Renal disorders:

Question 1

Renal diseases:

Obstructive Uropathy:

Answer 1

• Any condition, structural or functional, causing a
change in the normal urine flow anywhere within the the urinary tract.
• Causes vary with age and gender
• Congenital disorders (e.g.uretopelvic junction obstruction) in young children
• Nephrolithiasis (kidney stone formation) in young men
• Pregnancy in young women
• Benign or malignant tumours in

Question 2

Consequences of Obstruction:

- Pain

Answer 2

Pain
- The distention caused by the blockage causes
pain. The intensity usually reflects the rapidity
rather than degree of blockage.
• Acute blockage of the ureter may be
associated with excruciating pain, whereas slowly developing obstruction may be completely painless

Question 3

Outcome: Obstructive uropathy:

Answer 3

Important to clear obstruction as soon as possible -­‐ Why?

– Fibrosis, tissue damage/apoptosis, nephron and renal function affected within
7 days
– By 14 days damage to distal and proximal tubules of the nephron
– 3-­‐4 weeks damage is irreversible depending on severity of obstruction

• Does GFR improve after obstruction removal?
– Depends on how quickly it is treated

• What electrolyte abnormalities are associated with obstructive uropathy?
– Hyperkalaemia and metabolic acidosis
– Due to defects in the excretion of potassium or hydrogen.

Question 4

Outcome - Obstructive uropathy:

Answer 4

Hypertension in obstructive uropathy -­‐ why?
– Increase in blood volume
– Hypertension may be a secondary to renal failure in bilateral obstruction due to extracellular fluid volume expansion
– In acute unilateral obstruction increased renin secretion is usually
responsible.

• Complications
– Renal dysfunction/failure, cardiovascular (increase in blood volume
and electrolyte disturbances)

• Urinary tract infection

Question 5

Renal Calculi

Answer 5

• If flow blocked, urine backs up in pelvis
• Pressure forces filtrate back into interstitum
• Pressure causes atrophy of renal tissue and compression of vessels in m

Question 6

Renal Calculi:

Answer 6

• Masses of crystals,    
proteins, other   substances    
• Common cause of    
urinary tract obstruction    
• Usually unilateral

Question 7

Consequences of Obstruction:

- Complete obstruction:

Answer 7

Decreased glomerular filtration and resulting renal failure.

Question 8

Consequences of Obstruction:

- Hydroureter:

Answer 8

Obstruction of the ureter with accumulation of urine

Question 9

Consequences of Obstruction:

- Hydronephrosis:

Answer 9

retrograde increases in hydrostatic pressure in the renal pelvis and calyces can increase accumulation of urine in the renal collecting system.

Question 10

Consequences of Obstruction:

- Partial obstruction:

Answer 10

Chronically can cause compression, accumulation of urine, ischemic damage and atrophy with decreased concentrating ability of the
kidney.

Question 11

Hydroureter and hydronephrosis:

Answer 11

• Obstructive uropathy 5 : pathogenesis
• Renal tubules affected first
• Impaired concentration, then reduced GFR
• Kidney enlarged, pelvis and calyces are
dilated, calyces blunted
• Cortical tubules lost, with interstitial fibrosis.

Question 12

Clinical signs and symptoms

Hydroureter and hydronephosis:

Answer 12

• Pain -­ Colicky with stones
• Bladder symptoms (eg, prostatic enlargement): urgency, hesitancy, frequency
• Unilateral obstruction, complete or partial is often asymptomatic
• Bilateral partial obstruction – can’t
concentrate urine: polyuria, nocturia, possibly acidosis and hypertension
• Bilateral complete obstruction: oliguria/anuria
• If malignant – may see haematuria
• Detect via intravenous pyelogram or
ultrasound

Question 13

Nephrolithiasis - Kidney Stones

types of stones?

Answer 13

1. Calcium (75-­‐80%)
2. Struvite (15%) (Magnesium ammonium phosphate)
3. Uric acid (7%)
4. Cysteine (1%)

Question 14

Nephrolithiasis - Kidney Stones

Pathophysiology

Answer 14

Pathophysiology
• High urinary concentration of stone    forming substances        
• Changes in pH and temperature    
• Drugs and diet    
• Decreased urinary flow    
• Grow  in the renal papilla

Question 15

Nephrolithiasis - Kidney Stones:
Risk factors:

CALCIUM STONES (phosphates, oxalates)

Answer 15

• Smallest
• Middle-­‐aged men with family history
• Hypercalciuria – Elevated calcium in urine
• Hyperuricosuria – Excess uric acid in urine
• Bone demineralisation, following prolonged immobility, hyper-­ parathyroidism
• Diet high in vegetables –high oxalates

Question 16

Nephrolithiasis - Kidney Stones:
Risk factors:

STRUVITE STONES

Answer 16

•
Mg(NH
4
)PO
4
            -­‐magnesium    ammonium    
phosphate    
•
Women    infected    by    microbes    eg    proteus    and    
pseudomonas        
•
These    split    urea    to    ammonia,    producing    
alkaline    urine

Question 17

Nephrolithiasis - Kidney Stones:
Risk factors:

URIC ACID STONES

Answer 17

• Conditions → concentrated acidic urine:
• Ulcerative colitis or regional enteritis with fluid and bicarbonate loss,
• Sufferers with gout, high meat and fish diet, (purines broken down to uric acid)
• Leukaemia - cell breakdown

Question 18

Nephropathy

CYSTEINURIA

Answer 18

• Rare hereditary disorder
• Disorder of amino acid metabolism
• Decreased tubular reabsorption of cysteine

Question 19

Pathophysiology

Answer 19

• Stone formation not well understood
• High levels of stone-­‐forming substances in plasma &
urine, some medications
• Loss of inhibitors of precipitation
• High pH favours struvite stones & deposition of Ca2+
• with oxalate, phosphates & carbonates
• Low pH (acid) favours uric acid stones, as calcium urate
• Low urine output & high concentration
•Found in papillae, renal tubules, calyces or pelvis, most < 5mm, passed in urine

Question 20

Nephropathy - CYSTEINURIA

Clinical Manifestations

Answer 20

• Colicky pain ­‐ muscle spasm of ureter
• Flank pain, at costovertebral angle, may radiate into groin
• Nausea & vomiting with severe pain
• Haematuria

Question 21

Bladder - prostate enlargement,

hypertrophy & calculus:

Answer 21

Stone blocks exit from

bladder when muscles contract

Question 22

Bladder - prostate enlargement,
hypertrophy & calculus
- diagnosis?

Answer 22

• Blood & urine tests for stone forming substances
• Urine pH
• Red and white blood cells in urine
• Stones in urine (microscopy)
• Intravenous pyelogram
• GFR
• Computed Tomography, Ultrasound

Question 23

Bladder - prostate enlargement,
hypertrophy & calculus
- treatment and management:

Answer 23

• Adequate analgesia and high fluid intake
• Treat infections
• Dissolve stones and prevent reformation by:
- Increasing fluid intake and increasing urine output
- Decrease dietary intake of stone-­‐forming substances –Alter urine pH(Diet)
• Surgical removal of stones greater
than 0.5cm in width percutaneous puncture of kidney with forceps removal
• Shock wave lithotripsy for large calcium stones

Question 24

Bladder - prostate enlargement,
hypertrophy & calculus
- predisposing factors?

Answer 24

Family history and childhood infection relevant        
• Diabetes    
• Chronic disease    
• Renal calculi    
• Urinary tract obstruction    
• Immunosuppression    
• Pregnancy    
• Prostate disease  in older