Renal & Urology Overview Flashcards

1
Q

What are the functions of the kidney?

A
  • regulation of blood pressure & volume via RAAS
  • acid-base balance
  • electrolyte balance
  • production of new RBCs stimulated by Epo
  • contains 1-alpha-hydroxylase, which is needed to produce the active form of vitamin D
  • acts as a filter for the excretion of water-soluble waste products
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2
Q

How is the kidney involved in bone metabolism?

A
  • the prohormone, 25(OH)D is produced in the liver
  • the kidney contains 1-alpha-hydroxylase, which will hydroxylate the prohormone to produce the active hormone
  • active vitamin D leads to increased calcium absorption in the gut and the bone
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3
Q

How is renal function measured?

A

renal function = flow rate from the glomerulus into the Bowman’s capsule

  • this is the glomerular filtration rate (GFR)
    • ​it is a measure of the volume of blood being filtered by the glomerulus each minute
  • any value of GFR > 90 ml/min is considered normal
    • this means that the glomerulus is filtering 90ml of blood each minute
  • GFR typically reduces at a rate of 1 ml/min/year
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4
Q

What is the gold standard measurement of GFR?

A
  • the only way that GFR can be measured is with inulin clearance
  • inulin is freely filtered by the glomerulus, not secreted or reabsorbed in the tubules and is not synthesised or metabolised by the kidney
  • calculations involve concentrations of inulin in the urine and serum
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5
Q

How can blood urea be used as an endogenous marker of GFR?

A
  • urea is a by-product of protein metabolism that is freely filtered at the glomerulus
  • it has variable reabsorption (30-60%) depending on nutritional state, hepatic function and GI bleeding
    • e.g. GI bleed can raise serum urea
  • raised serum urea can indicate poor kidney function
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6
Q

How can serum creatinine be used to estimate GFR (eGFR)?

What equation is used to work this out and what factors does it take into account?

A
  • creatinine is derived from muscle cells, freely filtered at the glomerulus and not reabsorbed
  • the Cockcroft-Gault equation is used to estimate creatinine clearance and eGFR
    • this estimates how much creatinine is being cleared from the blood
  • creatinine clearance is affected by age, sex, ethnicity and weight
    • ​more creatinine is produced when there is more muscle mass
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7
Q

What would a normal urea : creatinine ratio be?

A
  • urea is reabsorbed by the tubules, but creatinine is not
  • normal urea to creatinine ratio is 40:1 to 100:1
  • this ratio is used when looking at different types of kidney injury
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8
Q

What is the problem with the Cockroft-Gault equation?

A
  • it is used to measure creatinine clearance as a measure of eGFR
  • it often overestimates the true GFR, especially when < 30 ml/min
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9
Q

If both of these people have a serum creatinine of 100, why is it important to measure eGFR?

A
  • creatinine clearance (eGFR) is important to measure when giving drugs that are renally cleared
  • if the drugs are not being cleared sufficiently, it can lead to renal toxicity
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10
Q
A

500ml of 0.9% saline over 15 minutes

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11
Q
A
  • this looks like a pre-renal AKI
  • need to give an IV fluid bolus and maintenance fluids
  • hold nephrotoxic medications
    • metformin
    • NSAIDs
    • ACE-inhibitors
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12
Q

What mnemonic can be used to remember the nephrotoxic drugs?

A

DAMN

  • D - diuretics
  • A - ACEi / ARBs
  • M - metformin (can predispose to lactic acidosis)
  • N - NSAIDs
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13
Q

What is meant by acute kidney injury?

Why does it occur and how is it measured?

A
  • a rapid decline in renal function over hours to days

there is failure to maintain homeostasis of:

  • fluid - leading to oliguria** or **volume overload
  • electrolytes - leading to hyperkalaemia
  • acid-base balance - leading to metabolic acidosis
  • it is measured by looking at urea and creatinine
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14
Q

What are 2 easy ways to spot an AKI?

Is it reversible?

A
  • the easiest way to recognise AKI is that the patient stops peeing
  • look at creatinine** as this will be **acutely raised
  • it is potentially reversible
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15
Q

What is meant by chronic kidney disease?

How is it diagnosed?

A
  • this is a chronic and irreversible process with 5 stages
  • there must be impaired renal function for > 3 months based on:
    • abnormal structure or function
    • or GFR < 60 ml/min for > 3 months
    • +/- evidence of kidney damage
  • this is progressive and irreversible, ending in end-stage renal failure
  • it is monitored by looking at eGFR
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16
Q

What symptoms may someone with an AKI present with?

A

symptoms depend on underlying cause, but typically:

  • oliguria / anuria
    • abrupt anuria suggests a post-renal cause
  • nausea & vomiting
  • dehydration
  • shortness of breath
  • confusion
    • encephalopathy from uraemia (build-up of urea in the brain)
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17
Q

What signs might someone with AKI present with?

