Week 14 - Nephrology/Urology Flashcards
List the 6 functions of the kidney?
- Metabolic waste excretion (urea, creatinine)
- Endocrine functions (vit D, EPO, PTH)
- Drug metabolism / excretion
- Acid / base
- Blood pressure control
- Control of solutes and fluid status (sodium, potassium, fluid)
What is the primary role of the kidneys?
Maintain fluid & electrolyte homeostasis in response to blood pressure and hormones
List the 6 structures of the kidney nephron?
- Glomerulus
- Bowman’s capsule
- Proximal convoluted tubule
- Loop of Henle
- Collecting tubule (to ureter)
Describe the glomerular filtration barrier?
Filters plasma & are not supposed to let through protein/cells/big molecules
What are the 2 structures of the glomerular filtration barrier?
- Podocyte foot processes
2. Capillary fenestrated endothelium
What 4 things control the glomerular filtration rate?
- Blood flow
- Intraglomerular pressure
- Transmembrane pressure- filtration barrier
- Oncotic pressure
What 4 things happen to the filtrate passing through the kidney tubules?
- Filtration
- Reabsorption
- Secretion
- Excretion
Where does filtrate reabsorption occur?
Peritubular capillaries
Where does filtrate filtration occur?
Bowan’s capsule
What is urinary excretion equal to?
Filtration - Reabsorption + Secretion
What is the normal amount of protein in the urine?
Less than 150mg protein / 24h
What makes up 15% of proteinuria?
Albumin
What makes up 85% of proteinuria?
Other proteins ie. Tamm, Horsfall, Immunoglobulin
What does urinalysis detect?
Albumin
What are 3 ways to measure urinary protein excretion?
- 24hr urine collection (grams / 24h)
- Protein:creatinine ratio (PCR) on morning spot sample (mg/mmol)
- Albumin:creatinine ratio (mg/mmol)
What is the normal range for male/female albuminuria?
- Male: <2.5
- Female: <3.5
What is the microalbuminuria range for male/females?
- Male: 2.5-35
- Female: 3.5-35
What is the macroalbuminuria range for male/females?
- Male: >25
- Female: >35
What is haematuria?
- Can be blood detectable on dipstick (non-visible haematuria)
- Visible haematuria- can come from anywhere in the urinary tract (kidneys, stones, infection, malignancy, cysts, inflammation)
What are the 7 things measured in a U&Es blood test?
- Sodium
- Potassium
- Chloride
- Urea
- Creatinine
- eGFR
- +/- bicarbonate
What 3 things would a substance to test U&Es ideally be?
- Freely filtered at glomerulus
- Not secreted
- Not reabsorbed
What is creatinine?
Creatine and phosphocreatine breakdown product
What is creatinine levels affected by?
- Slightly by diet
- Concentration affected by plasma volume
What % of creatinine is secreted by tubules?
Up to 15%
What 4 things affect urea levels in the body?
- Diet- high protein or GI bleed
- Tissue breakdown- corticosteroid
- Dehydration- passive reabsorption proximal tubule
- Liver failure (lowers urea)
What % of urea is reabsorbed?
Up to 40%
What is the renal clearance of a substance?
Volume of plasma which would be cleared of the substance per unit of time
What is the renal clearance equation?
Urine concentration of substance X Urine volume / Plasma concentration of substance (ml/min)
How is renal clearance usually described?
As Glomerular Filtration Rate
What 4 factors is the modification of diet in renal disease (MDRD) based on?
- Plasma creatinine concentration
- Age (adults only)
- Gender
- Race
What does the modification of diet in renal disease (MDRD) give values as?
ml/min per 1.73m2 body surface area
What 3 factors increase an individuals creatinine?
- Younger
- Males
- Races
What is the relationship between serum creatinine and GFR?
Inversely proportional & also depends on muscle mass
eGFR assumes _____ renal function?
Stable
What is the GFR value if the plasma creatinine concentration= 100micromols/l, but the patient has no kidneys or is making no urine?
GFR= 0
What is eGFR value important for?
Drug dosing
Who is the eGFR value not suitable for?
Acute kidney injury as it takes 3-4 days to build up
What are the 5 stages of chronic kidney disease?
- Stage 1: with another abnormality, otherwise regard as normal (eGFR => 90)
- Stage 2: with another abnormality, others regard as normal (eGFR 60-89)
- Stage 3: moderate impairment (eGFR 30-59)
- Stage 4: severe impairment (eGFR 15-29)
- Stage 5: advanced renal failure (eGFR <15)
What does CKD-EPI stand for?
Chronic Kidney Disease Epidemiology Collaboration (for patients with higher levels of eGFR)
What eGFR should be regarded as normal?
=>60 ml/min/1,73m2
- Unless they have evidence of kidney disease (persistent proteinuria/haematuria or both, microalbuminuria in patients with diabetes, structural kidney disease in adults or reflux nephropathy)
What 3 tests establish basic kidney function?
- Blood creatinine
- Calculating eGFR if patient is stable
- Urinalysis
What is glomerulonephritis?
Inflammatory diseases involving the glomerulus & tubules, categorised by biopsy findings
What are the 4 main targets for injury in glomerulonephritis?
