Kliniczne aspekty chorób układu moczowego 2 | Clinical Aspects of Urinary System Diseases 2

Key Diseases Covered in This Chapter

  1. Kidney Stones (Nephrolithiasis)
  2. Glomerulonephritis
  3. Pyelonephritis

Kidney Stones (Nephrolithiasis)

Overview

Kidney stones, or nephrolithiasis, are hard mineral and salt deposits that form in the kidneys. They are a common urological condition and can cause severe pain when passing through the urinary tract. Kidney stones vary in size and composition, with their formation influenced by various dietary, genetic, and environmental factors.

Pathophysiology

  • Formation: Kidney stones develop when substances like calcium, oxalate, and uric acid crystallize in the kidneys due to supersaturation in the urine. This process is influenced by factors such as dehydration, high salt intake, excessive calcium or oxalate consumption, and certain metabolic disorders.
  • Types of Stones:
    • Calcium Stones: The most common type, often composed of calcium oxalate or calcium phosphate.
    • Uric Acid Stones: Form in acidic urine, typically associated with a diet high in purines or conditions like gout.
    • Struvite Stones: Associated with chronic urinary tract infections (UTIs) caused by urease-producing bacteria, leading to the formation of large, staghorn-shaped stones.
    • Cystine Stones: Result from a rare genetic disorder called cystinuria, leading to excessive cystine in the urine.

Clinical Manifestations

  • Renal Colic: Intense, cramping pain typically starting in the flank and radiating to the lower abdomen or groin, caused by the stone moving through the ureter.
  • Hematuria: Blood in the urine, which may be visible (gross hematuria) or detected microscopically.
  • Nausea and Vomiting: Commonly accompany severe pain due to the autonomic response to renal colic.
  • Urinary Symptoms: Increased frequency, urgency, or dysuria, especially if the stone is near or obstructing the bladder.

Diagnostic Approach

  • Imaging:
    • Non-Contrast CT Scan: The gold standard for diagnosing kidney stones, providing detailed images of the stone’s size, location, and potential complications like hydronephrosis.
    • Ultrasound: Useful for detecting larger stones and assessing for hydronephrosis, especially in pregnant women or individuals where radiation exposure should be minimized.
    • KUB X-ray: A plain abdominal X-ray can detect radiopaque stones but is less sensitive than CT.
  • Urinalysis: To detect hematuria, crystalluria, or signs of infection, and to analyze stone composition if a stone has passed.
  • Blood Tests: Evaluate renal function (creatinine, BUN), and assess for hypercalcemia, hyperuricemia, or other metabolic abnormalities.

Treatment Options

  • Pain Management: NSAIDs or opioids are often used to manage the severe pain of renal colic.
  • Hydration: Encouraging increased fluid intake to facilitate stone passage.
  • Medical Expulsive Therapy: Alpha-blockers like tamsulosin may be prescribed to relax the ureter and help pass the stone.
  • Surgical Interventions:
    • Extracorporeal Shock Wave Lithotripsy (ESWL): Non-invasive treatment that uses shock waves to break up stones into smaller fragments that can be passed naturally.
    • Ureteroscopy with Laser Lithotripsy: Involves inserting a scope through the urethra to directly visualize and fragment the stone with a laser.
    • Percutaneous Nephrolithotomy (PCNL): A more invasive procedure for large or complex stones, where the stone is removed through a small incision in the back.

Glomerulonephritis

Overview

Glomerulonephritis refers to a group of diseases that cause inflammation of the glomeruli, the tiny filters within the kidneys responsible for removing excess fluids and waste from the blood. This inflammation can lead to impaired kidney function and, in severe cases, chronic kidney disease (CKD).

Pathophysiology

  • Immune-Mediated Inflammation: Glomerulonephritis is often triggered by an immune response, where antibodies or immune complexes deposit in the glomeruli, leading to inflammation and damage.
  • Primary Glomerulonephritis: Diseases that originate within the kidneys, such as IgA nephropathy or membranous nephropathy.
  • Secondary Glomerulonephritis: Occurs as a result of systemic diseases like lupus, diabetes, or infections (e.g., post-streptococcal glomerulonephritis).