A
  • hypertension
  • distended bladder
    • typically seen with an obstructive cause
  • postural hypotension due to dehydration
  • if they have fluid overload - raised JVP, peripheral / pulmonary oedema
    • ​i.e. in cirrhosis, heart failure, nephrotic syndrome
  • if they have vascular disease - bruising, rash, pallor
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18
Q

What classification system is used for AKI?

A

KDIGO classification system

  • need to check the patient’s baseline creatinine to determine whether a rise is significant

Stage 1:

  • 1.5x rise in creatinine compared to baseline
  • OR urine output <0.5 ml/kg/hr for > 6 hours

Stage 2:

  • 2x rise in creatinine compared to baseline
  • OR urine output <0.5 ml/kg/hr for > 12 hours

Stage 3:

  • 3x rise in creatinine compared to baseline
  • OR urine output < 0.3 ml/kg/hr for > 24 hours
  • OR anuria for > 12 hours
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19
Q

What are the risk factors for AKI?

What mnemonic can be used?

A

CHARD CH

  • C - chronic kidney disease
  • H - hypovolaemia
    • this is the most common cause of AKI
  • A - age > 75
  • R - renal transplant
  • D - diabetes
  • C - contrast administration
  • H - heart ailure
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20
Q

What is meant by a pre-renal cause of AKI?

What 4 states can lead to pre-renal AKI?

A

there is inadequate perfusion to the kidney

when there is decreased blood flow to the glomerulus, there is decreased blood filtration

  • this is most commonly due to hypovolaemia
  • systemic vasodilatation (e.g. in sepsis)
  • decreased cardiac output
  • intrarenal vasoconstriction
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21
Q

What is meant by renal and extrarenal losses leading to hypovolaemia and pre-renal AKI?

A

Renal loss:

  • loss of fluid from diuretic overuse
  • osmotic diuresis (e.g. diabetic ketoacidosis)

Extrarenal loss:

  • vomiting and/or diarrhoea
  • burns
  • sweating
  • blood loss
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22
Q

What can cause systemic vasodilatation or decreased cardiac output leading to pre-renal AKI?

A

Systemic vasodilatation:

  • sepsis
  • neurogenic shock

Decreased cardiac output:

  • heart failure
  • myocardial infarction
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23
Q

What can cause intra-renal vasoconstriction leading to pre-renal AKI?

A
  • cardiorenal syndrome
  • hepatorenal syndrome
  • renal artery stenosis
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24
Q

What are the consequences of pre-renal AKI?

What will happen to the urea:creatinine ratio and why?

A
  • reduced urine output
    • if there is no bloodflow to the kidney, urine cannot be produced
  • urea is raised much higher than creatinine so urea:creatinine > 100:1
  • this is due to dehydration and urea resabsorption by the kidneys
    • urea is still being reabsorbed as the kidneys themselves are not damaged
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25
Q

What is involved in the inital management of pre-renal AKI?

What factors need to be monitored?

A
  • start with NEWS monitoring and observe for life-threatening complication
    • should be able to identify hyperkalaemia / hypovolaemia
  • need to treat hypovolaemia
  • catheterise the patient to monitor fluid balance
  • need to monitor K+, lactate (for signs of sepsis) and daily creatinine
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26
Q

What is involved in investigations for pre-renal AKI?

A

Urine dipstick:

  • proteinuria and/or haematuria could be a sign of glomerulonephritis

USS:

  • should be performed within 24 hours unless there is an obvious cause

VBG:

  • check electrolytes, glucose & lactate
  • check platelets to rule out thrombotic cause like HUS or TTP
  • if AKI does not improve, consider investigations for intrinsic renal disease
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27
Q

What is involved in the management of pre-renal AKI?

A
  • bolus fluid and maintenance fluid
  • treat the underlying cause e.g. sepsis
  • stop nephrotoxic medications
  • stop / change medications that are heavily renally excreted
    • e.g. LMWH
    • if eGFR < 30 then use another form of prophylactic VTE
  • avoid radiological contrast
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28
Q

Which class of antibiotics are known to be nephrotoxic?

A

aminoglycosides

(e.g. amikacin, gentamicin)

these can cause acute tubular necrosis

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29
Q

What causes a renal AKI?

What are the 4 different types?

A
  • this is caused by cellular / intrinsic damage to the kidney
  • the different types depend on where the damage is located
    • tubular
    • glomerular
    • interstitial
    • vascular
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30
Q

What is the main tubular cause of renal AKI?

What causes this?

