Theme 10: Kidney and Urinary Tract Pathology Flashcards
What parameters define nephrotic syndrome?
Proteinuria >3.5g/24hrs
or
Urine protein/creatinine ratio >300-350mg/mmol
If a patient passes 100-400 ml of urine in 24 hours, this is described as:
a) Dysuria
b) Anuria
c) Oliguria
d) Polyuria
c) Oliguria
If a patient passes <100 ml of urine in 24 hours, this is described as:
a) Dysuria
b) Anuria
c) Oliguria
d) Polyuria
b) Anuria
If a patient passes >3000 ml of urine in 24 hours, this is described as:
a) Dysuria
b) Anuria
c) Oliguria
d) Polyuria
d) Polyuria
Which renal function test uses a formula that takes into account age, sex and ethnicity?
eGFR
Uses the abbreviated MDRD equation
Fluids and solutes that are reabsorbed by the renal tubules are returned to the circulation by the __?__
Peritubular capillary network
What is the primary cause of nephrotic syndrome in adults?
Membranous nephropathy
- Usually M aged <60y
- Related to autoantibodies against PLA2R
True or false: Nephrotic Syndrome results from damage to the glomerulus
True
Glomerular damage increases the permeability to albumin and other plasma proteins.
True or false: Nephritic syndrome involves the loss a lot of blood?
True
Nephritic syndrome is characterised by haematuria. This is due to podocytes developing large pores which allow blood and protein to escape in the urine.
Nephrotic syndrome is characterised by proteinuria.
What is the clinical picture associated with nephrotic syndrome?
Frothy urine caused by massive proteinuria (>3.5g in 24hrs).
This causes hypoalbuminaemia, leading to oedema (due to loss of intravascular colloid pressure) and hyperlipidemia (liver compensates for albumin loss but also creates lots of lipids at the same time).
NephrOtic and prOtein both have an ‘O’!
What are the primary causes of nephrotic syndrome?
Adults:
- Membranous glomerulonephritis
Children:
- Minimal change glomerulonephritis
Both:
- Focal segmental glomerulosclerosis
What are the primary causes of nephritic syndrome?
Post-infectious glomerulonephritis
- Streptococcal
- Appears weeks after URTI
IgA Nephropathy
- Appears a day or two after URTI
What clinical picture is seen with acute renal failure?
Anuria/oliguria (<400 ml/24hrs)
- Malaise
- Nausea
- Vomiting
- Electrolyte imbalance
What is the most common cause of renal artery stenosis?
Atheroma
What complications arise from renal artery stenosis?
Ischaemic injury to affected kidney –> reduced function
Activation of RAAS –> hypertension
__?__ results in a permanently reduced eGFR due to a reduction in the number of functional nephrons.
Chronic renal failure
How can renal disease cause anaemia?
Reduced renal function = reduced EPO production
What is isolated haematuria?
Haematuria (+/- proteinuria) with normal renal function
Causes:
- IgA nephropathy
- Thin basement membrane disease
- Alport’s disease (type IV collagen abnormality)
- Urological malignancy (e.g. renal cell carcinoma)
What are the risk factors for acute pyelonephritis?
Female (ascending infection)
Diabetes
Instrumentation
Urinary tract structural abnormalities
What are the major complications associated with acute and chronic pyelonephritis?
Acute pyelonephritis:
- Abscess formation
Chronic pyelonephritis:
- Scarring
- Chronic renal failure
What are the risk factors associated with chronic pyelonephritis?
Urinary tract obstruction
Urinary reflux
Which condition is associated with:
- Intimal fibrosis of arcuate sized arteries
- Arteriolar hyalinosis
- “Flea-bitten” appearance
Hypertensive nephropathy (or nephrosclerosis)
Thickening of vessel wall = reduced lumen = reduced blood flow
Scattered petechiae create ‘flea-bitten’ appearance
Kimmelstiel-Wilson lesions are associated with which condition?
Diabetic nephropathy (a.k.a diabetic nodular glomerulosclerosis)
What is the most abundant protein found in normal urine?
Uromodulin (Tamm-Horsfall protein)
Macroglossia is associated with which urinary tract malignancy?
Wilms Tumour
Patients with Beckwith-Wiedemann syndrome often have macroglossia (a large tongue) and are also at increased risk of developing Wilms’ tumours. In severe cases of macroglossia, there are problems with swallowing (NG tube), problems breathing (tracheostomy tube) and problems with speech development.
You see evidence of urolithiasis on your patient’s X ray. What is the stone least likely to be made of?
a) Calcium
b) Struvite (magnesium ammonium phosphate)
c) Urate
c) Urate
Not only are urate stones much less common than Calcium/ struvite stones, they are also radiolucent (ie you cannot see them on a plain X ray).
