Diseases of the renal system 2 Flashcards Preview

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Flashcards in Diseases of the renal system 2 Deck (41):
1

What is obstructive uropathy?

- Obstruction of the urinary tract
- Can occur anywhere from the renal pelvis to the urethral meatus
- Onset may be chronic or acute
- Unilateral or bilateral

2

What are the pelvic causes of urinary tract obstruction?

- calculi
- tumours
- ureteropelvic stricture

3

What are the ureter-intrinsic causes of urinary tract obstruction?

- calculi
- tumours
- clots
- sloughed papillae
- inflammation

4

What are the ureter-extrinsic causes of urinary tract obstruction?

- pregnancy
- tumours (i.e. cervix)
- retroperitoneal fibrosis

5

What are the bladder causes of urinary tract obstruction?

- calculi
- tumours
- functional (e.g. neurogenic)

6

What are the prostatic causes of urinary tract obstruction?

- Hyperplasia
- carcinoma
- prostatitis

7

What are the urethral causes of urinary tract obstruction?

- Posterior valve stricture
- tumours (rare)

8

What are the possible sequelae of urinary tract obstruction?

- Infection- cystitis, ascending pyelonephritis
- Stone/calculi formation
- Kidney damage - Acute or chronic

9

What do the consequences of a urinary tract obstruction depend on?

- Site of obstruction
- Degree of obstruction
- Duration of obstruction

10

What is the result of obstructive uropathy - acute complete obstruction?

- Reduction in glomerular filtration rate
- Mild dilatation and mild cortical atrophy

- Can cause acute renal failure

11

What is the result of obstructive uropathy - chronic and intermittent?

- Continued glomerular filtration -> Dilatation of pelvis+calyces

- Filtrate passes back into interstitium -> Compression of medulla -> Impaired concentrating ability

- Eventual cortical atrophy, fall in renal filtration and renal failure



12

What are the clinical features of obstruction?

Acute bilateral obstruction
- Pain,
- Acute renal failure and anuria

Chronic unilateral obstruction
- Asymptomatic initially
- If unresolved cortical atrophy and reduced renal function

Bilateral partial obstruction
- Initially polyuric with progressive renal scarring and impairment

13

What is the epidemiology of renal calculi?

- Affect 7-10% of the population - increasing
- Male predominance
- Peak onset 20 – 30
- Can form anywhere in the urinary tract but most commonly in the kidney

14

What is the pathogenesis of renal calculi?

- Either due to an excess of substances which may precipitate out e.g. Ca+
- A change in the urine constituents causing precipitation of substances e.g. change in pH
- Poor urine output – Supersaturation
- Decreased citrate levels

15

How are renal calculi composed?

By composition
- Calcium stones (70%) - calcium oxalate +/- calcium phosphate
- Struvite stones (15%) – magnesium ammonium phosphate
- Urate stones (5%) – uric acid
- Cystine stones (1%)

16

What is the most common cause of calcium stones?

Most commonly identified cause is hypercalciuria, due to:
- Hypercalcaemia
- Bone disease, PTH excess, sarcoidosis
- Excessive absorption of intestinal Ca+
- Inability to reabsorb tubular Ca+
- Idiopathic

17

What are the other risk factors for calcium stones?

- Gout: forms a core for Ca+ crystal formation
- Hyperoxaluria:
-- Hereditary
-- Excess dietary intake

18

What is the pathogenesis of struvite stones?

1. Urease producing bacterial infection (proteus)
2. Urease converts urea to ammonia
3. Causes a rise in urine pH
4. Precipitation of magnesium ammonium phosphate salts
5. Large “staghorn” calculi

19

What are the causes of urate stones?

Hyperuricaemia
- Gout
- Patients with high cell turn over e.g. leukaemia

Idiopathic

20

What are the causes of cystine stones?

- Rare
- Occur in the presence of an inability of kidneys to reabsorb amino acids

21

What investigations do you performs for renal calculi?

- Non-contrast CT scanning is gold standard-
sensitivity of >95%
- Ultrasound in pregnancy or where CT not possible 30-67% sensitive
- Intravenous urography 70% sensitive for stones

22

What are the sequelae of renal calculi?

- Obstruction
- Haematuria
- Infection
- Squamous metaplasia +/- Squamous cell carcinoma

23

What percentage of cancers are renal cell?

3%

24

What is the most common kind of renal cell carcinoma?

clear cell

25

What is the epidemiology of renal cell carcinoma?

- Peak (65-80)
- Male > female (3:2)

26

What are the risk factors for renal cell carcinoma?

- Tobacco
- Obesity
- Hypertension
- Oestrogens
- Acquired cystic kidney disease (due to chronic renal failure
- Asbestos exposure

27

What is Von Hippel-Lindau Syndrome?

- The most common of several cancer syndromes observed in RCC
- VHL gene required for breakdown of Hypoxia Inducible Factor-1 (HIF-1) oncogene
- Therefore loss of gene function causes cell growth and increased cell survival
- Tumours develop in kidneys, blood vessels, pancreas
- VHL mutations also commonly identified in clear cell RCC

28

What is the presentation of Von Hippel-Lindau Syndrome?

Local symptoms:
- Hematuria, palpable abdominal mass, costovertebral pain

Incidental

Late presentation:
- systemic symptoms or metastases (25%)

Paraneoplastic syndromes

29

What are paraneoplastic syndromes?

- Clinical syndromes caused by tumours
- Not related to the tissue that the tumour arose from
- Not related to invasion by the tumour itself or its metastases

30

What are the paraneoplastic syndromes associated with renal cell carcinoma?

- Cushing’s syndrome - ACTH
- Hypercalcaemia - parathyroid hormone related peptide
- Polycythaemia - EPO

31

What is the morphology of clear cell RCC?

- Well defined yellow tumours
- Often with haemorrhagic areas
- May extend into perinephric fat or into renal vein

32

What is the morphology of papillary RCC?

- More cystic
- More likely to be multiple

33

What is the microscopic appearance of clear cell RCC?

- Clear cell has clear cells
- Delicate vasculature
- Usually small bland nuclei

34

What is the microscopic appearance of papillary RCC?

- Papillary tumours
- Cuboidal, foamy cells
- Surrounding fibrovascular cores often containing foamy macrophages or calcium

35

What is the prognosis of renal cell carcinoma?

- Overall 5 year survival ~45%
- Organ confined > 70%
- Tumours extending into perinephric fat or renal vein ~ 50%
- Distant metastases = very poor prognosis (

36

What percentage of bladder tumours are urothelial cell carcinomas?

95%

37

What do urothelial cell carcinomas arise from?

Arising from the specialised multilayered epithelium

38

Where else might urothelial cell carcinomas arise from?

Anywhere from the renal pelvis to the urethra

39

What are the risk factors for urothelial call carcinoma?

Risk factors:
- Age
- Gender (male>female)

Carcinogens
- Smoking
- Arylamines
- Cyclophosphamide
- Radiotherapy

40

What is the presentation of urothelial call carcinoma?

- HAEMATURIA – most common
- Urinary frequency
- Pain on urination
- Urinary tract obstruction

41

What is the prognosis of urothelial cell carcinoma?

- Recurrences are common
- Outcome depends on grade and stage
- Grade: low grade TCC 98% alive at 5 years
- Stage: Muscle invasion = 60% 5 year survival
- Poor prognosis for metastatic disease

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