- Podocytes
- Basement membrane
- Mesangial cells
- Glomerular capillaries
What are the 2 pathophysiological mechanisms of glomerulonephritis?
- Extrinsic: antibodies, immune complexes, complement
2. Intrinsic: cytokines, growth factors, proteinuria
List 8 secondary causes of glomerulonephritis?
- CV: SBE
- Resp: bronchiectasis, lung cancer, TB
- ID: Hepatitis, HIV, chronic infections
- Rheum: RA, lupus, amyloid
- Drugs: NSAIDS, bisphosphates, heroin
- Gastro: ALD, IBD, coeliacs disease
- Diabetes
- Haem: myeloma, CLL, PRV
List the 3 approaches to glomerulonephritis?
- Presentation, history
- Kidney biopsy findings
- Likely cause & specific management
What are 3 ways to examine a biopsy of the kidney cortex?
- Light microscopy (glomerular and tubular structure)
- Immunofluorescence (looking for Ig and complement)
- Electron microscopy (glomerular basement membrane and deposits)
Give 8 examples of kidney disease?
- Minimal change nephropathy
- Rapidly progressive glomerulonephritis (RPGN)
- Membranoproliferative
- Membranous nephropathy
- Crescentic glomerulonephritis/vasculitis
- Post-infectious
- Diabetic nephropathy
- Lupus nephropathy
How does a disruption of glomerular filtration barrier present clinically?
ABNORMAL URINE
Describe Rapidly progressive glomerulonephritis (RPGN)?
- Rapid rise in serum creatinine
- Crescentic damage
- Vasculitis/lupus/IgA: often have other clinical features
Describe nephritis?
- Blood and protein in urine, high blood pressure, rising sCr
- Proliferative / acute inflammation
- IgA / lupus / post-infectious
Describe nephrotic?
- > 3.5g/d proteinuria, low sAlb, oedema
- Non-proliferative, podocyte damage (scarring)
- Minimal change / FSGS / Membranous
Describe overlap glomerulonephritis?
- Blood / heavy proteinuria
- IgA / MCGN / lupus
Describe 2 other presentations of glomerulonephritis?
- Urinary abnormalities alone
2. Hypertension
What are the 4 factors of nephrotic syndrome?
- 3.5g proteinuria per 24h (urine PCR >300)
- Serum albumin <30
- Oedema
- Hyperlipidaemia
What are the 2 complications of nephrotic syndrome?
- Risk of venous thromboembolism
2. Increased risk of infection
List the 4 stages in the glomerulonephritis model?
- Insult precipitant
- Injury
- Response to injury –> disease
- Outcome
What are the possible therapeutic strategies for glomerulonephritis stage 1: Insult precipitant (infection, antibody)?
Control infection & connective tissue disease
What are the 2 possible therapeutic strategies for glomerulonephritis stage 2: Injury?
- Remove antibody/immune complex
2. Block antibody
What are the 3 possible therapeutic strategies for glomerulonephritis stage 3: response to injury?
- Steroids
- Cytotoxics
- Anti-hypertensives
What are the possible therapeutic strategies for glomerulonephritis stage 3: response to injury?
- Dialysis
- Transplantation
- Slow progression
- Resolution
List the 4 aspects of IgA nephropathy from mild –> severe (spectrum of disease)?
- Minor Urinary abnormalities
- Hypertension
- Renal impairment & heavy proteinuria
- Rapidly progressie glomerulonephritis
Describe the epidemiology of IgA nephropathy (mesangial disease)?
- The most common primary glomerular disease
- Up to 1% of the “normal” population
- Precipitated by infection? Synpharyngitic
- May be secondary to HSP, cirrhosis, coeliac disease
List the 3 pathophysiological abnormalities in IgA nephropathy (mesangial disease)?
- Abnormal/ over-production of IgA1, IgA I/C
- Mesangial IgA, C3 deposition
- Mesangial proliferation
What are the 3 clinical signs of IgA nephropathy (mesangial disease)?
- Haematuria
- Hypertension
- Proteinuria (varies with prognosis)
What do almost 1/3rd of IgA nephropathy (mesangial disease) progress to?
End stage renal failure (ESRF)
What is the treatment for IgA nephropathy (mesangial disease)?
- No specific therapy
- Antihypertensive
- ACE inhibitors
Describe the epidemiology of Membraneous glomerulonephritis?
- A disease of adults
- 10% secondary to malignancy, CTD, drugs
Describe the pathophysiology of membraneous glomerulonephritis?
- Anti-phospholipase A2 receptor antibody in 70%
- Immune complexes in basement membrane/ sub-epithelial space
How does Membraneous glomerulonephritis typically present?
Presents with the nephrotic syndrome: commonest primary cause, often chronic
Describe the variable natural history/prognosis of Membraneous glomerulonephritis?
- A 1/3rd spontaneously remit
- A 1/3rd progress to ESRF over 1-2 years
- A 1/3rd persistent proteinuria, maintain GFR
What are 3 ways to treat membraneous nephropathy?
- Treat underlying disease if secondary
- Supportive non-immunological: ACEi, statin, diuretics, salt restriction
- Specific immunotherapy: Steroids, Alkylating agents (cyclophosphamide), Cyclosporin
List the 2 alternative agents used to treat membraneous nephropathy?
