Renal stone disease Flashcards
1
Q
What are the clinical features of renal calculi?
A
- mostly asymptomatic
- sudden onset of severe loin pain (starting ~ level of the costovertebral angle)
- pain radiates to groin
- pain is less intermittent than biliary or intestinal colic (may have periods of relief or just a constant dull ache)
- may have haematuria
- may have dysuria, or urinary retention
- patient may be writhing in agony
- pyrexial
- N+V
2
Q
What are the risk factors for developing renal calculi?
A
- Anatomical anomalies in the kidneys and/or urinary tract (e.g. horseshoe kidney, ureteral stricture)
- FHx of renal stones
- HTN
- Gout
- Hyperparathyroidism
- Immobilisation
- Relative dehydration
- Metabolic disorders (chronic metabolic acidosis, hypercalciuria, hyperuricosuria)
- Deficiency of citrate in the urine
- Cystinuria
- Drugs (some diuretics and calcium/vitamin D supplements)
3
Q
What investigations are used to diagnose underlying predisposition to renal calculi?
A
- Dipstick urine:
- red cells (suggestive of urolithiasis)
- white cells and nitrites (suggestive of infection)
- pH (pH >7 suggests Proteus sp; pH <5 suggests uric acid stones) - Midstream urine specimen (MC&S)
- Bloods (FBC, CRP, renal function, U&Es, calcium, phosphate, creatinine)
- Prothrombin time and INR (if intervention planned)
- Non-enhanced CT scan = imaging modality of choice (has replaced IVP)
- USS (differentiate radio-opaque from radiolucent stones + detecting obstruction)
- Plain x-rays of kidney, ureter and bladder (KUB) (useful to visualise passage of radio-opaque stones)
4
Q
What is the role of diet in management of stone disease?
A
- increase fluid intake to maintain urine putput at 2-3L per day
- reduce salt intake
- reduce the amount of meat/animal protein consumed
- reduced oxalate-rich foods (e.g. chocolate, rhubarb, nuts) and urate-rich foods (e.g. offal and certain fish)
- dirnk regular cranberry juice (increases citrate excretion and reduced oxalate + phosphate excretion)
- maintain calcium intake at normal levels
5
Q
What are the indications for hospital admission for patients with renal calculi?
A
- Fever
- Solitary kidney
- Known non-functioning kidney
- Inadequate pain relief or persistent pain
- Inability to take adequate fluids due to N+V
- Anuria
- Pregnancy
- Poor social support
- Inability to arrange urgent outpatient department follow-up
- People >60 if there are concerns on clinical condition or diagnostic certainty (e.g. leaking aortic aneurysm may present with identical symptoms)
6
Q
What is the initial management of an acute presentation of renal calculi?
A
- NSAIDs (diclofenac IM or PR) = 1st line analgesia for renal colic
- Anti-emetic and rehydration
- Majority of stones will pass spontaneously, but may take 1-3 weeks (conservative management for up to 3 weeks unless ot develops signs of infection/obstruction)
- medical expulsive therapy (to facilitate passage of stone):
- CCBs (e.g. Nifedipine) or alpha blockers (e.g. Tamsulosin)
- Prednisolone occasionally added when an alpha blockers is used
7
Q
What is the surgical management of a ureter that is blocked/at risk of being blocked as a result of stones?
A
- a JJ stent which is inserted using a cystoscope
→ think hollow tube with both ends coiled
→ can also be used as a temporary holding measure (prevent contraction of ureters and therefore reduced pain)
8
Q
What surgical procedures can be performed to remove renal stones?
A
- Percutaneous nephrolithotomy
- used for large stones (>2cm), staghorn calculi and cystine stones
- stones removed using a nephroscope - Ureteroscopy
- involves the use of laser to break up the stone and has an excellent success rate - Open surgery
- rarely necessary
- usually reserved for complicated cases (multiple stones)
- if all of the above therapies have failed
- also extracorporeal shock wave lithotripsy:
- shock waves are directed over the stone to break it apart
- stone particles will then pass spontaneously
