Stones Flashcards
What are the 5 different types of renal stone?
Calcium Oxalate (most common)
Calcium phosphate
Urate stones
Cysteine stones
Magnesium ammonium phosphate/struvite stones
What condition are cysteine stones typically seen with?
Homocystinuria patients
What type of stones do magnesium ammonium phhosphate/struvite stones form?
Stag horn calculi
Why do struvite stones/stag horn calculi typically form and why?
Due to infections
The bacteria have urease enzymes which make the urine more alkaline and the struvite/magnesium ammonium phosphate forms in alkaline urine
What organism most commonly causes struvite stones?
Proteus mirabilis
What 2 things make urate stones different. To the other stones?
- Can be dissolved by making urine more alkaline
- Not visible. On plain radiographs (x-rays)
What are the risk factors for developing renal stones?
Dehydration
Male
Obese
Diet (high in meat, salt and protein)
Genetics (Homocystinuria = cysteine stones)
Old age
Bowel disease (affect absorption of calcium oxalate)
Hyperparathyroidism (calcium phosphate stones)
Cancer
CKD
Gout
How may renal stones present?
Sudden severe flank pain, loin to groin/scrotum
Constant or colicky
LUTs (frequency)
Haematuria
What are some differentials for a patient presenting with sudden/severe flank pain (loin to groin)?
AAA
Renal stones
Pyelonephritis
Bowel obstruction
Lower lobe pneumonia
MSK issue
Psoas abscess
Pancreatitis
Appendicitis
Ectopic pregnancy
Ovarian torsion.
Ovarian abscess
Biliary pathology
What would you tend to find on examination of a patient with renal. Stones?
May have a temperature
Flank. Tenderness
External hernial orifices fine
External genitalia fine
What Ix would you do. With a patient with sudden severe flank pain?
Urine dip
Pregnancy test
FBC
LFTs
U+Es
Amylase
Serum urate + calcium
What is the imaging of choice for a patient with suspected renal stones?
CT KUB (non contrast with patient prone)
However US may be done priori
Before any intervention, what is the management of renal stones?
IV fluid hydration
Analgesia
What analgesia is given for renal stones?
NSAIDs like Diclofenac IM
If NSAIDs insufficient give IV Paracetamol
If this fails try an opioid
Morphine (oral, IM or IV)
When do you give emergency intervention for a renal stone?
Infected obstructed kidney
Renal impairment
Uncontrollable pain
Singular kidney
What are the 2 emergency interventions for an infected obstructed kidney?
Retrograde JJ stent
Percutaneous nephrostomy
What is a retrograde JJ stent in decompressing an infected obstructed kidney?
Who inserts it?
Done under anaesthesia?
Urologist inserts a stent guided by cystoscopy through the urethra, bladder, ureters to the kidney
Done under general anaesthetic
What is a Percutaneous nephrostomy in decompressing an infected obstructed kidney?
Who inserts it?
Done under anaesthesia?
When interventional radiologist insert a stent by puncturing through the skin straight into the renal pelvis
Its done under local anaesthetic making it good for sicker patients that cant under go GA and is a quicker procedure
What are the 3 definitive treatments of non emergency renal stones/colic?
Extracorporeal shockwave lithotripsy
Percutaneous nephrolithotomy
Flexible ureteroscopy + laser lithotripsy
What renal stones are visible on plain radiograph (X-ray)?
Which are not?
Visible = calcium oxalate, calcium phosphate, cysteine and struvite
Non visible = urate
What imaging modality is used for stone surveillance if a stone is being managed conservatively?
Plain radiograph (stone must be radio opaque so not urate)
What 2 non emergency treatments of stones are good for smaller stones?
Extracorporeal shockwave lithotripsy
Flexible ureteroscopy + laser lithotripsy
What non emergency tretament method is best for larger stones like stag horn calculi?
Percutaneous nephrolithotomy
Why is Extracorporeal shockwave lithotripsy not appropriate for larger stones?
Lager stones likley broken down into lots of smaller stones which can get stuck forming STEINSTRASSE
