Hematuria

Madelaine Behrens, Laura Binari, Patrick Steadman

Background

  • Definition: 3 urinalyses with three or more RBC/hpf; 1 urinalysis with 100 RBC/hpf or gross hematuria (1 cc blood/L urine can induce color change)
  • Causes:
    • Transient hematuria: exercise-induced, menses, trauma, cystitis/prostatitis
    • Concurrent pyuria/dysuria: consider urinary tract infection or bladder malignancy
      • Malignancy risk factors: male sex, age > 50, smoking Hx, exposures to benzene/aromatic amine, cyclophosphamide, indwelling foreign body, pelvic irradiation, chronic UTIs, heavy NSAID use, urologic disorders (nephrolithiasis, BPH)
    • Recent URI: think infection related glomerulonephritis, IgA, vasculitis, anti-GBM
    • Positive family Hx of hematuria: consider PKD, sickle cell disease
    • Bleeding from other sites: think inherited/acquired bleeding disorder, anticoagulation
    • Unilateral flank pain: ureteral calculus, renal malignancy, IgA nephropathy

Glomerular

Kidney

Ureter/Bladder

Prostate/Urethra

Other
IgA Nephropathy, IgAVasculitis, Lupus Nephritis, Infection related glomerulonephritis, ANCA-associated, Anti-GBM disease, Genetic (thin Basement Membrane Nephropathy/Alport Syndrome), MPGN Pyelo, RCC, PKD, sickle cell disease, papillary necrosis, Malignant HTN, arterial embolism, vein thrombus Cystitis, Urothelial Malignancy, nephrolithiasis, ureteral stricture, hemorrhagic cystitis (chemo/rads), traumatic Foley/procedure BPH, prostate cancer, TURP, urethritis (STI) Exercise-induced, bleeding diathesis, meds (AC), menses, TB, schistosomiasis

Evaluation

  • Step 1: Confirm the presence of hematuria
    • Dipstick positive heme: urinary RBCs (hematuria), free myoglobin or free hgb
    • Centrifuge the urine
      • Red sediment  true hematuria (urinary RBCs)
      • Red supernatant +
        • Positive dipstick: myoglobulin or hemoglobin
        • Negative dipstick: porphyria, pyridium, beets, rhubarb, or ingestion of food dyes
  • Step 2: Determine if there is a GLOMERULAR or NON-GLOMERULAR source of bleeding

Characteristics of Glomerular vs Extraglomerular Bleeding:

Color (if gross hematuria)

Clots

Proteinuria

RBC morphology

RBC casts
Glomerular Red, Cola, Smoky Absent May be >500 mg/day Dysmorphic RBCs present May be present
Extra-glomerular Red/Pink Present/Absent <500 mg/day Normal (isomorphic) Absent
  • Glomerular bleeding
    • Isolated hematuria: differential includes IgA nephropathy, thin BM dx, Alport’s
    • Nephritic syndrome (new proteinuria, pyuria, HTN, edema, rise in Cr): post-infectious GN, MPGN, ANCA vasculitis, Goodpasture’s, lupus nephritis
    • Workup: anti-GMB, anti-DNase/ASO, ANA, ANCA, C3, C4, cryo, Hep B/C, HIV
    • Indications for renal biopsy: glomerular bleeding + risk factors for progressive disease, including albuminuria > 30 mg/day, new hypertension > 140/90 or significant elevation over baseline BP, rise in serum creatinine
  • Extraglomerular bleeding
    • If historical clues suggest nephrolithiasis, start with non-con CT A/P
    • Gross hematuria otherwise should be evaluated with CT A/P w/ and w/o contrast (CT urography); will need to see Urology for cystoscopy (often done as outpatient referral)
      • CT Urography is more sensitive than IV pyelogram for renal masses and stones
      • Pregnant patients: renal and bladder ultrasound preferred over CT
    • If clots are passed, more likely to be secondary to lower urinary source; high burden of clots poses a risk of obstruction (urologic emergency)
    • If extraglomerular bleeding with clots: hematuria catheter needs to be placed ASAP (2 valve catheter, 20-24 Fr (!); page urology if nursing unable to obtain)
  • Who needs cystoscopy: All patients with clots and all patients with gross, nonglomerular hematuria in whom infection has been ruled out

