Sudden stopping of urination in children can be a concerning symptom that may indicate an underlying medical issue. There are several potential causes for this symptom, including:

1. Urinary tract obstruction: This can occur due to a blockage in the urinary tract, such as a urinary stone, which obstructs the flow of urine.

2. Urinary tract infection (UTI): Infections in the urinary tract, particularly in the urethra or bladder, can cause discomfort and difficulty in urination, leading to sudden stopping of urination.

3. Neurological issues: Conditions affecting the nerves that control bladder function, such as spinal cord injury or neurological disorders, may lead to problems with urination.

4. Psychological factors: Children may experience sudden stopping of urination due to psychological issues such as stress or anxiety.

5. Structural abnormalities: Structural abnormalities in the urinary tract, such as congenital abnormalities or anatomical defects, can also cause difficulties with urination.

6. Trauma: Injury to the urinary tract or surrounding areas can result in difficulties with urination.

If a child experiences sudden stopping of urination, it is important to seek medical attention promptly. A pediatrician or a pediatric urologist can conduct a thorough evaluation to determine the underlying cause and recommend appropriate treatment. Ignoring such symptoms can lead to complications, so timely medical intervention is essential.