A

acute tubular necrosis

  • ischaemia
  • drugs
    • NSAIDs
    • paracetamol
    • ACE inhibitors
  • toxins
    • contrast
    • myoglobulinuria in rhabdomyolysis
  • these cause death of the tubular epithelial cells than form the renal tubules of the kidneys
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31
Q
A
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32
Q

How are the renal tubular epithelial cells damaged in acute tubular necrosis?

A
  • prolonged hypoperfusion state leading to ischaemia
    • this can be due to pre-renal AKI from sepsis that has not been treated and has progressed
  • systemic vasodilation - sepsis, DIC
  • exogenous and endogenous nephrotoxic agents
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33
Q

How does acute tubular necrosis cause AKI?

A
  • death of renal tubular epithelial cells leads to sloughing of these cells and obstruction of the tubules
  • there is increased hydrostatic pressure within the tubules, which leads to reduced GFR
  • there is reduced filtration / reabsorption
  • this leads to reduced urine output
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34
Q

What are exogenous and endogenous nephrotoxins that can cause ATN?

A

Exogenous (drugs):

  • aminoglycosides
  • NSAIDs
  • contrast media
  • cisplatin
  • calcineurin inhibitors
  • amphotericin B

Endogenous:

  • myoglobinaemia (rhabdomyolysis)
  • haemoglobinuria
  • uric acid crystals
  • IgG light chains in myeloma
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35
Q

What urine findings would you expect to see in ATN?

A
  • muddy brown granular casts of epithelial cells
  • myoglobinuria and haemoglobinuria
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36
Q

What features of renal AKI would you expect to see in ATN?

How would urea : creatinine be affected?

A
  • raised urea
  • raised creatinine
  • raised potassium
  • metabolic acidosis
  • in renal causes of AKI, urea : creatinine is < 40 : 1
    • the kidney itself is not functioning, so urea cannot be reabsorbed
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37
Q

Hyperkalaemia is a complication of renal AKI.

What is involved in the management of this condition?

A
  • medical emergency so escalate senior help and start ABCDE approach
    • hyperkalaemia carries risk of cardiac arrhythmias + cardiac arrest
  • continuous cardiac monitoring + baseline ECG + IV access
  • stop any nephrotoxic drugs
  • give 10ml 10% calcium gluconate** IV over **10 mins
    • this protects the myocardium but onset is 4 hours
  • give 100ml 20% dextrose** with **8U insulin** over **15 mins
  • give 10-15mg nebulised salbutamol
  • sodium bicarbonate 1.26% over 6 hours to correct acidosis
  • monitor ECG changes
  • (insulin and salbutamol both work to drive K+ back into cells and out of the blood)*
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38
Q

What ECG changes are associated with hyperkalaemia?

A
  • tall tented T waves
  • small / absent P waves
  • broad QRS complex
  • increased PR interval
  • bradycardia
  • VT
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39
Q

What is the main cause of glomerular renal AKI?

A

glomerulonephritis

  • this is inflammation of the glomeruli and nephrons
  • there are many different types of glomerulonephritis with different aetiologies
    • e.g. postinfectious
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40
Q

How does glomerulonephritis show up on urine dipstick and BP?

A
  • blood pressure can range from normal to malignant hypertension
  • proteinuria and haematuria will be present on urine dipstick
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41
Q

What are the consequences of glomerular inflammation on renal function?

How do these present?

A

Loss of barrier function:

  • when podocytes are damaged and the barrier is lost, there is loss of protein and blood
  • proteinuria (mild to nephrotic syndrome)
  • haematuria (mild to macrocytic)

Loss of filtering capacity:

  • reduced excretion leads to accumulation of waste products and AKI
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42
Q

What is the interstitial cause of renal AKI?

A

interstitial nephritis

  • this is caused by drugs, infection and infiltration
  • it involves inflammation of the renal interstitium (fluid surrounding the renal tubules)
  • there will be eosinophils in the urine
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43
Q

What are the vascular causes of renal AKI?

A
  • this is caused by vessel obstruction
    • thrombosis
    • vasculitis
    • haemolytic microangiopathy
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44
Q

In order to make urine, how many layers do the solutes have to pass through?

A
  • blood enters glomerulus via an afferent arteriole
  • within the glomerulus, solutes must then pass through the wall of the Bowman’s capsule
    • endothelial cells
    • glomerular basement membrane
    • slit diaphragms of podocytes
  • solutes (urea, electrolytes, waste products) are then within the urinary space
  • they will then pass into the renal tubules that lead to the collecting ducts
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45
Q

What is meant by acute pyelonephrititis?

A
  • inflammation of the renal pelvis of the kidney
  • it is a form of upper urinary tract infection that is usually caused by bacteria
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46
Q

What is the difference between a lower and an upper urinary tract infection?

A
  • a lower UTI affects the urethra and the bladder
  • an upper UTI affects the ureters and the kidneys
  • an upper UTI is usually caused by ascending infection
    • bacteria begin by colonising the urethra / bladder and then make their way up the ureter to the kidney
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47
Q

What are the risk factors for an upper UTI?

