The Case Of The Injured Kidneys Flashcards
Intravenous Contrast Media - Used in … (3)
- Contrast enhanced plain films –IVU
- CT scanning
- Angiography / interventional procedures
Intravenous Contrast Media - What is it, what does it do and how is it given?

- Iodinated hydrocarbon ring
- Iodine atomic number 53
- Increases absorption of x-rays
- Injected intravenously
Side effects of iodinated contrast (5)
- Warmth / Flushing
- Headache
- Nausea
- Itching / rash
- Metallic taste
- These do NOT indicate allergy to contrast
Reactions to contrast (Allergy)
- Urticaria
- Bronchospasm
- Laryngeal oedema
- Hypotension
- Generalised anaphylaxis
- Incidence of severe reactions: 0.04%
- Incidence of major anaphylaxis: 0.004%
Reactions to contrast (Allergy)
- Incidence of severe reactions: …%
- Incidence of major anaphylaxis: …%
- Urticaria
- Bronchospasm
- Laryngeal oedema
- Hypotension
- Generalised anaphylaxis
- Incidence of severe reactions: 0.04%
- Incidence of major anaphylaxis: 0.004%
Patients at risk of contrast reaction
- Previous contrast reaction
- Asthma (6 times increase risk of reaction)
- NOT shellfish allergy or topical Iodine reaction
Contrast reaction - what do we give?
- Oxygen and IV fluids,
- Anti-hystamine – chlorphenamine 10mg
- Hydrocortisone – 200mg
- Adrenaline(IM) – 1:1000 (500mcg initially)
RCR recommendations - contrast
- Doctor available whenever IV contrast is injected
- If risk factors – decision to inject contrast is taken by radiologist only.
- Patient never left alone in first 5 mins after injection
- Facilities / drugs for treating reaction readily available
Contrast-Mediated Nephrotoxicity
- Nephrotoxicity:
- defined as …% increase in serum creatinine 48-72hrs following contrast injection
- A leading cause of hospital acquired …, with increased in-hospital/1yr mortality
- Direct cytotoxic effect on proximal renal tubules (and exacerbate renal vasoconstriction)
- Nephrotoxicity:
- defined as 25% increase in serum creatinine 48-72hrs following contrast injection
- A leading cause of hospital acquired AKI, with increased in-hospital/1yr mortality
- Direct cytotoxic effect on proximal renal tubules (and exacerbate renal vasoconstriction)
- Risk of Nephrotoxicity if:
- renal impairment (raised creatinine)
- Diabetes
- Metformin therapy
- Caution if dehydration, high dose of contrast, CCF
Risk of Nephrotoxicity if:
- …. impairment (raised …)
- D…
- … therapy
- Caution if …, … dose of contrast, CCF
Risk of Nephrotoxicity if:
- renal impairment (raised creatinine)
- Diabetes
- Metformin therapy
- Caution if dehydration, high dose of contrast, CCF
Preventing contrast induced AKI
- Stop …. (48hrs post contrast injection)
- Pre- and post-hydration (oral/IV) – intra-vascular volume expansion maintains renal perfusion
- Use of contrast is on a risk Vs benefits basis
- e.g. Trauma or cancer imaging.
- …. mandated if:
- History of renal disease or DM
- …. dose of CM than average
- If using IA route that will directly expose the kidneys to a larger/more concentrated dose
- Stop Metformin (48hrs post contrast injection)
- Pre- and post-hydration (oral/IV) – intra-vascular volume expansion maintains renal perfusion
- Use of contrast is on a risk Vs benefits basis
- e.g. Trauma or cancer imaging.
- eGFR mandated if:
- History of renal disease or DM
- Larger dose of CM than average
- If using IA route that will directly expose the kidneys to a larger/more concentrated dose
Preventing contrast induced AKI
- Stop Metformin (… post contrast injection)
- Pre- and post-hydration (oral/IV) – intra-vascular volume expansion maintains renal …
- Use of contrast is on a risk Vs benefits basis
- e.g. Trauma or cancer imaging.
- eGFR mandated if:
- History of renal disease or ….
- Larger dose of CM than average
- If using IA route that will directly expose the kidneys to a larger/more … dose
- Stop Metformin (48hrs post contrast injection)
- Pre- and post-hydration (oral/IV) – intra-vascular volume expansion maintains renal perfusion
- Use of contrast is on a risk Vs benefits basis
- e.g. Trauma or cancer imaging.
- eGFR mandated if:
- History of renal disease or DM
- Larger dose of CM than average
- If using IA route that will directly expose the kidneys to a larger/more concentrated dose
Imaging in AKI
- Exclude …. – i.e. is obstruction the cause of the AKI
- s…
- …: TCC, prostate, gynae
- 1st Investigation – renal …
- Exclude hydronephrosis – i.e. is obstruction the cause of the AKI
- Stones
- Tumour: TCC, prostate, gynae
- 1st Investigation – renal U/S
CT Imaging- Kidneys
- Left image shows - Right … – normal size kidneys (preserved …. thickness)
- Right image shows - Left …. –