- Rituximab
2. Anti-CD20 MAb
What are the 5 possible outcomes for membraneous nephropathy?
- Complete remission
- Partial remission
- End Stage Renal Disease (ESRD)
- Relapse
- Death
What is the commonest form of glomerulonephritis in children?
Minimal change disease
What does minimal change disease cause?
Nephrotic syndrome
What are the 2 causes of minimal change disease?
- Idiopathic
2. Secondary to malignancy
What s the pathophysiology of minimal change disease?
- Foot process fusion
- T cell, cytokine mediated
- Target glomerular epithelial cell, basement membrane charge
Describe the presentation of minimal change disease?
- Acute presentation may follow URTI
- GFR - normal, or reduced due to intravascular depletion
- Relapsing course (50% will relapse)
What does minimal change disease early cause?
Renal failure
What % of minimal change disease will relapse?
50%
What is the treatment for minimal change disease?
High dose steroids: Prednisolone 1mg/Kg for up to 8 weeks
What is crescentic glomerulonephritis/ rapidly progressive glomerulonephritis?
- Group of conditions which demonstrate glomerular crescents on kidney biopsy
- Aggressive disease: progress to ESRF
List the 5 common causes of crescentic glomerulonephritis/ rapidly progressive glomerulonephritis?
- ANCA vasculitis (MPO / PR3)
- Goodpasture’s syndrome (anti-GBM)
- Lupus nephritis
- Infection associated
- HSP nephritis
What are the 7 basics for approaching a patient with potential glomerulonephritis?
- A full medical and drug (including recreational) history
- UEs
- Dip urine for blood
- Quantify proteinuria
- Check albumin
- Check USS
- Glomerulonephritis screen
What are the 5 tests in the Glomerulonephritis screen?
- HbA1c / random glucose
- ANCA / anti-GBM
- ANA / PLA2R / virology
- Complement / ANA / dsDNA
- Complement / virology (hep B, C, HIV) / Igs / RF
What disease can be detected when measuring HbA1c / random glucose in the Glomerulonephritis screen?
Diabetic nephropathy
What disease can be detected when measuring ANCA / anti-GBM in the Glomerulonephritis screen?
Vasculitis
What disease can be detected when measuring ANA / PLA2R / virology in the Glomerulonephritis screen?
Membraneous
What disease can be detected when measuring Complement / ANA / dsDNA in the Glomerulonephritis screen?
Lupus
What 2 diseases can be detected when measuring Complement / virology (hep B, C, HIV) / Igs / RF in the Glomerulonephritis screen?
- Membranoproliferative glomerulonephritis (MPGN)
2. Focal segmental glomerulosclerosis (FSGS)
List 4 systemic diseases that are associated with renal dysfunction?
- Diabetes mellitus
- Atheromatous vascular disease
- Amyloidosis
- Systemic lupus erythematosis
List 5 ways that systemic diseases manifest in the kidneys?
- Acute kidney injury (AKI)
- Chronic kidney disease (CKD)
- Nephritic syndrome
- Proteinuria
- Nephrotic syndrome
What 4 questions should you ask when suspecting systemic diseases are affecting the kidneys?
- Renal impairment old or new?- previous U&E
- Proteinuria?- Urinalysis & quantitative proteinuria (uPCR)
- Which is it?- AKI/CKD/nephritis/nephrotic syndrome/proteinuria
- Clues to systemic disease?- history and examination
What are 3 other tests to confirm a diagnosis of systemic disease affecting the kidneys?
- Special antibodies, complement, eosinophils,
- Imaging
- Renal biopsy
What do 30-40% of diabetics develop?
Kidney problems
What are 26% of people starting renal replacement therapy?
Diabetic
Why is nephropathy important?
As the stage of diabetic nephropathy increases so does the % mortality rates per annum
What are the 2 main features of diabetic nephropathy?
- Proteinuria is hallmark
2. Associated with retinopathy
What is the chain reaction than hyperglycaemia causes in the kidney nephron?
Volume expansion –> Intra-glomerular hypetension –> Proteinuria –> Hypertension & renal failure
List the 5 structural changes associated with the diabetic kidney glomerulus?
- Thickening of the glomerular basement membrane
- Fusion of foot processes
- Loss of podocytes
- Denuding of glomerular basement membrane
- Mesangial matrix expansion
List 4 kidney complications associated with diabetic kidney disease?
- Anaemia
- Bone & mineral metabolism
- Retinopathy
- Neuropathy
What 2 things reduce the risk of diabetic nephropathy?
- Tight glycaemic control
2. Good BP control: ACEi/ARB/SGLT-2 inhibitors
Describe the effect of diabetes on the kidney nephron?
- Afferent arteriole vasodilation
- Efferent arteriole vasoconstriction
- Increased intraglomerular pressure
- Increased GFR
- Increased glucose & sodium reabsorption
- Increased glucose excretion in urine
What affect do SGLT-2 inhibitors have on the diabetic kidney?
- Afferent arteriole vasoconstriction
- Efferent arteriole unaffected
- Decreased intraglomerular pressure & normalisation of GFR
Give an example of an SGLT-2 inhibitors?