A

the risk factors for upper UTI are very similar to those of a lower UTI

  • female sex
  • sexual intercourse
  • indwelling catheter
  • diabetes
  • urinary tract obstruction
  • vesicoureteral reflux (VUR)
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48
Q

What is meant by vesicoureteral reflux (VUR)?

Why does it happen?

A
  • urine can move backwards up the urinary tract
  • this occurs when the vesicoureteral orifice fails
    • this is a one way valve that allows urine to flow from each ureter into the bladder
  • this can be due to a primary congenital defect
  • OR it can be due to bladder outlet obstruction
    • ​this leads to increased pressure within the bladder, which distorts the valve
49
Q

Why is someone with vesicoureteral reflux more likely to get acute pyelonephritis?

A
  • when there is a bladder outlet obstruction, there is also urinary stasis
  • this makes it easier for bacteria to adhere to and colonise the urinary tract
  • bacteria can ascend from the bladder, up the ureters and into the renal pelvis
50
Q

What are the most common organisms that cause acute pyelonephritits via ascending infection?

A
  • E. coli
  • Enterobacter spp.
  • Proteus spp.
  • these are all commonly found in bowel flora
51
Q

Other than ascending infection, how else may the renal pelvis become infected to cause acute pyelonephritis?

Which organisms are associated with this method of transmission?

A
  • kidneys can be infected via haematogenous spread
    • this is the spread of infection via the bloodstream
  • pyelonephritis from haematogenous spread is usually a complication of sepsis, bacteraemia or infective endocarditis
  • this is most commonly due to E. coli or Staphylococcus spp.
52
Q

Is acute pyelonephritis usually unilateral or bilateral?

A
  • it is usually unilateral (affects one kidney only)
53
Q

What might be found in the urine of someone with acute pyelonephritis?

Why does this occur?

A

white blood cells in urine + white blood cell casts

  • bacteria start adhering to the renal epithelium, which triggers an inflammatory response
  • cytokines attract neutrophils to the renal interstitium
  • neutrophils infiltrate and die off
  • dead neutrophils pass through the urinary tract and are excreted in the urine
  • cells and protein debris may be cast into the shape of the tubule and then excreted - this is cast
54
Q

What triad of symptoms is associated with acute pyelonephritis?

What condition is it difficult to distinguish from?

A
  • it is difficult to clinically distinguish from a lower UTI
  • the triad of:
    • flank pain (usually unilateral) at the costovertebral angle
    • nausea & vomiting
    • fever

occurs more often in acute pyelonephritits than lower UTI

  • onset is typically sudden with signs and symptoms of both systemic inflammation and bladder inflammation
55
Q

What are common signs and symptoms associated with acute pyelonephritits?

A
  • flank pain and/or tenderness at the costovertebral angle
  • fever and/or rigors
  • nausea & vomiting
  • myalgia
  • flu-like symptoms
  • may have polyuria / nocturia / haematuria
56
Q

What is the treatment for acute pyelonephritis?

A
  • an antibiotic is started once a midstream or catheter specimen of urine has been obtained for C&S
  • drink lots of fluids to avoid dehydration
  • use paracetamol for the pain
57
Q

Which antibiotics might be prescribed in acute pyelonephritits?

A
  • ciprofloxacin
  • trimethoprim
    • only if in line with C&S results
  • co-amoxiclav
    • only if in line with C&S results
  • cefalexin
    • ​this is prescribed in pregnancy
58
Q

What are the possible complications of acute pyelonephritis?

A
  • sepsis
  • recurrent urinary tract infections - which can lead to chronic pyelonephritis
  • parenchymal renal scarring
  • renal abscess formation
  • preterm labour in pregnancy
59
Q

What is meant by chronic pyelonephritis?

A
  • chronic inflammation of the renal pelvis and kidney
  • usually caused by recurrent episodes of acute pyelonephritis, which leads to the kidney becoming visibly scarred
60
Q

Does acute pyelonephritis always lead to chronic pyelonephritis?

A
  • an episode of acute pyelonephritis usually clears up with NO complications
  • certain people are predisposed to having recurrent episodes of acute pyelonephritis
  • this eventually leads to chronic pyelonephritis and permanent scarring of the renal tissue
61
Q

What is the most common risk factor for having recurrent episodes of acute pyelonephritis that progresses to chronic pyelonephritis?

A

vesicoureteric reflux (VUR)

  • urine flows backwards up the urinary tract due to failure of the vesicoureteric orifice
  • this occurs due to a primary congenital malformation
  • or due to bladder outlet obstruction, which increases the pressure within the bladder and distorts the valve
62
Q

How does chronic obstruction of the urinary tract increase risk of chronic pyelonephritis?

