Ultrasound image of fetal bladder obstruction with the characteristic “keyhole” sign (B: Bladder, u: urethra). Fetal Lower Urinary Tract Obstruction (LUTO): a practical review for providers: Haeri S - Maternal health, neonatology, and perinatology (2015). Not altered. CC.
Urinary tract obstruction is the impediment of the normal urine flow predisposing to infection and to stone formation. Urinary tract obstruction may be due to urolithiasis.