Hi.
Noted the detailed history about your child and as you are becoming FNP your findings are most welcome.
My thoughts.
The Pulsation on one side of neck with bruit sound on auscultation can be due to some problem with artery in the neck.
This can be best diagnosed by the Color Doppler studies and evaluation by a Cardiologist.
If anything is found to be positive full further evaluation will help whether he needs an active treatment now or later and go for the advised. Always take a
second opinion of another Specialist in the said field.
As for the pain in abdomen,
vomiting and fever with negative Psoas test, no rebound the cause can be anything related to worms,
colitis,
enteritis and so on.
Needs a clinical evaluation by Pediatric Surgeon,
Ultrasonography, tests of blood, urine and stool.
Further management as per the cause found.
Hope I have answered your query. Let me know if I can assist you further.
Regards,
Dr. T. Chandrakant, General Surgeon