- Right hydronephrosis – normal size kidneys (preserved cortical thickness)
- Left hydronephrosis – 5mm stone dependent in renal pelvis ? Further stone in ureter?
Nephrostomy Insertion

Renal sepsis:
- ….:
- U/S is usually normal in acute ….
- CT often normal. May be oedema, debris, gas or perinephric stranding
- Pyelonephritis:
- U/S is usually normal in acute pyelonephritis
- CT often normal. May be oedema, debris, gas or perinephric stranding

Peri-nephric abscess
- Left - Large … within the perinephric fat posterior to the kidney
- Right - … from …. obstruction. Perinephric abscess extening into … muscle
- Both of these abscesses can be drained under…guidance (exactly the same technie as the nephrostomy)

- Left - Large abscess within the perinephric fat posterior to the kidney
- Right - Pyelonephritis from stone obstruction. Perinephric abscess extening into psoas muscle
- Both of these abscesses can be drained under U/S guidance (exactly the same technie as the nephrostomy.
Reminder of key functions - Kidneys
- Fill in the blanks


Reminder of key functions - Kidneys
- Fill in the blanks


What is kidney failure?
- Loss of … …
- –Irreversible, slow, progressive….CKD
- Urine output …
- –Potentially reversible, rapid onset…AKI
- Oliguria (low urine output)
- Anuria (no urine output)
- –Irreversible, slow, progressive….CKD
- Degrees of failure
- Stages 1-… in CKD
- Stages 1-… in AKI
- Loss of functioning nephrons
- –Irreversible, slow, progressive….CKD
* Urine output preserved- –Potentially reversible, rapid onset…AKI
- Oliguria (low urine output)
- Anuria (no urine output)
- –Potentially reversible, rapid onset…AKI
- –Irreversible, slow, progressive….CKD
- Degrees of failure
- Stages 1-5 in CKD
- Stages 1-3 in AKI
What is kidney failure?
- Loss of functioning nephrons
- –Irreversible, slow, progressive……..
- Urine output preserved
- –Potentially reversible, rapid onset…….
- … (low urine output)
- …. (no urine output)
- –Irreversible, slow, progressive……..
- Degrees of failure
- Stages 1-5 in ….
- Stages 1-3 in ….
- Loss of functioning nephrons
- –Irreversible, slow, progressive….CKD
- Urine output preserved
- –Potentially reversible, rapid onset…AKI
- Oliguria (low urine output)
- Anuria (no urine output)
- Degrees of failure
- Stages 1-5 in CKD
- Stages 1-3 in AKI
Degrees of failure - Kidneys

What can go wrong? - Kidney tubules

What can go wrong? - Kidney Glomeruli

What can go wrong? - Kidney Blood Vessels

What can go wrong? - Kidney Interstitium

Effects of diabetes on the glomerulus

Pathogenesis of diabetic kidney disease
- Podocyte damage leading to …
- High glucose environment—
- > reactive oxygen species->vascular endothelial cell damage - Tubulo-interstital and glomerular …
- Podocyte damage leading to albuminuria
- High glucose environment—
- > reactive oxygen species-àvascular endothelial cell damage - Tubulo-interstital and glomerular fibrosis

Who gets diabetic kidney disease?

Tubules


What is ATN?
Acute tubular necrosis (ATN) is a kidney disorder involving damage to the tubule cells of the kidneys, which can lead to acute kidney failure.
Types of injury in ATN - Ischaemic (8)
- Diarrhoea, vomiting
- Bleeding
- Dehydration
- Burns
- Renal losses via diuretics or osmotic diuresis
- Third fluid sequestration (e.g nephrotic syndrome)
- Oedematous states such as heart failure and cirrhosis cause reduced kidney perfusion.
- Coagulopathy, such as disseminated intravascular coagulation
Types of injury in ATN - Toxic (9)
- Aminoglycosides
- Amphotericin B
- Acyclovir
- Cisplatin
- Cidofovir
- Uric acid (gout)
- Light chain accumulation (myeloma)
- Myoglobin (rhabdomyolysis)
- Ethylene glycol
Types of injury in ATN - Sepsis (3)
- Systemic hypoperfusion
- Endotoxins leading to vasoconstriction
- Inflammatory cytokines-àROS-àinjury
AKI: What works?
Goals of therapy are to prevent AKI or need for RRT
- Effective……….. Once AKI is present
- … (…% saline)
- Prevent …
- Avoid …
- Treat …
- Specific treatment (mostly …)
- Effective……….. Once AKI is present
- Hydration (0.9% saline)
- Prevent hypotension
- Avoid nephrotoxins
- Treat obstruction
- Specific treatment (mostly immunosuppression)