Nephrolithiasis

Madison Bandler

Background

  • Formation of kidney stones occurs when urine becomes supersaturated with stone-forming substances, leading to crystallization. This process can be influenced by various factors, including metabolic disorders, genetic predispositions, dietary habits, and dehydration
  • Classified into four main types based on their composition:
    • Calcium stones (oxalate or phosphate)
      • ~75-80% of stones
      • Driven by increased intestinal absorption of calcium, enhanced bone resorption, or decreased renal tubular reabsorption of calcium with low levels of urinary citrate further increasing risk
    • Uric acid stones
      • ~9-10% of stones
      • Primary risk factors are high levels of uric acid in the urine, low urinary volume, and persistently low urinary pH, which makes uric acid less soluble
    • Cystine stones
      • ~1% of stones
      • Occur in setting of genetic disorder with defective reabsorption of cystine and other dibasic amino acids (ornithine, lysine, and arginine) in the renal proximal tubules
    • Struvite stones
      • ~10% of stones
      • Typically take months to years to form, more common in women with recurrent UTIs from urease producing bacteria

Evaluation

  • BMP
  • Uric acid
  • Parathyroid Hormone level should be measured if primary hyperparathyroidism is suspected, particularly when serum calcium is high or high normal
  • Urinalysis for pH, erythrocytes, leukocyte esterase, citrate, nitrites, urine culture
    • Patients with uric acid stones may have persistent urine pH of 5-5.5 rather than the expected variation in pH of 5 in the morning and 6.5 in the evening
    • Patients with RTAs usually have urine pH of 6.5
    • Patients with struvite stones usually have urine pH of 8.5
  • For high-risk or recurrent stone formers, additional metabolic testing is recommended. At VUMC most commonly will see Litholink, which is a send out Labcorp test. This includes one or two 24-hour urine collections analyzed for total volume, pH, calcium, oxalate, uric acid, citrate, sodium, potassium, and creatinine. This testing helps identify metabolic and environmental risk factors, informing dietary and medical therapy

Imaging

  • CT abdomen and pelvis w/o contrast is typically first line
  • MR urography (MRU) without and with IV contrast or CT abdomen and pelvis with IV contrast may be appropriate as the next imaging study if CT w/o cntrast is inconclusive
  • Renal and bladder ultrasound may be used in pregnant patients

Management

  • Stones less than 5 mm often pass spontaneously. Follow-up imaging within 14 days is recommended to monitor stone position and assess for hydronephrosis
  • Alpha blockers, such as tamsulosin, may be used to facilitate the passage of distal ureteral stones less than 10 mm
  • NSAIDs are ideal for acute pain control if no contraindications
  • Thiazide Diuretics are indicated for patients with recurrent calcium stones and hypercalciuria
  • Potassium Citrate is recommended for patients with hypocitraturia and calcium phosphate stones, as well as for uric acid and cystine stones to raise urinary pH
  • Allopurinol for patients with recurrent calcium oxalate stones and hyperuricosuria

Operative Management

  • Extracorporeal Shock Wave Lithotripsy (ESWL): Suitable for renal stones between 10 and 20 mm, especially in favorable anatomical locations
  • Ureteroscopy: An option for lower pole stones between 1.5 and 2 cm, and for stones resistant to ESWL
  • Percutaneous Nephrolithotomy (PCNL): Indicated for stones larger than 20 mm, staghorn calculi, and stones in patients with CKD

Prevention of recurrent urinary tract stones

  • 50% of patients will have recurrent stone at 10 years and 80% will have recurrent stone at 20 years
  • Increase fluid intake to achieve a urine volume of more than 2.5 L/day and adhere to a low-sodium diet
  • Weight loss and exercise
    • Diets consisting of low sodium, low animal protein (source of uric acid), and low oxalate (beets, berries, chocolate, rhubarb, nuts and leafy greens) with no calcium restriction may be beneficial. During a meal it may help to combine calcium rich food with oxalates that will bind in the intestinal lumen and be excreted in stool
    • Adding citrus fruits may increase citrate and reduce stone formation
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