urology Flashcards
what does KUB X-ray mean?
kidney ureter bladder xray
what are intrinsic risk factors for renal stones?
- age 20-40
- sex male
- race- Caucasian
- gene - happens in 25% of patients
what are extrinsic risk factors for renal stones?
- diet and fluid- high salt diet
- climate- hot climate
- occupation- factory workers working in hot conditions are more likely
what are the genetic risk factors?
- hyper calciuric patients- this can be polygenic or monogenic
- familial renal tubular acidosis
- cytinugia- autosomal recessive
- xanthine and dihydroxyadenine
what are the different types of salts that can form stones?
- Calcium Oxalate
60% - Calcium Phosphate
20% - Urate
10% - Struvite
8% - Cystine
1%
what are the small molecules that can inhibit stone formation?
Citrate
Phytate
Pyrophosphate
Magnesium
they do this by binding to calcium and stopping it from aggregating
what are some urinary macromolecules that can inhibit kidney stone formation?
- Urinary prothrombin fragment 1
- Nephrocalcin
- osteopontin
- Tamm-Horsfall glycoprotein
- Bikunin
UNOT-B
which anatomical factors that cause urine stasis and increase the risk of stone formation?
- calyceal diverticulum- small pouches in the kidney that do not empty freely
- anatomical variant such as ureteric junction obstruction
what are randalls plaques?
subepithelial calcification of the renal papilla.
They act as an anchor for calcium oxalate crystals and are considered to be a predisposing factor for renal stone formation.
what is the presentation of kidney stones?
- Pain- acute cholic- loin to groin pain
- Haematuria (visible, non-visible)
- Urinary tract infection
what is the treatment for kidney stones?
Medical
Medical Expulsive Therapy - MET
Chemolysis - Uric acid stones
Shock Wave Lithotripsy - ESWL Ureteroscopy & Ureterorenoscopy Percutaneous Surgery - PCNL Laparoscopic Surgery Open Surgery
what is the treatment of a episode?
NSAIDs
Analgesics
Opiates
Antiemetics
what is a gold standard for imaging renal stones?
non contrast CT scan
What is the chance of passing the kidney stone based on stone position?
Prox ureter-> 22%
Mid ureter-> 46%
Distal ureter-> 71%
what is the chance of passing the stone based on stone size?
– <4mm 80%
– 4-6mm 59%
– >6mm 21%
what is the VUJ?
vesicleuroteric junction- where the ureters meet the bladder
what percentage of VUJ stones <5mm are spntaneously passed?
94%
- that’s why its sometimes good to take a conservative approach
when would yo treat a kidney stone?
- if patient is in uncontrolled and persistent pain
- kidney is deteriorating in function
- patient only has one kidney
how does ESWL work
- a spike in energy initially breaks the stone, then a fall will break it down into smaller pieces
How effective is ESWL depending on the kidney position?
Renal Pelvis= 86-9%
Upper pole= 71-83%
Interpolar= 23-84%
Lower pole= 37-68%
what does steinstrasse mean?
its when stones form one on top of another ‘stone street’ at the end of the ureter
what are the complications of ESWL?
Steinstrasse Residual fragment re-growth Fragment colic Sepsis Macro haematuria Renal haematoma Symptomaic Renal haematoma Asymptomatic Bowel perforation Liver & splenic haematoma
what is URS
form of minimally invasive surgery using a small telescope that is passed through the urethra and into the ureter to remove a stone
what is the effect of URS depending on position?
distal- 94%
mid- 86%
proxima- 81%
when would percutaneous surgery be used to remove a kidney stone?
- when the stone is >2cm
- when the stone is complex
what are examples of complex kidney issues that would require PCNL?
Multiple stones Lower pole - unfavourable features Calyceal diverticulum Ectopic kidney Horseshoe Obese Abnormal anatomy Difficult retrograde access Encrusted stents
what type of stones are you at risk of with chemotherapy?
Chemotherapy and cell death can increase uric acid levels. In this acute setting the uric acid stones are unlikely to be coated with calcium and will therefore be radiolucent.
which stones are associated with inherited metabolic disorders?
Cystine
what is the first line analgesic for renal colic?
- 75mg diclofenac IM
what does Periureteric fat stranding on a non contrast CT indicate?
spontaneously passed stone
what are struvite stones composed of?
ammonium magnesium phosphate, triple phosphate
which bacteria predispose to renal struvite stones?
they form in alkaline urine (ammonia producing bacteria such as Ureaplasma urealyticum and Proteus therefore predispose)
what is the treatment for obstructive urinary calculi with infection?
the stone is obstructing the ureter and causing hydronephrosis (ultrasound scan shows dilation of the renal pelvis)
These patients are at risk of urosepsis so urgent renal decompression via a ureteric stent or percutaneous nephrostomy should be performed to relieve the obstruction. They must also receive antibiotics for the upper urinary tract infection.
Nifedipine may be used in some patients with small, uncomplicated renal stones. It relaxes the ureters and aids passing of the renal stone
what is the use of Urinary alkalinization?
to prevent the formation of uric acid stones.
