Urinary Tract Infection + stones Flashcards
What is a UTI?
Infection of
urethra
Bladder
Kidney
What direction does and infection usually travel?
What are the risk factors for ascending infection?
Bladder emptying fault = urine stasis = increased p(bacterial growth)
Catheters
Diabetes mellitus
Females = short urethra
Sex = honeymoon cystitis = infection @ tract
At UTI what does:
Urinalysis show
Urine dipstick show
Culture show
Urinalysis =
cloudy urine + >10 WBC’s/high-power field
Urine dipstick =
leukocyte esterase positive
due to pyuria = pus @ urine
Increased nitrites (Bacteria convert nitrates-> nitrites)
Culture > 100,000 colony forming units
What is sterile pyuria
Patient presents with sterile pyuria >10 WBC/HPF @urinalysis + leukocyte esterase @urine dipstick. Culture is negative. What is the diagnosis?
Pyuria + negative urine culture
Urethritis - neisseria + gonorrhoea
How does pyelonephritis present
Fever,
supra-pubic pain
+
flank pain
(Inflammation –> sensitisation of nerve of capsule of kidney)
⬆️urine frequency + WBC casts + leukocytosis
Explain white casts
What is pyelonephritis?
What reflex causes an increase risk of pyelonephritis ?
Infection ascends from ureter to kidney – > inflammatory cells come into tubule –>
inflammatory cells cast themselves into shape of tubule – >️urine WBC cast
Infection of kidney
Vesico-ureteral reflux
What is the leading cause of UTI
Shows colonies with green metallic sheen on EMB agar
Escherichia. coli
What is the second leading cause of UTI in sexually active women?
Staphylococcus saprophyticus
What is the third leading cause of UTIs with a large mucoid capsule + viscous colonies
Klebsiella pneumonia
What organism has a strain that produces a red pigment and is often nosocomial and drug resistant?
What organism is just Nosocomial + drug resistant
Serratia Marcescens
Enterococcus
What organism produces urease and is associated with struvite stones and on agar We see swarming due to motility with alkaline urine
Proteus mirabilis
What organism has a blue green pigment with a fruity odour Usually nosocomial and drug resistant
Pseudomonas Aeruginosa
What are the diagnostic markers for UTI bugs
Leukocyte esterase = WBC activity
Nitrite test = bacterial species
Urease test = urease producing buds eg proteas + klebsiella
What causes chronic pyelonephritis?
Interstitial fibrosis + atrophy of tubules due to multiple bouts of a cute pyelonephritis
What are to risk factors for chronic pyelonephritis
The vesico ureteral reflux @children
Obstruction
A malformation of what can result in vesico-ureteral infection in children
What three things happen due to this
Angle of the ureter into the bladder
Chronic scarring, interstitial fibrosis, tubular atrophy
In chronic pyelonephritis what do we see @ gross examination + histology?
Gross exam =
asymmetric cortical medullary scarring
Blunted calyx
Histology =
Atrophic tubules +
proteinaceous material = Resemble colloid Of thyroid follicles = thyroidization of kidney i.e. Casts resemble thyroid tissue
Calcium stone
When precipitates?, X-ray, urine Crystal,
Causes? Treatment?
Precipitate at:
Increased pH = calcium phosphate
Decreased pH calcium oxalate
X-ray = radiopaque
Urine Crystal = envelope/dumbbell shaped calcium oxalate
Hypercalcaemia
Idiopathic hypercalciuria – most common cause
@Crows = small-bowel damage – >increased oxalate resorbtion – > Bind calcium –> stone
Treatment = hydrochlorothiazide = calcium sparing diuretic
AMP stone
When precipitates?, X-ray, urine Crystal,
Ammonium magnesium phosphate = 15%
Increased pH
Radiopaque
Coffin lid
Caused by urease positive birds e.g. Proteus CHuck norris hates PUNKSSS - Cryptococcus H pylori Proteus Ureaplasma nocardia klebsiella Staph epidermis staph saprophyticus
ADULT Patient has alkaline ammonia in his urine with staghorn calculi what type of kidney stone is it? What treatment is required ?
Ammonium magnesium phosphate kidney stone
Needs eradication of infection \+ surgery = Extracorporeal shock wave lithotripsy Ureteroscopic stone extraction
Uric acid stone
When precipitates?, X-ray, urine Crystal,
Causes? Treatment?
Decreased pH
Radiolucent – visible @CT
Urine Crystal = rhomboids/rosettes
RF =
arid climates +
decreased urine volume
acidic pH
Associated with Hyperuricaemia - gout OR myeloproliferative disorders Lots of cells – >lots of turnover – > Increased uric acid
Treat = urine alkalinisation + hydration + allopurinol
Cysteine stone
When precipitates?, X-ray, urine Crystal,
Causes? Treatment?
Decreased pH, radiolucent, hexagonal
AR genetic defect of cysteine reabsorbing PCT transporter of tubules = cystinuria – >
Decreased reabsorption of cysteine – >
cysteine accumulate + filtrate – >
increased risk of stone
Treat = hydration + urine alkalinisation + Captopril
A child has Staghorn calculi and is sodium cyanide nitroprusside positive what does he have ?
Cysteine kidney stone
Given all the kidney stones and their percentages
Calcium 80% >Ammonium magnesium phosphate 15% > uric acid 5% > cysteine 1%
What are the risk factors for a kidney stone
DeV PHUCH
Deiry products - have phosphates + oxalates
⬇️Volume of urine/⬆️solute
pH alteration:
alkaline - Ca2+ & PO43- crystallisation
acid - URIC acid + cysteine stone
HyperParaThyroid primary
Urease bugs
Citrate
HyperCalcinuria without hypercalcaemia
Explain how a kidney stone forms
Solute achieves high enough concentration that it precipitates out as a stone