A
  • obstruction of the urinary tract leads to urinary stasis
  • when urine stands still, it is easier for bacteria to adhere to and colonise the tissue in the urinary tract
  • this makes recurrent lower UTIs, and therefore also upper UTIs, more likely
63
Q

What can cause bilateral obstruction of the urinary tract?

Does this affect one or both kidneys?

A
  • bilateral obstruction refers to obstruction of the urethra
  • it leads to an increase in pressure within the bladder, so will affect both kidneys
  • it can be caused by:
    • congenital malformations - such as posterior urethral valve which obstructs flow through the urethra
    • benign prostatic hyperplasia
    • cervical carcinoma
  • BPH and cervical carcinoma can compress the urethra and cause it to shut
64
Q

What is meant by unilateral obstruction?

Will this affect one or both kidneys?

A
  • this is an obstruction higher up in the urinary tract (e.g. ureters)
  • this will only affect one kidney
  • the most common cause of unilateral obstruction is renal calculi (kidney stones)
65
Q

What changes occur in the kidney when there is recurrent inflammation?

Which parts of the kidney tend to be affected?

A
  • one episode of inflammation may not lead to any permanent damage
  • recurrent inflammation eventually leads to fibrosis and scarring of the renal interstitium
  • renal tubules will atrophy
  • these changes tend to be found in the upper and lower poles of the kidney
66
Q

What would be seen on imaging in chronic pyelonephritis?

A
  • CT urogram shows blunting / flattening of the renal calyces
67
Q

What is seen on histology in chronic pyelonephritis?

A
  • some tubules may be dilated and full of glassy-looking proteinaceous material called colloid
  • colloid forms as a result of chronic inflammation
  • it ends up becoming shaped like the tubules and forming colloid casts** that are **excreted in the urine
  • this is sometimes called “thyroidisation of the kidney” as the colloid resembles thyroid tissue
68
Q

What happens in xanthogranulomatous pyelonephritis (XGP)?

A
  • this is a rare form of chronic pyelonephritis
  • it occurs when an infected kidney stone causes a chronic obstruction
  • the combination of infection and increased pressure creates granulomatous tissue
    • there is destruction of the renal parenchyma, which is replaced with granulomatous tissue
69
Q

How can xanthogranulomatous pyelonephritis be recognised on histology?

A

the presence of granulomatous tissue

  • this is full of foamy (fat-laden) macrophages
  • it is easily confused for a kidney tumour on imaging
70
Q

What are the signs and symptoms of chronic pyelonephritis?

A

the same as acute pyelonephritis + hypertension

71
Q

How is chronic pyelonephritis treated?

A

need to treat the underlying cause of recurrent infection

  • surgery to correct VUR / remove obstruction
  • kidney transplant
  • nephrectomy - removal of some or all of the kidney
  • dialysis may be needed
72
Q

What type of infection and kidney stone is associated with development of xanthogranulmoatous pyelonephritis (XGP)?

A
  • staghorn kidney stone is large and branching in nature
  • it is associated with _*Proteus* infections_
  • Proteus bacteria will alkalinise the urine, leading to an ammonia smell
  • chronic Proteus infections are associated with XGP, which presents with necrotic, haemorrhagic masses with foamy macrophages
73
Q

What is cystitis?

What different things can cause it?

A
  • cystitis is a lower UTI that involves inflammation of the bladder
  • it is usually due to bacterial infection, but can also be caused by:
    • fungal infection
    • trauma to the bladder
    • chemical irritation
    • foreign bodies (e.g. kidney stone)
74
Q

What is meant by an ascending and descending infection?

Which is more common in cystitis?

A
  • lower UTIs are nearly always caused by ascending infection

Ascending infection:

  • bacteria migrate from the rectal area** to the **urethra
  • they then migrate up the urethra and into the bladder

Descending infection:

  • bacteria start in the blood or lymph
    • this is most commonly pyelonephritis as a consequence of sepsis/bacteraemia
  • they infect the kidneys and then descend down the ureters and into the bladder and urethra
75
Q

What is meant by urine being sterile?

What 2 mechanisms are in place to prevent bacteria from growing in the urine?

A
  • normally urine is sterile and contains NO bacteria
  • urine is high in urea** and has a **low pH which helps to stop bacterial growth
  • the unidirectional flow when urinating helps prevent bacteria invading the urethra and bladder
76
Q

Which Gram-negative and Gram-positive bacteria commonly cause cystitis?

A

Gram-negative:

  • Escherichia coli
    • this is the most common cause of lower UTI
  • Proteus mirabilis
  • Klebsiella pneumoniae
  • ​Enterobacter spp. and Citrobacter spp.

