Urinary Tract Infection + stones

Question 0

What is a UTI?

Answer 0

Infection of
urethra
Bladder
Kidney

Question 1

What direction does and infection usually travel?

What are the risk factors for ascending infection?

Answer 1

Bladder emptying fault = urine stasis = increased p(bacterial growth)

Catheters

Diabetes mellitus

Females = short urethra

Sex = honeymoon cystitis = infection @ tract

Question 2

At UTI what does:
Urinalysis show
Urine dipstick show
Culture show

Answer 2

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

Question 3

What is sterile pyuria

Patient presents with sterile pyuria >10 WBC/HPF @urinalysis + leukocyte esterase @urine dipstick. Culture is negative. What is the diagnosis?

Answer 3

Pyuria + negative urine culture

Urethritis - neisseria + gonorrhoea

Question 4

How does pyelonephritis present

Answer 4

Fever,

supra-pubic pain
+
flank pain
(Inflammation –> sensitisation of nerve of capsule of kidney)

⬆️urine frequency + WBC casts + leukocytosis

Question 5

Explain white casts
What is pyelonephritis?
What reflex causes an increase risk of pyelonephritis ?

Answer 5

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

Question 6

What is the leading cause of UTI

Shows colonies with green metallic sheen on EMB agar

Answer 6

Escherichia. coli

Question 7

What is the second leading cause of UTI in sexually active women?

Answer 7

Staphylococcus saprophyticus

Question 8

What is the third leading cause of UTIs with a large mucoid capsule + viscous colonies

Answer 8

Klebsiella pneumonia

Question 9

What organism has a strain that produces a red pigment and is often nosocomial and drug resistant?

What organism is just Nosocomial + drug resistant

Answer 9

Serratia Marcescens

Enterococcus

Question 10

What organism produces urease and is associated with struvite stones and on agar We see swarming due to motility with alkaline urine

Answer 10

Proteus mirabilis

Question 11

What organism has a blue green pigment with a fruity odour Usually nosocomial and drug resistant

Answer 11

Pseudomonas Aeruginosa

Question 12

What are the diagnostic markers for UTI bugs

Answer 12

Leukocyte esterase = WBC activity

Nitrite test = bacterial species

Urease test = urease producing buds eg proteas + klebsiella

Question 13

What causes chronic pyelonephritis?

Answer 13

Interstitial fibrosis + atrophy of tubules due to multiple bouts of a cute pyelonephritis

Question 14

What are to risk factors for chronic pyelonephritis

Answer 14

The vesico ureteral reflux @children

Obstruction

Question 15

A malformation of what can result in vesico-ureteral infection in children
What three things happen due to this

Answer 15

Angle of the ureter into the bladder

Chronic scarring, interstitial fibrosis, tubular atrophy

Question 16

In chronic pyelonephritis what do we see @ gross examination + histology?

Answer 16

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

Question 17

Calcium stone
When precipitates?, X-ray, urine Crystal,

Causes? Treatment?

Answer 17

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

Question 18

AMP stone

When precipitates?, X-ray, urine Crystal,

Answer 18

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

Question 19

ADULT Patient has alkaline ammonia in his urine with staghorn calculi what type of kidney stone is it? What treatment is required ?

Answer 19

Ammonium magnesium phosphate kidney stone

Needs 
eradication of infection
\+
surgery = 
Extracorporeal shock wave lithotripsy
Ureteroscopic stone extraction

Question 20

Uric acid stone
When precipitates?, X-ray, urine Crystal,

Causes? Treatment?

Answer 20

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

Question 21

Cysteine stone
When precipitates?, X-ray, urine Crystal,

Causes? Treatment?

Answer 21

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

Question 22

A child has Staghorn calculi and is sodium cyanide nitroprusside positive what does he have ?

Answer 22

Cysteine kidney stone

Question 23

Given all the kidney stones and their percentages

Answer 23

Calcium 80% >Ammonium magnesium phosphate 15% > uric acid 5% > cysteine 1%

Question 24

What are the risk factors for a kidney stone

Answer 24

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

Question 25

Explain how a kidney stone forms

Answer 25

Solute achieves high enough concentration that it precipitates out as a stone