urine to pH >6.5 which stabilised the less toxic form
Maintain urine output at 300mL/hr
Patient is recently started on antibiotics, they are noted to have a rising GFR, fever and rash. Renal biopsy shows inflammatory infiltrate in the interstitium. Diagnosis?
Acute interstitial nephritis- eosinophilic inflammation of tissue between the tubules in response a new drug starting
Commonest cause of haemolytic uraemic syndrome?
E Coli 0157 (often after undercooked meat)
PC: abdo pain, bloody diarrhoea, AKI
Low Hb, low platelets, blood/protein on dip
Cause of thrombotic thrombocytopenic purpura?
Deficiency in ADAM13 protease needed to cleave von Willebrand factor = vWF multimers, platelet aggregation and fibrin deposition
Rx of thrombotic thrombocytopenic purpura?
Plasma exchange
Steroids
? Ecluzumab (targets C5 pathway)
How often should you check diabetics for microalbuminaemia?
Yearly- sign of CKD
Volume of albumin excreted in 24 hours in a diagnosis of microalbuminaemia?
30-300mg
What are the USS criteria for diagnosing autosomal dominant polycystic kidney disease by age?
18-39 years = >3 cysts in total across both kidneys
40-59 years = >2 cysts in each kidney
>60 years = >4 cysts in each kidney
What extrarenal structural abnormalities are associated with polycystic kidney disease?
Intra-cranial aneurysm (risk of sub-arachnoid haemorrhage)
Liver + ovarian cysts
Mitral valve prolapse
Which type of polycystic kidney disease more typically presents in infancy?
What is ti associated with?
Autosomal recessive PCK
Associated with congenital hepatic fibrosis
Which neuroectodermal syndromes are associated with renal cysts?
Tuberous sclerosis (angiofiroma, epilepsy, periungual fibroma) Von hippel-lindau (phaeochromocytoma, cranioangiomas, renal + pancreatic cysts, RCC)
Deaf child has been getting haematuria, what rare syndrome could it be?
Alport’s: leads to focal segmental glomerulosclerosis
May also get ocular defects- bulging lens capsule on slit lamp
Inheritance and cause of Alport’s syndrome?
X-linked mutation in the a5 chain of type IV collagen
Associated with sensorineural deafness, ocular defects and kidney disease
What complication are children with alport’s syndrome at risk of after a kidney transplant?
Goodpasture’s disease (anti-GBM) as Alport’s is due to a mutation in type IV collagen, so may form anti-GBM antibodies
In diabetics, what in source of the damage to the kidneys in pathological terms?
Glycosylation of proteins from high glucose levels that is not mediated by enzymes triggers an inflammatory response and deposition of collagen.
What kind of kidneys can you only ever feel?
Polycystic kidneys that are HUGE or if they’ve had a transplants
(Ballot through abdomen palpation)
Which nerve roots carry kidney pain from the capsule or parenchyma?
T10-L1 nerve roots
How big is a kidney typically on ultrasound?
10-12cm
First imaging modality if kidney damage is suspected?
Ultrasound to determine whether’s it’s an acute or chronic condition (will be shrunken with fibrosis)
MRI is good for looking at what component of the kidney?
The vasculature, ie renal artery stenosis
Kidney will look smaller if artery is stenosed
What kind of hormones do the kidneys break down?
Insulin and parathyroid hormone
What kind of pH abnormalities does kidney failure cause?
Metabolic acidosis- as no longer excreting hydrogen ions
Will breath fast to compensate
What tests indicate nephrotic syndrome?
HOP
Serum albumin (low)
Oedema (examination)
Proteinuria (urine dipstick/ ACR)
What immunoglobulin gets deposited on the membrane in membranous glomerulopathy?
IgG
What is the pathology of tubular necrosis?
When the epithelial cells lining the tubules slough off
Causes an AKI
What is the difference between a high creatinine and a high creatinine kinase?
Creatinine indicates kidney injury
Creatinine kinase is an enzyme released from muscle damage ie in rhabdomyosis
What part of the metabolism of vitamin D does the kidney do?
It hydroxlates the 1st carbon on 1,25 dihydroxy vitamin D3
How does tertiary hyperparathyroidism occur in CKD and how is it treated?
Secondary hyper-PTH leads to autonomous production by the PTH gland
Driving it is raised phosphate (not excreted), low vit D3 and low Ca2+ (from no VitD)
Standard medical treatment for CKD?
Sodium bicarbonate- metabolic acidosis (from failure to excrete H+) Antihypertensives Diuretics (fluid retension) Phosphate binders (reduce high PTH) VitD3 analogs Erythropoetin
