Urinary Tract Infection (UTI): Although the question specifies painless enuresis, UTIs are a common cause of enuresis in children and can sometimes be asymptomatic. A UTI could lead to an overactive bladder or urinary urgency, resulting in enuresis.

Constipation: Constipation is a common issue in children and can cause urinary incontinence due to the proximity of the rectum to the bladder and urethra. Pressure from a full rectum can lead to bladder irritation and incontinence.
Overactive Bladder: This condition is characterized by a sudden, intense urge to urinate, which can lead to daytime enuresis if the child cannot reach the toilet in time.
Neurogenic Bladder: Although less common, neurogenic bladder due to spinal cord issues or other neurological problems can cause enuresis. However, it might be accompanied by other neurological signs.

Diabetes Mellitus: Uncontrolled diabetes can lead to polyuria (excessive urine production), which might cause enuresis. It's crucial to rule out diabetes due to its significant impact on health if left untreated.
Spinal Cord Anomalies or Tumors: Conditions affecting the spinal cord, such as spina bifida or tumors, can disrupt normal bladder control, leading to enuresis. Early detection is critical for effective management.
Urethral Obstruction: Obstructions, such as posterior urethral valves in boys, can cause urinary retention and subsequent enuresis.

Ectopic Ureter: An ectopic ureter is a congenital anomaly where the ureter opens at a location other than the normal entrance in the bladder. This can cause continuous incontinence.
Bladder Exstrophy: A rare congenital anomaly where the bladder is open and turned inside out, often associated with other genital and sometimes bowel anomalies.
Prune Belly Syndrome: A rare condition characterized by the absence of abdominal muscles, undescended testicles, and urinary tract anomalies, which can lead to enuresis among other symptoms.