Makindo Medical Notes

Stones < 5-mm and distal ureteral stones, will most likely spontaneously pass within 4 weeks, without the need for urologic intervention. Stones 5-10mm stones may be helped to pass with MET. Usually Tamsulosin 400 microgram OD.

About

• Renal or ureteric colic generally describes an acute and severe loin pain caused when a urinary stone moves from the kidney or obstructs the flow of urine.
• Common surgical referral and priority is to ensure not missing other sinister diagnosis such as AAA

Epidemiology

• It is common, with an annual incidence of 1–2 cases per 1000 people, and recurrence rates are high.

Aetiology

• Renal colic is due to stretching of the renal capsule and is excruciating intermittent pain, usually originating in the flank or kidney area, which radiates across the abdomen towards the suprapubic region
  • Acute inflammation
  • Bleeding into the the kidney
  • Acute pyelonephritis
  • Expanding Renal cyst
  • Pelvi-ureteric obstruction due to
    • Renal calculus
    • Blood clot
• Ureteric colic is experienced as pain which radiates along the course of the ureter, frequently into the region of the genitalia and inner thigh. Classically loin to groin/scrotum. It is due to passage of
  • Calculus
  • Sloughed papilla
  • Blood clot.

Renal Stones

• Calcium oxalate or calcium phosphate: high calcium or oxalate
• Struvite (magnesium ammonium phosphate) - proteus mirabilis which produces urease
• Cystine stones (cystinuria)
• Urate stones (idiopathic or hyperuricosuric state).

Risk Factors for Stones

• Chronic dehydration, family history
• Gastrointestinal conditions (e.g. Crohn's disease)
• Certain medications (such as protease inhibitors).

Clinical

• Patients may have experienced this before. Severe intermittent colicky pain classically loin to groin/scrotum. Patients are restless and roll about not lying still.
• Hesitancy of micturition or an intermittent urinary stream (suggesting urinary tract obstruction)
• Fever and sweats (suggesting coexisting UTI) hypotension, tachycardia, high lactate can suggest Urosepsis needing admission
• Ask about nausea, vomiting, abdominal distension , fever.

Clinical

• Fever, urinary tract symptoms, haematuria
• Family history of nephrolithiasis and UTI
• History of fractures or prolonged immobilisation.
• Intake of milk, alkali, salt and vitamins A, D and C.

Investigations

• FBC, U&E, WCC, CRP. Glucose, Ca, P, PTH, CXR
• Urinalysis: may be normal even with stones. Macroscopic or microscopic haematuria is common. Pyuria with or without bacteria may be seen.
• Low dose non-contrast CT-KUB during pain-sensitive for stones and can identify the ureteric obstruction. Imaging should be within 24 hrs. Patient may be able to have this next day as an ambulatory patient.
• USS is preferred over CT for pregnant women, children, and young people
• Renal Stones: Urinary excretion of calcium, phosphate, oxalate, urate and cystine should be performed on at least two separate occasions.
• Chemical analysis: Stones should sieve and caught and undergo morphological and biochemical analyses should be performed

Differential

• Appendicitis
• Diverticulitis.

Need for admission

• Clinically unwell / Dehydrated
• Diagnostic uncertainty ? AAA ? Appendix
• Need for pain control
• Urosepsis/Pyelonephritis and stones
• Solitary kidney
• Transplant kidney
• Worsening renal function
• Suspected obstruction

Left renal calculus

Management

• Immediate admission under Urology if signs of sepsis or systemic infection. High risk for AKI and priority are those with pre-existing CKD or a single or transplanted kidney, or if bilateral obstructing stones are suspected. Patients may have had similar episodes before. Otherwise well patients can be managed as an outpatient if can eat and drink, pain is managed and renal function normal. They can return for CT KUB.
• If Nausea and vomiting or systemic signs of infection then admit for IV fluids at least 2L/day. Also, Admit if there is uncertainty about the diagnosis.
• Consider admission and IV antibiotics if any suggestion of urinary obstruction or urosepsis or UTI. An obstructed system with an infection needs a nephrostomy or ureteric stenting.
• Ensure analgesia, IV paracetamol or IV or PR Diclofenac 75 mg, repeating as necessary. Opioids can usually be avoided. NSAIDs are the first line.
• Management depends on the size of the stone, severity of symptoms, location of the stone (renal or ureteric), and the age of the person. Stones more than 6 mm tend to be less likely to pass and may need intervention.
• Options include watchful waiting, medical expulsive therapy, and surgical treatment.
• Watchful waiting if the stone is less than 5 mm and for those where stone larger than 5 mm and the patient agrees to watchful waiting after an informed discussion of the possible risks and benefits.
• Medical expulsive therapy: alpha-blocker is given. Used for distal ureteric stones less than 10 mm.

Surgical treatment

• Usually needed for Ureteric stones and renal colic within 48 hours of diagnosis or readmission if the pain is ongoing and not tolerated or the stone is unlikely to pass. Consider
• Shockwave lithotripsy (SWL): non-invasive outpatient treatment that focuses shock waves on the stone to break it up. Stone particles are passed spontaneously.
• Percutaneous nephrolithotomy (PCNL) a procedure in which a nephroscope is passed percutaneously into the collecting system and the stone is fragmented and extracted through the nephroscope.
• Ureteroscopy (URS): involves the use of various energy sources (such as lasers) to break up the stone.
• Open surgery: rare cases in which SWL, PCNL, and URS fail or are unlikely to be successful

Prevention

• Prevention: Often increase fluid intake. Restrict dietary oxalate for oxalate stones.
• Dietary advice: increasing fluid intake, adding fresh lemon juice to drinking water, avoiding carbonated drinks, reducing salt intake, maintaining a normal dietary calcium intake, eating a balanced diet, and maintaining a healthy weight. Also, avoid soft drinks e.g. coke acidified by phosphoric acid rather than citric acid. Lemon and orange good and raise the pH of urine. Mineral water with bicarbonate is good.
• Potassium citrate for adults with recurrence of stones that are > 50% calcium oxalate and with hypercalciuria or hypocitraturia.
• Thiazide treatment for adults > 50% calcium oxalate and hypercalciuria, after restricting their sodium intake to no more than 6 g a day.

References

• Renal or ureteric colic - acute