Nephrology Flashcards
What is an AKI?
Potentially reversible acute decline in kidney function, measured by creatinine and urine output
What are the KDIGO criteria for stage 1 AKI?
Cr increase >26 w/i 48hrs OR Cr increase >1.5-2x baseline
Urine output <0.5ml/kg/hr for 6 consecutive hours
What are the KDIGO criteria for stage 2 AKI?
Cr increase >2-3x baseline
Urine output <0.5ml/kg/hr for 12 consecutive hours
What are the KDIGO criteria for stage 3 AKI?
Cr increase >3x baseline OR Cr increase >354 OR requiring RTT
Urine output <0.3ml/kg/hr for 24hrs OR anuric >12hrs
How does AKI present?
Uraemia
Acidosis
Hyperkalaemia
Fluid overload
Anuric
What risk factors are there for AKI?
Old patients
Volume depletion
Cardiac failure
Nephrotoxic medications
Iodine contrast
Systemic illness
What are the three types of AKI?
Pre-renal (66%)
Renal (20%)
Post-renal
How can the causes of a pre-renal AKI be classified?
Volume depletion
Systemic vasodilation
Intrarenal vasoconstriction
Fluid redistribution
What is the main sequelae of un-treated pre-renal AKI?
Acute tubular necrosis
How can the causes of a renal AKI be classified?
Glomerular
Interstitial disease
Tubular disease
Vascular disease
What are the glomerular causes of a renal AKI?
GPA/SLE
Anti-GBM
Post-strep
What are the tubular causes of a renal AKI?
Nephrotoxics - NSAIDs, PPIs, cephalosporins, penicillins
EBV/CMV/HIV
Sarcoid
Allergic
What are the vascular causes of a renal AKI?
RV thrombosis
Scleroderma
Atheroembolic disease
Shock
HUS
TTP
Vasculitis
How can the causes of a post-renal AKI be classified?
Intrarenal
Bilateral tract
Urethral obstruction
Others - TB, post-op, neuropathy
What are the intrarenal causes of a post-renal AKI?
Light chain precipitation
Urate sludge
Tumour lysis
What are the bilateral tract causes of a post-renal AKI?
Stones
Retroperitoneal fibrosis
Papillary necrosis
What are the urethral obstruction causes of a post-renal AKI?
Post valve
Retroperitoneal fibrosis
BPH
Prostate ca
Urethral strictures
How should AKI be investigated?
Pre-renal - BP, volume status
Renal - urine dip
Post-renal - USS + bladder scan
What are the options for imaging the kidneys?
USS - 1st choice
CTKUB - no contrast, pick up stones
CTU - contrast, not-effective if eGFR low
How can a pre-renal AKI be distinguished from ATN?
Pre-renal - lower urinary Na and Urea, higher urine osmolality
ATN - higher urinary Na, urinary/plasma osmolality equal, urinary casts
How should an AKI be managed?
A-E
Stop DAMN (diuretics, ACEi/ARB, metformin, NSAIDs)
Treat reversible cause
Monitor UO (catheter)
Dialysis
When should dialysis be considered in AKI?
AEIOU
Acidosis (pH <7.2)
Electrolytes (refractory K+ >6.5)
Intoxication (poisoning e.g. Aspirin)
Oedema (pulmonary)
Uraemia (encephalopathy, pericarditis)
What is nephrotic syndrome?
Heavy proteinuria causing hypoalbuminaemia and oedema
How does nephrotic syndrome present?
Polyuria
Polydipsia
Frothy urine
Oliguria/anuria
SOB/fatigue (pulmonary oedema)
What are the potential complications of nephrotic syndrome?
Infection
Hypercoagulability (VTE)
Hypocalcaemia
What is the management of nephrotic syndrome?
Na/fluid restrict
Diuretics
LMWH
Trial steroids - if no response –> biopsy
What are the histopathological classifications of 1o nephrotic syndrome?
Minimal change
Membranous nephropathy
Focal segmental glomerulosclerosis (FSGS)
What are the risk factors for minimal change nephrotic syndrome?
Hodgkin’s lymphoma
NSAIDs
Common in children
Prev. episodes (2/3 recur)
What is the treatment for minimal change nephrotic syndrome?
Steroids (80% respond) –> cyclophosphamide if resistant
What is the outcome for minimal change nephrotic syndrome?
1/3 1x episode
1/3 infrequent recurrence
1/3 frequent recurrence
What is the treatment for membranous nephrotic syndrome?
Combination steroid + cyclophosphamide
What are the 2o causes of nephrotic syndrome?