Which of the following are linked to benign prostatic hyperplasia?
(select one or more options)
a) Invasion in to the bladder wall
b) Detrusor muscle hypertrophy
c) Predisposition to UTIs
d) Autoimmune cross-reactivity
b and c
b) Detrusor muscle hypertrophy
- BPH narrows the urethra, meaning the bladder muscle (the detrusor muscle) needs to work hard to get urine past the blockage. As the muscle is working harder, it gets bigger to adapt to this new environment
c) Predisposition to UTIs
- Stasis of urine in the bladder predisposes to UTI’s. This would make the bladder appear red and inflamed
BPH is benign so does not invade.
There is no autoimmune component to BPH.
Which of the following is a risk factor for urothelial carcinoma?
a) Occupational exposure to dyes
b) BRCA gene mutation
c) Cryptorchidism
d) VHL gene mutation
a) Occupational exposure to dyes
Occupational exposure to dyes is a recognised risk factor for the development of urothelial carcinoma. BRCA + is a risk factor for prostate cancer, cryptorchidism is a risk factor for testicular cancer and VHL + is a risk factor for renal cell carcinoma.
Which of these complication is least likely to result from penile cancer?
a) Urinary obstruction
b) Bowel obstruction
c) Sexual dysfunction
d) Death
b) Bowel obstruction
Advanced penile cancer has a poor prognosis and can be fatal (~10% 5YSR if mets present). Urinary and sexual function are affected if the tumour grows and compresses the urethra. There is no common association with bowel symptoms.
A 2 year old child presents with a urological malignancy. Which of the following is the most likely diagnosis?
a) Renal cell carcinoma
b) Seminoma
c) Wilms’ tumour
d) Urothelial carcinoma
c) Wilms tumour
Wilms’ tumour is a relatively common paediatric malignancy. RCC and urothelial carcinoma are diseases of the elderly and seminoma is a disease of young men.
A patient with prostate cancer develops back pain. What is this most likely caused by?
a) Local effect of primary tumour
b) Effect of distant metastases
c) Paraneoplastic syndrome
b) Effect of distant mets
The bones are a common site for prostate carcinoma metastases, and if they go to the spine, the presenting symptoms is often back pain.
What is the most common cancer of the kidney?
Clear cell carcinoma
Which groups are most at risk of renal cell carcinoma?
Renal cell carcinomas most commonly affect the elderly, males and those with Von Hippel-Lindau syndrome
What are the local effects of the primary tumour in renal cell carcinoma?
Haematuria
Abdominal pain
Where do renal cell carcinomas commonly metastasise?
Lung (SoB)
Bone (pain)
True or false: Paraneoplastic syndromes are rare in renal cell carcinoma
False:
PNS are common in RCC and include:
- Cachexia
- Hypertension (increased renin secretion)
- Polycythemia (increase EPO secretion)
Nephroblastoma is also known as __?__
Wilms’ Tumour
Wilms tumours arise from which cells?
Nephroblasts (the primitive cells that differentiate into kidney cells)
Which groups are at greatest risk of developing Wilms’ tumour?
Children under 5
Beckith-Wiedemann, WAGR and Denys-Drash are all associated with which urological cancer?
Wilms Tumour
What are the local effects of the primary tumour in Wilms Tumour?
Abdominal distention
Haematuria
True or false: Metastasis is rare in Wilms tumours
True
What paraneoplastic syndromes are associated with Wilms’ tumours?
There aren’t any common associations. PNS are rare in Wilms’ tumour
Which gene is usually implicated with development of a Wilms’ tumour?
WT1
What is the most common composition of urinary tract calculi?
Calcium (70%)
‘staghorn’ calculi are associated with which type of renal stones?
a) Calcium
b) Urate
c) Cystine
d) Struvite
d) Struvite
Urate renal calculi are associated with:
(select all that apply)
a) Hypercalcaemia
b) Gout
c) Malignancy
d) UTI
b and c
Urate stones are associated with gout (caused by urate crystals) and malignancy (high cell turnover = lots of DNA in the blood, which is converted into urate)
Which renal stones are associated with UTI?
Struvite stones are associated with UTIs
Urease producing bacteria cause increased conversion of urea to ammonia, leading to a rise in pH. This allows precipitation of magnesium ammonium phosphate (struvite) salts, leading to stones.
Which condition is caused by the ureter entering the bladder at an abnormal angle?
Vesicoureteral reflux (VUR)
What are the symptoms associated with vesicoureteral reflux?
Usually asymptomatic
+/- symptoms of UTI or renal impairment, if present
True or false: Vesicoureteral reflux generally affects children under 2 and they tend to ‘grow out of it’
True
Which urological malignancy is associated with smoking and exposure to industrial chemicals (e.g. dyes)?
Urothelial (transitional) cell carcinoma
