Pheochromocytoma is a neuroendocrine tumor that secretes high amounts of catecholamines. When our body is in a situation of fight or flight the the simpatic nervous system is very activated and will make sure the body responds in a way that can assure the survival. This sympatic nervous system releases catecholamines, just like the tumor. So, in both cases the catecholamines will move the blood mostly to skeletal muscles and the brain. Meanwhile, there is less blood flow in the bowels, leading to constipation. It can also lead to sweat way more,causing dehydration and again, inhibiting bowel function.