Infection (bacterial, parasitic)
Immune/inflammatory (SLE, RA)
Metabolic (DM)
Malignant
Drugs (NSAIDs, penicillamine, heroin etc.)
Toxins
Pregnany
Transplant rejection
What is the treatment for FSGS?
Combination steroid + cyclophosphamide
Often causes ESRF
What are the 5 stages of diabetic nephropathy?
1 - Hyperfiltration (increase eGFR)
2 - Silent stage (early histological change)
3 - Incipient nephropathy/microalbuminuria (30-300mg/24hr)
4 - Overt nephropathy/persistent proteinuria. eGFR decline/HTN
5 - ESRF
What are the presenting features of nephritic syndrome?
Haematuria
Reduced eGFR
Oliguria
Uraeia
Fluid retention
HTN –> headache, LVH
What are the causes of nephritic syndrome?
Post infection w/ Group A Strep (proliferative)
Infections (bacterial, viral, parasitic)
Immune/inflammatory (RA, SLE)
What is IgA Nephropathy?
Most common form of idiopathic glomerulonephritis leading to CKD
What are the risk factors for IgA Nephropahty?
Commonly occurs post URTI
Coeliac disease
Young patients
Male
What is Haemolytic Uraemic Syndrome?
Most common cause of AKI in paeds
Triad of
-thrombocytopenia
-AKI
-microangiopathic haemolytic anaemia (Coomb’s negative)
What are the risk factors for HUS?
Post e.coli infection (0157:H7)
Tumours
Pregnancy
Ciclosporin
SLE
HIB
How should HUS be managed?
Supportive therapy only
No need for a/b
What is tubulointerstitial nephritis?
Inflammation of renal interstitium
What are the causes of tubulointerstitial nephritis?
Drugs (nephrotoxics, abx - Pen, Rifampicin)
Infections (staph, strep, CMV/EBV)
Immune
Chronic TIN fibrosis 2o reflux/DM
How does tubulointerstitial nephritis present?
Polyuria
Nocturia
Polydipsia
Glycosuria
Urticaria
Fever
Arthralgia
How is tubulointerstitial nephritis treated?
Stop offending drugs
Fluids
Prednisolone
What is renal tubular acidosis?
Acidaemia 2o failure of kidneys to form acidic urine
What are the two types of renal tubular acidosis?
Distal
-most common
-unable to excrete H+
Proximal
-unable to resorb HCO3-
What are the risk factors for distal RTA?
1o
Marfan’s
SLE
Sjogren’s
What are the risk factors for proximal RTA?
Sjogren’s
Myeloma
Nephrotic syndrome
Wilson’s disease
How does RTA present?
Polyuria
Acidotic
Arrhythmias (K+)
Renal calculi
Muscle weakness
What is polycystic kidney disease?
Most common inherited cause of renal disease
What is the inheritance pattern of PKD?
Autosomal dominant
High/complete penetrance
What are the two types of PKD?
Type 1 - Chromosome 16 (80%)
Type 2 - Chromosome 4
How dose PKD present?
Typically w/ complications
Loin pain
Palpable kidneys
Gross haematuria (following trauma)
UTI
Stones
ESRF - 70% by 70y/o
What are the extrarenal manifestations of PKD?
HTN
Infertility
Liver cysts
Mitral valve prolapse/aortic root dilation –> aortic dissection
Berry aneurysm –> SAH
How is PKD diagnosed?
Imaging - USS/CT
If <30 - FHx +ve and 2 cysts
If 30-59 - 2 cysts both kidneys
If >60 - 4 cysts both kidneys
What is the management of PKD?
Counselling/risk factor modification
MRA screen for berry aneurysm
STatin/Aspirin
Laparoscopic cyst removal
ESRF (50%)
What is CKD?
Abnormal kidney function/structure
Diagnosis based on reduced function/evidence kidney damage
What are the stages of CKD?
1 - eGFR >90 (but proteinuria)
2 - eGFR 60-90 (but proteinuria)
3 - eGFR 30-59
4 - eGFR 15-29
5 - eGFR <15
How is CKD diagnosed?
eGFR measurements + proteinuria
2 values at 3/12
How is CKD managed?
Slow progression (BUPA)
-blood pressure control
-underlying illness control
-protein intake
-avoid obstruction/dehydration/infection/nephrotoxics
What is the first line drug for BP control in CKD?
ACE inhibitors
What are the contraindications for ACEi in CKD?
Fixed renal aa stenosis
Pregnancy
Oligohydramnios
Prev. hypersensitvity/angioedema
What are the complications of CKD?
