Dear loretta I am sorry to hear about your son.
I agree your son is not gaining weight as because he is not taking
and absorbing sufficient food for his physical growth and devolopment.
This is a condition which Paeditricians levelled as Falure to thrive.
Causes and diagnosis: Causeses of failure to thrive are so many. Some are recognisable
with Physical examinations and some needs special tests.Congenital heart deseases, physical
deformities like cleft palate
can be diagnosed physically. Coeliac desease needs special tests
called jejunal biopsy, Cystic fibrosis
needs sweat test. The diarrhoea may be due to parasitic
infestation and needs stool examination.Some times child may have got acid reflux
which is very painful and he refrains from feeding and he needs to be investigated with gastroscopy.
There are grops of conditions called imborn error of metabolism
whch need blood tests, so also milk allergy
Management and treatmen: Your Paedtrician will definitely do necessary investigations
probably admitting the child to hospital and I am sure he will be okay.Kindest regardsDr. S.K.Mukherjee