Empagliflozin
What are the 3 main effects of SGLT-2 Inhibitors?
- Glycosuria
- Natriuresis
- Cardiac & Renal protection
What is crucial about diagnosing diabetic nephropathy?
If no protein in urine & no retinopathy then it isn’t diabetic nephropathy
Describe the diagnosis of renal artery stenosis?
- Clinical diagnosis
- No angiogram/CT angiogram/MRI
- Unlike narrowed coronary arteries, there is evidence that angioplasty/stenting is rarely effective in renal vessels
Describe the 4 steps of pathogenesis of renovascular disease?
- Progressive narrowing of renal arteries with atheroma
- Perfusion falls 20%. GFR falls but tissue oxygenation of cortex & medulla maintained
- RA stenosis progresses to 70%. Cortical hypoxia causes microvascular damage & activation of inflammatory & oxidative pathways
- Parenchymal inflammation & fibrosis progress & become irrreversible. Restoration of blood flow provides no benefit
Describe the medical management of renal artery stenosis?
- BP control (not ACEi/ARB)
- Statin
- If diabetic, good glycaemic control
Describe the lifestyle management of renal artery stenosis?
- Smoking cessation
- Exercise
- Low sodium diet
Describe the angioplasty management of renal artery stenosis?
- Rapidly deteriorating renal failure
- Uncontrolled ↑BP on multiple agents
- Flash pulmonary oedema
List 6 differential diagnosis for nephrotic syndrome?
- Various GNs (IgA, minimal change, membranous, FSGS)
- Diabetic nephropathy
- Lupus nephritis
- Viral infections (HBV, HCV, HIV)
- Amyloidosis
- Myeloma
List 3 investigations you would do for nephrotic syndrome?
- Blood tests: glucose, ANA, HBV/HCV/HIV PCR
- Protein electrophoresis/urinary Bence Jones proteins
- Kidney biopsy
What is amyloidosis?
Deposition of highly stable insoluble proteineous material in extracellular space (felt-like substance made of beta-pleated sheets) i.e. in the kidney, heart, liver gut
Describe 2 features of amyloidosis?
- Specific ultrastructural features (8-10nm fibrils)
2. High affinity for the constituents of the capillary wall
Describe the light microscopy of amyloidosis?
Congo red stain: Apple green birefringence
Describe the electron microscopy of amyloidosis?
Amyloid fibrils 9-11nm cause mesangial expansion
What are the 2 classes of amyloidosis?
- AA = systemic amyloidosis (inflammation/infection)
2. AL = immunoglobulin fragments from haematological condition eg myeloma
Describe the treatment of AA amyloid?
Treat the underlying source of inflammation/infection
Describe the treatment of AL amyloid?
Treat the underlying haematological condition
What is glomerular disease?
Nephritic syndrome: AKI with blood and protein on dipstick
List 4 differential diagnosis for nephritic syndrome?
- Vasculitis: ANCA- associated
- Vasculitis: anti-GBM disease
- Vasculitis: lupus nephritis
- IgA nephropathy (crescentic variety)
What is systemic lupus erythematosis (SLE)?
Auto-immune disease: immune complex mediated glomerular disease, serious but treatable!
Describe the pathophysiology of systemic lupus erythematosis (SLE)?
Multiple auto- antibodies directed against DNA, histones, snRNPs, transcriptional/translational machinery
Describe the epidemiology of systemic lupus erythematosis (SLE)?
- Female»male (2-12:1)
- African > Asian > Caucasian
- Genetic predisposition (12+ genes identified) & environmental trigger
Describe the 4 stages of lupus nephritis pathophysiology?
- Auto-antibodies produced against dsDNA or nucleosomes (anti-dsDNA, anti-histone)
- Form intravascular immune complexes or attach to GBM
- Activate complement (low C4)
- Renal damage
How do you confirm a diagnosis of systemic lupus erythematosis (SLE)?
Renal biopsy (stages the disease)
What is the treatment for systemic lupus erythematosis (SLE)?
Immunosuppression: steroids/MMF/cyclophosphamide/rituximab
What does renal involvement in systemic disease confer?
Worse prognosis
What are the 5 clinical signs of cystitis (infection of the bladder)?
- Dysuria
- Frequency
- Urgency
- Suprapubic pain
- Haematuria
What are the 5 specific clinical signs of pyelonephritis (infection of the kidney)?
- Fever (>38ºC)
- Chills/rigors
- Flank pain
- Costo-vertebral angle tenderness
- Nausea/vomiting
List the 8 risk factors for a UTI?
- Infancy: boys and girls under 1 year
- Abnormal urinary tract: congenital or other abnormalities
- Females
- Bladder dysfunction/incomplete emptying
- ‘Foreign’ body
- Diabetes mellitus
- Renal transplant
- Immunosuppression
What 3 factors in females makes UTI’s more common?
- Anatomy
- Sexual intercourse
- Pregnancy
What 3 factors in bladder dysfunction/incomplete emptying makes UTI’s more common?
- Constipation (‘dysfunctional elimination syndrome’)
- Neurogenic bladder
- Prostate enlargement in men
What 2 “foreign” bodies can make UTI’s more common?
- Catheters
2. Stones
Why does diabetes mellitus make UTI’s more common?
