A 3–year–old boy presents with fever; dysuria and gross hematuria. Physical examination shows a prominent suprapubic area which is dull on percussion. Urinalysis reveals red blood cells but no proteinuria. Which of the following is the most likely diagnosis –
It is a case of Posterior Urethral Valve presenting with Urinary tract Infection.
PUV is the most common cause of obstructive uropathy in a male child.
The key to diagnosis are -

Age and sex of the patient

Urinary tract infection is rare in a male child, greater than one year old and less than 5 years old. Presence of urinary tract infection in this age group suggests, the presence of some obstructive uropathy. ( posterior urethral valve in this case)

Presence of Suprapubic dullness

Presence of suprapubic dullness suggests urinary retention, which is seen in this case due to obstruction caused by posterior urethral valves:
Acute glomerulonepluitis
Urinary tract infection
Posterior urethral valves
Teratoma