The … compartment is affected in all the forms of renal disease.
The tubulointerstitial compartment is affected in all the forms of renal disease.
AKI - drug causes
- Gentamicin
- Vancomycin
- NSAIDS
- Ethlyene glycol
AKI - UTI causes
- Leptospirosis
- CMV
Renal Blood Vessels
Renal vascular disease
Final common pathway
Treatments in CKD
- Each condition might have specific treatment.
- e.g. Diabetes-good … control
- e.g. ….-iv fluids including iv bicarbonate
- …/… (like ramipril)
- … inhibitors (like dapagliflozin)
- Each condition might have specific treatment.
- e.g. Diabetes-good glycaemic control
- e.g. Rhabdomyolysis-iv fluids including iv bicarbonate
- ACEi/ARB (like ramipril)
- SGLT2 inhibitors (like dapagliflozin)
Renal replacement therapy comprises either …. or ….
Renal replacement therapy comprises either transplantation or dialysis
Renal Function: responsible for … (4)
- Excretion of waste
- Maintenance of extracellular fluid(ECF) volume and composition
- Hormone synthesis(erythropoeitin, vitamin D, Renin/Aldo)
- Also contribute to gluconeogenesis
Kidneys receiving …% of cardiac output
- Kidneys receiving 25% of cardiac output
- Blood → glomerular capillary tuft → glomerular filtrate
- Glomerular filtrate is ultrafiltrate of …
- Glomerular filtrate has similar composition to … except …
- Total filtration rate of the kidneys depends on … pressure, osmotic pressure and integrity of … membrane
- Kidneys receiving 25% of cardiac output
- Blood → glomerular capillary tuft → glomerular filtrate
- Glomerular filtrate is ultrafiltrate of plasma
- Glomerular filtrate has similar composition to plasma except protein
- Total filtration rate of the kidneys depends on hydrostatic pressure, osmotic pressure and integrity of basement membrane
- Normal Glomerular filtration rate (GFR) is approximately … ml/min ˷ 170L/24h much of it is reabsorbed in proximal convoluted tubules(PCT)
- Estimated GFR (eGFR) is used in clinical practice
- Normal Glomerular filtration rate (GFR) is approximately 120 ml/min ˷ 170L/24h much of it is reabsorbed in proximal convoluted tubules(PCT)
- Estimated GFR (eGFR) is used in clinical practice
Biochemical investigation of kidney function
Creatinine
Creatinine origin

Biochemical investigation of kidney function
Creatinine - limitations (5)
- Creatinine starts to rise only when there is a significant decline in glomerular filtration (~50% glomeruli lost)
- Serum levels can increase with ingestion of large amounts of meat
- Patient with fluid overload has a lower serum creatinine due to dilution of blood
- Malnutrition and inactivity decreases muscle mass, thus decrease serum creatinine
- Sensitivity of serum creatinine in mild to moderate renal impairment is poor.
GFR vs serum creatinine
Levey et al Ann Int Med 1999

_Biochemical investigation of kidney function Creatinine Clearance (Ccr) - GFR_
- To assess GFR(clearance test) : measuring the urinary excretion of a substance that is completely …, not secreted, reabsorbed or metabolised
- Inulin, iohexol– meet the criteria but not suitable in routine clinical use, rarely used as rarely required to accurately measure GFR (kidney donor assessment)
- -The most widely used clearance test is Ccr, (Cr is secreted by renal tubules but negligible when GFR is normal)
- Cr Clearance = U x V/P (ml/min)
- U= Urinary Cr concentration -µmol/L
- V= Urine flow rate -ml/min
- P= Plasma Cr concentration - µmol/L
- To assess GFR(clearance test) : measuring the urinary excretion of a substance that is completely filtered, not secreted, reabsorbed or metabolised
- Inulin, iohexol– meet the criteria but not suitable in routine clinical use, rarely used as rarely required to accurately measure GFR (kidney donor assessment)
- -The most widely used clearance test is Ccr, (Cr is secreted by renal tubules but negligible when GFR is normal)
- Cr Clearance = U x V/P (ml/min)
- U= Urinary Cr concentration -µmol/L
- V= Urine flow rate -ml/min
- P= Plasma Cr concentration - µmol/L