Gram positive:

  • Staphylococcus saprophyticus
    • this is the 2nd most common cause of lower UTI
    • it is more prevalent in sexually active young females
  • Enterococcus spp.
77
Q

What are the risk factors for cystitis?

A
  • sexual intercourse
  • female gender
  • diabetes mellitus
  • foley / indwelling catheter
  • infant boys with foreskin (opposed to being circumcised)
  • impaired bladder emptying
78
Q

How does sexual intercourse increase risk of cystitis?

What usually causes this?

A
  • sexual intercourse allows bacteria to be introduced into the urethra
  • this is referred to as “honeymoon cystitis”
  • it is more common in younger females
  • it is usually caused by Staphylococcus saprophyticus
79
Q

Why does being female increase the risk of cystitis?

A
  • females have a shorter urethra
  • this means that bacteria ascending up the urethra do not have to travel as far
  • the urethra is also closer to the rectum, which is where most of the causative organisms originate from
  • in post-menopausal women, a decrease in oestrogen leads to the loss of the normal protective vaginal flora, increasing risk of UTI
80
Q

How does diabetes mellitus act as a risk factor for cystitis?

A
  • diabetes is a risk factor due to the presence of hyperglycaemia
  • normally, when there is an infection, neutrophils move out of the circulatory system (blood) towards the infection in the process of diapedesis
  • neutrophils also carry out phagocytosis

hyperglycaemia inhibits diapedesis and phagocytosis

  • this means that neutrophils are less effective at killing bacteria
81
Q

Why does impaired bladder emptying increase risk of cystitis?

A
  • impaired bladder emptying leads to urinary stasis
  • when the urine is not moving, there is increased opportunity for bacteria to adhere to and colonise the bladder
  • e.g. in bladder tumour
82
Q

What are the typical symptoms of cystitis?

A
  • suprapubic pain
  • dysuria
    • this is pain on urinating / difficulty urinating
  • frequent urination
  • increased urgency
83
Q

How can the symptoms of cystitis (lower UTI) be used to distinguish it from pyelonephritis (upper UTI)?

A
  • cystitis typically DOES NOT have systemic symptoms
    • nausea & vomiting
    • fever / rigors
    • pain at costovertebral angle
  • if these symptoms are present then consider upper UTI
84
Q

What type of cell is present in the urine in cystitis?

How can this make the urine appear?

A

PYURIA

  • this is the presence of WBCs in the urine, suggesting inflammation
  • it can make the urine appear cloudy
  • it is normal to have some WBCs in the urine, but becomes abnormal when there are > 10 WBCs/mm3
85
Q

If you dipstick the urine of someone with cystitis, what would you expect to see and why?

A

Leukocyte esterase:

  • this is an enzyme produced by WBCs that is positive in pyuria

Nitrites:

  • gram-negative bacteria convert nitrates into nitrites
    • nitrities will not always be positive in UTI
    • associated with E. coli, Klebsiella & Proteus
86
Q

What is the gold-standard test for diagnosing cystitis?

A

urine culture

  • considered positive when there are > 100,000 CFUs per ml in a midstream urine sample
87
Q

What is sterile pyuria?

What does it suggest if this is present?

A
  • this occurs when there is pyuria** but **urine culture is negative
  • as there is pyuria, leukocyte esterase will be positive
  • this suggests urethritis (inflammation of the urethra)
  • this is commonly caused by Neisseria gonorrhoeae and Chlamydia trachomatis
    • these are both sexually transmitted infections
  • urethritis presents with the same symptoms as cystitis so this is used to distinguish between them
88
Q

What 3 imaging techniques may be used in cystitis?

A

Renal ultrasound:

  • used in children to identify kidney malformations

Voiding cystourethrogram (VCUG):

  • this involves injection of radiocontrast fluid and watching how it moves when urinating
  • this can be used to detect vesicoureteral reflux (VUR)

Renal scintigraphy:

  • involves injection of DMSA and detecting evidence of renal scarring
89
Q

What is involved in the treatment for cystitis?

A
  • antibiotics targeted at the bacterial cause are given
    • symptoms tend to clear up within a few days
  • pain medication
  • advice for preventing further infections:
    • ​drinking as much fluid as possible to flush out bacteria
    • emptying the bladder as much as possible
    • urinating after sexual intercourse
    • good hygiene - wiping from urethra to rectum
90
Q

What is meant by hydronephrosis?

A

a disease caused by excessive amounts of water (in the form of urine) causing dilation of the kidneys

91
Q

What is the normal flow of urine like?

A
  • urine is produced by the nephrons
  • it passes through the renal papillae and into the calyces
  • from the calyces it enters the renal pelvis, which drains into the ureter
92
Q

Why does hydronephrosis occur?

What are the 2 main categories of causes?

