URO - Hematuria, Kidney stones Flashcards
(51 cards)
Renal causes of haematuria
- Glomerular:
Glomerulonephritis - Tubular and parenchymal:
Polycystic kidney
Pyelonephritis
Renal infarction
RCC
Post-renal causes of haematuria
Stone: Urolithiasis
Infection: UTI (rare)
Tumor: CA bladder, prostate
Trauma: Blunt trauma, iatrogenic e.g. catherization, TURP…etc
BPH
Non-infectious cystitis: previous radiation, chemotherapy
Exercise-induced hematuria: transient
Non-renal causes of haematuria
Benign idiopathic hematuria (rare): a/w exercise, febrile illness or vaccination, familial
Bleeding tendencies (rare): hematological disorders, anti-coagulants…etc
Define gross vs microscopic hematuria
□ Gross: visibly bloody or brown urine (as little as 1mL of blood/L urine)
□ Microscopic: >3 RBC per high-power field in ≥2 of 3 freshly voided, clean catch samples
False mimics of gross and microscopic hematuria
Gross:
→ Food: beetroot (anthrocyanins) → red urine
→ Drugs: levodopa (dark), senna, rifampicin, pyridium (orange)
→ Diseases: porphyria, alkaptonuria, bilirubinuria
Microscopic:
→ Menstruation (F)
→ Dehydration (concentrates urinary RBCs)
→ Heme in urine (also have peroxidase activity)
- Myoglobinuria due to rhabdomyolysis
- Haemoglobinuria due to intravascular haemolysis
List false positives and false negatives of dipstick hematuria
False positive: menstrual blood, hemoglobinuria, myoglobinuria, dehydration
False negative: Urine with high solute gradient, High ascorbic acid level, Nitrites (UTI), pH <5.0, Proteinuria
Define significance of initial stream, terminal stream and whole stream hematuria/ Timing of hematuria
□ Initial stream → anterior urethra (distal to urogenital diaphragm)
□ Terminal stream → bladder neck or posterior urethra
□ Throughout → bladder and upper urinary tract
Differentiate extraglomerular and glomerular hematuria
- Color
- Clots
- Proteinuria
- Urine microscopy
Hallmarks of nephrological causes of microscopic hematuria
- RBC cast - RBC extravasated into tubular lumen and complex with Tamm-Horsfall protein matrix)
- Dysmorphic RBC - RBC passage through defective basement membrane with osmotic damage
- Proteinuria
List nephrological causes of microscopic hematuria
Autoimmune diseases: - Berger's disease/ IgA nephropathy - Henoch-Scholein purpura/ IgA Vasculitis (lower limb purpura, arthralgia, hypertension) - Goodpasture syndrome/ Anti-GBM disease (autoimmune disease vs kidneys and lungs) Acute interstitial nephritis (mostly from infection or allergic drug reactions) Acute nephritic syndrome Alport's syndrome (SN deafness, Lens dislocation, mutation in collagen type IV)
Define irritative and obstructive LUTS
Irritative symptoms: frequency, urgency/urge incontinence, nocturia
→ Indicates storage problem (bladder pathology)
Obstructive symptoms: hesitancy, weak stream ± straining, terminal dribbling, incomplete emptying
→ Indicates voiding problem (urethral obstruction)
Dysuria: indicates ongoing infection or inflammation → UTI
Ddx painful and painless hematuria
Painful:
→ Loin pain → pyelonephritis, renal infarct, rarer causes (RCC, renal stones, GN)
→ Ureteric colic → ureteric stone or bleeding with clot colic in upper tract
→ Suprapubic pain → cystitis
→ Perineal pain → prostatitis
Painless: classically, painless gross haematuria in >35y/o = malignancy
→ Malignancy (esp if in advanced age)
→ Renal parenchymal diseases, eg. glomerulonephritis
Risk factors for urological malignancies
□ Male, advanced age (>35y), smoker118
□ Occupational exposure to chemicals or dyes (esp jobs involving plastic, petroleum, organic solvents)
□ Drugs, eg. aristoochic acid in TCM, cyclophosphamide, analgesic abuse
□ Hx of prior urinary sympotoms: gross haematuria, urological disease, irritative urinary symptoms, chronic UTI
□ Previous surgical/ medical: chronic indwelling FB, Radiation
□ FHx of renal cell carcinoma (FHx of urothelial CA is NOT a/w ↑risk)
□ FHx of kidney diseases, eg. polycystic kidney disease, stone disease
Outline P/E for hematuria
What to look for?