Glycosuria promotes bacterial growth
Describe the gender shift with age associated with UTI’s in childhood?
- Much more common in childhood for F > M
- M > F within first 6 months
- 50% of males present < 1 year
- 80% of females present > 1 year
What is the relevance of treating a UTI in childhood?
- Identifying structural abnormality
- Reducing risk of further damage
Describe the structural abnormalities associated with UTI’s in childhood?
- Congenital renal tract abnormality in up to 50%
- Vesico-Ureteric Reflux (VUR) in 30-40%
What are the 3 consequences of UTI’s in childhood?
- Renal Scarring in 10 - 15% (irreversible)
- Chronic Kidney Disease (CKD)
- Hypertension risk increases with burden of scarring: 10-20%
What are 5 “upper tract” UTI’ symptoms?
- Fever
- Lethargy
- General malaise
- Vomiting
- Loin pain
What are 5 “lower tract” UTI symptoms?
- Non specific abdo. pain
- Urgency
- Frequency
- Wetting
- Frank haematuria
When are non-specific UTI symptoms more likely in children?
<2 years
What signs are needed for a diagnosis of acute pyelonephritis/ upper urinary tract infection?
- Bacteriuria and fever > 38°C
- Bacteriuria, loin pain/tenderness and fever of less than 38°C
What signs are needed for a diagnosis of cystitis/ lower urinary tract infection?
Bacteriuria and symptoms or signs of UTI that are not systemic
What are 3 investigations used to diagnose urinary tract infections?
- Multistix (leucocyte esterase + nitrite)
- Microscopy/flow cytometry
- Urine culture
Describe the use of Multistix (leucocyte esterase + nitrite) for UTI diagnosis?
- Useful for child >3 years
- Positive LE & nitrite → UTI in 90%
- Negative for LE & nitrite → No UTI
Describe the use of microscopy/flow cytometry for UTI diagnosis?
Flow cytometry negative for pus cells and bacteria → No UTI
How would you culture urine in all children <3 years with clinical suspicion?
- Obtain urine before starting antibiotics
- “Clean catch”; supra pubic aspiration; catheter specimen
What is the definition of a UTI on urine culture?
- Single organism => 105 CFU/ml (contamination risks)
- Any growth of single organism if SPA
What are the 2 rules of UTI management?
- Prompt identification
2. Antibiotic treatment
When would you teat urine in an infant or child?
Presenting with unexplained fever of 38ºC or higher OR
symptoms and signs suggestive of UTI
Describe the antibiotic treatment for UTIs?
- “Best guess” while awaiting culture and sensitivities
- Oral antibiotic unless severely ill, vomiting, infant <3 months (in practice often < 6 months)
What are the 2 types of IV antibiotic treatment for UTIs?
- 3rd generation cephalosporin: Cefotaxime, Ceftriaxone
2. Aminoglycoside: Gentamicin (monitor levels and renal function)
What are the 5 oral antibiotics given to treat UTIs?
- Co-amoxiclav
- Nitrofurantoin
- Trimethoprim
- Cephalosporin
- Quinolone
Describe when you would image for UTI’s in childhood?
- Age: < 6 months, 6 mo-3 years, > 3 years
- Presentation: pyelonephritis v. cystitis
- Infection: atypical or recurrent
- Family history: Vesico-ureteric reflux
- Imaging abnormalities found: ultrasound, nuclear medicine
Describe when you would give antibiotic prophylaxis for UTIs in childhood?
- Not routinely in ‘simple’ UTI
- Consider for CAKUT
What are 3 antibiotics which can be given prophylactically for UTIs in childhood?
- Trimethoprim
- Nitrofurantoin
- Co-amoxiclav
What are the 3 PROS of ultrasound imaging for UTIs?
- Radiation free
- Readily available
- Good for filleted drainage tracts & cysts
What are 2 CONS of ultrasound imaging for UTIs?
- Operator dependent
2. Less sensitive for scarring, parenchymal change
What is the PRO for Micturating Cystourethrogram (MCUG) for UTIs?
Gold standard for VUR & PUV
What are the 2 CONS for Micturating Cystourethrogram (MCUG) for UTIs?
- Radiation
2. Invasive: UTI risk
What are the 3 types of nuclear medicine imaging scans for UTIs?
- DMSA (static)
- MAG3 indirect cystogram
- MAG3 diuresis renogram
What is the gold standard imaging for scars in UTIs?
DMSA (static) nuclear medicine scan
What is the gold standard imaging for obstruction in UTIs?
MAG3 Diuresis venogram nuclear medicine scan
What indicates renal fixed scarring on a Renal Isotope Imaging (DMSA scan)?
Poor uptake of isotope and irregular kidney outline
What are 3 mechanisms of renal scarring?
- Immunology
- Genetics
- Dysplasia
What are 10 risk factors for renal scarring?
- Age
- High grade VUR
- Anatomical obstruction
- Dysfunctional voiding
- Frequent episodes of APN
- Therapeutic delay
- Bacterial virulence factors
- Host response
- Low birth weight
- Prenatal dysplasia
What are 2 congenital abnormalities of kidney and urinary tract (CAKUT)?
