Kidney Stones

Kidney stones, or renal calculi, are solid masses made of crystals that originate in the kidneys and can migrate into the ureter where they cause renal colic.

Causes

  • Dehydration: Insufficient fluid intake increases the risk.
  • Diet: High in salt, protein, or glucose can contribute.
  • Genetic Factors: Family history increases risk.
  • Medical Conditions: Such as hypercalciuria, hyperoxaluria, hyperuricosuria, cystinuria, and certain metabolic disorders.
  • Medications: Such as diuretics or calcium-based antacids.
  • Obesity: Linked to an increased risk of kidney stones.

Diagnosis

  • History:
    • Symptoms: Severe pain in the back or side that may radiate to the lower abdomen or groin, hematuria (blood in the urine), urinary urgency, nausea, and vomiting.
    • Past History: Previous episodes of stones, urinary infections, or surgeries.
    • Diet and Fluid Intake: Assess for risk factors like low fluid intake or high intake of stone-forming foods.
    • Family History: Of kidney stones.
  • Examination:
    • Abdominal Exam: To check for tenderness ie AAA
    • Kidney Evaluation: Flank tenderness upon percussion.
  • Investigations:
    • Urinalysis: To look for blood, crystals, or signs of infection.
    • Blood Tests: To check kidney function, calcium, uric acid, and phosphorus levels.
    • Imaging: Non-contrast helical CT scan is the gold standard. Ultrasound or X-rays can also be used.
    • Stone Analysis: If a stone is passed, analyzing its composition can help guide management.

Differential Diagnosis (DDx)

  • Urinary Tract Infection (UTI): Especially if fever and dysuria are present.
  • Appendicitis or Diverticulitis: In cases of lower abdominal pain.
  • Ectopic Pregnancy: In women of childbearing age with abdominal pain.
  • Gastrointestinal Conditions: Like cholecystitis or pancreatitis.
  • Abdominal Aortic Aneurysm: Particularly in older patients

Management

  • Conservative Treatment (stones <= 6mm)
    • Hydration: To help pass the stone.
    • Pain Management: NSAIDs or opioids.
    • Medical Expulsive Therapy: Alpha-blockers like tamsulosin to facilitate stone passage.
  • Interventional Procedures:
    • Extracorporeal Shock Wave Lithotripsy (ESWL): Non-invasive, uses shock waves to break up stones.
    • Ureteroscopy: Endoscopic removal of stones in the ureter or kidney.
    • Percutaneous Nephrolithotomy: For larger stones.
  • Dietary and Lifestyle Modifications:
    • Fluid Intake: Increase to produce at least 2.5 liters of urine per day.
    • Diet: Lower salt and animal protein intake, moderate calcium intake, avoid high oxalate foods if oxalate stones are present.
    • Weight Management: In case of obesity.
  • Preventive Medication: Depending on the stone type:
    • thiazide diuretics for calcium stones,
    • allopurinol for uric acid stones,
    • potassium citrate for uric acid and cystine stones.
  • Follow-Up:
    • Regular monitoring, especially for recurrent stone formers.

Conclusion

Management of kidney stones involves acute treatment to relieve pain and facilitate stone passage, followed by strategies to prevent recurrence. This includes dietary changes, adequate hydration, and in some cases, medication. Understanding the type of stone and underlying risk factors is crucial for effective prevention.