The high level of blood CO2, constipation
and weight gain suggest that your child may have Cushing's syndrome, that occurs due to high level of Cortisol hormone in body. However, you must get the diagnosis from your doctor after examining the baby properly.
The features are - central obesity (excess deposition of fat on trunk, sparing limbs), round face ( called 'MOON FACE', excess sweating, purple or red striae on trunk, high blood pressure
, constipation etc.
Cause of the disease may me Endogenous (inside the body) or Exogenous (externally induced).
Endogenous - ACTH secreting tumors of Pituitary gland
or Adrenal gland. Sometimes, from other gland tumors (paraneoplastic).
Exogenous - Long term steroid medications (iatrogenic) .
Diagnosis - often done clinically. Laboratory examinations are - 24 hrs urine cortisol level and Dexamethasone suppression test
Treatment - depends on cause. Prognosis is good if treated early.
Get your child examined by Endocrinologist
and start the treatment.