- Vesico-Ureteric Reflux (VUR)
- Obstruction of urinary drainage tracts
- Both may be associated with congenital renal dysplasia
What 3 things are indicated on antenatal alerts- ultrasound?
- Dilated drainage tract
- Renal parenchyma: ‘bright kidneys’
- Oligohydramnios
What are 3 post-natal confirmations for kidney injury?
- Ultrasound
- MCUG
- NM studies: DMSA, MAG-3
What is Vesico-ureteric reflux (VUR)?
Retrograde passage of urine from the bladder into the upper urinary tract
Describe the prevalence of vesico-ureteric reflux (VUR)?
Most common urologic finding in children:
- ~1 percent of newborns
- 30-40% of young children with UTI
Describe the 5 grades of Vesico-ureteric Reflux?
- Grade I: reflux into a non-dilated ureter only
- Grade II: reflux into the renal pelvis & calyces without dilatation
- Grade III: reflux into a mildly to moderately dilated ureter & renal pelvis with no or only slight blunting of fornices
- Grade IV: moderate dilatation & tortuosity of the ureter & renal pelvis, with obliteration of the sharp angle of the fornices but maintenance of papillary impressions in most calyces
- Grade V: gross dilatation & tortuosity of the ureter, renal pelvis, & calyces with loss of papillary impressions
What does MCUG stand for?
Micturating cysto-urethrogram
What does Bilateral vesico-ureteric reflux appear like on a MCUG?
- Dye refluxing into both ureters & renal pelvi-calyceal systems
- Dye filled bladder
Describe the presentation of Vesico-ureteric reflux (VUR)?
- Antenatal hydro-uretero-nephrosis
- UTI & Pyelonephritis: VUR in 30-40%
Describe briefly the grading of vesico-ureteric reflux (VUR)?
- ‘Low grade’: I-II
- ‘High grade’: III-V
Describe the association between vesico-ureteric reflux (VUR) and spontaneous resolution?
- 90% of low grade reflux
- 30-40% of high grade reflux
What does a UTI + vesico-ureteric reflux (VUR) equal?
- 30% ‘renal scarring’
- Much damage due to VUR is prenatal = dysplasia
Describe the medical management of UTI + vesico-ureteric reflux (VUR)?
Antibiotic prophylaxis for high grade VUR (III-V) until toilet trained by day
Describe the surgical management of UTI + vesico-ureteric reflux (VUR)?
- ‘STING’ procedure: Submucosal Teflon INJection
- Open ureteric re-implantation
- Role of circumcision
When would you consider surgical management for a UTI + vesico-ureteric reflux (VUR)?
‘Failed’ medical management:
- Recurrent, proven febrile UTI
- New scarring
What are the 2 commonest complications of circumcision?
- Haemorrhage
2. Infection
What are 5 potential renal areas of obstruction?
- Pelvis/ureter (PUJ)
- Ureter
- Ureter/Bladder (VUJ)
- Bladder
- Urethra
What are the 3 factors to defining an obstruction?
- Identification of the level of obstruction
- Severity
- Duration
What are the 3 types of bladder outlet obstruction?
- Posterior Urethral Valve
- Prostatic Hypertrophy
- Functional obstruction
What is Posterior Urethral Valve the commonest cause of?
Commonest congenital cause of bladder outlet obstruction in male infants
What is prostatic hypertrophy the commonest cause of?
Commonest acquired cause of bladder outlet obstruction in world
What are the 2 types of function bladder outlet obstruction?
- Neurogenic Bladder: Spina Bifida, Sacral agenesis, Spinal Dysraphism, Transverse Myelitis, Trauma
- Prune Belly Syndrome
List the 4 presentations of posterior urethral valve obstruction?
- Antenatal hydronephrosis
- Urinary tract infection
- Poor urinary stream
- Renal dysfunction
What are the 2 potential posterior urethral valve structures affected leading to obstruction?
Valve leaflets or circumferential diaphragm
What are the 3 means of management for posterior urethral valve obstruction?
- Valve resection
- Antibiotic prophylaxis
- CKD care
What are the two % outcomes for posterior urethral valve obstruction?
- Chronic Renal Failure: 7%
2. Mortality: 7%
Describe the presentation of Pelvi-ureteric junction obstruction?
- Commonest cause of hydronephrosis in children
- Frequently noted on antenatal ultrasound
- Abdominal mass, pain, haematuria, UTI
Describe the presentation of Vesico-ureteric junction obstruction?
- Anatomical narrowing v. functional obstruction
- Antenatal dilatation, UTI, Abdominal mass, pain, haematuria
Describe the observant management of Pelvi-ureteric junction obstruction?
- USS & DMSA
- MAG 3 diuresis renogram
Describe the surgical management of Pelvi-ureteric junction obstruction?
Pyeloplasty
Describe the observant management of Vesico-ureteric junction obstruction?
- 50%-90% improve or resolve
- USS & DMSA
- MAG 3 diuresis renogram
Describe the surgical management of Vesico-ureteric junction obstruction?
- Temporary: stent insertion
- Definitive: resection & re-implantation
When would you consider surgical management for Vesico-ureteric junction obstruction?
For symptoms or increasing dilatation up to 30% require surgery
What are the 3 main consequences of renal scarring from pyelonephritis?
