POST-RENAL FAILURE Flashcards
What is post renal failure?
Obstruction of urinary outflow tract at any point from
renal pelvis to distal urethra
The likelihood of functional impairment depends on:
– duration of the obstruction
– Whether it is partial or complete
– Whether it involves one or both kidneys
Nephrolithiasis
Kidney Stones in minor or major Calyces of the kidney
Ureterolithiasis
Kidney stones in the Ureter
In renal calculi there is
Supersaturation of stone constituents in urine
Renal calculi: male to Female ratio
3:1
What stone is more common in women
Stones due to infection (struvite)
Most urinary calculi develop between
20-50 years
Initial stone attack after_______ relatively
uncommon
age 50
2 imaging for renal stones
- KUB
* Spiral CT
Renal Calculi Tx:
aimed at prevention.
Medication for stone less than 5mm
Tamsulosin (if < 5mm)
Four Types of stones and their occurrence %
Calcium oxalate (70%) - most common
Uric acid (15%) - High purines
Struvite (15%) - Occur with infection ↑pH
Cystine (15%)- Genetic disorder
Calcium Oxalate Stones
• Start with _____plaques which is
Randall’s plaques – predisposing factor for stone formation
Calcium oxalate is a
subepithelial calcification of the renal papilla
Act as anchor for calcium oxalate crystals
Randall’s plaques (CET)
- Calcium phosphate precipitates in basement membrane of loops of Henle
- erodes into the interstitium, and then accumulates
in the subepithelial space of the renal papilla - The subepithelial deposits eventually erode through the papilla into minor calyces
Most common metabolic abnormality
Hypercalciuria
3 causes of Calcium Oxalate stone
Absorptive
Resorptive
Renal-leak
Explain Absoprtive cause of Calcium oxalate
↑dietary Ca++ = ↑intestinal absorption
Explain Resoprtive cause of Calcium oxalate
↑resorption from bone (hyperparathyroidism)
Explain Renal-leak cause of Calcium oxalate
Renal-leak: tubules fail to properly reclaim Ca++
Assoc’d. w/ 2o hyperparathyroidism & Chronic Renal Failure
Excessive dietary calcium restriction is IT ADVANTAGEOUS?
NOT advantageous, it can cause hyperoxaluria
Increases free dietary dietary ______ =
↑oxalate absorption
Calcium oxalate crystals
Dianion, binds with many metals to form insoluble
precipitates.
Also increase risk of Oxalate stones
Excessive amounts of Vitamin C (> 2000 mg/day)
Preventative Treatment for Calcium oxalate
Calcium citrate is recommended supplement
Calcium citrate work as an
Works as an oxalate binder, reducing oxalate absorption from the intestinal tract.
Calcium citrate decreases
Decreases risk of stone formation
Calcium should be administered with
meals, especially those that contain high-oxalate foods
Uric Acid Stones in blood
• Hyperuricemia
Uric acid is a by-product of
purine metabolism via xanthine oxidase pathway
Normal uric acid
• Normal: 2-7 mg/dl (blood); 600 mg/d (urine)
_____people with ↑ uric acid are
• 95%; asymptomatic
Uric acid deposit in joint
GOUT
In urine = uric acid crystals if pH
< 5.5 obstruct tubules and/or form uric acid stones
High _______diet especially -____Associated with gout
PURINE; Excess alcohol ingestion (especially Beer)
Increased risk factors for URIC ACID (CPD, BHCD)
Chronic renal insufficiency PKD DM2 Bartter’s Syndrome Hemolysis Chemotherapy (Tumor Lysis Syndrome) Dehydration
Medications risk for Uric acid (NACH)
HCTZ, ASA, Cyclosporine, Niacin
Uricostatic drugs Example
allopurinol
What does uricostatic drugs do ?
– reduces uric acid production through competitive
inhibition of xanthine oxidase
Uricosuric drugs Example
ex. probenecid
What does Uricosuric drug do?
increases urinary uric acid excretion by blocking tubular
re-absorption of urate
Struvite stones Form in
chronic upper urinary tract infection due to a urease-producing organism
Struvite stones composition
Are composed of magnesium ammonium phosphate (struvite) & calcium carbonate.
Normal urine is undersaturated with ammonium
phosphate – struvites occur when___
ammonium phosphate
ammonia production is increased & urine pH is elevated which decreases the solubility of phosphate causing stones to form.
Cystine Stone is what kind of disorder?
Autosomal recessive disorder caused by a tubular
defect in amino acid transport
Cystine Stone causes
Excessive excretion of cystine, ornithine, lysine and arginine
Cystine is only soluble in
urine up to 24 - 48 mg/dl.
In Cystine stone, In affected pts, excretion is about _______/day
480 - 3500 mg/day.