Vitals: fever (pyelonephritis), HTN (nephritic syndrome)
General examination: pallor (anaemia), oedema (GN), rashes (vasculitis, CTD), bruises (bleeding tendency)
Abdominal examination:
□ Loin tenderness → renal pathology
□ Ballotable renal mass → RCC (rare), polycystic kidney, gross hydronephrosis (rare)
□ Renal bruit → renal artery stenosis (infarction)
□ Distended bladder → bladder outflow obstruction
DRE and external genitalia:
□ DRE for pelvic mass and prostatic enlargement
□ Varicocele may be due to large Lt RCC extending into renal vein
□ Urethra for urethral bleeding, clots
± other systems:
□ CVS: new murmurs (endocarditis)
□ Lungs: crackles, wheezes (Goodpasture’s syndrome)
First-Investigations for hematuria (excluding imaging)
Blood:
□ CBC: anaemia (uncommon in haematuria alone), leukocytosis (UTI)
□ RFT: renal impairment and electrolyte abnormalities
Urinalysis
1. Repeat dipstick to confirm haematuria and detect other pathologies
2. Biochemistry for protein and glucose
3. Microscopy: centrifuged
→ Confirm presence and delineate morphology of RBC
→ Detect WBC (pyuria = >5WBC/HPF) and organisms
4. Microbiology:
→ Culture and sensitivity → exclude UTI
→ EMU × AFB → exclude urinary tract TB
5. Cytology for malignant cells
2 mandatory investigations for gross hematuria
Cystoscopic exam of bladder
Upper tract imaging
List all imaging modalities for Ix of hematuria
Cystoscopy (standard)
Upper tract imaging (standard): Non-contrast CT, Ultrasound, CT urogram*, MR urogram, IV urogram
XR kidney, ureter and bladder (KUB)
Invasive:
- Retrograde pyelogram
- Ureteroscopy
Flexible cystoscopy
- Indication
- Function
- Field of examination
Indication: ALL patients with gross non-glomerular haematuria
Direct visualization of pathology, biopsy for histopathology
Field: Anterior and posterior urethra, entire bladder
USG for Ix of hematuria
- Indication
- Advantage
- Disadvantage
Indication:
Bedside screening for hydronephrosis, renal mass, renal stones
Advantage:
- Detect renal and bladder lesions
- Allow prostate size measurement
Disadvantage:
- Cannot detect ureter lesions e.g. ureteral stones
- Indirect evidence of obstruction
- No functional information
IV urogram
- Indication
- Advantages
- Disadvantages
Indication:
Upper tract imaging
Advantage:
- Direct evidence of obstruction
- Functional assessment
Disadvantage:
- Contrast anaphylaxis, nephrotoxicity
- Miss small parenchymal tumors
- No coronal and sagittal imaging
MR urogram
- Indications
- Advantages
- Disadvantages
Indications: pregnancy, contrast allergy, children, renal impairment
Advantage: No radiation
Disadvantage: image inferior to CT scan, poor images for stones, expensive
Invasive urogenital imaging
- Examples
- Indications
suspicious of serious pathology, eg. cancer, strictures
□ Eg. retrograde pyelogram: injection of contrast by catheterization of lower ureter via cystoscopy
□ Eg. ureteroscopy for brush cytology
Risk stratification system for microscopic haematuria
Investigations of low, intermediate and high risk patients
AUA microhematuria risk stratification system:
Low risk: repeat urinalysis in 6 months or Cystoscopy + USG kidneys
Intermediate risk: Cystoscopy + USG kidneys
High-risk: Cystoscopy + CT urogram
Urine cytology for malignant cells
- Recommended or not? Why?
- Specificity and sensitivity
Not recommended
- Only positive in HIGH grade cancer
- Negative in most low grader bladder cancer
- Poor sensitivity (50%) for bladder cancer
- Dependent on cytopathologist experience