- Hypertension
- Chronic kidney disease
- Mortality
What is a cyst?
Sac like structure containing fluid
Where do cysts arise in the kidneys?
Arise from the tubules
How do cysts cause problems?
Compressing other structures, replacing useful tissue, becoming infected, bleeding, pain
What is the inheritance of adult polycystic kidney disease?
Autosomal dominant
Describe the prevalence of adult polycystic kidney disease (APKD)?
- Commonest inherited kidney disorder
- 5-10% of patients with end stage renal failure
Describe the 2 mutations in adult polycystic kidney disease (APKD)?
- PKD 1 gene mutation (chromosome 16) = 85% (1270 mutations)
- PKD 2 gene mutation (chromosome 4) = 15% (200 mutations)
What are polycystins?
Membrane proteins involved in intracellular calcium regulation
What is overexpressed in cyst cells?
Polycystins
Where are polycystins located?
In renal tubular epithelia (and liver and pancreas ducts)
Describe the 4 natural history steps of adult polycystic kidney disease?
- Cysts gradually enlarge
- Kidney volume increases
- Some compensation
- eGFR falls, usually 10y before kidneys fail
What are the 3 factors when diagnosing polycystic kidney disease via ultrasound?
- Differentiate between ‘simple renal cysts’
- Family history: ultrasound at age 21 (if negative, should be repeated age 30 or will miss 14%)
- No family history: 10 or more cysts in both kidneys, renal enlargement, liver cysts
What imaging tests are more sensitive for polycystic kidney disease diagnosis?
CT or MRI better than ultrasound
List the 2 adult polycystic kidney disease renal complications?
- 50% risk ESRD by age 50y
2. Cyst ‘accidents’ 60%
List 7 other complications of adult polycystic kidney disease?
- Hypertension
- Intracranial aneurysms (3%)
- Mitral valve prolapse 25%
- Aortic incompetence 10%
- Colonic diverticular disease
- Liver / pancreas cysts
- Hernias
Describe the 5 factors to managing adult polycystic kidney disease?
- Management is supportive
- Early detection and management of blood pressure
- Treat complications
- Manage extra-renal associations
- Renal replacement therapy
What is Tolvaptan treatment for adult polycystic kidney disease?
Vasopressin V2 receptor antagonist
List the 5 consequences of Tolvaptan treatment for adult polycystic kidney disease?
- Delay onset of RRT by around 4-5 years
- Heavy monitoring
- Hepatotoxicity
- Hypernatraemia
- Very expensive
What 2 situations do the Scottish medicines consortium (SMC) recommend the use of Tolvaptan treatment?
CKD3 & declining renal function
List 4 other rare cystic diseases?
- Von Hippel Lindau
- Tuberous sclerosis
- Medullary cystic disease
- Autosomal recessive PKD
Describe Von Hippel Lindau?
- Multiple benign and malignant tumours
- Autosomal dominant
Describe Tuberous sclerosis?
- Multiple benign tumours brain, eyes, heart, kidney, skin
- Epilepsy and learning difficulties
- Autosomal dominant
Describe Medullary cystic disease?
- Medulla not cortex, small to normal sized kidneys; gout
- Autosomal dominant
Describe autosomal recessive PKD?
- Children
- Hepatic fibrosis
Describe the inheritance of Alport’s Syndrome?
Usually X-linked: if inherited, affected or carrier
Describe the prevalence of Alport’s Syndrome?
Second most common inherited kidney disease (1/5000 prevalence)
Describe the 4 collagen abnormalities associated with Alport’s syndrome?
- Alpha 3 gene mutation
- Alpha 4 gene (COL3A4) mutation OR
- Alpha 5 (COL3A5) gene mutation
List the 2 signs of Alport’s syndrome?
Deafness & renal failure (can affect other organs including eyes)
Where is collagen 4 found?
Basement membranes
Describe the abnormal glomerular basement membrane in Alport’s syndrome?
- Initially thin
- Becomes split & laminated with many different layers
List the 4 clinical consequences of Alport’s syndrome?
- Microscopic haematuria, proteinuria and end stage renal failure (ESRF)
- 90% on dialysis or transplant by age 40y, 50% by age 25y
- Sensorineural hearing loss late childhood
- Female Alport’s carriers: 12% ESRF by age 40y
Describe the inheritance of Fabry’s disease?
Rare X-linked storage disorder
Describe the abnormality in Fabry’s disease?
- Alpha galactosidase A deficiency resulting in accumulation of globotriaosylceramide (Gb3
- Gb3 accumulates in glomeruli, particularly podocytes causing proteinuria and ESRF
What are 3 other consequences of Gb3 accumulating in the glomeruli?
- Neuropathy
- Cardiac
- Skin features (Angiokeratoma)
How do you diagnose Fabry’s disease?
- Measure alpha-Gal A activity in leukocytes
- Renal biopsy: inclusion bodies of G3b
How do you manage Fabry’s disease?
Enzyme replacement therapy
What do dialysed patients have a 5% risk of?
End stage renal failure
Why does acute kidney injury confer an additional mortality?
Due to sepsis, bleeding, respiratory failure etc
What is the definition of acute kidney injury (severity)?
