Hematuria(Blood in urine) causes and differential diagnosis

Causes of visible blood urine/gross hematuria/macroscopic hematuria:

1) Trauma

Kidney injury is usually secondary to a blunt injury to the flank or abdomen. Penetrating injuries from gunshots and stab wounds are less common causes. Rarely deceleration injuries in motor vehicle accidents, and laceration by fractured lower ribs present with gross hematuria.

Ureteral trauma is rare and most commonly iatrogenic(during a surgery/endoscopic procedures).

Bladder trauma can be commonly seen in motor vehicle accidents with pelvic fractures.

Urethral injury is seen almost exclusively in males, and presents as blood at the tip of the urethra (It is important not to catheterize patients with suspected urethral injury before they have been evaluated by urology.)

2) Nephrolithiasis

Usually causes microscopic hematuria but gross hematuria can been seen. Family history of kidney stones is present in many but not all patients.

3) Hematologic

Sickle cell anemia, Bleeding disorders and patients on warfarin/heparin can present with gross hematuria. Renal vein thrombosis, which can happen in a setting of hyper-coagulable state such as renal cell carcinoma or nephrotic syndrome, generally presents with pain and gross hematuria.

4) Structural causes

Benign prostatic hyperplasia (BPH) increases chances of urethral bleed and gross hematuria. Kidney lesions such as polycystic kidney, medullary sponge kidney, and medullary cystic disease may be associated with gross hematuria. Vascular malformations and arterial-venous fistulas are rare causes of hematuria.

5) Infectious

Lower urinary tract infections and pyelonephritis are common causes of macroscopic hematuria.Urinary TB may present with hematuria.

6) Medical renal disease

Hints to a medical renal disease include: Proteinuria, Hypertension, Renal failure, Dysmorphic RBCs and casts in urine.(e.g. SLE, Glomerulonephritis etc)

Benign familial hematuria is a genetic disease resulting in thinning of the basement membranes. Alport syndrome is an inherited disorder which has hematuria in addition to proteinuria, deafness, and high BP leading to renal failure.

7) Oncologic

Renal cell carcinoma, transitional cell carcinoma and kidney metastasis can present with hematuria. Prostate cancer can present with intermittent gross hematuria. Therapy for certain other cancers for e.g. Cyclophosphamide for leukemia can cause hemorrhagic cystitis and hematuria. Radiotherapy can cause damage to bladder mucosa and hematuria.

8) Miscellaneous

Menstrual bleeding, pseudohematuria (due to certain medications or food - rifampicin, pyridium, beets, rhubarb etc) should be distinguished from real hematuria.