A
  • it occurs when there is an obstruction to the normal flow of urine
  • this increases pressure within the urinary system and causes the walls of the structures involved to dilate
  • this can occur due to internal causes - i.e. an obstruction within the urinary tract
    • e.g. kidney stones
  • or it can occur due to external compression
    • ​e.g. foetus compressing the urinary tract in pregnancy
93
Q

What is the difference between hydroureter and hydronephrosis?

A
  • it is hydroureter when there is dilation of the ureter
  • it is hydronephrosis when there is dilation of the ureter, renal pelvis and calyces
94
Q

What causes antenatal hydronephrosis (in the foetus)?

At what point does this become concerning?

A
  • often the cause is unknown and it develops and disappears on its own
  • if it persists past the third trimester then you are concerned about an underlying pathology
  • this could be congenital ureteropelvic junction obstruction
    • the ureteropelvic junction connects the kidney to the ureter
    • if it fails to canalise during development then this obstructs the flow of urine
  • or it could occur due to vesicoureteral reflux
95
Q

What are the 2 most likely causes of hydronephrosis in a young child?

A

the cause is likely to be congenital

  • ureterocoele
    • this is a sac of tissue in the distal ureter that obstructs the flow of urine into the bladder
  • posterior urethral valves
    • ​these are flaps of tissue that obstruct the outflow of urine
96
Q

What are the 2 most common causes of hydronephrosis in adults?

A
  • the most common cause is kidney stones
  • benign prostatic hyperplasia
    • an enlarged prostate blocks the flow of urine out of the urethra
97
Q

What damage can long-standing hydronephrosis lead to?

A
  • long-standing hydronephrosis can lead to nephron destruction
  • this leads to a rise in serum creatinine and electrolyte disturbances
  • continued damage can cause dilated ureter and renal pelvis
  • as well as compression atrophy** - this is **thinning of the renal cortex and medulla
98
Q

What are the typical symptoms and complications of hydronephrosis?

A
  • symptoms are typically related to the obstruction
    • groin pain / flank pain
    • urinary tract infection
    • nausea / fever
    • pain on urination / increased frequency
  • hydronephrosis itself only causes symptoms once there is serious damage to the kidneys
  • it can cause post-renal azotemia
    • ​an obstruction to urine flow leads to the kidneys reabsorbing more urea
    • this leads to an increase in nitrogen-containing compounds in the blood
99
Q

How is hydronephrosis usually diagnosed and graded?

A
  • it is usually diagnosed and graded using ultrasound
  • 0 - there is no dilation
  • 1 - there is dilation involving the renal pelvis, but not the renal calyces
  • 2 - there is dilation of the renal pelvis + calyces
  • 3 - there is moderate dilation of renal pelvis + calyces

with mild cortical thinning

and flattening of the papillae

  • 4 - there is severe dilation + cortical thinning
100
Q

What additional investigations may be performed in adults and children to diagnose hydronephrosis?

A

Children:

  • intravenous urography or pyelography
    • used to assess for evidence of congenital ureteropelvic junction obstruction

Adults:

  • CT scan is performed to look for kidney stones
101
Q

What is the acute treatment for hydronephrosis?

A
  • insertion of a nephrostomy tube
  • this tube is inserted through the skin and into the renal pelvis
  • it allows for accumulated urine to be drained out
102
Q

What is involved in the chronic treatment of hydronephrosis?

A
  • a ureteric stent may be inserted to keep the ureter open
  • a pyeloplasty may be performed - this is a surgical remake of the renal pelvis
  • lower urinary obstructions (e.g. BPH) can be treated with insertion of a urinary catheter to keep the urethra open
103
Q

What is meant by benign prostatic hyperplasia (BPH)?

A
  • this is the non-cancerous growth of the prostate gland
  • hyperplasia means increase in the number of cells
  • benign (non-cancerous) means that they do not invade into neighbouring tissues
  • it is common in men > 50 and is considered a normal part of aging
104
Q

Where is the prostate located?

Which structure passes through it?

A
  • it is a small gland about the size of a walnut
  • it is located inferior to the bladder and anterior to the rectum
  • the urethra passes through the prostate gland before reaching the penis
    • this part of the urethra is known as the prostatic urethra
105
Q

What are the 3 zones of the prostate?

What are they surrounded by and what do they contain?

A
  • the prostate is surrounded by a capsule of tough connective tissue and smooth muscle

Peripheral zone:

  • this is the largest zone and is the outermost posterior section
  • it contains 70% of the glandular tissue

Central zone:

  • it contains 25% of the glandular tissue and the ejaculatory ducts that join with the prostatic urethra

Transitional zone:

  • it contains 5% of the glandular tissue and the prostatic urethra
  • contains transitional cells that are also found in the bladder
106
Q

What types of cells are found within the basement membrane that surrounds the tiny prostate glands?