Anaemia
Bones - fractures, deformity, 2o hyperparathyroidism
CVD
Drug-related side effects (reduced excretion)
Emotional dysregulation (sexual dysfunction)
Fluids (Pulmonary oedema –> IV Furosemide)
Growth restriction
HTN
Immunosuppression
Joint problems
Killed by kidneys (death)
Legs restless (Clonazepam)
What are the options for RRT?
Haemodialysis
Peritoneal dialysis
Renal transplant
Describe the structure of haemodialysis
3 treatments/week
3-5hrs/treatment
Done at hospital/satellite site
Requires AVF
Describe the structure of peritoneal dialysis
Ambulatory exchange/exchange episodes t/o day
8hr exchange o/n (8-20L)
Requires peritoneal catheter insertion
When is peritoneal dialysis considered preferable?
1st 2 years of dialysis (preserves renal function)
Haemodynamic instability
Poor veins
What are the advantages of peritoneal dialysis?
Flexibility
No diet restriction/needles
What are the negative aspects of haemodialysis?
Fixed schedule
Travel to hospitals
Permanent access/recurrent needle sticks
Diet/fluid restriction
Haemodynamic instability
AVF creation
What are the common problems w/ arterio-venous fistulas?
Formation (takes 6-8/52 to mature)
Infection
Thrombosis
Stenosis
Steal syndrome
What is steal syndrome?
Distal ischaemia 2o insertion of AVF
-blood preferentially flows through AVF
What are the potential complications of haemodialysis?
Sepsis
Blood loss
Infective endocarditis
Disequilibration syndrome
Bioincompatability (interaction b/w machines and blood)
What is Disequilibration syndrome?
Neurological sx post dialysis
-confusion
-headache
-dizziness
-coma
-convulsions
What are the contraindications to peritoneal dialysis?
Major intrabdominal problems (e.g. adhesions)
Poor motivation/hygiene
Emactiona
COPD
Stoma in-situ
What are the potential complications of peritoneal dialysis?
Hernia
Encapsulating peritoneal sclerosis
Infection/blockage
PD peritonitis
What virology needs checking prior to renal transplant?
CMV
HCV
HBV
HIV
VZV
EBV
What is the prognosis post renal transplant?
Best prognosis of RRT
95% survival 1yr, 90% graft survival
15yr graft srvival
What are the potential complications of renal transplant?
Bleeding
Graft thrombosis
Infection
Leaks
Rejection
Describe hyperacute transplant rejection
Minutes-hrs
Type II HR (IgG)
Causes vessel thrombosis
Describe acute transplant rejection
<6/12
Type IV HR (T-cell)
Treated w/ steroids/immunosuppression
Describe chronic transplant rejection
> 6/12
Antibody/cell fibrosis to kidney (chronic allograft nephropathy
Recurrence of CKD
How should prescribing in CKD change?
Consider reducing maintenance dose (reduced metabolism/excretion)
Increase doses of diuretics/renally acting drugs
Reduce doses of nephrotoxics
What are the causes of Hypokalaemia?
Reduced intake
Excessive losses (sweating, GI, endocrine, renal)
Transcellular shifts
How does Hypokalaemia present?
Cramps
Tetany
Weakness
Palpitations (arrhythmias)
Nephrogenic Diabetes insipidus
How should Hypokalaemia be managed?
Mild - Sando K+, K+ sparing diuretics
Severe - IV K+
Magnesium
What are the causes of Hyperkalaemia?
Excess intake (TPN, a/b, idiopathic, blood transfusion)
Reduced losses (addisons, ACE-i, spironolactone, AKI)
Transcellular shift (acidosis, haemolysos, rhabdomyolsis)
How does Hyperkalaemia present?
Palpitations/arrhythmias
Cardiac arrest
How shoulder Hyperkalaemia be managed?
Stop nephrotoxics
Calcium gluconate (10ml 10% IV)
Salbutamol nebs
50ml 50% IV Dextrose
Actrapid 10 units
Calcium resonium - non-invasive, takes days
Haemodialysis
When should haemodialysis be considered for Hyperkalaemia?
If K+ >7 (esp. if ECG changes) OR refractory
How is anion gap calculated?
(Na + K) - (Cl + HCO3)
What are the causes of a non-anion gap metabolic acidosis?
GI loss of HCO3- (diarrhoea)
Saline infusion (hyperchloraemic metabolic acidosis)
Chronic pancreatitis
Renal tubular acidosis
What are the causes of a high anion-gap metabolic acidosis?
Lactic acidosis
Ketoacidosis e.g. DKA
Alcohol (methanol toxicity, ketoacidosis)
Iron toxicity/Isoniazid
Salicylate toxicity
Ethanol/ethylene toxicity
Renal causes