Clinical Manifestations

  • Hematuria: Often described as “tea-colored” or “cola-colored” urine due to the presence of red blood cells.
  • Proteinuria: Excessive protein in the urine, which may lead to frothy urine.
  • Hypertension: Elevated blood pressure due to fluid retention and kidney dysfunction.
  • Edema: Swelling, particularly in the face, hands, and feet, due to protein loss and fluid retention.
  • Oliguria: Reduced urine output, indicating severe kidney dysfunction.

Diagnostic Approach

  • Urinalysis: Detects hematuria, proteinuria, and the presence of red blood cell casts, which are highly suggestive of glomerular inflammation.
  • Blood Tests:
    • Serum Creatinine and BUN: Elevated levels indicate impaired kidney function.
    • Complement Levels: Low levels can indicate certain types of glomerulonephritis, such as lupus nephritis or post-infectious glomerulonephritis.
    • Antibody Tests: Tests for antinuclear antibodies (ANA), anti-double-stranded DNA, or anti-glomerular basement membrane antibodies may help identify the underlying cause.
  • Renal Biopsy: The definitive diagnostic tool, providing histological evidence of glomerular inflammation, immune deposits, and the extent of damage.

Treatment Options

  • Corticosteroids: Often used to reduce inflammation in the glomeruli.
  • Immunosuppressive Agents: Drugs like cyclophosphamide or mycophenolate mofetil may be prescribed for severe or resistant cases.
  • Antihypertensive Therapy: ACE inhibitors or ARBs are used to control blood pressure and reduce proteinuria.
  • Plasmapheresis: In severe cases, particularly those associated with rapidly progressive glomerulonephritis (RPGN), plasmapheresis may be used to remove harmful antibodies from the blood.
  • Management of Complications: Treatment of hypertension, hyperkalemia, and potential dialysis in cases of acute kidney injury (AKI) or severe chronic kidney disease (CKD).

Pyelonephritis

Overview

Pyelonephritis is a type of urinary tract infection (UTI) that affects the kidneys, leading to inflammation and potential renal damage. It is usually caused by bacterial infection and can be acute or chronic in nature. Acute pyelonephritis is a medical emergency that requires prompt treatment to prevent complications.

Pathophysiology

  • Ascending Infection: Most cases of pyelonephritis result from an ascending infection, where bacteria travel from the lower urinary tract (bladder) up the ureters to the kidneys.
  • Common Pathogens: Escherichia coli (E. coli) is the most common causative organism, but other bacteria like Proteus, Klebsiella, and Staphylococcus saprophyticus can also be involved.
  • Chronic Pyelonephritis: Recurrent or persistent infections can lead to chronic pyelonephritis, characterized by scarring of the renal parenchyma and progressive kidney dysfunction.

Clinical Manifestations

  • Fever and Chills: Often present in acute pyelonephritis, indicating systemic infection.
  • Flank Pain: Severe pain on one or both sides of the back, where the kidneys are located.
  • Dysuria and Urinary Symptoms: Painful urination, urgency, and frequency often accompany the condition.
  • Nausea and Vomiting: Common due to the systemic inflammatory response.
  • Costovertebral Angle Tenderness: Tenderness upon percussion over the area where the kidneys are located, a hallmark sign of pyelonephritis.

Diagnostic Approach

  • Urinalysis: Reveals pyuria (white blood cells in the urine), bacteriuria, and sometimes hematuria.
  • Urine Culture: Essential for identifying the causative organism and determining its antibiotic sensitivity.
  • Blood Tests: Elevated white blood cell count (leukocytosis) and elevated C-reactive protein (CRP) indicate inflammation. Blood cultures may be positive in severe cases.
  • Imaging: Ultrasound or CT scan may be used to assess for complications such as abscess formation, hydronephrosis, or renal scarring in chronic cases.

Treatment Options

  • Antibiotics: The cornerstone of treatment for pyelonephritis. Oral antibiotics like ciprofloxacin or trimethoprim-sulfamethoxazole may be used for mild cases, while intravenous antibiotics such as ceftriaxone or piperacillin-tazobactam are required for more severe or hospitalized patients.
  • Hydration: Increased fluid intake helps flush out bacteria and support kidney function.
  • Analgesics: Pain management with NSAIDs or acetaminophen.
  • Hospitalization: Required for severe cases, particularly those with high fever, significant pain, or signs of sepsis. Intravenous antibiotics and supportive care are provided.
  • Surgical Intervention: In rare cases, surgical drainage of abscesses or correction of anatomical abnormalities may be necessary to prevent recurrent infections.