Causes of Blood in Ascites
I believe you're asking about causes of blood in urine (hematuria) rather than ascites, as the evidence provided addresses hematuria evaluation. I'll answer regarding hematuria causes and management.
Major Categories of Hematuria Causes
Urologic/Non-Glomerular Causes
Malignancy represents the most critical cause to exclude, accounting for 30-40% of gross hematuria cases and 2.6-4% of microscopic hematuria cases. 1 This includes:
- Bladder cancer (transitional cell carcinoma) - the most frequently diagnosed malignancy in hematuria workups 1
- Renal cell carcinoma 1, 2
- Upper tract urothelial carcinoma 1
- Prostate cancer 1
Urinary tract infection is among the most common benign causes of both microscopic and macroscopic hematuria 3, 1, 4. However, the presence of UTI does not exclude concurrent malignancy and should not defer complete evaluation in high-risk patients 5.
Urolithiasis (kidney/ureteral stones) classically presents with painful hematuria and flank pain 3, 1, 2.
Benign prostatic hyperplasia (BPH) is a common cause in older men but does not exclude concurrent malignancy 1, 6.
Trauma to kidneys or lower urinary tract causes hematuria proportional to injury severity 3, 1.
Glomerular/Renal Parenchymal Causes
Glomerulonephritis (post-infectious, IgA nephropathy) presents with tea-colored urine, proteinuria >2+ on dipstick, red blood cell casts, and >80% dysmorphic RBCs on phase contrast microscopy 3, 1.
Alport syndrome - hereditary nephritis with associated hearing loss and ocular abnormalities 3, 1.
Thin basement membrane nephropathy - autosomal dominant condition causing persistent microscopic hematuria 1.
Lupus nephritis and vasculitis - systemic diseases with renal involvement 3, 1.
Metabolic and Systemic Causes
Hypercalciuria and hyperuricosuria can cause microscopic hematuria and predispose to nephrolithiasis 1.
Sickle cell disease causes hematuria through renal papillary necrosis 3, 1.
Coagulopathies (hemophilia) may contribute but typically unmask underlying structural pathology rather than being the primary cause 3, 1.
Benign/Transient Causes
Vigorous exercise can cause transient hematuria that resolves with rest 1.
Menstrual contamination in women can cause false-positive results 1.
Critical Clinical Pearls
Anticoagulation or antiplatelet therapy (including warfarin, aspirin, Pradaxa, etc.) does NOT cause hematuria - these medications only unmask underlying pathology that requires investigation. 3, 1, 6 Evaluation must proceed regardless of anticoagulant use.
Gross hematuria carries a 30-40% malignancy risk and mandates urgent urologic referral with cystoscopy and CT urography, even if self-limited. 3, 1
Tea-colored or cola-colored urine suggests glomerular disease and warrants nephrology evaluation in addition to urologic workup 1, 2.
Microscopic hematuria is defined as ≥3 RBCs per high-power field on microscopic examination - dipstick positivity alone (without microscopic confirmation) should not trigger extensive workup due to 65-99% specificity 3, 1.
Age-Specific Risk Stratification
In children, glomerulonephritis and congenital anomalies predominate, with isolated microscopic hematuria without proteinuria or dysmorphic RBCs typically not requiring imaging 3, 1.
In adults >35-40 years, particularly males ≥60 years with smoking history >30 pack-years or occupational chemical exposure, malignancy risk is substantially elevated and requires complete urologic evaluation with cystoscopy and CT urography 3, 1, 5.