UTI/Interstitial Disease Flashcards
What are the two routes of infection? Which is most common?
- Hematogenous
- Ascending = most common
What are the sources of hematogenous and ascending infections? What bacteria causes them?
Hematogenous = Distant source (septicemia or infective endocarditis) likely in presence of ureteral obstruction, debilitated, immunosuppressive therapy
- Bacteria= Non enteric such as staphylococci, certain fungi, viruses
Ascending = Fecal flora
- Bacteria= E coli most common
- Other – Proteus, Klebseilla, Enterobacter
What are some uro-pathogenic virulence factors?
Bacterial Adhesion: Adhesive molecules on Pili (P or fimbria)
“O” Antigens (certain strains more resistant)
Endotoxin (↓ ureteric peristalsis)
What are some examples of host defenses that aid against pathogenesis?
Mechanical:
- Bladder emptying/ urine flow,
- Ureteric peristalsis
Chemical:
- Prostatic secretions (antibacterial),
- Urine osmolality, pH, Ammonia,
- Blood group Ag’s (P2<<p1 p1 carry uropathogenic strains more often than others>
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What are some pre-disposing factors for getting a UTI?
- Being female: short urethra, bacteria, sex
- Pregnancy
- Instrumentation (entry into bladder from urethra)
- Decreased urine flow / urine stasis
- Incomplete voiding
- Urinary tract obstruction- BPH, stones, tumor
- Diverticulum
- Neurogenic bladder-DM, spinal cord injury
- Vesicoureteral reflux
- Immune compromise
- Kidney / UT disease
There are two causes of UTI: vesicoureteral reflux (VUR) and urinary tract obstruction. Explain how you would get vesicoureteral reflux…
- No valve at the ureterovesicle junction
- The oblique course of the ureter into the bladder forms an effective valve
- When this portion enters perpendicularly (wrong) the functionality is lost
- Retrograde flow of urine from bladder into the ureter and renal pelvis
There are primary and secondary VUR’s.
T/F: secondary VUR’s are usually seen in children and resove spontaneously
FALSE = describes primary
Primary:
- Congenital abnormality of VU anatomy
- Common in infants, usually mild
- Decreases in freq & severity during childhood
- Spontaneous remission
Secondary:
- Neurogenic bladder (paraplegia, spina bifida)- bladder atony; older children and adults
What is pathologic condition is being shown in this image?
Vesicoureteral Reflux
- See below different grades
What is this additional complication called (seen below) that results from VUR?
Reflux nephropathy
What are some of the many causes of urinary tract obstructions? What are specialized tests to detect them?
- Intrinsic: tumors of UT, Calculi, Sloughed necrotic papillae, Blood clots
- Stricture
- Urethral valves
- Extrinsic compression: Tumors (pelvic, retroperitoneal), Retroperitoneal fibrosis, Hemorrhage, Iatrogenic
- Functional: Neurologic disease, DM
- Idiopathic
Tests: Intravenous pyelogram/ urogram (IVP, IVU) or retrograde pyelogram
UT obstruction predisposes to infection/ recurrence and interferes with eradication.
T/F: obstruction with an infection can lead to chronic pyelonephritis?
True
Obstruction + Infection:
− ↑ pressure
− inflammation
− ischemia
– direct injury
What is the technical name for kidney stones? What percentage are radio-opaque?
NEPHROLITHIASIS
Radio-opaque: Calcium oxalate and phosphate 70%
Semiopaque: Magnesium ammonium phosphate 15-20%
Not usually radioopaque: Uric acid, cystine, others
What population/ risk factors are more likely to have kidney stones?
- M>F
- Peak 20-30 years
- Factors: hypercalcemia, increased uric acid, low pH, decreased volume, bacteria
- Locations: Tubules, calices, Pelvis, UB
- Bacterial infection can make urine more alkaline and cause struvite stones
-5-10% Americans
What would you call this beast?
Staghorn Calculus: looks like deer antlers
- Causes: Gross irreg scarred atrophied tubules with chronic inflammation and acute inflammation-casts in tubules
What are some consequences of of UT obstruction?
- Hydronephrosis, hydroureter
- Infection
- Chronic obstructive pyelonephritis
- Renal failure
- Hypertension
The image shows one of the complications of a urinary tract obstruction. What is it?
Hydronephrosis: A condition characterized by excess fluid in a kidney due to a backup of urine
- Dilated calices and ureter
- Atrophied tubules and periglomerular fibrosis
- Advanced stages of chronic pyelonephritis will develop secondary FSGS (focal segmental glomerulosclerosis)
UTI’s can be still be asymptomatic with > 100,000 bacteria / ml. But what are the usual symptoms of a UTI?
Symptoms depend on region (see image)
-children can different and non-specific
What condition is shown in the image?
Acute Pyelonephritis
- see neutrophils in tubule (neutrophils = acute)
- Can also cause microabscesses (also acute inflammation of neutrophils)- see below
How can you tell if someone has acute pylonephritis?
Inflammation and lymphocytes in interstitium
-look at dark cells below
Flip this card to look at necrotizing papillitis (infection in papilla) and pyenephritosis (pus in medulla)….
Papillary necrosis causes:
- DM (almost all papillae, same stage)
- Analgesic nephropathy (almost all, different stages)
- Sickle cell disease (few)
- Obstruction (variable)
This is what happens in chronic pyelonephritis. Flip card to see histo
Characteristics of chronic pyelonephritis
- Chronic inflammation
- Atrophy of tubules
- Periglomelular fibrosis
