Thank you for your query.
It appears that your son has developed an intestinal infection which is giving rise to the diarrhoea
. There is no relationship to the head injury
which appears to be normal. I suggest that you get a stool routine examination done and in the interim start with some probiotics to recondition the intestinal flora. Ensure that he does not get dehydrated by giving him plenty of oral fluids in the form of lemonade, buttermilk, cocounut water.
I hope I have answered your query to your satisfaction.
Wishing your son an early recovery.
Rajiv K Khandelwal