Hi,
The following are few causes of pain abdomen in a 12 yr old.
1) trauma as in your boy's case
2)acute appendicitis
3)
Colic and constipation
4) Gastroenteritis
5) Amoebic dysentery
But you mentioned about a
bruise of 2 inches on his body. You hadn't mentioned the site of the bruise. If it is on the abdomen, it's obvious that he would have pain.
If someone comes to my clinic with similar complaint, I would suggest the following:
1) As you had already done, take pain medication
2) If your pain returns, you do need an
ultrasound abdomen and pelvis
3) You also need a thorough in person clinical examination
4) If the pain doesn't come down even after 1 day, kindly consult your physician for a specific diagnosis and appropriate treatment.
Take care. Hope I have answered your question. Let me know if I can assist you further.
Regards,
Dr. Pallavi M., Anesthesiologist