A
  • each of the tiny glands that make up the prostate is surrounded by a basement membrane
  • within this basement membrane is a layer of cube-shaped basal cells
  • neuroendocrine cells are interspersed between the basal cells
  • there is a row of luminal columnar cells within the lumen / centre of the gland
107
Q

What is secreted by the luminal cells of the prostate?

A
  • they secrete substances into the prostatic fluid which make it slightly alkaline
  • they also give nutrients into the prostatic fluid which nourish the sperm and help them to survive in the acidic environment of the vagina
108
Q

What is involved in the process of ejaculation?

Where do sperm, semen and prostatic fluid join together?

A
  • during an ejaculation, sperm leave the testes and travel through the vas deferens into the ejaculatory ducts
  • the ejaculatory ducts** join with the **prostatic urethra
  • smooth muscle within the prostate contracts to push prostatic fluid into the urethra
    • here it joins with the sperm and semen (from seminal vesicles)
109
Q

What is secreted by luminal cells that aids with ejaculation?

What does it do?

A

prostate specific antigen (PSA)

  • this helps to liquefy the gel-like semen after ejaculation, which helps free up the sperm so they can swim more easily
110
Q

What hormones do the basal and luminal cells of the prostate rely on for survival?

Where do these hormones come from and how do they exert an effect?

A
  • basal and luminal cells rely on stimulation from androgens
  • testosterone is produced in the testes
  • dihydrotestosterone is produced within the prostate gland
  • androgens are steroid hormones so they can cross the cell membrane and bind to androgen receptors in the nucleus
  • this process inhibits apoptosis, which allows the basal and luminal cells in the prostate to keep growing and multiplying
111
Q

How does dihydrotestosterone differ from testosterone?

How is it produced?

A
  • it is produced in the prostate by 5a-reductase
  • 5a-reductase converts testosterone into dihydrotestosterone
  • dihydrotestosterone is 10x more potent than testosterone as it can bind to androgen receptors for longer
112
Q

What happens to the levels of testosterone and dihydrotestosterone with increasing age?

A
  • after the age of 30 men produce 1% less testosterone per year
  • the amount of testosterone decreases with age
  • 5a-reductase activity increases with age
  • there is an increase in levels of dihydrotestosterone
  • normal prostate cells respond to the increase in dihydrotestosterone by living longer and multiplying
    • this leads to an increase in the size of the prostate gland
113
Q

What is the association between BPH and prostate cancer?

What type of nodules form in BPH?

A
  • BPH carries no increased risk of developing cell mutations that lead to prostate cancer
  • the entire prostate gland enlarges uniformly
  • small hyperplastic nodules form within the prostate gland
  • these nodules are smooth, elastic and firm
    • they can sometimes be mistaken for prostate cancer
114
Q

Where do hyperplastic nodules tend to form within the prostate?

How can this lead to effects on the bladder?

A
  • hyperplastic nodules tend to form in the periurethral zone
    • this is the area surrounding the prostatic urethra
  • nodules can compress the urethra and make it more difficult for urine to pass through
  • urine builds up in the bladder and causes it to dilate
  • smooth muscle in the bladder wall contracts harder in response
  • this leads to bladder hypertrophy - the walls thicken and become easily irritated
  • stagnation of urine in the bladder also promotes bacterial growth and can lead to UTIs
115
Q

What are the symptoms of BPH and when do they start?

A
  • symptoms start when the prostatic urethra becomes obstructed and include:
  • hesitancy - trouble initiating urination
  • dribbling - a weak and inconsistent stream of urine
  • dysuria - pain on urination
  • straining whilst urinating to overcome obstruction
  • as urine builds up in the bladder it causes a constant sense of incomplete bladder emptying

this increases frequency of urination at night (nocturia)

116
Q

How can BPH be diagnosed?

What blood test may be performed?

A

through digital rectal examination (DRE)

  • the anterior wall of the rectum lies along the posterior prostate
  • an enlarged prostate could indicate BPH, whilst hard nodules could be a sign of prostate cancer
  • levels of PSA are elevated in BPH
    • this is produced by healthy prostate cells
    • there is an increase in number of prostate cells in BPH
117
Q

What is the first-line treatment for BPH?

How does this medication work?

A
  • treatment involves 5a-reductase inhibitors** like **finasteride
  • this shrinks the prostate by inhibiting conversion of testosterone into dihydrotestosterone
  • this relieves the obstruction and allows the urine to flow normally
118
Q

What are the other 2 treatments available for the treatment of BPH?

A

a1-antagonists:

  • these bind to a1 receptors on smooth muscle in the neck of the bladder, prostate and urethra
  • they cause relaxation of the smooth muscle, allowing urine to pass

Surgical intervention:

  • this involves removal of part or all of the prostate through transurethra resection of prostate (TURP)