- No agreed definitions
- “Decline of renal excretory function over hours or days …recognized by the rise in serum urea and creatinine”
What is AKI e-alerts?
Uses an algorithm to highlight when creatinine changed to indicate patient has AKI
What are the 3 scenarios when an AKI e-alert would go off?
- Serum creatinine ≥1.5 times higher than the median of all creatinine values 8–365 days ago
- Serum creatinine ≥1.5 times higher than the lowest creatinine within 7 days
- Serum creatinine >26 µmol/L higher than the lowest creatinine within 48 h
What is the KDIGO definition of stage 1 acute kidney injury?
Serum creatinine ≥1.5 and < 2.0 times AKI baseline or >=26.0 µmol/l increase above AKI baseline
What is the KDIGO definition of stage 2 acute kidney injury?
Serum creatinine >=2.0 and < 3.0 times AKI baseline
What is the KDIGO definition of stage 3 acute kidney injury?
Serum creatinine 3.0 times AKI baseline or >=354 µmol/l increase above AKI baseline
What are the 3 classifications for acute renal failure?
- Pre-renal= circulatory failure “shock”
- Renal= the cells of the kidney
- Post Renal= Obstruction
What are the 3 types of renal (intrinsic) disease?
- Glomerular: glomerulonephritis
- Tubular (obsruction & dysfunction): ischaemic cute tubular necrosis, nephrotoxic cute tubular necrosis, myeloma cast nephropathy
- Tubulointerstitial: drugs, myeloma sarcoid
What are 4 types of pre-renal (reduced renal perfusion) diseases?
- Hypovolaemia & hypotension: diarrhoea/vomiting/burns, inadequate fluid intake, blood loss through trauma
- Reduced effective circulating volume: cardiac failure, septic shock, cirrhosis
- Drugs: ACE1, NSAIDS
- Renal artery stenosis
What are 6 types of post-renal diseases?
- Renal papillary necrosis
- Kidney stones (at any level)
- Retroperitoneal fibrosis
- Carcinoma of the cervix
- Prostatic hypertrophy/malignancy
- Urethral strictures
What are the 2 key facts of the kidneys?
- Kidneys need a blood supply to make urine
2. And need an unobstructed collecting system to ensure that urine can be excrete
What are all post renal causes of kidney disease?
Obstructive- Anything between renal pelvis and urethral meatus which obstructs flow of urine
What are the 4 broad categories of intrinsic acute kidney injury?
- Large blood vessels
- Small blood vessels & glomeruli
- Tubulointerstitium
- Acute tubular necrosis (ischaemic/toxic)
What are the 3 most common causes of intrinsic acute kidney injury?
- Acute tubular necrosis- 80%
- Obstructive- 10%
- Glomerulonephritis (primary & secondary)- 3%
What drug specifically can cause renal acute kidney injury?
Gentamicin
Give 1 example of a glomeruli (vasculitis) cause of acute kidney injury?
Glomerulonephritis
Give 2 examples of a tubular cause of acute kidney injury?
- Tubulo-interstitial nephritis
2. Rhabdomyolysis
What is Acute tubular necrosis generally?
Any pre-renal cause of AKI if severe/of sufficent duration
Describe the prognosis of Acute tubular necrosis?
- Usually reversible
- ~10-15% will never recover renal function
- A further 10-15% will have chronic renal impairment
What is Acute tubular necrosis always due to?
Under perfusion of the tubules and/or direct toxicity
Give 4 examples of acute tubular necrosis causes?
- Hypotension
- Sepsis
- Toxins
- Or often, all three
List 3 exogenous toxins which can cause acute tubular necrosis?
- Drugs (eg, NSAID’s gentamicin,ACEinh)
- Contrast
- Poisons (eg, metals, antifreeze)
List 5 endogenous toxins which can cause acute tubular necrosis?
- Myoglobin
- Haemoglobin
- Immunoglobins
- Calcium
- Urate
What happens to the glomerular filtration as pressure falls?
Prostaglandins dilate afferent arteriole to increase flow as MAP falls towards 80mmHg
What are the 5 things to target when managing acute kidney injury?
- Acute or chronic?
- Bloods: both urea and creatinine ↑
- Potassium (biggest thing to kill the patient)
- Urine output (usually <400ml/day)
- Clinical assessment of fluid status (BP, JVP, oedema, heart sounds)
- Underlying diagnosis (history, exam, meds)
What are the 6 steps to treatment of acute kidney injury?
- Immediate
- Airway & breathing
- Circulation: shock- restore renal perfusion
- Remove causes: drugs, sepsis
- Exclude obstruction & consider ‘renal’ causes
- Ask for help: ICU or renal unit
What are the 7 steps in the diagnostic process of acute kidney injury?
- AKI or CKD?
- History and exam (e.g. septic, rashes, haemoptysis, rhabomyolysis etc)
- Drugs (prescribed, OTC, supplements, radio-contrast and abuse)
- Urinalysis
- Renal ultrasound
- ‘GN’ screen: ANCA, ANA, Immunoglobulins + EP, complement, aGBM, Urine Bence Jones protein
- Others blood film, LDH, CK etc
How do you exclude obstruction in kidney disease?
Renal ultrasound