Cystine stone formed in
4th decade
2 types of Bladder calculi
Primary and Secondary
Most common types of bladder calculi
Primary (most common) – Occurs from urinary stasis. Incomplete emptying results in concentration of solutes which crystalize
Secondary bladder calculi when does it occur
Secondary – Result from migrated urinary calculi – Concretions on foreign material (ie. catheters)
Causes of Primary stones (CUNB)
– Cystocoele
– Urethral obstruction
– Neurogenic bladder
– Bladder outlet obstruction
Cystocoele, what occurs?
Pubocervical fascia torn by childbirth, allows bladder to herniate into the vagina.
Tx of cystocoele
Tx: surgical correction if severe.
Neurogenic Bladder is
Bladder dysfunction secondary to injury of central or
peripheral nerves controlling urination
Neurogenic bladder can be the result of
Nerve injury caused by infection, trauma, CA or
vascular insult.
Additional causes of neurogenic bladder can be
– MS
– Parkinson disease
– Spinal cord injury
– stroke complications
On cystogram with neurogenic bladder you see
Cystogram with “pine cone” or “Christmas tree” bladder
Tx of neurogenic bladder depends on
Etiology
Bladder Outlet Obstruction caused by 3 (BCO)
- BPH
- CA – Prostate, Bladder, Cervical
- Outflow tract obstructed
Bladder Outlet obstruction Treatment:
Tx: Treat underlying condition
– Relive obstruction and Prevent UTI
Urethral Obstruction :Most commonly affects
males
Urethral Strictures caused by:
– Infection
– Inflammation
– Trauma
– Iagtrogenic
Inflammation cause of urethral strictures
Balanitis Xerotica Obliterans
Infectious cause of urethral stricutres
Gonococcal
Traumatic cause of urethral strictures
Straddle injury or pelvic Fractures
Iatrogenic cause of urethral strictures
Prolonged cath., or surgical procedures)
Urethral Valves: what are they?
– Congenital obstructive lesion of proximal urethra.
–Obstruction during active nephrogenesis results in cystic renal dysplasia.
Bladder diverticuli Treatment
surgical correction
What is Urethral Diverticulum?
• Abnormal outpouching of urethral wall
Urethral Diverticulum affects_____more than ____
Affects females more often than males
Urethral Diverticulum occurs between ages of
40 – 70
Urethral diverticulum caused by
Caused by trauma or repeated infections of periurethral ducts
In urethral diverticulum ,Periurethral glands
secrete mucins which protect urethra from irritative, potentially toxic effects of urine
Multiple Myeloma Uropathy is what kind of disease?
Cancer of plasma cells.
Multiple Myeloma Uropathy produces
monoclonal immunoglobulin.
Multiple Myeloma Uropathy Causes
renal insufficiency ,bone pain, hypercalcemia, anemia, and recurrent infections.
In Multiple Myeloma uropathy overproduction of?
Overproduction of Ig light chains (Bence Jones proteins) filtered by glomeruli
What happens to light chains in Multiple Myeloma?
Light chains saturate reabsorptive capacity of PCT
and **combine with filtered proteins & Tamm-Horsfall
mucoprotein to form obstructive casts
Signs/Symptoms of Multiple Myeloma Uropathy
PPHR
Signs/Symptoms: Persistent unexplained bone pain, particularly at night or at rest • Proteinuria • Hypercalcemia • Renal insufficiency
Multiple Myeloma Uropathy occurence
Occurs > 40 yrs. of age; m:f 1.6:1
Treatment of Multiple Myeloma Uropathy
– Dialysis
– Chemotherapy/radiation, poss. marrow transplant
Other Congenital Obstructive Uropathy
– most common prenatally detected obstructive ds.
- Ureteropelvic Junction Obstruction (UPJ)
* Ureterovesical Junction Obstruction (UVJ)
What is Ureteropelvic Junction Obstruction (UPJ)
most common prenatally detected obstructive ds.
What is Ureterovesical Junction Obstruction (UVJ)
– second most common prenatally detected obstructive ds.
Ureteropelvic Junction Obstruction (UPJ)
• Two types
Intrinsic obstruction and Extrinsic obstruction:
UPJ INTRISIC obstruction
stenosis secondary to scarring or presence of
ureteral valves
UPJ EXTRINSIC obstruction
compression secondary to vessel or fibrous band passing anterior to pelvis & ureter
TX of UPJ obstruction
Surgical correction
Cystine stone Treatment
Water why?
• Water, water and more water
Maintain solubility.
Cystine Stone and pH tx
• Increase urine pH > 7.5
– increases cystine solubility
Cystine stone treatment Medication
D-penicillamine
– binds cystine and reduces urine supersaturation
Tx of Hyperurecemia other than meds
- Hydration
- Diet modifications
- Cessation of offending medication